Abstract：
BACKGROUND:We sought to develop a tandem mass spectrometry assay in which the enzymatic activities of 3 lysosomal enzymes (α-glucosidase, α-galactosidase A, and α-l-iduronidase) could be quantified in dried blood spots by using a single assay buffer. METHODS:A 3-mm dried blood spot punch was incubated in a single assay buffer with 3 different substrates and internal standards. The sample was processed by a simple liquid-liquid extraction by using ethyl acetate. The extract was dried down and resuspended in solvent for injection into the tandem mass spectrometer. Products and internal standards were monitored by multiple reaction monitoring. RESULTS:Assay for the 3 lysosomal enzymes was successfully achieved with acceptable statistics. The assay can be performed by using a minimal quantity of disposable supplies and equipment. The entire procedure fits into a 48-h cycle including data analysis. Data from 5990 anonymous newborn dried blood spots showed an approximate bell-shaped distribution of enzymatic activities (mean values of 19.0, 11.5, and 3.5 μmol · h(-1) · (L blood)(-1) for α-glucosidase, α-galactosidase A, and α-l-iduronidase, respectively. Blank values obtained in the absence of blood were 0.13, 0.24, and 0.45 μmol · h(-1) · (L blood)(-1), respectively). By assaying 3 enzymes at once, problematic samples are spotted for reanalysis if enzyme activity values are low for all enzymes (for example, if insufficient blood is present in the assay). CONCLUSIONS:This method demonstrates that a triplex assay in a single buffer and with minimal supplies and labor can be adapted to a high-throughput newborn screening laboratory for the analysis of Pompe, Fabry, and mucopolysaccharidosis-I (Hurler) diseases.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Duffey TA,Bellamy G,Elliott S,Fox AC,Glass M,Turecek F,Gelb MH,Scott CRdoi
10.1373/clinchem.2010.152009subject
Has Abstractpub_date
2010-12-01 00:00:00pages
1854-61issue
12eissn
0009-9147issn
1530-8561pii
clinchem.2010.152009journal_volume
56pub_type
杂志文章abstract：:Lactate dehydrogenase (LD) isoenzymes 1 and 2 in human serum were separated on a column of diethylaminoethyl-Sephadex. Samples layered on mini-columns were eluted with buffered sodium chloride (100, 150, and 200 mmol/liter). Lactate dehydrogenase activity in column effluents was measured by the Wacker method, and thei...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1978-03-01 00:00:00
abstract：:We describe a chromatographic procedure for sensitive (2.0 mumol/L), specific quantification of vanillylmandelic acid (VMA) in urine with iso-VMA as an internal standard. After rapid extraction from urine, the VMA is determined by isocratic reversed-phase ion-pair chromatography on a bonded C8 column and detection of ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-04-01 00:00:00
abstract：:We have assessed Calbiochem single-vial enzymatic reagent systems for the analysis for cholesterol and triglycerides, using manual and centrifugal analyzer techniques. Analysis for cholesterol by both techniques had acceptable performance by the short-term criteria of the Center for Disease Control (CDC) during this s...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1978-11-01 00:00:00
abstract：:We describe modifications to two cartridges, those for alkaline phosphatase and creatinine, on an 18-channel SMAC (Sequential Multichannel Analyzer Computerized), which allow all 18 tests to be run with a commonly prediluted sample. This decreases the required sample size and eliminates the problem of fibrin clots in ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1980-05-01 00:00:00
abstract：:Genetic engineering of beta-galactosidase (EC 3.2.1.23) has led to the development of a new homogeneous assay system, CEDIA. The Z gene of the lac operon of Escherichia coli encodes a large enzymatically inactive polypeptide that spontaneously aggregates and folds to form active beta-galactosidase. Using recombinant D...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-09-01 00:00:00
abstract：BACKGROUND:Whether low plasma 25-hydroxyvitamin D concentrations cause osteoporotic fractures is unclear. We tested the hypothesis that low plasma 25-hydroxyvitamin D concentrations are associated with increased risk of osteoporotic fractures using a Mendelian randomization analysis. METHODS:We genotyped 116 335 rando...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1093/clinchem/hvaa049
更新日期：2020-05-01 00:00:00
abstract：:We describe a procedure based on equilibrium dialysis that allows the simultaneous determination of free testosterone and testosterone bound to non-sex-hormone-binding globulin (non-SHBG) in plasma. After saturating SHBG with 5 alpha-dihydrotestosterone (DHT) according to a technique recently described, the percentage...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1993-06-01 00:00:00
abstract：:The aim of this investigation was to study the distribution of arsenic species in human organs following fatal acute intoxication by arsenic trioxide. The collected autopsy samples of most organs were ground and dried, and the total arsenic was measured by electrothermal atomic absorption spectrometry (ETAAS). The ars...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1999-02-01 00:00:00
abstract：:This rapid radioimmunoassay for aldosterone is performed directly on 100 microL of unprocessed plasma, with 125I-labeled aldosterone as the labeled antigen. Our use of steroid-free plasma in preparing the standard curve resulted in an overestimate of aldosterone; this problem was overcome by adding to such plasma a mi...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1983-02-01 00:00:00
abstract：:In the present clinical evaluation of Triage immunoassay for detection of drugs of abuse, we examined a possible connection between the laboratory skills of the personnel using it and the quality of analytical results; we also evaluated the degree of concordance between the Triage results and those obtained by an inst...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1996-09-01 00:00:00
abstract：:Six alpha-amylase (EC 3.2.1.1) isoenzymes have been resolved electrophoretically on cellulose acetate membranes in a discontinuous buffer system. The fastest migrating isoenzymes are of salivary origin (S1, S2, S3), the slower ones of pancreatic origin (P1, P2, P3). We determined the amylase isoenzyme distribution in ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-01-01 00:00:00
abstract：:Intravascular monitoring of arterial blood gases provides the means to detect precipitous change in cardiopulmonary function almost instantaneously, promising major improvement in the ability to manage critically ill patients. Attempts to miniaturize and repackage conventional electrodes for continuous intravascular u...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1990-08-01 00:00:00
abstract：:We describe a simple method in which a water-soluble mixture of triocatanoin and a surfactant, "Triton X-114," are used in preparing solutions of triglycerides (triacylglycerols) in either human serum, solutions of albumin, or water. Analytical recovery added triglyceride was quantitative by two methods. The addition ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-08-01 00:00:00
abstract：BACKGROUND:Cross-sectional studies have reported seasonal variation in high-sensitivity C-reactive protein (hsCRP). However, longitudinal data are lacking. METHODS:We collected data on diet, physical activity, psychosocial factors, physiology, and anthropometric measurements from 534 healthy adults (mean age 48 years,...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2008.111245
更新日期：2009-02-01 00:00:00
abstract：:This paper compares a logistic curve and a mass-action curve in their ability to represent radioimmunoassay standard curves. A data base from 10 different assays is used in this comparison. Six of the 10 assays could be modeled equally well by either the logistic or the mass-action curve. In one case the mass-action c...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1983-10-01 00:00:00
abstract：:We describe an automated (ABA-100) enzymic method for determination of urinary oxalate by use of oxalate oxidase (EC 1.2.3.4) isolated from beet stems. The H2O2 produced by the oxidation of oxalate by oxalate oxidase is measured by coupling with oxidation and conjugation of 3-methyl-3-benzothiazolinone hydrazone with ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1983-10-01 00:00:00
abstract：:Ornithine carbamoyltransferase (EC 2.1.3.3) activity is a sensitive, specific indicator of hepatocellular injury. This paper describes development of an improved automated procedure for measurement of this activity. Triethanolamine-ethylenediaminetetraacetate is used as a buffer, and activity is determined by measurin...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1975-05-01 00:00:00
abstract：:We describe optimal conditions for immobilization of two monoclonal antibodies to progesterone for solid-phase assays. Polystyrene surfaces are refined with Protein A to achieve uniform, reproducible, stable, and sterically accessible immobilization of immunoglobulins (IgG). To this end, we optimized the amount of imm...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-08-01 00:00:00
abstract：:A precolumn derivatization method was optimized for rapid and specific analysis of total urinary hydroxyproline by HPLC. After an overnight hydrolysis, urine samples dried and reconstituted with the internal standard cysteic acid (in sodium hydrogen carbonate, pH 9.3) were derivatized with N,N-diethyl-2,4-dinitro-5-fl...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1992-03-01 00:00:00
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：:Highly purified human lactate dehydrogenase 1 has been used in an interlaboratory evaluation and improvement progran in clinical chemistry in New York State since 1971. Although there are difficulties in determining and assigning the most nearly accurate values for test samples in the absence of a reference method and...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1977-06-01 00:00:00
abstract：:The manual Reference Method of the Centers for Disease Control for serum iron (CDC/RM/Fe) and a semiautomated adaptation of it were used to evaluate two working methods: one, a detergent solubilization procedure for the Roche Cobas-Bio analyzer, the other, the Kodak Ektachem 700 procedure, based on dry-film technology...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1990-10-01 00:00:00
abstract：:Intra- and interindividual components of biological variation have been determined for total thyroxin (TT4), free thyroxin (FT4), total triiodothyronine (TT3), free triiodothyronine (FT3), and thyrotropin (TSH). Calculated analytical goals (CV, %) for the precision required for optimal patient care are: TT4 less than ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-06-01 00:00:00
abstract：BACKGROUND:The new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was developed to address the systematic underestimation of the glomerular filtration rate (GFR) by the Modification of Diet in Renal Disease (MDRD) Study equation in patients with a relatively well-preserved kidney function. The per...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2009.135111
更新日期：2010-03-01 00:00:00
abstract：:To demonstrate oligoclonal IgG bands (I) in unconcentrated cerebrospinal fluid, we used isoelectric focusing in agarose followed by protein transfer to cellulose nitrate membrane, double-antibody peroxidase labeling, and avidin-biotin amplification. I can be reliably seen after isoelectric focusing of 5-microL specime...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1984-07-01 00:00:00
abstract：:We describe an enzymatic fluorometric method for determining glucose concentrations in blood samples by analysis on a semi-solid surface (silicone-rubber pads). The method is an adaptation of existing spectrophotometric procedures based on the sequential coupling reactions with glucose-6-phosphate dehydrogenase and NA...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1975-11-01 00:00:00
abstract：:Using automated measurements of kappa and lambda light chains and IgG, IgA, and IgM, we assessed the utility of the kappa/lambda ratio and the heavy chain/light chain ratio in characterizing monoclonal immunoglobulins previously identified by sensitive electrophoresis on agarose gel and typed by immunofixation or immu...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-10-01 00:00:00
abstract：:Using a continuous-flow (Technicon SMAC) analyzer, we measured the concentration of 20 analytes in capillary blood sera from 149 neonates in an intensive-care unit. Included were term and pre-term babies, both groups with and without asphyxia. The values obtained, especially for those enzymes and analytes that are rel...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1984-04-01 00:00:00
abstract：:In this liquid-chromatographic method for the determination of bromide in human serum, an important and unique feature is pre-analysis ultrafiltration of the sample, which effectively removes proteins. The chromatographic system consists of an anion-exchange column (Whatman Partisil SAX 10-micron particles), an isocra...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1984-05-01 00:00:00
abstract：:Measurement of the mass concentration of serum enzymes by radioimmunoassay provides direct quantitation of specific isoenzymes and may be less subject to some of the limitations of traditional assay procedures for enzymes. We describe the development of a sensitive and specific radioimmunoassay for the muscle isoenzym...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1978-03-01 00:00:00
