bluuebunny/crossref_metadata_2025_split huggingface dataset:
Macromolecular alkaline phosphatase and an immunoglobulin G that inhibited alkaline phosphatase in a patient's serum.
Authors: Nakagawa H , Umeki K , Yamanaka K , Kida N , Ohtaki S 
Published: January 2020

Abstract
Macromolecular alkaline phosphatase (EC 3.1.3.1) was found in the serum of a patient suffering from myasthenia gravis (adult type II) complicated with thymoma, and was shown by immunoelectrophoresis to be bound to immunoglobulins A and G (IgG). Placental alkaline phosphatase, complexed with either the patient's serum or IgG purified from the patient's serum, remained at the origin on electrophoresis, with significant loss of activity. Intestinal alkaline phosphatase, complexed with either the patient's serum or the patient's IgG, migrated to a position similar to that of the macromolecular alkaline phosphatase in the patient's serum on electrophoresis. About 50% of the placental alkaline phosphatase activity was inhibited with 0.1-0.2 g of the patient's IgG per liter, but 6.93 g of the IgG per liter was required for about 20% inhibition of the intestinal alkaline phosphatase activity. The complex of intestinal alkaline phosphatase with the patient's IgG was fairly heat stable. From these results, we concluded that the macromolecular alkaline phosphatase in the patient's serum consisted of intestinal alkaline phosphatase and IgG that was specific for placental alkaline phosphatase.
Some considerations of methodology and standardization of apolipoprotein A-I immunoassays.
Authors: Steinberg K K , Cooper G R , Graiser S R , Rosseneu M 
Published: January 2020

Abstract
Apolipoprotein A-I (apo A-I) is the major protein of high-density lipoprotein. Compelling evidence suggests that measurement of concentrations of apo A-I in serum may be useful in predicting and assessing ischemic heart disease. The following review of methods of isolation, characterization, and assay of apo A-I has been developed to assess the possibility of standardizing apo A-I immunoassays. We consider the properties of apo A-I that have an effect on its quantification, such as self-association, polymorphism, and stability characteristics. We attempt to review critically the various methods presented, but more information about the physicochemical properties of the protein is required before definitive recommendations can be made.
A new reagent strip (Visidex) for determination of glucose in whole blood.
Authors: Sherwood M J , Warchal M E , Chen S T 
Published: January 2020

Abstract
A new solid-phase reagent strip for determination of glucose in whole blood, Visidex, has been developed specifically for visual use in conjunction with a calibrated color scale. Two reagent pads are used, each formulated for a different portion of the range of clinical values, to maximize the visual resolution available to the user. Colorimetric examination of reacted reagent pads indicated that the label color blocks match closely the appearance of the reagent pads; that the reagent pads exhibit good precision; and that the colors of the reagent pads are independent of operator technique, sample volume (20-50 microL), and effects of potential interferents studied (although high concentrations of fluoride slightly inhibited color development). Glucose measurements obtained visually with the Visidex system correlated well with values obtained with a YSI Glucose Analyzer (for two separate studies, slope = 0.96 and 1.04, r = 0.99 and 0.96, and n = 172 and 543, respectively).
Improved measurement of acetylsalicylic acid esterase in serum.
Authors: Sørensen S 
Published: January 2020

Abstract
A fixed-time incubation method for measuring acetylsalicylic acid esterase was improved by using a higher concentration of the substrate, acetylsalicylic acid, and an activator, Ca2+. The enzymatic activity in serum was 25-fold that measured by earlier methods. Inhibition studies showed a pattern similar to that reported for cholinesterase. Use of cholinesterase inhibitor in sample tubes for determination of acetylsalicylic acid and salicylic acid is recommended.
Clinical evaluation of Eastman Kodak's Ektachem 400 Analyzer.
Authors: Kadinger C L , O'Kell R T 
Published: January 2020

Abstract
We evaluated the performance of the Kodak Ektachem 400 Analyzer in a 16-week clinical trial. We assessed four potentiometric tests and nine colorimetric tests for precision and correlation with results obtained some other commonly used instruments (Technicon SMA II and C800 System, Du Pont aca II, and Baker CentrifiChem). The comparison was favorable for all tests except albumin, sodium, and carbon dioxide. The reagents are stable. Little refrigerator storage space is needed. The computer system and the modular component design of the Ektachem 400 Analyzer make operation, troubleshooting, and preventive maintenance relatively easy.
Further evaluation of luminol-enhanced luminescence in the diagnosis of disorders of leukocyte oxidative metabolism: role of myeloperoxidase.
Authors: Cohen M S , Shirley P S , DeChatelet L R 
Published: January 2020

Abstract
Chemiluminescence can be used to identify defects in the oxidative metabolism of granulocytes. This procedure has recently been adopted for use with microliter quantities of whole blood, appropriate for prenatal or neonatal study. Although the contribution of myeloperoxidase to the chemiluminescence assay has been noted, the possible diagnostic confusion between chronic granulomatous disease of childhood (which is rare and severe) and myeloperoxidase deficiency (which is common and of little clinical consequence) has not been stressed. We report a father and his infant daughter whose cells emitted no light in the luminol-enhanced luminescence assay; both patients are totally peroxidase deficient. These results emphasize the hereditary nature of myeloperoxidase deficiency, and the possibility for erroneous diagnosis of chronic granulomatous disease of childhood based on the luminol-enhanced luminescence test.
Interlaboratory proficiency survey of high-density lipoprotein cholesterol measurement.
Authors: Warnick G R , Benderson J M , Albers J J 
Published: January 2020

Abstract
Proficiency surveys of Seattle-area laboratories suggest only slight improvement in overall performance in high-density lipoprotein (HDL) measurement between 1978 and 1982, although the reported workload for HDL has increased by 15%. The mean interlaboratory SD was 64 mg/L (ranging from 34 for a pool averaging 299 mg/L to 136 for a pool averaging 886 mg of HDL cholesterol per liter) in 1982, compared with 79 mg/L (range 48-155) in 1978-79. Of the individual laboratory results in the current survey, 39% deviated by more than 50 mg/L from target values as compared with 37% in 1978-79. The discrepant values were primarily ascribable to method inaccuracy: only 30% of laboratories in 1982 reported results that averaged within 30 mg/L of target values (vs 50% in 1978). For within-run precision, 80% of laboratories in 1982 had SDs of less than 30 mg/L, vs 70% in 1978. The 1982 survey included a lyophilized serum prepared by spray freezing and bulk lyophilization (Hyland Omega), identical to the pools used in the College of American Pathologists Comprehensive Chemistry Survey, and five pools of frozen plasma. Interlaboratory variation and biases for the Omega pool were similar to those for the frozen pools.
Clinical implications of differences between two recommended procedures for determination of aspartate aminotransferase.
Authors: Dols J L , van Zanten A P 
Published: January 2020

Abstract
We compared two officially recommended methods for determination of aspartate aminotransferase (EC 2.6.1.1): that of the International Federation of Clinical Chemistry (IFCC) and that of the Deutsche Gesellschaft für Klinische Chemie (DGKC). We used automated enzyme analyzers, initiating the reactions with 2-oxoglutarate. Normal values, 10-30 U/L (IFCC) and 7-18 U/L (DGKC), were apparently insensitive to intra-individual variations. Samples obtained from patients with heart disease showed a markedly different amount of activation with pyridoxal phosphate as compared with samples from other patient categories. Ratios for aspartate aminotransferase/alanine aminotransferase, as used in the differentiation of liver disease, can still be used with either method for determination of aspartate aminotransferase.
Development and analytical performance of automated tests for antithrombin III and plasminogen on the Du Pont aca analyzer.
Authors: Perry J F , Siefring G E , Reider M C , Coleman P L , Wehrly J A 
Published: January 2020

Abstract
We describe assays for functional antithrombin III (AT III) and plasminogen in plasma with the Du Pont aca discrete clinical analyzer. Both are two-stage kinetic assays, based on synthetic substrate methodologies, and require 20-microL sample volumes. In the AT III assay the sample is incubated with excess thrombin and heparin to form the functionally inactive AT III-thrombin complex. Residual thrombin is measured through its rate of hydrolysis of a lysine thioester and is inversely related to analyte concentration. In the plasminogen assay excess streptokinase is reacted with the sample to form an enzymatically active complex. The substrate hydrolysis rate of this complex is measured, which is linearly related to the concentration of plasminogen in the sample. Reaction conditions for both assays were optimized by univariate and response surface techniques. The assay for AT III has a range of 0 to 150% of the value for normal human plasma (% NHP) with a CV of 3% at 80% NHP. The plasminogen assay is linear from 25 to 200% NHP with a CV of less than 2% at 80% NHP. No significant interferences with either method by common blood components or drugs were found.
Radioenzymatic assay for direct measurement of plasma pyridoxal 5'-phosphate.
Authors: Camp V M , Chipponi J , Faraj B A 
Published: January 2020

Abstract
A radioenzymatic assay for measurement of pyridoxal 5'-phosphate (PLP) is described, based on the incubation of L-[3H]tyrosine (10(6) cpm, spec. acty. 1.88 Ci/mol) in the presence of the apoenzyme tyrosine decarboxylase (EC 4.1.1.25) from Streptococcus faecalis and PLP in phosphate buffer (0.1 mol/L, pH 5.5) at 37 degrees C for 60 min. The decarboxylated metabolite formed, [3H]tyramine, was selectively extracted into ethyl acetate, and the tritium radioactivity in the sample was determined by liquid scintillation counting. As little as 0.5 nmol of PLP can be detected per liter. The assay is specific, no cross reactivity having been noted for several compounds closely related to PLP. With this we could directly measure the concentrations of PLP in plasma without prior deproteinization and ether washing of the samples. Using the assay to determine plasma concentrations of PLP in healthy adult populations, we found results that were comparable with previously reported data.
Ultracentrifugation in swinging-bucket and fixed-angle rotors evaluated for isolation and determination of high-density lipoprotein subfractions HDL2 and HDL3.
Authors: Demacker P N , van Sommeren-Zondag D F , Stalenhoef A F , Stuyt P M , van't Laar A 
Published: January 2020

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 hydrated densities of the lipoproteins, and after only 2.2 X 10(8) gav . min obtained an equilibrium distribution of the lipoproteins along the gradient. The density distribution of the HDL of 120 sera obtained from apparently healthy persons and from patients with different types of hyperlipoproteinemia was bimodal. The HDL2 could be isolated in the density range 1.072-1.098 kg/L and the HDL3 at 1.100-1.176 kg/L, the latter fraction being more heterogeneous. At a solvent density of 1.100 we obtained similar results for HDL2-and HDL3-cholesterol by ultracentrifugation in two different fixed-angle rotors with tube angles of 15 degrees or 35 degrees. Independent of the rotor and the ultracentrifugation technique, subfractionation at d = 1.100 resulted in more distinct stained entities than ultracentrifugation at d = 1.125. In the swinging-bucket rotor procedure, interference by sinking pre-beta-lipoproteins was minimized because, having hydrated densities between 1.058 and 1.075, they could be removed without aspirating the HDL2. The method is both accurate and precise. For HDL2- and HDL3-cholesterol determined in a thawed frozen serum pool, CVs were 8.8 and 6.3%, respectively (n = 18).
Liquid-chromatographic quantification of piracetam.
Authors: Nalbandian R M , Kubicek M F , O'Brien W J , Nichols B , Henry R L , Williams G A , Goldman A I , Adams D , Teng C M 
Published: January 2020

Abstract
Piracetam, an analog of gamma-aminobutyric acid, absorbs maximally at 197 nm. Its molar absorptivity at 208 nm and pH 4.5 is 3576 (SD 251) L . mol-1 cm-1, approximately 45% of its absorptivity at 197 nm. Direct quantification of piracetam at 197 nm in biological extracts is complicated by the fact that many other compounds absorb between 190 and 220 nm due to carbon-nitrogen bonding. Chromatography of methanol extracts of serum and aqueous humor on a reversed-phase C-18 column developed isocratically with KH2PO4 (0.1 mol/L, pH 4.8) allows detection and quantification of 0.2 mmol of piracetam per liter. Under these conditions the retention time of piracetam is about 5 min. The detector response is linear for quantities between 5 and 15 nmol. The method is rapid, inexpensive, and convenient for the clinical laboratory.
An automated dry-slide enzymatic method evaluated for measurement of creatinine in serum.
Authors: Toffaletti J , Blosser N , Hall T , Smith S , Tompkins D 
Published: January 2020

Abstract
We evaluated an automated dry-slide enzymatic method involving creatinine iminohydrolase for measurement of creatinine in serum with the Kodak Ektachem analyzer. The means (and SD) for three commercially available quality-control sera, analyzed during eight weeks, were 9.7 (1.0), 16.6 (0.9), and 61 (2.1) mg/L. The regression equation for 105 samples measured with the Technicon SMAC (x) and Ektachem Analyzers (y) was: y = (0.89 +/- 0.007)x + (1.7 +/- 0.3) mg/L and for 170 samples measured with the Beckman Astra (x) and Ektachem analyzers (y): y = (1.00 +/- 0.005)x - (1.9 +/- 0.16) mg/L. Sixty-one samples from renal-transplant patients showed nearly the same agreement. The enzymatic method had no interference from substances that interfere with many Jaffé methods for creatinine, including acetoacetate. The drugs cephalothin and cephoxitin did not interfere, but 5-fluorocytosine interfered significantly with creatinine in the Ektachem method. Values for several ketone-positive sera were 5 to 10 mg/L higher by the Astra relative to the Ektachem. Grossly hemolyzed or lipemic samples were analyzed without difficulty. We conclude that this enzymatic method for creatinine in serum has the speed and precision necessary for routine clinical laboratory use and, except for one drug, the method appears to be specific for creatinine.
Deficiency of glycerol kinase (EC 2.7.1.30).
Authors: Eriksson A , Lindstedt S , Ransnäs L , von Wendt L 
Published: January 2020

Abstract
We describe the case of a 10-year-old boy who had been admitted on several occasions with a diagnosis of gastroenteritis. He had been severely ill, and on one occasion lost consciousness. He had a metabolic acidosis on these occasions. Examination of the urine by gas chromatography-mass spectrometry showed a large peak, identified as glycerol. The concentration of glycerol in the urine was 40-280 mmol/L and the concentration in plasma about 2 mmol/L. He was subjected to a fast of 21 h, at the end of which he expressed feelings of discomfort and nausea, began vomiting, and became somnolent. During this period the blood glucose concentration was only slightly decreased, the plasma glycerol concentration increased to 4.9 mmol/L, and the plasma lactate concentration increased to 3.8 mmol/L. During work on a bicycle ergometer for 35 min (40 W) he complained of muscle pain and became nauseated, but there was no significant increase in the concentration of plasma glycerol. The activity of glycerol kinase (EC 2.7.1.30) in leukocytes and cultured fibroblasts was less than 1% of the value for healthy subjects.
An enzymic radiochemical method for determining phosphatidylglycerol in amniotic fluid.
Authors: Siegel L , Walker S I , Robin N I 
Published: January 2020

Abstract
We describe an enzymic quantification of phosphatidylglycerol in amniotic fluid. Phosphatidylglycerol is hydrolyzed in alkali and the resulting glycerol is then enzymatically phosphorylated with adenosine 5'-[gamma-32P]triphosphate to yield glycero[32P]phosphate. After removal of excess [gamma-32P]ATP by charcoal, the radioactivity of the glycerophosphate is measured in a liquid scintillation counter. Triglyceride in the amniotic fluid is hydrolyzed by lipase before extraction and thus does not interfere with the analysis. This method is specific for phosphatidylglycerol. Preliminary studies suggest that a phosphatidylglycerol value greater than or equal to 10 nmol/mL correlates with fetal lung maturity.
Apoenzyme content of serum aminotransferases in relation to plasma pyridoxal-5'-phosphate concentration.
Authors: Westerhuis L W , Hafkenscheid J C 
Published: January 2020

Abstract
To investigate the considerable variation in stimulation of serum aminotransferase activities by pyridoxal-5'-phosphate added in vitro, we determined the pyridoxal-5'-phosphate content of plasma, using the tyrosine decarboxylase reaction together with the catalytic activities of alanine aminotransferase and aspartate aminotransferase, with and without pyridoxal-5'-phosphate supplementation, within a group of normal human individuals. We found a very significant inverse linear relationship between plasma pyridoxal-5'-phosphate concentration and stimulation of the activities of these enzymes in serum after supplementation with pyridoxal-5'-phosphate. We conclude that the degree of stimulation of the apoenzyme of the two serum aminotransferases clearly depends on the pyridoxal-5'-phosphate concentration in vivo.
Quantitative liquid-chromatographic estimation of bilirubin species in pathological serum.
Authors: Lauff J J , Kasper M E , Ambrose R T 
Published: January 2020

Abstract
Earlier we described a "high-performance" liquid-chromatographic procedure for separating the four distinct fractions of bilirubin (unconjugated, monoconjugated, diconjugated, and protein-bound) in pathological human serum (J. Chromatogr. 226: 391-402, 1981). We have modified the prechromatography precipitation of the serum globulins required in that method and have measured the bilirubin content of the precipitate spectrophotometrically. On average, the precipitate contained less than 10% of the total bilirubin in the serum samples. Adding the value obtained for the precipitate to that obtained by chromatography for the individual bilirubin fractions gave an estimate of the concentration of the total bilirubin in the sample. For 357 samples from 132 patients, this total value correlated well with that obtained by the Jendrassik-Gróf diazo procedure (slope = 1.00; r = 0.995, linear least-squares fit). The CV for the total and fractional bilirubin measurements was, on average, less than or equal to 5% for pathological sera. Serum sampled at different times from the same patient showed significant changes in the distribution of bilirubin among the four fractions.
Enzymic assay for phosphatidylcholine and sphingomyelin in serum.
Authors: Blaton V , De Buyzere M , Spincemaille J , Declercq B 
Published: January 2020

Abstract
We describe a method for the direct enzymatic determination of phosphatidylcholine and sphingomyelin in serum. Phospholipase C (EC 3.1.4.3) and sphingomyelinase (EC 3.1.4.12) are used to hydrolyze phosphatidylcholine and sphingomyelin, respectively, with high specificity; alkaline phosphatase (EC 3.1.3.1) is used to cleave inorganic phosphorus. The choline group, after oxidation with choline oxidase (EC 1.1.3.17), is detected with 4-aminoantipyrine. Alternatively, phosphorus is assayed with metavanadate. The excellent agreement between results of this modification of a procedure described by Artiss et al. (Microchem. J. 26: 1017, 1980) for amniotic fluid and of the conventional thin-layer chromatographic method makes this an attractive method for determination of both phospholipid subclasses in serum.
Ionized calcium in human milk determined with a calcium-selective electrode.
Authors: Allen J C , Neville M C 
Published: January 2020

Abstract
We measured the concentration of ionized calcium in human milk with a Radiometer ionized calcium analyzer at 37 degrees C. This instrument is designed to use simultaneous outputs from a pH electrode and a calcium ion-selective electrode to obtain the true ionized calcium in blood plasma. Because both the ionic strength and the pH of human milk differ significantly from that of plasma, we used a calibration curve that corrected for these variables. No other substances in milk interfered with the electrode response to Ca2+. The Ca2+ concentration of milk decreased and the pH increased as CO2 was lost to the atmosphere. Samples collected in glass capillaries, which minimized CO2 loss, contained 2.84 (SD 0.56) mmol of Ca2+ per liter at pH 6.98. We emphasize the importance of maintaining physiological CO2 concentrations when Ca2+ is being measured in milk.
Ferritin concentrations in plasma from capillary (finger prick) blood and venous blood compared.
Authors: Mejía L A , Viteri F E 
Published: January 2020

Abstract
Investigating the feasibility and validity of determining plasma ferritin concentration in blood obtained by finger prick, we studied 29 adults (ages 21-49 years) and 35 children (ages 14-66 months). Blood was sampled simultaneously in the same subject from both the antecubital vein (venous blood) and by finger pricking (capillary blood). The plasma was obtained by centrifugation. Ferritin concentration was determined by immunoradiometric analysis. Ferritin concentration in plasma from capillary blood was significantly higher than in venous plasma (p less than 0.01). This difference was more marked in children. The correlation between ferritin from the two blood sources was highly significant (r2 = 0.945 and 0.994 for samples from adults and children, respectively), and the slopes of the respective regression lines in both children and adults were significantly different from 1 (p less than 0.0001). We conclude that, despite the close association between the two procedures, the determination of ferritin concentration in capillary blood plasma overestimates the concentration of ferritin in venous blood plasma.
Chronic hyperamylasemia and chronic pelvic inflammatory disease.
Authors: Jacobs E , Jennette J C , Reavis R A 
Published: January 2020

Abstract
A 54-year-old woman with chronic pelvic inflammatory disease and pyelonephritis developed persistent hyperamylasemia with transient increases in the amylase-creatinine clearance ratio. Even though chronic pancreatitis was suspected clinically, at postmortem examination the pancreas was found to be normal. We suggest that the hyperamylasemia resulted from entry into the circulation of amylase produced within sequestered endosalpingeal epithelial cysts, possibly amplified by impaired renal clearance. Thus, the potential of the serum amylase assay as a sign of serous ovarian tumors is further indicated.