bluuebunny/crossref_metadata_2025_split huggingface dataset:
Information induction for predicting acute myocardial infarction.
Authors: Rudolph R A , Bernstein L H , Babb J 
Published: January 2020

Abstract
We show how to make an unsupervised discrimination of disease and nondisease states by measuring information and using newer notions of inductive reason. We also present a new theory of group-based reference values that is based on measuring information uncertainty. We use data on the isoenzymes creatine kinase-MB (CK-MB) and lactate dehydrogenase-1 (LD1) and on the percentage of LD1 from 101 patients with acute myocardial infarction (AMI) and from 41 patients with suspected, but unfounded, infarction (non-AMI). Calculating the Shannon entropy, a concept from information theory, of the data base allows determination of a difference in entropy values ("effective information"), which determines decision cutoff values that produce binary-base patterns yielding the fewest classification errors. Redundancy in testing is important because it provides the information to approach a goal of errorless discrimination by coding the test results and meeting the conditions of the "Noisy Channel Theorem" of information theory. This redundancy improves the predictive value of diagnosis by isolating the area of equivocation to evident patterns. Results for CK-MB and LD1 are 99% correct in assigning cases to AMI and non-AMI categories; adding %LD1 increases the proportion of errorless binary patterns from 25% to 90%.
High-performance liquid affinity chromatography: rapid immunoanalysis of transferrin in serum.
Authors: Ohlson S , Gudmundsson B M , Wikström P , Larsson P O 
Published: January 2020

Abstract
We describe a new method for quantitatively measuring substances of clinical interest by high-performance liquid affinity chromatography (HPLAC). As a model system we selected analysis for transferrin in human serum with immobilized antibodies in a high-performance liquid chromatographic system. SelectiSpher-10 Activated Tresyl columns (5 or 10 x 0.5 cm) were used for in situ coupling of polyclonal antibodies to transferrin. The amount of transferrin eluted was determined by integrating the eluted peak at 280 nm. The whole analytical procedure--including injection of sample, washing, elution, and analysis of data--takes only 7 min. We characterized the HPLAC system for analysis of transferrin in several ways: intra-assay CV approximately 3%; inter-assay CV 2-9%; linear response up to 1 mg/mL column volume; detection limit approximately 3 micrograms; analytical recovery 98% +/- 2%; purity of eluted sample greater than 95% (SDS-PAGE). The HPLAC method was compared with "rocket" immunoelectrophoresis, a commonly used method of analysis for transferrin, and there was excellent correlation between the two methods (r = 0.96, n = 60). Benefits of this HPLAC technique include high precision, rapid analysis, and simplified sample handling.
A new approach to the quality control of steroid receptor assays.
Authors: Borsotti M , Quercioli M , D'Ettole R , Piffanelli A , Messeri G 
Published: January 2020

Abstract
Lyophilized cytosols prepared from calf uterus and human breast tumor tissue are commonly used to assess the reliability of routine steroid receptor assays. However, preanalytical error (sample preparation, storage, homogenization) cannot be detected in this way. Participating laboratories were asked to mail us all their receptor results obtained over a four-month interval, and to include some information about the patients involved (age, menopausal status, nodal status). After verifying the homogeneity of the populations investigated, we computed consensus means for the percentages of positive samples and for their absolute value. Despite the homogeneity of the characteristics of the populations studied, results from some laboratories systematically differed from the consensus mean. This approach to the quality control of steroid receptors allows evaluation of the whole procedure, from sample preparation to analysis, and thus may be helpful as an addition to the usual practice of distribution of cytosols and tissue powders for assay.
Use of the Reflotron system for cholesterol assay in capillary blood, venous blood, and serum--evaluation of accuracy and lot-to-lot reagent comparability.
Authors: Boerma G J , Gelderland J , van Gorp I , Leijnse B 
Published: January 2020

Abstract
Since its recalibration in 1987, the Reflotron "dry-chemistry" cholesterol method can produce accurate results. Here we report how cholesterol concentrations in venous blood, plasma, and serum determined with Reflotron compare with values determined for fingerstick samples. When no EDTA is used in the latter, accurate results may meet the WHO/CDC criterion of a maximum bias less than or equal to 5%. Reflotron users should avoid use of EDTA. Lot-to-lot variation among the solid-phase reagent carriers was evaluated in four lots of these strips. The largest difference, 0.4 mmol/L, was seen in a commercial quality-control serum with a cholesterol concentration of approximately 7 mmol/L. The maximum differences in results for several serum pools were not always found between the same reagent lots, although the highest results in five of six materials occurred with a single lot of strips. As in all clinical chemical testing, regular quality control is necessary.
Determination of 4,4'-methylenebis(2-chloroaniline) in urine by liquid chromatography with ion-paired solid-phase extraction and electrochemical detection.
Authors: Okayama A , Ichikawa Y , Yoshida M , Hara I , Morimoto K 
Published: January 2020

Abstract
This highly specific and sensitive method for measuring urinary 4,4'-methylenebis(2-chloroaniline) (MBOCA) involves liquid chromatography with electrochemical detection. Before chromatography, urine samples are prepared by ion-paired solid-phase extraction on a disposable octadecylsilica column with acidic methanol solution containing 1-heptanesulfonic acid. This enhances the specificity of the method. Mean overall recovery ranged from 97.1% to 99.5% at added MBOCA concentrations of 20 and 100 micrograms/L in urine. Sensitivity for urine was 1 microgram/L. The intra-assay CV was 2.2% at a MBOCA concentration of 100 micrograms/L. We believe that this method is acceptable for routine measurement of MBOCA in urine from individuals exposed to this industrial chemical.
Automating the quantification of heme in feces.
Authors: van den Berg J W , Koole-Lesuis R , Edixhoven-Bosdijk A , Brouwers N 
Published: January 2020

Abstract
We present a modification of the HemoQuant assay, a good but lengthy and tedious method for determining heme in feces by means of its transformation to porphyrins. The laborious extraction procedure was replaced by a simple centrifugation procedure. The nonhomogeneous hot oxalic acid suspension was replaced by acetic acid. We observed no significant difference in results between samples analyzed by the older method vs the present modification (r = 0.996, n = 52). Mean (and SD) analytical recoveries of added hemoglobin and protoporphyrin were 99% (7%) and 93% (6%), respectively. The analytical procedure can now be automated by using discrete samplers and a flow-through fluorometer. Initial sampling and dilution of feces are still done manually, however. The excellent specificity, sensitivity, and overall analytical performance of the original method are retained, while circumventing the practical inconveniences of this reliable screening test for occult blood in feces.
Physiological changes in human erythrocyte cholinesterase as measured with the "pH-stat".
Authors: Garcia-López J A , Monteoliva M 
Published: January 2020

Abstract
Cholinesterase activity in human erythrocytes was determined in 1903 blood samples by the "pH-stat" method. Differences in activity were examined as a function of sex, age, and pregnancy. Reliability intervals for the population average and approval or normality intervals for individual values were established. Sex- and age-related differences were very significant.
Kinetic rate assay of urinary N-acetyl-beta-D-glucosaminidase with 2-chloro-4-nitrophenyl-N-acetyl-beta-D-glucosaminide as substrate.
Authors: Makise J , Saito E , Obuchi M , Kanayama M , Ichikawa K , Harakawa K , Yoshida K 
Published: January 2020

Abstract
In this new procedure for determining the activity of N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30; NAG) in urine, a new synthetic substrate, 2-chloro-4-nitrophenyl-N-acetyl-beta-D-glucosaminide is used. No sample blank is required because the activity is determined kinetically. Very high precision is possible, with CVs of less than 3.8% both within-run and between-run. Glucose, ascorbic acid, bilirubin, bromosulfonphthalein, and phenosulfonphthalein do not interfere. The reference interval (mean +/- 2 SD) for healthy subjects was 1.9-11.1 U per gram of creatinine. NAG activity can be determined over a wide range (2-500 U/L) with high sensitivity. The method is suitable for use with various automated analyzers, and it should be useful for screening for renal diseases.
Measurement of parathyrin in blood from thyroid veins: two radioimmunoassays compared in patients with primary hyperparathyroidism.
Authors: Muñoz-Torres M , Diaz J , Escobar-Jimenez F , Gonzalez-Calvin G , Vara C , Ruiz Requena M E , Vara R , Morales I 
Published: January 2020

Abstract
We measured parathyrin (PTH) in peripheral venous blood samples and in thyroid veins (both homolateral and contralateral to the lesion) in 13 patients with surgically confirmed parathyroid adenomas. Two different RIAs were used, one specific to the mid-region of the molecule (44-68, M-PTH), the other specific to the carboxy-terminal region (65-84, C-PTH). With the M-PTH assay we established a statistically significant multiple correlation (P less than 0.05) between the PTH concentrations in blood from the peripheral and thyroid veins; no significant correlation was found when we used the C-PTH assay. Our results confirm the superiority of the M-PTH RIA over the C-PTH RIA for study of hormonal secretion in primary hyperparathyroidism.
Influence of timing in the fructosamine assay.
Authors: Frandsen E K , Bacchus R A 
Published: January 2020

Abstract
The fructosamine assay, based on the measurement of the reducing activity in serum at alkaline pH, provides an index of protein glycation. The reducing activity is expressed in equivalents of 1-deoxy-1-morpholinofructose (DMF) by direct comparison with the activity either of this synthetic compound or with a secondary protein standard calibrated against DMF. This study reports the influence of assay timing on the apparent serum fructosamine concentration. The kinetics of alkaline reducing activity in serum differed from that in both DMF and a secondary protein standard. When compared with DMF, activity in serum increased but decreased relative to the protein standard as the pre-incubation interval of the assay was shortened. The use of secondary protein standards results in underestimation of serum fructosamine concentrations when the pre-incubation phase of the assay is shorter than that used for the calibration of the secondary standard. Ascorbate exerted an inhibitory effect in fructosamine assays with pre-incubation times exceeding 5 min. The inhibition increased with both the concentration of ascorbate and the duration of the pre-incubation.
A model for the effect of bias for cholesterol on the population at risk.
Authors: Kroll M H , Ruddel M , Elin R J 
Published: January 2020

Abstract
The location of the Reference Value for an analyte within the population distribution affects the magnitude of error due to methodological bias. Using the gaussian distribution, we evaluated the effects of systematic and proportional biases of the method (positive and negative), mean value, and standard deviation on the magnitude of error. We chose four Reference Values for cholesterol as a model. For a population with a mean of 2.0 and SD of 0.36 g of cholesterol per liter, a 3% positive proportional bias causes sixfold more error at the 50th percentile than at the 97.5th. In general, the error for a given bias (proportional or systematic) is greater for a Reference Value within the body than at the tails of the distribution. Further, the magnitude of the error varies as a function of the mean and standard deviation of the population.
Qualitative study of fecal alpha 1-proteinase inhibitor in normal subjects and patients with Crohn's disease.
Authors: Mizon C , Becuwe C , Balduyck M , Colombel J F , Cortot A , Mizon J , Degand P 
Published: January 2020

Abstract
We applied sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting to analyze fecal alpha 1-proteinase inhibitor (alpha 1 PI) from healthy subjects and patients with Crohn's disease. A component with Mr 38,000 was characterized in normal fecal extracts as well as in six pathological samples. In these cases, the Crohn's disease activity index (CDAI), a clinical index of severity of the disease, was 170 (SEM 47). In contrast, alpha 1 PI of Mr 51,000 was detected in fecal extracts from eight patients with active Crohn's disease (CDAI = 287, SEM 39). We conclude that fecal alpha 1 PI can be considered a marker of intestinal disease activity.
Adulterants causing false negatives in illicit drug testing.
Authors: Mikkelsen S L , Ash K O 
Published: January 2020

Abstract
Illicit-drug users may attempt to falsify results by in vitro adulteration of specimens. We investigated eight additives (NaCl, Visine, handsoap, Drano, bleach, vinegar, golden-seal tea, and lemon juice) claimed by drug users to invalidate enzyme immunoassay (EIA) drug assays. We also analyzed adulterated urine specimens to determine if they could be identified, adding adulterants at several concentrations to 222 EIA-positive specimens confirmed by gas chromatography and mass spectrometry (GC/MS) to contain illicit drugs. To identify adulterated urines, we monitored pH, relative density, and urine color and turbidity at adulterant concentrations that falsified EIA results. Specimens contaminated with NaCl had relative densities greater than 1.035. Liquid Drano, bleach, and vinegar shifted urine pH outside the physiological range. Golden-seal tea caused a dark appearance, and specimens containing liquid soap were unusually cloudy. Lemon juice had no effect on the assays. Visine was the only adulterant not detected. The adulterants interfered somewhat differently with each of the drug assays. EIA assays for illicit drugs can be invalidated by specimen adulteration producing false-negative results. Therefore, if urine drug testing is to be conducted, pH, relative density, and appearance should be assessed and suspect specimens should be rejected. Not all adulterants can be detected, so observed collection is strongly recommended.
"Flipped" patterns of lactate dehydrogenase isoenzymes in serum of elite college basketball players.
Authors: Rotenberg Z , Seip R , Wolfe L A , Bruns D E 
Published: January 2020

Abstract
We kinetically measured total lactate dehydrogenase (LD, EC 1.1.1.27), total creatine kinase (CK, EC 2.7.3.2), and aspartate aminotransferase (AST, EC 2.6.1.1.) in 16 elite college basketball players, before the competition season and not in close temporal relation to near-maximal exercise, and in 17 healthy non-athlete controls. LD isoenzymes were determined by both electrophoretic and immunoprecipitation methods. CK-MB isoenzyme was measured electrophoretically. We found significantly higher mean LD-1 values and LD-1/LD-2 ratios in the players than the controls: 31.6 (SD 3.7)% vs 25.8 (SD 3.2)% (P less than 0.005) and 1.1 (SD 0.13) vs 0.87 (SD 0.16) (P less than 0.001), respectively. A "flipped" LD pattern (LD-1 greater than LD-2) was found in half the players and in six of the eight black athletes, but in only two of the control group and in none of the black controls. Mean CK activity in serum exceeded normal values in the serum of the athletes and was higher in comparison with the control group [274 (SD 156) vs 103 (SD 82) U/L]. Mean CK was significantly higher in the eight athletes with the flipped LD pattern than in those with LD-1 less than LD-2 [322 (SD 163) vs 180 (SD 98) U/L; P = 0.05], and also in comparison with CK in the two controls with flipped LD pattern. We saw no significant difference in mean CK between the nine players with normal immunochemical LD-1/LD ratios and the seven players with above-normal ratios. CK-MB was not detected in either athletes or controls. None of the players had any clinical or electrocardiographic evidence for myocardial ischemia or infarction. Evidently the flipped LD pattern usually found in patients with acute myocardial infarction and reported in some athletes after extreme exercise such as ultra-marathon running may also be found in athletes who are in their "basal fitness shape" but who are not involved in competitive physical activity.
Sensitive, practical bioassay of thyrotropin, with use of FRTL-5 thyroid cells and magnetizable solid-phase-bound antibodies.
Authors: Tokuda Y , Kasagi K , Iida Y , Hatabu H , Hidaka A , Misaki T , Konishi J 
Published: January 2020

Abstract
We have developed a new method for assessing the bioactivity of thyrotropin (TSH) in human serum by measuring cAMP production in FRTL-5 thyroid cells as an index of stimulation. To eliminate serum inhibitors of the cAMP response to TSH, we purified samples by mixing them with anti-TSH antibodies coupled to magnetizable particles. This method of immunoaffinity purification was simple and suitable for the measurement of a large number of samples. The detection limit of the bioassay was 3.13 milli-int. units of human TSH per liter. Intra-assay and interassay coefficients of variation ranged from 5.4 to 8.6% and from 12.6 to 21.5%, respectively. The concentrations of bioassayable TSH closely correlated with those of immunoassayable TSH, both in the immunoaffinity-purified samples (r = 0.946, P less than 0.001) and in the serum samples (r = 0.945, P less than 0.001) from 14 euthyroid subjects and 53 hypothyroid patients with Hashimoto's thyroiditis. The bioactivity-to-immunoactivity ratio was almost constant (0.84 +/- 0.30; mean +/- SD) over the range of concentrations of immunoassayable TSH in serum, 6.3 to 177 milli-int. units/L. We also demonstrate that the technique is applicable to measurements of bioactivities of circulating forms of immunoreactive TSH in different pathophysiological conditions.
Clinical and analytical evaluation of two immunoassays for direct measurement of creatine kinase MB with monoclonal anti-CK-MB antibodies.
Authors: Apple F , Preese L , Bennett R , Fredrickson A 
Published: January 2020

Abstract
We examined the clinical and analytical performance of two immunoassays (Becton Dickinson CK-MB; Ciba-Corning Magic Lite CK-MB) in which monoclonal anti-CK-MB antibodies are used for directly measuring creatine kinase (EC 2.7.3.2) isoenzyme MB (CK-MB) in serum, and also one electrophoretic method (Ciba-Corning). Within- and between-assay precision for both immunoassays was good at the upper reference limits (less than 10% CV). Analytical recoveries ranged from 102 to 114%. Both immunoassays were free from interference by CK-BB, mitochondrial-CK, macro-CK, adenylate kinase, and CK-MM. Retrospectively, we evaluated four categories of patients, using both immunoassays and electrophoresis: normal controls, acute myocardial infarction (AMI) patients, severe skeletal muscle trauma patients, and acutely ill patients known not to have AMI. In general, there were excellent correlations among all three methods. CK-MB activity (U/L) measured by the Becton Dickinson immunoassay was approximately 50% of the mass concentration (microgram/L) of the Magic Lite immunoassay and 50% of the activity concentration (U/L) determined by electrophoresis. Both immunoassays were easy to perform and sensitive to the low CK-MB concentrations often found with low total-CK activities.
Serum lipoperoxidation products in an infant with hemolytic-uremic syndrome.
Authors: Brown R E , Alade S L , Knight J A , Evans B J 
Published: January 2020

Abstract
We detected increased concentrations of lipoperoxidation products, as malondialdehyde, in the serum of an infant with classic hemolytic-uremic syndrome. The concentrations declined when peritoneal dialysis was initiated and eventually returned to normal after clinical recovery. Our observation adds to the existing body of evidence that links the pathogenesis of hemolytic-uremic syndrome to peroxidative damage and to the rationale for using antioxidant agents as part of the therapy for this disease process.
Alkaline phosphatase isoenzymes in serum determined by high-performance anion-exchange liquid chromatography with detection by enzyme reaction.
Authors: Parviainen M T , Galloway J H , Towers J H , Kanis J A 
Published: January 2020

Abstract
This rapid, reproducible method for separating and determining individual alkaline phosphatase (EC 3.1.3.1) isoenzymes in serum is based on high-performance liquid chromatography with a weak anion-exchange column (SynChropak AX 300). The isoenzymes so resolved are detected by using an on-line enzyme reaction followed by spectrophotometric monitoring at 405 nm of the 4-nitrophenol formed. Complete diagnostic profiles of the various isoenzymes present in normal and pathological sera are obtained within 20 min. The mean (and SD) normal concentrations of the bone B1 and intestinal isoenzymes in serum of adults were 3.7 (4.3) and 4.5 (3.9) U/L, respectively (n = 14), and of the bone isoenzyme B2 and liver isoenzymes L1 and L2, 5.8 (8.6), 33.0 (10.6), and 12.0 (4.8) U/L, respectively (n = 17). Concentrations of the B2 and L1 isoenzymes in adults over age 40 years differed significantly from those in adults younger than 40 years, that of bone isoenzyme being lower (P less than 0.05) and that of the liver isoenzyme being higher (P less than 0.001) in the younger adults.
Neopterin estimation compared with the ratio of T-cell subpopulations in persons infected with human immunodeficiency virus-1.
Authors: Fuchs D , Banekovich M , Hausen A , Hutterer J , Reibnegger G , Werner E R , Gschnait F D , Dierich M P , Wachter H 
Published: January 2020

Abstract
We measured neopterin, a biochemical indicator for the activation of cell-mediated immune reactions, in urines from 105 individuals at risk of infection with human immunodeficiency virus-1 (HIV-1), 83 of whom were seropositive for antibody to HIV-1. We compared absolute numbers of T-cell subsets (CD4+ helper/inducer T-cells, CD8+ suppressor/cytotoxic T-cells), and the ratio of CD4+ T-cells to CD8+ T-cells with the urinary neopterin concentrations. Concentrations of neopterin in urine were inversely correlated with absolute numbers of CD4+ T-cells and with CD4+/CD8+ ratios in anti-HIV-1 seropositive subjects but not in those seronegative. Various statistical comparisons of the data further demonstrated that neopterin concentrations showed larger differences between anti-HIV-1 seronegative and seropositive subjects than absolute numbers of CD4+ T-cells or CD4+/CD8+ ratios. These results seem to indicate that neopterin concentrations increase earlier in the course of HIV-1 infection, before effects on T-cell subpopulations are detectable, and may further support the suggestion that neopterin measurement could be of use for monitoring infected subjects or predicting the progression of disease.