bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solid-phase enzymoimmunoassay for osteocalcin in human serum or plasma, with use of a monoclonal antibody.
Authors: Power M J , Fottrell P F 
Published: January 2020

Abstract
In this solid-phase enzymoimmunoassay on microtiter plates for osteocalcin in serum or plasma, we use an osteocalcin-horseradish-peroxidase conjugate and a monoclonal antibody raised against bovine osteocalcin. We thoroughly standardized the assay for measurement of osteocalcin in both serum and plasma, demonstrating independence of sample volume, and determining the analytical recovery and within-and between-assay CVs. The detection limit was between 0.6 and 1.1 micrograms/L and the ED50 was 16 micrograms/L for a 5-microL sample volume. The intra-assay CV over the range 3 to 74 micrograms/L was less than or equal to 15%. The interassay CV over the range 3.6 to 46 micrograms/L was less than or equal to 16%. Results by this assay and by an in-house radioimmunoassay in which the same monoclonal antibody was used correlated well (r2 = 0.948). Osteocalcin concentrations in serum and plasma as measured with the present assay agreed well with published values.
Fluorometric method for phenylalanine microplate assay adapted for phenylketonuria screening.
Authors: Gerasimova N S , Steklova I V , Tuuminen T 
Published: January 2020

Abstract
We adapted the method of McCaman and Robins for fluorometry of phenylalanine to a microplate assay for routine phenylketonuria screening. Sensitivity is 15 mumol/L for the plasma assay and 30 mumol/L for the dried blood-spot assay, with CV less than 10% for both assays. Results for human plasma by microplate assay correlated well (r = 0.99) with results of amino acid analyzer determination of phenylalanine. When measurements are performed in an automated reader, the microplate assay has considerable advantages over conventional measurements in cuvettes: smaller volumes of reagents and automation enabling high throughput and convenience. Because the described method is a quantitative one, we can postulate that, compared with the semiquantitative Guthrie inhibition bioassay, this microplate assay is more reliable, easier to perform, and about twofold less costly.
Determination of serum desipramine and 2-hydroxydesipramine for pharmacokinetic applications by HPLC with ultraviolet detection.
Authors: Kenney J T , Orsulak P J , Kolodner R M , Burton M E 
Published: January 2020

Abstract
This procedure for measuring desipramine and its 2-hydroxy metabolite in serum at a minimum concentration of 1 micrograms/L involves high-performance liquid chromatography (HPLC), with ultraviolet detection at 214 nm. After desipramine and 2-hydroxydesipramine are extracted from alkalinized serum by a single-step solvent extraction, they are separated by HPLC and quantified with amitriptyline as the internal standard. Desipramine, 2-hydroxydesipramine, and amitriptyline are separated in 6 min. The standard curve is linear (r = 1.000) for both desipramine and 2-hydroxydesipramine concentrations over the range of 1 to 100 micrograms/L, and the assay demonstrates an excellent precision profile, even at low concentrations. Between-run CVs for 20 and 60 micrograms/L controls (n = 20) were 3.9% and 3.6% for desipramine and 3.4% and 3.8% for 2-hydroxydesipramine, respectively. In a pharmacokinetic evaluation of patients with depression, we examined single-dose elimination curves before and after a four-week regimen of desipramine treatment. The results showed that the method's simplicity and high precision render it ideal for pharmacokinetic studies of desipramine.
Biochemical contribution to diagnosis and study of a new case of D-glyceric acidemia/aciduria.
Authors: Fontaine M , Porchet N , Largilliere C , Marrakchi S , Lhermitte M , Aubert J P , Degand P 
Published: January 2020

Abstract
During organic acid screening by gas chromatography/mass spectrometry, we detected a large peak corresponding to glyceric acid in a patient's urine sample. The D(+) configuration was demonstrated by a polarimetric method and by enzymatic stereospecificity of D-glycerate dehydrogenase (EC 1.1.1.29). We biochemically investigated this fifth reported case of D-glyceric acidemia. In our patient, loading tests with L-serine and fructose led to an increase of D-glyceric acid in both plasma and urine. Determination of other metabolites involved in D-glycerate metabolism revealed no abnormality in any sample examined. After comparing all our results with those of the preceding observations described in the literature, we suggest a possible enzymatic defect located on one of the metabolic pathways shared by fructose and L-serine, possibly at the level of hepatic D-glycerate kinase (EC 2.7.1.31). Nevertheless, a primary defect of L-serine catabolism cannot be entirely excluded.
Plasma glutathione S-transferase and F protein are more sensitive than alanine aminotransferase as markers of paracetamol (acetaminophen)-induced liver damage.
Authors: Beckett G J , Foster G R , Hussey A J , Oliveira D B , Donovan J W , Prescott L F , Proudfoot A T 
Published: January 2020

Abstract
Concentrations of glutathione S-transferase (GST; glutathione transferase; EC 2.5.1.18) B1 subunits, F protein, and the activity of alanine aminotransferase (ALT; EC 2.6.1.2) were measured in sequential plasma samples taken from nine patients with self-administered paracetamol (acetaminophen) poisoning. GST exceeded the reference interval in all patients at the time of admission, and F protein was increased in seven. In contrast, abnormal activities of ALT in plasma were found in only one of the nine on admission, a patient admitted 12 h after poisoning. Subsequent to admission nine, eight, and five patients, respectively, had abnormal concentrations of GST, F protein, and ALT. When expressed as multiples of the upper reference limit, the highest values for GST measured in each patient always far exceeded the greatest abnormalities in ALT; this was true for F protein in only five patients. Patients in whom the concentration of GST exceeded 10 micrograms/L on admission subsequently went on to develop moderate or severe liver damage, despite treatment with N-acetylcysteine. F protein and ALT measurements on admission were not as efficient as GST at predicting the clinical outcome of the patients. We conclude that GST and F protein offer clear advantages over ALT for detecting minor degrees of acute liver dysfunction, particularly when only centrilobular damage may be involved.
Effect of ingestion of hemoproteins on fecal excretion of hemes and porphyrins.
Authors: Rose I S , Young G P , St John D J , Deacon M C , Blake D , Henderson R W 
Published: January 2020

Abstract
Stools from asymptomatic volunteers on diets containing red meat, whole blood, or high fiber were analyzed for their content of hemes and dicarboxylic (heme-derived) porphyrins by the "HemoQuant" assay, the "Hemoccult" test, and "high-performance" liquid chromatography (HPLC). In 49 subjects, ingestion of red meat increased HemoQuant-determined combined fecal heme plus dicarboxylic porphyrins by an average 375%; the contribution of heme-derived porphyrins to total fecal porphyrins increased from 37% to 78%. Of subjects on a red-meat diet, 27% passed stools with a porphyrin content suggestive of a porphyria, compared with only 4% on a red-meat-free diet. These increases were due largely to protoporphyrin and its derivatives pemptoporphyrin and deuteroporphyrin, all of which were present in feces as iron-free porphyrins and iron-ligated (heme) forms. Ingestion of blood had an effect similar to that of red meat, but ingestion of fiber had no effect. These effects of dietary and endogenous hemoproteins must be considered when such methods are used to test feces for occult blood or to test for excess fecal porphyrins as an indicator of a porphyria.
Computerized quantitative analysis of coomassie-blue-stained serum proteins separated by two-dimensional electrophoresis.
Authors: Burgess-Cassler A , Johansen J J , Santek D A , Ide J R , Kendrick N C 
Published: January 2020

Abstract
Two-dimensional electrophoresis in combination with Coomassie Blue staining was refined for use as a quantitative method. Microcomputer software was developed for use with the IBM AT and compatible computers for analyzing the gels. To test the refined method to determine its usefulness in simultaneous measurements of 28 human serum proteins, we measured each protein relative to a single standard (bovine serum albumin) polymerized at different concentrations in a calibration scale, rather than using 28 individual standards. All samples were analyzed in triplicate. We evaluated calibration, linearity of response, recoveries, units, within-run CV, and between-run CV. The five isoforms of apolipoprotein A-I were analyzed in samples from 16 healthy donors and the isoform ratios determined. The method as presented here should prove useful for diagnosis of non-urgent disease states and for analysis for protein isoforms in relation to disease; it should also be applicable to assays of proteins in other fluids and tissues.
Relative importance of estrogen and progesterone receptor assays as prognostic indicators in primary breast cancer: a short-term study.
Authors: Brocklehurst D , Wilde C E , Finbow J A , Brett R , Champion A E , Dewhurst D G 
Published: January 2020

Abstract
This short-term study of the relative importance of estrogen and progesterone receptors shows that progesterone receptor correlates better than estrogen receptor with tumor recurrence regardless of lymph-node status. Life-table analysis has effectively identified only two groups of patients that may be classified by progesterone receptor status alone. Progesterone-receptor negativity correlated well with tumors of histological Grade III; estrogen-receptor positivity correlated with Grade I and II tumors. The earlier recurrence of Grade III breast tumors may explain why progesterone receptor is a better prognostic indicator than estrogen receptor in short-term studies.
Solid-phase sample extraction for rapid determination of methylmalonic acid in serum and urine by a stable-isotope-dilution method.
Authors: Rasmussen K 
Published: January 2020

Abstract
Methylmalonic acid concentrations are increased in serum in vitamin B12 (cobalamin) deficiency. Here I demonstrate the successful use of anion-exchange extraction for improving newly developed analytical procedures and describe well-documented, reliable performance of this method for rapid determination of methylmalonic acid. The sorbent counter ion is formate, and the elution solvent is formic acid. The dicyclohexyl derivative is measured by selected ion monitoring. For serum, the assay curve is linear from 0.026 to 200 mumol/L. The normal reference interval is 0.08 to 0.56 mumol/L. Added methylmalonic acid is accurately quantified. The sensitivity and the precision exceed those of the current method by three orders of magnitude. The total and within-day CVs are 4.6% to 7.9% and 2.6% to 4.7%, respectively. Similar figures were obtained for urine. This convenient method is useful for evaluation of cobalamin deficiency, especially in patients with normal or moderately depressed cobalamin concentrations in serum.
How sensitive are immunometric assays for thyrotropin?
Authors: McConway M G , Chapman R S , Beastall G H , Brown E , Tillman J , Bonar J A , Hutchison A , Allison T , Finlayson J , Weston R 
Published: January 2020

Abstract
The usual method for calculation of the "sensitivity" of thyrotropin immunometric assays is multireplicate analysis of the zero analyte standard. Although this is a statistically valid estimate of the scatter likely to be found in the response variable, it is unrelated to normal analytical practice (usually analysis in duplicate) and estimates intra-assay errors only. This study was designed to assess the analytical performance of 10 immunometric assays used routinely for measurement of thyrotropin in human serum. Response data from each assay were accumulated to provide (a) an estimate of "sensitivity" from multireplicate analysis and (b) an estimate of "minimum detection limit," relating directly to errors associated with routine performance and derived from a minimum of 500 duplicate analyses. We conclude that the "minimum detection limit" should be promoted as a more meaningful measure of assay performance at low analyte concentrations than the "sensitivity" derived from multireplicate analysis of the zero-analyte standard.
Automated enhanced latex agglutination assay for rheumatoid factors in serum.
Authors: Winkles J W , Lunec J , Gray L 
Published: January 2020

Abstract
This improved assay of rheumatoid factors in serum, described here for use with the Baker "Encore" centrifugal analyzer, is efficient, with 250-sample throughput per hour; reproducible, with between-batch CV = 5% and within-batch CV = 2% (mid-assay range); and results correlate well (r = 0.9) with those by other methods. The method is fully quantitative and automated, involves no predilution steps, and can be adapted for use in a wide range of systems. It has a sensitivity of 96% and specificity of 80% in diagnosing rheumatoid arthritis.
Concentrations of carotenoids, retinol, and tocopherol in plasma, in response to ingestion of a meal.
Authors: Brown E D , Rose A , Craft N , Seidel K E , Smith J C 
Published: January 2020

Abstract
Field studies and epidemiological surveys may necessitate obtaining a blood sample from a nonfasted subject for nutritional assessments. We measured the effect of a standardized test meal, eaten after an overnight fast, on the concentrations of seven carotenoid fractions, retinol, and tocopherol in plasma of eight healthy adults. The 790-calorie test meal did not alter the measured concentrations. We conclude that blood sampled up to 4 h after breakfast can be validly used for these measurements.
Differences between capillary and venous blood-alcohol concentrations as a function of time after drinking, with emphasis on sampling variations in left vs right arm.
Authors: Jones A W , Jönsson K A , Jorfeldt L 
Published: January 2020

Abstract
Twelve healthy men drank 0.8 g of ethanol per kilogram of body weight during 30 min after an overnight (10 h) fast. At nine exactly timed intervals (30-390 min after the start of drinking), blood was sampled through indwelling catheters in cubital veins on the left and right arms. Immediately thereafter, capillary blood was sampled from fingertips on the left and right hands. The blood ethanol concentration (BAC) was determined by headspace gas chromatography. The SD for alcohol determinations in venous blood, including the left vs right arm sampling variation, was 30 mg/L (range 8.3-83 mg/L), whereas for capillary blood the SD was 35 mg/L (range 11-60 mg/L). This difference much exceeded the purely analytical errors: SD = 2.67 mg/L for venous blood and 14.2 mg/L for fingertip blood. During the first 60 min after the subjects started to drink, capillary BAC exceeded venous BAC, the mean difference at 30 min being 136 mg/L (range 36-216 mg/L). In the postabsorptive state later than 60 min after drinking, venous BAC exceeded capillary BAC [mean difference 58 mg/L (range 0.0-170 mg/L]), the values for venous and capillary BAC crossing 37 min (range 6-77 min) after the end of drinking. Apparently, the source of blood analyzed, venous or capillary, must be considered in clinical pharmacokinetic studies of ethanol.
Novel immunoradiometric assay of thyroglobulin in serum with use of monoclonal antibodies selected for lack of cross-reactivity with autoantibodies.
Authors: Piechaczyk M , Baldet L , Pau B , Bastide J M 
Published: January 2020

Abstract
A multisite immunoradiometric assay for measurement of serum thyroglobulin (Tg), designated Magnogel-IRMA-Tg, has been developed, involving magnetic microbeads (Magnogel). This assay is based on the use of five anti-Tg monoclonal antibodies (MAbs) directed against three antigenic regions on the Tg molecule that are not recognized by anti-Tg autoantibodies (aAbs). Four of these MAbs, directed against two antigenic domains, were coupled to the magnetic beads and were used to trap the serum antigen. Another MAb, directed against the third region, was iodinated and served as the labeled second antibody. The Magnogel-IRMA-Tg technique is reproducible, rapid, and sensitive (lower detection limit, 3 micrograms/L). The assay reliably measures serum Tg in the presence of anti-Tg aAbs.
Chromatofocusing and isoelectric focusing in immobilized pH gradients compared for characterization of human hemoglobin variants.
Authors: Paleari R , Arcelloni C , Paroni R , Fermo I , Mosca A 
Published: January 2020

Abstract
We compared the performance of two highly resolving methods, chromatofocusing (CRF) and isoelectric focusing in immobilized pH gradients (IPGF), for the separation of human hemoglobin variants. Lysates containing 13 different hemoglobins, including variants of clinical and geographical importance, and four electrophoretically "silent" variants (Hb Brockton, Hb Cheverly, Hb Köln, and Hb Waco) were analyzed. Both techniques showed a good intrarun precision (CV = 0.87% for CRF, 0.27% for IPGF) and high and similar resolving power (0.010 pH units, with the pH gradients used in this work). The use of an ultranarrow IPGF range (pH 7.15-7.35; pH gradient = 0.019 pH/cm) allowed the resolution between Hb Brockton, Hb Köln, and Hb A. In some cases (Hb D-Los Angeles, Hb F, Hb Waco), the variants were separated from Hb A in different orders, depending on which technique was used, probably because of the different analytical principles of the two methods. As a second-level test, both procedures are informative for characterization of human hemoglobin variants.
Atomic absorption spectrometric determination of selenium in human blood components.
Authors: Hansson L , Pettersson J , Eriksson L , Olin A 
Published: January 2020

Abstract
We separated blood from five healthy blood donors into plasma, erythrocytes, platelets, and leukocytes; counted the number of cells in each fraction; and determined the selenium content of each component by hydride generation atomic absorption spectrometry. The mean (+/- SD) selenium concentrations and amounts measured were as follows: whole blood 102.3 +/- 16.1 micrograms/L, plasma 76.9 +/- 10.6 micrograms/L, erythrocytes 13.7 +/- 2.8 ag per cell, platelets 4.8 +/- 1.1 ag per cell, and leukocytes 99 +/- 26 ag per cell.
Measurement of estrone-3-glucuronide in urine by rapid, homogeneous time-resolved fluoroimmunoassay.
Authors: Barnard G , Kohen F , Mikola H , Lövgren T 
Published: January 2020

Abstract
We describe a liquid-phase nonseparation time-resolved fluorescence immunoassay for measuring estrone-3-glucuronide in undiluted urine. The sensitivity, specificity, and accuracy are similar to those for a conventional separation fluoroimmunoassay or radioimmunoassay, but the speed, convenience, precision, reliability, and clinical utility of the new method are more advantageous. The labeled antigen, a fluorescent europium chelate covalently linked to estrone-3-glucuronide, is incubated for 10 min with a limited concentration of polyclonal or monoclonal antibodies to estrone-3-glucuronyl-6-bovine serum albumin and 10 microL of standard or sample (undiluted urine) in microtiter wells. The fluorescence emanating from the antibody-free label, which is proportional to the concentration of estrone-3-glucuronide in the standard or sample, is then measured in a time-resolved fluorometer. The method is useful for monitoring ovarian function in women.
Biological variation of urinary N-acetyl-beta-D-glucosaminidase: practical and clinical implications.
Authors: Stolarek I , Howey J E , Fraser C G 
Published: January 2020

Abstract
The analytical, within-subject, and between-subject components of variation of N-acetyl-beta-D-glucosaminidase (NAG) were estimated from duplicate assays of 10 timed first morning and 10 untimed urine specimens collected from each of 15 ostensibly healthy individuals. Results were expressed in terms of activity, NAG/creatinine ratio, and excretion rate. Current analytical methods can achieve desirable performance standards. NAG has little individuality, and conventional population-based reference intervals are therefore useful. In view of the practicability and relatively low within-subject variation, for routine clinical purposes we prefer assay of NAG in first morning urine, expressing the results in terms of activity. Using the results of assays of different specimens, we found that the correlation between urinary albumin and NAG varied considerably, owing to the large intrinsic variability of both analytes; this might explain previous conflicting results.
A new immunoradiometric assay for corticotropin evaluated in normal subjects and patients with Cushing's syndrome.
Authors: Raff H , Findling J W 
Published: January 2020

Abstract
We evaluated a new, commercially available two-site immunoradiometric assay (IRMA) for corticotropin (ACTH) in human plasma. The precision and detection limit were an improvement over radioimmunoassay (RIA). Addition of ACTH 1-24 or ACTH 18-39 to plasma containing ACTH 1-39 resulted in a decrease in measured ACTH. Results by both IRMA and RIA are reported and compared for normal subjects, patients with Cushing's disease, and patients with ectopic ACTH. Effects of administering dexamethasone, metyrapone, ACTH 1-24, and corticoliberin were evaluated. The present assay is more sensitive, specific, and reproducible than RIA. The presence of fragments of ACTH or "big" ACTH that are reactive in RIA may lead to artifactually low ACTH concentrations by IRMA. Therefore, RIA may still be necessary for differential diagnosis of ectopic ACTH syndromes. However, the IRMA is an improvement for evaluating pituitary--adrenal function in patients with low concentrations of ACTH in plasma.
Rapid determination of toxic cyanide concentrations in blood.
Authors: Lundquist P , Sörbo B 
Published: January 2020

Abstract
This method for the rapid colorimetry of cyanide in blood, applicable to patients exposed to toxic levels of cyanide, is based on the König reaction, which produces a chromophore from cyanide as well as thiocyanate. The latter compound, normally present in blood, is confined to plasma. Thus, its interference with determination of cyanide was eliminated by performing the assay on the erythrocytes, which contain most of the blood cyanide. Furthermore, cyanide was trapped in the erythrocytes and stabilized during the initial washing steps by conversion of hemoglobin to methemoglobin with inorganic nitrite.
Three methods compared for estimating the fraction of testosterone and estradiol not bound to sex-hormone-binding globulin.
Authors: Pearce S , Dowsett M , Jeffcoate S L 
Published: January 2020

Abstract
Here we propose and validate, both theoretically and experimentally, a new technique for measuring the percentage of non-sex-hormone-binding globulin (SHBG) bound to testosterone and estradiol. In this method, SHBG is saturated with 1 mumol of 5 alpha-dihydrotestosterone per liter and the non-protein-bound fraction is subsequently measured in treated and untreated samples by centrifugal ultrafiltration dialysis (CUFD). We compared this technique with two previously published methods for measuring the percentage of albumin-bound steroid--ammonium sulfate precipitation and heat denaturation of SHBG followed by CUFD--and also with previously published computer predictions. The ammonium sulfate precipitation gave results closest to the computer-predicted percentage of albumin-bound testosterone and estradiol. Of the two techniques involving CUFD, the 5 alpha-dihydrotestosterone saturation method was the more reproducible. Results by both CUFD methods were higher than the computer-based predictions for albumin-bound steroid in pregnancy serum, in part perhaps because the CUFD measurements represent the non-SHBG-bound fraction rather than that which is albumin-bound alone.