bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lactobacillus casei microbiological assay of folic acid derivatives in 96-well microtiter plates.
Authors: Horne D W , Patterson D 
Published: January 2020

Abstract
Microbiological assay is still widely used for estimating folic acid derivatives in serum and other biological samples. We describe here a modification of this procedure involving use of 96-well microtiter plates. This procedure, used with modern, computer-interfaced microtiter-plate readers and data-reduction software, greatly shortens the time and minimizes reagent costs for this assay. Under the conditions of our assay procedures, all folic acid derivatives tested gave equal growth response for Lactobacillus casei. Results for assays of rat liver extracts showed excellent agreement between the standard bioassay and the 96-well procedure.
Clinical Diagnosis of Mood Disorders
Authors: Rush A John 
Published: January 2020

Abstract
Vol 34:
p 813: In the fifth full paragraph in column 2, the second sentence should read "In 1934, von Meduna, a Hungarian psychiatrist..." (instead of 1983), and in the third sentence "1983" should read "1938." In the acknowledgements section to this paper, "MH-4115" should read "MH-41115."
p 1018: Add Richard A. Patrick to this list of authors' names.
p 1113: second column, 14th line from bottom, "32.1%" should read "10.9%" and, in the next line, "consistent" should read "inconsistent." Two lines further down, "60.7%" should read "18.5%" (see Letter by M. R. Hammer, in press).
p 1493: It is stated (column 2, third paragraph) that a DB-1701 column does not contain a nitrogen atom in its stationary phase. This is incorrect. The Phase is a 14% cyanopropylphenylsiloxane polymer.
p 1541: In the first full sentence in the right-hand column, "similarly higher" should read "similar."
p 1629: In the right-hand column, the second-to-last paragraph, the ninth line from the bottom should read "...0.5 mL of a reagent solution containing, per liter, 10 g of dextran sulfate (500 000 Da) and 0.5 mol of MgCL2"
p 1945: In line 6, column three, "0.65" should "0.965."
p 2148: Add I. Morales to this list of authors' names.
Quantification of lactate dehydrogenase-1 in serum with use of an M-subunit-specific monoclonal antibody.
Authors: Vaidya H C , Porter S E , Landt Y , Silva D P , Dietzler D N , Ladenson J H 
Published: January 2020

Abstract
We have developed a rapid, one-step assay for measuring lactate dehydrogenase-1 (LD-1) activity in serum after extraction of LD-2, LD-3, LD-4, and LD-5 isoenzymes by an immobilized M-subunit-specific monoclonal antibody (D.8.1). In the assay, 100 microL of serum is mixed with 50 microL of a suspension of 0.8-micron-diameter latex particles coated with 30 micrograms of the monoclonal antibody D.8.1, then incubated at room temperature for 5 min. The latex particles, to which LD-2 through LD-5 are bound, are pelleted by centrifugation for 2 min at 12,000 X g, and the LD-1 activity is measured kinetically in the supernatant fluid. We optimized the assay for antibody immobilization, antibody concentration, and time and temperature of incubation. Serum bilirubin concentrations up to 0.33 g/L (0.56 mmol/L) did not interfere in the assay. Hemolysis interfered solely through LD-1 released from erythrocytes. The within-assay CV for low-concentration quality-control material (LD-1 33 U/L) was 3.5% (n = 9) and for high-concentration material (LD-1 185 U/L) was 1.9% (n = 8); the between-assay CVs for the two materials were 6.1% (n = 9) and 2.5% (n = 10), respectively. The LD-1 activity measured in 98 samples by our assay compared well with a two-step polyclonal antibody-based assay (Isomune-LD, Roche Diagnostic Systems; r = 0.998) and with an electrophoretic method (Paragon, Beckman Instruments; r = 0.956).
Reference values for fructosamine concentrations in children's sera: influence of protein concentration, age, and sex.
Authors: De Schepper J , Derde M P , Goubert P , Gorus F 
Published: January 2020

Abstract
Fructosamine and protein (total and fractionated) were measured in the serum of 170 normal children, ages two weeks to 15 years. The mean fructosamine concentration was 2.12 mmol/L, 5% lower than the mean value observed for adults. We observed no sex-related difference in fructosamine values, but saw a pronounced age dependency of reference values. For children younger than three years, the mean concentration of fructosamine was 15% lower than in adults, but glycated protein concentrations increased with age, reaching essentially adult values by age six years. Expressing fructosamine concentrations per gram of serum total protein or of albumin weakened the influence of age, but did not eliminate it completely. We report reference intervals for fructosamine concentrations in children's sera.
Lactate dehydrogenase isoenzyme-1 in serum for detection of peri-operative myocardial infarction after cardiac surgery.
Authors: Rotenberg Z , Squires J E , Johnston M T , Hoyt J , Gibson R S , Bruns D E 
Published: January 2020

Abstract
We prospectively studied changes in serum lactate dehydrogenase isoenzyme-1 (LD-1, EC 1.1.1.27) in 99 consecutive patients after either coronary artery bypass grafting (CABG, n = 61), isolated cardiac-valve replacement (n = 24), or the two procedures combined (n = 14); 86 of these had no clinical evidence of peri-operative myocardial infarction (MI). Blood was sampled immediately after surgery and at 6-h intervals for up to 42 h thereafter. LD-1 was isolated by using the LD M-subunit antiserum. Samples from the non-MI patients were used to establish the reference intervals for LD-1. By 24 h after surgery, mean serum LD-1 values were higher (P less than 0.001) in non-MI patients who underwent isolated valve replacement (222 +/- 74 U/L) or combined CABG and valve replacement (266 +/- 58 U/L) than in 50 non-MI patients who underwent CABG alone (134 +/- 42 U/L). Separate reference intervals were determined for CABG and other patients at each sampling time. By 24 h after operation, LD-1 exceeded these reference intervals in the 10 CABG and two combined-procedure patients in whom other evidence of MI was present. Measurement of LD-1 24 to 42 h after cardiac surgery appears to be a useful test for the diagnosis of perioperative MI.
Error estimation in the quantification of alkaline phosphatase isoenzymes by selective inhibition methods.
Authors: Tillyer C R 
Published: January 2020

Abstract
A method for calculating, by selective inhibition, the activities in serum of isoenzymes of alkaline phosphatase (EC 3.1.3.1) originating from bone, liver, intestine, and placenta produced results for a sample of patients for which the imprecision was five- to 25-fold higher than that of the alkaline phosphatase method used--too imprecise for routine clinical use. Error analysis by direct calculation and by Monte Carlo estimation revealed that the algorithm used in the method completely accounted for the increase in imprecision of the isoenzyme estimations. I recommend that all methods involving such algorithms or the principle of multicomponent analysis should undergo a thorough error analysis by use of the techniques described here, to obtain an estimate of the increase in imprecision that is ascribable to the particular numerical technique used.
Activity of dipeptidyl peptidase IV and post-proline cleaving enzyme in sera from osteoporotic patients.
Authors: Gotoh H , Hagihara M , Nagatsu T , Iwata H , Miura T 
Published: January 2020

Abstract
The activity of dipeptidyl peptidase IV (EC 3.4.14.5) in human sera from normal controls and osteoporotic patients was assayed with Gly-Pro-4-methylcoumaryl-7-amide (Gly-Pro-MCA) as substrate, at pH 8.7. The mean normal value for the activity in serum of 120 healthy subjects (ages 20-86 y) was 54.0 (SE 0.9, range 34.3-81.6) U/L at 37 degrees C and differed slightly but significantly between the younger group (less than 50 y old) and those older than 50 y. Values for the younger men were slightly but significantly higher than for the older men. Overall, however, the enzyme activities in serum were above normal in patients with osteoporosis. In contrast, the activity of post-proline cleaving enzyme (PPCE) was not increased in serum from patients with osteoporosis, as determined with succinyl-Gly-Pro-4-methylcoumaryl-7-amide (Suc-Gly-Pro-MCA) as substrate. These results suggest that high activities of dipeptidyl peptidase IV in serum of patients with osteoporosis are probably related to its severity.
Improved rapid assay of uric acid in serum by liquid chromatography.
Authors: Tanaka M , Hama M 
Published: January 2020

Abstract
This improved method for rapid determination of uric acid in serum is based on high-performance liquid-gel-permeation chromatography, with hydrophilic and highly porous vinyl alcohol copolymer as packing material. It has the following advantages: no need for sample deproteinization or use of a precolumn, more than 500 serum samples can be analyzed without having to regenerate or recondition the analytical apparatus, and the analysis for uric acid is a one-step procedure. Correlation coefficients between this method and other methods are very good (r = 0.998, 0.999).
Secretion of creatine kinase MB isoenzyme by an immature teratoma with predominant rhabdomyosarcomatous elements.
Authors: Emancipator K , Kudelka A P , Bradford G , Leonard K A , Zarrabi M H 
Published: January 2020

Abstract
A 37-year-old man with metastatic immature (malignant) teratoma with prominent rhabdomyosarcomatous elements had markedly increased activity of creatine kinase (EC 2.7.3.2) MB in serum. There was no electrocardiographic evidence of infarction or ischemia, and autopsy revealed no myocardial infarction, significant coronary atherosclerosis, myocarditis, or invasion of the heart by tumor. A high proportion of the creatine kinase activity in a homogenate of the tumor was attributable to the MB isoenzyme. Persistent increases of creatine kinase-MB and an unusually high MB isoenzyme activity, out of proportion to total creatine kinase activity, may indicate a nonmyocardial origin of this isoenzyme.
Quantitative analysis for isoforms of creatine kinase MM in plasma by chromatofocusing, with on-line monitoring of enzyme activity.
Authors: Nohara R , Sobel B E , Jaffe A S , Abendschein D R 
Published: January 2020

Abstract
Changes in the proportions of individual isoforms of the MM isoenzyme of creatine kinase (CK; EC 2.7.3.2) in plasma promptly reflect both myocardial infarction and coronary recanalization. However, quantitative methods developed thus far are too slow or cumbersome for routine use in making clinical decisions. We report a convenient, quantitative chromatofocusing assay with on-line fluorometric detection of isoform activity in the column eluent that provides results within 40 min from the time of sample application. Sample eluted from a microbore chromatofocusing column (1.8-mL bed volume) is split between a reaction stream, into which CK reagents are added, and a reference stream. After incubation at 37 degrees C, NADPH formed by reaction of isoforms with CK reagent is detected at 340 nm. The system can detect activity of individual isoforms in plasma samples having total CK activity greater than or equal to 21 U/L (30 degrees C). Results correlated closely with those obtained by previously validated, but slow, chromatofocusing (r = 0.98, n = 30) and protein immunoblotting (r = 0.90, n = 20) procedures.
The gamma-glutamyltransferase isoenzyme pattern in serum as a signal discriminating between hepatobiliary diseases, including neoplasias.
Authors: Sacchetti L , Castaldo G , Salvatore F 
Published: January 2020

Abstract
We have used the gamma-glutamyltransferase (GGT) isoenzyme pattern in serum as a means for discriminating between hepatobiliary diseases, including neoplasias. The reference pattern, determined in 142 normal subjects with a simplified conventional cellulose acetate electrophoretic procedure, contained two GGT bands, alpha 1-GGT and alpha 2-GGT, in proportions of 60-80% and 20-40%, respectively. Sera from 95 hepatobiliary patients showed typical isoenzyme features: (a) a beta-migrating GGT form that was less than 10% of the total GGT in chronic hepatitis and cirrhosis, and less than or equal to 30% of the total GGT in cirrhosis with intrahepatic cholestasis and in cases of extra- and intrahepatic obstructive jaundice, including liver neoplasias; (b) a gamma-migrating GGT band and (or) a "dep-GGT" (nonmigrating) band in cases of extrahepatic jaundice; and (c) an albumin-migrating GGT band that had a diagnostic sensitivity of 75% for hepatic tumors. The diagnostic specificity of this last band is 92% toward other hepatic disorders and 91% toward nonhepatic neoplasias; we consider it a potential specific marker for primary or metastatic liver neoplasias.
Effect of iodination site on binding of radiolabeled ligand by insulin antibodies and insulin autoantibodies.
Authors: Diaz J L , Wilkin T J 
Published: January 2020

Abstract
Four human insulins and four porcine insulins, each monoiodinated to the same specific activity at one of the four tyrosine residues (A14, A19, B16, B26) and purified by reversed-phase liquid chromatography, were tested in a radiobinding assay against a panel of insulin-antibody (IA)-positive sera from 10 insulin-treated diabetics and insulin-autoantibody-positive (IAA) sera from 10 nondiabetics. Of the 10 IAA-positive sera, five were fully cross reactive with both insulin species, and five were specific for human insulin. The rank order of binding of sera with the four ligands from each species was random for IA (mean rank values of 1.9 for A14, 2.0 for A19, 2.5 for B16, and 3.6 for B26 from a possible ranking range of 1 to 4), but more consistent for non-human-insulin-specific IAA (mean rank values 1.3 for A14, 3.8 for A19, 1.7 for B16, and 3.2 for B26 for labeled human insulins; 1.2 for A14, 4.0 for A19, 1.8 for B16, and 3.0 for B26 for labeled porcine insulins). The rank order of binding was virtually uniform for human-insulin-specific IAA (mean values 1.2 for A14, 3.0 for A19, 1.8 for B16, and 4.0 for B26). The influence of iodination site on the binding of labeled insulin appears to be dependent on the proximity of the labeled tyrosine to the antibody binding site and the clonal diversity, or restriction, of insulin-binding antibodies in the test serum. When IA and IAA are measured, the implications of this study regarding the choice of assay ligand may be important.
Concurrent liquid-chromatographic assay of retinol, alpha-tocopherol, beta-carotene, alpha-carotene, lycopene, and beta-cryptoxanthin in plasma, with tocopherol acetate as internal standard.
Authors: Thurnham D I , Smith E , Flora P S 
Published: January 2020

Abstract
A method is described for simultaneously determining retinol, alpha-tocopherol, beta-carotene, alpha-carotene, lycopene, and beta-cryptoxanthin in 0.25 mL of plasma. Plasma mixed with sodium dodecyl sulfate is deproteinized with ethanol containing tocopherol acetate, then extracted with heptane. The evaporated organic layer is reconstituted with mobile phase (methanol/acetonitrile/chloroform, 47/47/6 by vol) and injected onto a 100 x 4.6 mm 3-micron column of Spherisorb ODS-2 (LKB) at 1.5 mL/min. The alpha- and beta-carotenes are well resolved during the 6.5-min run. Retinol is monitored at 325 nm, the tocopherols at 292 nm, and the carotenoids at 450 nm. Extraction of concentrations as great as 135 mumol/L is complete. Intrabatch CVs were 1.7%, 2.3%, 4.1%, 10.4%, 6.4%, and 3.6% for retinol, alpha-tocopherol, beta-carotene, alpha-carotene, lycopene, and beta-cryptoxanthin, respectively. Interbatch CVs for measurements on 30 occasions over 11 weeks were about 10% for all components except alpha-tocopherol (5.3%). Results agree well with those for retinol, alpha-tocopherol, and beta-carotene in quality-control samples.
Improved assay for bismuth in biological samples by atomic absorption spectrophotometry with hydride generation.
Authors: Froomes P R , Wan A T , Harrison P M , McLean A J 
Published: January 2020

Abstract
This simple, rapid, sensitive, reliable, and economical assay for bismuth in plasma, erythrocytes, and urine is based on atomic absorption spectrophotometry with hydride generation. Acid digestion eliminates the problem of foaming, which hitherto has complicated such assay of bismuth in plasma and erythrocytes. The detection limit of the assay has been improved to 0.1 micrograms/L, as compared with a previously documented limit of 2.5 micrograms/L. Average recovery exceeded 95% in all biological fluids. Economy of use derives from elimination of need for electrodeless discharge lamps and atomic absorption grade borohydride. Determination of basal concentrations of bismuth in clinical samples of body fluids gave reference intervals of 0.1-3.5 micrograms/L for plasma, 0.3-4.6 micrograms/L for urine.
A dry-reagent strip for quantifying carbamazepine evaluated.
Authors: Croci D , Nespolo A , Tarenghi G 
Published: January 2020

Abstract
We examined a new colorimetric homogeneous immunoassay for carbamazepine based on the apoenzyme reactivation immunoassay system (ARIS) principle. The test, in dry-reagent strip format, is to be used with the Ames Seralyzer reflectance photometer. Within-run CVs (n = 20) were 3.0%, 2.7%, and 2.8% at 3.0, 6.1, and 12.1 mg/L; between-run CVs (n = 15, in 15 days) were 4.1%, 2.7%, and 1.9% at 6.0, 9.1, and 12.1 mg/L. Mean analytical recovery was 99.9 (SD 2.3)%. Results by this test (y) for clinical plasma specimens (n = 96) compared very well with those obtained by fluorescence polarization immunoassay (y = 1.01 x - 0.02, r = 0.995) and by liquid chromatography (y = 0.99 x + 0.14, r = 0.990). Bilirubin (45 mg/L), uric acid (145 mg/L), and various anticoagulants at about fourfold the usual concentrations did not interfere. High concentrations of cholesterol (4.9 g/L), triglycerides (3.8 g/L), and hemoglobin (4 g/L) caused slight positive interference. Carbamazepine-10,11-epoxide cross reacted only at greater than or equal to 5 mg/L. The two-point calibration line was validly stored for at least three weeks. Free carbamazepine also can be measured. The test is convenient and rapid (test time 80 s), and thus is particularly useful in all clinical settings where prompt testing is needed.
Intact parathyrin in postmenopausal women.
Authors: Sokoll L J , Morrow F D , Quirbach D M , Dawson-Hughes B 
Published: January 2020

Abstract
To establish a reference range, we measured intact parathyrin (parathyroid hormone, PTH) in 245 healthy postmenopausal women, ages 42-75 years, with use of the Allegro Intact PTH Kit from Nichols Institute Diagnostics. We also assayed serum from a subset of 120 of the women with kits specific for mid-molecule PTH. The mean intact PTH concentration for the 245 women was 32 ng/L (95% confidence interval 14-60 ng/L). Intact PTH values in these subjects were not normally distributed, although calcium concentrations in the same samples were. There was positive, but not significant (r = 0.12, P = 0.06), correlation between intact PTH and age, and a significant negative correlation between serum calcium and intact PTH that was not observed between calcium and mid-molecule PTH. The improved sensitivity of the intact PTH assay makes it useful in studies of calcium homeostasis in the normal population.
Immunoassay of low concentrations of albumin in urine by latex particle counting.
Authors: Cambiaso C L , Collet-Cassart D , Lievens M 
Published: January 2020

Abstract
We describe here a nonisotopic immunoassay, based on particle-counting technology, for the determination of urinary albumin. The assay takes only 35 min and has been fully automated on the IMPACT (Acade Diagnostic Systems, Brussels, Belgium) machine. The system measures albumin within a linear range between 6.25 and 50 mg/L and has a detection limit of 0.4 mg/L. Analytical recoveries at three concentrations ranged between 96% and 102%. Within-run precision ranged from 1.6% to 9.5%. The method was compared with a commercial nephelometric immunoassay system and a correlation coefficient of 0.996 was found for 216 urine samples. No antigen excess affects the shape of the curve in our system, whereas in nephelometry a 3 g/L solution of albumin starts to decrease the dose-response curve.
Stability and electrophoretic characteristics of creatine kinase BB extracted from human brain and intestine.
Authors: Chastain S L , Ketchum C H , Grizzle W E 
Published: January 2020

Abstract
Creatine kinase (CK; EC 2.7.3.2) isoenzyme BB extracted from brains of rats reportedly undergoes modification at 37 degrees C, leaving an electrophoretic variant that accounts for most of the residual CK activity. This variant, called CK-BB', migrates on electrophoresis similarly to creatine kinase isoenzyme MB. Using electrophoresis and immunoinhibition with antiserum to creatine kinase isoenzyme MM, we found CK-BB to be the only identifiable cytoplasmic isoenzyme in surgical samples from human brain and intestine. In contrast, we found that some samples of brain obtained at autopsy contain CK-BB'. We also found that CK-BB extracted from human brain was converted to CK-BB' upon incubation in serum or plasma at 37 degrees C. We found a similar development of CK-BB' in incubation mixtures of serum or plasma containing CK-BB obtained from surgical samples of human intestine. The development of CK-BB' during infarction of the gastrointestinal system may thus be a source of false-positive CK-MB in the laboratory verification of myocardial infarction when electrophoresis is used as the only method to identify CK isoenzymes.
Liquid-chromatographic assay of ibuprofen enantiomers in plasma.
Authors: Mehvar R , Jamali F , Pasutto F M 
Published: January 2020

Abstract
This stereospecific "high-performance" liquid-chromatographic (HPLC) assay is suitable for pharmacokinetic studies of ibuprofen (IB). Very efficient extraction of the drug and internal standard, (+/-)-2-(4-benzoylphenyl)butyric acid, from plasma with isooctane/isopropanol (95/5, by vol) is followed by sequential reaction of the enantiomers with ethyl chloroformate and (S)-(-)-1-(1-naphthyl)ethylamine. The reactions take place at ambient temperature in less than 4 min. The naphthylethylamide derivatives of IB enantiomers and internal standard are then extracted into chloroform. After the organic layer is evaporated, the reconstituted residue is chromatographed at ambient temperature on a C18 reversed-phase column with a mobile phase of acetonitrile/water/acetic acid/triethylamine (55/45/0.1/0.02 by vol) at a flow rate of 1 mL/min. The IB diastereoisomers, detected at 232 nm, are free of interfering peaks and have a resolution factor of 2.2. Within the examined enantiomer concentration range of 0.1 to 20 mg/L in plasma, the peak-area ratios varied linearly with the corresponding IB concentrations. We used the assay to study the pharmacokinetics of IB enantiomers in plasma of a subject who took a single 600-mg dose of racemic drug.
Quinidine-induced decrease of intracellular esterase activity in a hepatoma cell line.
Authors: Markovic O T , Young D S , Markovic N S 
Published: January 2020

Abstract
Using image-analyzing equipment, we measured the effect of quinidine on the activity of naphthol AS-D chloroacetate esterase, alpha-naphthyl butyrate esterase, alpha-naphthyl acetate esterase, and acid phosphatase in individual cells of a human Hep G2 hepatoma cell line. The impact of the drug on the morphology of the cells was also observed. Depending on the concentration of quinidine applied, various changes occurred, the most extreme being cell death. However, at some drug concentrations that did not appear to affect visible cell structures, the activity of the esterases was decreased. This lessened enzyme activity did not seem to be related to the enzymes leaking from the cells, because the activity of acid phosphatase was unaffected. Inhibition of the esterase activity was related to the interval of exposure to quinidine in the perfusing medium and to the concentration of the drug. We consider the system described here to be a potential replacement for experiments with animals in the study of hepatotoxicity.