bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fibronectin is unsuitable as a tumor marker in pleural effusions.
Authors: Delpuech P , Desch G , Fructus F 
Published: January 2020

Abstract
We studied 75 patients with nonmalignant pleural effusions (50 with pneumopathy, 16 with pulmonary tuberculosis, and nine with congestive heart failure) and 33 patients with malignant pleural effusions. We selected 105 mg/L as the most suitable cutoff concentration of fibronectin for distinguishing between the two groups. We found high concentrations of fibronectin in 21 of the 33 patients with malignant pleural fluid but also in 37 of the 75 patients with nonmalignant pleural fluid. Evidently, measuring fibronectin in pleural fluid will not help in differentiating nonmalignant from malignant pleural fluids (diagnostic accuracy: 55%).
Salivary progesterone excellently reflects free and total progesterone in plasma during pregnancy.
Authors: Meulenberg P M , Hofman J A 
Published: January 2020

Abstract
To see if saliva is a valid substitute for plasma in assay of progesterone even when concentrations of hormone and binding proteins are fluctuating, we determined the concentrations of total and free progesterone in plasma and salivary progesterone in specimens from 36 women volunteers during the course of pregnancy and six weeks postpartum, using a highly specific RIA for total progesterone after extraction and chromatographic purification of the steroid. The free fraction in plasma was determined via equilibrium dialysis, followed by the same RIA analysis for progesterone in the dialysate. Despite the dramatic increases in concentrations of total progesterone and binding proteins in plasma during pregnancy, we found highly significant correlations between total and free progesterone in plasma and salivary progesterone in the group as a whole as well as individuals (P less than 0.001 in almost all cases). The proportion of free progesterone in plasma and of salivary progesterone relative to total progesterone in plasma remained constant at approximately 1% and 0.5%, respectively, whereas during the postpartum period there was much more variance. Evidently salivary progesterone is a very good alternative to plasma as a sample for use in follow-up during pregnancy.
Streptokinase binds to lactate dehydrogenase subunit-M, which shares an epitope with plasminogen.
Authors: Podlasek S J , McPherson R A 
Published: January 2020

Abstract
The bacterial thrombolytic agent streptokinase binds to human, porcine, and chicken lactate dehydrogenase (EC 1.1.1.27; LD) isoenzyme subunit M, but not to the H or C subunits. There is amino acid sequence homology between LD and the streptokinase binding site on plasminogen to account for this interaction that results in the formation of high-molecular-mass complexes in serum that contain LD activity. Binding of highly immunogenic streptokinase with LD may lead to induction of anti-LD autoantibodies, known to occur in some patients after therapeutic administration of streptokinase for treatment of acute myocardial infarction. This interaction may also be a general mechanism for inducing autoimmunity against other proteins that share the streptokinase binding epitope.
An immunoassay of human band 5 ("tartrate-resistant") acid phosphatase that involves the use of anti-porcine uteroferrin antibodies.
Authors: Whitaker K B , Cox T M , Moss D W 
Published: January 2020

Abstract
We describe an immunoassay for human band-5 acid phosphatase in which antibodies to porcine uteroferrin, immobilized on Sepharose particles, are used. Band-5 acid phosphatase is the tartrate-resistant isoenzyme normally expressed in tissue macrophages such as osteoclasts and alveolar macrophages. The immunoassay is similar in reproducibility and sensitivity to assays based on inhibition by d-tartrate. However, compared with the latter, the greater specificity of the immunoassay makes it markedly less susceptible to errors arising from the presence of non-band-5 acid phosphatases, e.g., from prostate.
Specific binding of cardiac glycoside drugs and endogenous digitalis-like substances to particulate membrane fractions from human placenta.
Authors: Paci A , Cocci F , Piras F , Ciarimboli G , Clerico A 
Published: January 2020

Abstract
We studied the characteristics of binding of cardiac glycosides to particulate membrane fractions from human placenta, to demonstrate that placental tissue is a suitable source of receptors for digitalis drugs. Moreover, we performed preliminary experiments with 125I-labeled digoxin and placental particulates to develop a radioreceptor assay for measurement of endogenous substances with activity similar to cardiac glycoside drugs (EDLS). Placental membrane fractions were incubated with [3H]ouabain (10 nmol/L) or 125I-labeled digoxin (50 pmol/L). With both ligands, binding followed a pseudo-first-order reaction kinetics and was saturable. Scatchard analysis revealed a single class of sites [for ouabain, KD = 20.2 +/- 5.8 nmol/L (mean +/- SEM), Bmax = 3.1 +/- 0.9 nmol per gram of protein; for digoxin, KD = 29.7 +/- 1.9 nmol/L, Bmax = 24.3 +/- 1.1 nmol per gram of protein]. As expected, digoxin was less potent than ouabain in displacing both tracers from digitalis drugs receptors; progesterone, cortisone, digitoxose, furosemide, bumetanide, and propranolol had no or little effect. Specific 125I-labeled digoxin binding was competitively inhibited by plasma and (or) urine extracts from newborns, adults, pregnant women, and patients with renal insufficiency. Inhibition of binding and volume of plasma and urine assayed were linearly related. These findings support the hypothesis that cardiac glycosides and EDLS can interact with the human placenta and suggest placental tissue to be a suitable source of receptors for cardiac glycosides.
Empirically determined lead-poisoning screening cutoff for the Protofluor-Z hematofluorometer.
Authors: Stanton N V , Gunter E W , Parsons P J , Field P H 
Published: January 2020

Abstract
A recently introduced hematofluorometer, the "Protofluor-Z" (Helena Laboratories, Beaumont, TX), has several novel features, most notably reporting units expressed as the molar ratio of zinc protoporphyrin (ZPP) to heme, i.e., micromoles of ZPP per mole of heme. We analyzed human blood specimens on the Protofluor-Z and by an ethyl acetate/acetic acid extraction procedure. Data from three laboratories were pooled and used to provide a comparison of the two methods. Results indicate that, with the Protofluor-Z, a value of 70 mumol of ZPP per mole of heme is approximately equivalent to the recommended screening cutoff of 35 micrograms of erythrocyte protoporphyrin per 100 mL of whole blood used in programs for pediatric lead-poisoning prevention. This empirically determined value is slightly lower than either that recommended by the manufacturer or a theoretical cutoff value that was determined mathematically.
Analysis for alpha-amylase isoenzymes by automated isoelectric focusing.
Authors: Lessard F , Dion R 
Published: January 2020

Abstract
We describe the fractionation of alpha-amylase (EC 3.2.1.1) isoenzymes by use of the Pharmacia "Phastsystem" electrophoresis apparatus. The separation is done by isoelectric focusing on "Phastgel IEF 5-8." A complete run, including staining, takes 4 h and can easily resolve eight isoenzymes. Samples can be analyzed in a routine laboratory with use of conventional reagents.
Total protein determined in human breast milk by use of coomassie brilliant blue and centrifugal analysis.
Authors: Bergqvist Y , Karlsson L , Fohlin L 
Published: January 2020

Abstract
This simple method of centrifugal analysis for total protein in human breast milk is based on the change in the wavelength of the absorbance maximum of Coomassie Brilliant Blue G-250 when the dye is bound to protein. Within-run and between-day CVs were 3.8% and 4.8%, respectively. Compared with a micro-Kjeldahl method for determination of total nitrogen, the coefficient of correlation was 0.99.
Autoantibodies to lactate dehydrogenase in serum identified by use of immobilized protein G and immobilized jacalin, a jackfruit lectin.
Authors: Backer E T , Harff G A 
Published: January 2020

Abstract
In this method for identifying autoantibodies to lactate dehydrogenase (anti-LDs) in serum, we used immobilized Protein G to bind IgG-complexed LD and immobilized jacalin to bind IgA-complexed LD, leaving non-complexed LD in solution. The non-complexed LD and total LD were kinetically measured. We report results as LD bound to immobilized Protein G and LD bound to immobilized jacalin. Using sera demonstrating IgG and IgA anti-LDs by immunoelectrophoresis (IEP), respectively, we optimized the method for incubation time and concentration of binding agents. We demonstrated concomitant binding of LD and greater than or equal to 98% of IgG and of LD and greater than or equal to 92% of IgA. For LD bound to immunobilized Protein G the detection limit was 10 U/L, within- and between-run CVs ranged from 2.9% to 9.1%, and values for normal sera were less than or equal to 3% of total LD. Results for LD bound to immobilized jacalin were similar. We tested 10 sera displaying aberrant LD electrophoretograms: In seven, LD bound to immobilized Protein G was increased (range: 26-99% of total LD), indicating IgG-complexed LD. This was confirmed by IEP, demonstrating IgG1,2, or IgG3 anti-LDs in these sera. In the other three sera, LD bound to immobilized jacalin was increased (range: 38-72% of total LD), indicating IgA-complexed LD. This was confirmed by IEP, demonstrating IgA anti-LDs in these sera. Evidently this method is an alternative to IEP for identifying anti-LDs in serum.
Effect of glycation of low-density lipoprotein on the immunological determination of apolipoprotein B.
Authors: Press R D , Wilding P 
Published: January 2020

Abstract
Non-enzymatic glycation of low-density lipoprotein (LDL) may contribute to the premature atherogenesis of patients with diabetes mellitus. To assess whether glycation of apolipoprotein B, the predominant protein of LDL, interferes with the ability to immunologically quantify this protein, we prepared and purified glycated LDL by incubating normal plasma samples with high concentrations of glucose. Although both the plasma and the LDL specimens incubated with glucose contained significantly more glycated protein than control specimens, the quantitative interaction of an apolipoprotein B-specific antibody with glycated vs nonglycated LDL was not significantly different. We conclude that apolipoprotein B can be accurately quantified immunologically despite the presence of clinically excessive degrees of LDL glycation.
Studies on methylmalonic acid in humans. I. Concentrations in serum and urinary excretion in normal subjects after feeding and during fasting, and after loading with protein, fat, sugar, isoleucine, and valine.
Authors: Rasmussen K 
Published: January 2020

Abstract
Determination of methylmalonic acid (MMA) in serum or urine for evaluation of tissue cobalamin (vitamin B12) deficiency is becoming an important diagnostic procedure. Here I present the first investigation of dietary influence on concentrations of MMA in serum and urine. Everyday meals caused an increase in urinary excretion, whereas the concentration in serum was not increased significantly. It is difficult to prime the accumulation of MMA in normal subjects by stressing the metabolic pathway; after loading subjects with 100 mmol of isoleucine or valine, the absolute amount of MMA excreted increased by only about 3 mumol. Its concentration in serum tended to decrease and its urinary excretion declined after lack of protein intake for more than 15 h. Although a linear relationship was demonstrated, for the first time, between concentrations in serum and urinary excretion, my results indicate that patients with early evidence of cobalamin deficiency and normal subjects may best be differentiated by measurements in serum, especially in the case of nonfasting (i.e., ambulatory) patients.
Studies on methylmalonic acid in humans. II. Relationship between concentrations in serum and urinary excretion, and the correlation between serum cobalamin and accumulation of methylmalonic acid.
Authors: Rasmussen K , Moelby L , Jensen M K 
Published: January 2020

Abstract
Methylmalonic acid (MMA) concentrations are increased in cobalamin (vitamin B12) deficiency, but the relative diagnostic usefulness of determination of MMA in serum vs urine has not yet been assessed. We obtained urine collections and matched serum samples from 28 healthy volunteers and from 20 consecutive patients admitted for clinical and hematological evaluation because of low cobalamin concentrations in serum. Increased concentrations of MMA in serum were found in 12 patients, in all of whom a clinical diagnosis of cobalamin deficiency was established. By contrast, cobalamin deficiency was excluded in seven of the eight remaining patients, who all had normal MMA concentrations. Here we report that linear relationships exist between MMA concentrations in serum (investigated range: 0.05-34.2 mumol/L) and MMA concentrations in urine (r = 0.74), concentrations relative to creatinine (r = 0.98), and MMA excretion rates (r = 0.97) (P less than 0.001 in each instance). Our data are consistent with glomerular filtration and passive reabsorption of MMA by the tubules. We demonstrate, for the first time, a negative correlation between concentrations of cobalamin and MMA in serum in clinical cobalamin deficiency (r = -0.69; P less than 0.01; n = 12); when the values for MMA were log transformed, the correlation with cobalamin was much better (r = -0.84; P less than 0.0005).
Simultaneous liquid-chromatographic determination of vitamin K1 and vitamin E in serum.
Authors: Cham B E , Roeser H P , Kamst T W 
Published: January 2020

Abstract
We describe a high-performance liquid chromatographic procedure for the simultaneous measurement of vitamins K1 and E in human serum. Delipidated human serum (free of vitamins K1 and E) was used to make standard solutions of these vitamins, and cetyl naphthoate and alpha-tocopheryl acetate were the internal standards for vitamin K1 and vitamin E, respectively. A simple, novel separation method utilizing liquid-liquid partition chromatography was used as a preparative "clean-up" procedure. Cetyl naphthoate and vitamin K1 (after post-column reduction) were detected by fluorescence, alpha-tocopheryl acetate and vitamin E by ultraviolet absorption. Sensitivity (detection limit) of the assay was 30 pg for vitamin K1 and 5 ng for vitamin E per injection. The method is specific, precise, and more rapid than previously described procedures. Within- and between-assay CVs were 8.1% and 12.9%, respectively, for vitamin K1; 3.5% and 6.0%, respectively, for vitamin E. Analytical recoveries of vitamins K1 and E were 80% and 93%, respectively, from serum and from delipidated serum (standards). The average neonatal serum concentration of vitamin K1 was 83 ng/L, 2.5 mg/L for vitamin E; for normolipidemic adults, the values were 343 ng/L and 7.9 mg/L, respectively, and for hyperlipidemic adults, 541 ng/L and 11.1 mg/L, respectively.
Rapid enzymatic determination of urinary oxalate.
Authors: Li M G , Madappally M M 
Published: January 2020

Abstract
This new reagent kit for the quantitative measurement of oxalate in urine is a modification of an earlier Sigma oxalate assay procedure (procedure no. 590), a coupled enzyme assay involving oxalate oxidase and horseradish peroxidase. The new analytical procedure includes methods for processing urine specimens to eliminate interference with oxalate color development at 590 nm by ascorbic acid, divalent cations, and other urinary constituents. The reaction is complete in less than 5 min, and results are linearly related to oxalate concentration up to at least 1 mmol/L. Assay sensitivity and within-run and between-run precision were within the limits acceptable for other urinary oxalate procedures. Analytical recovery of added oxalate was close to 100%. This specific, simple, rapid procedure is suitable for routine clinical use.
Greater than expected alanine aminotransferase activities in plasma and in hearts of patients with acute myocardial infarction.
Authors: Giesen P L , Peltenburg H G , de Zwaan C , Janson P C , Flendrig J G , Hermens W T 
Published: January 2020

Abstract
Early increases in the activity of alanine aminotransferase (ALT, EC 2.6.1.2) in plasma are observed in about 7% of patients with acute myocardial infarction (AMI), of whom about half die. Some type of liver injury, secondary to AMI, could be responsible for this phenomenon. However, quantitative analysis shows that the release of ALT in most of these patients conforms to the myocardial release pattern. Moreover, extra release of hepatic aspartate aminotransferase (EC 2.6.1.1) is not observed. These findings suggest that the heart may occasionally contain a high ALT activity. This hypothesis was verified by determination of enzyme activities in 10 hearts obtained from patients who died after AMI. The mean ALT activity in these hearts, 21 (SD 12) U per gram wet weight, significantly (P less than 0.01) exceeds the value of 7.7 (SD 4.9) U/g found for seven control hearts and may reflect increased amino acid metabolism in the energy-depleted heart muscle, as described earlier for skeletal muscle.
Simultaneous determination of pentoxifylline and three metabolites in biological fluids by liquid chromatography.
Authors: Lambert W E , Yousouf M A , Van Liedekerke B M , De Roose J E , De Leenheer A P 
Published: January 2020

Abstract
We describe a sensitive and specific liquid-chromatographic assay for pentoxifylline and three of its metabolites in human plasma and urine. Addition of hydrochloric acid to the sample before extraction, and incorporation of acetic acid in the chromatographic eluent, allow the simultaneous determination of the four compounds plus an internal standard in one chromatographic run. Unlike gas-chromatographic procedures, this method does not involve derivatization no similar analysis of serum or plasma samples has been described before now. The method has been applied successfully to routine analysis and to pharmacokinetic studies.
Alpha-amylase determination with the Reflotron reagent carrier system: use of whole blood, plasma, and serum, and effect of isoenzymes.
Authors: Bais R , Badenoch J , Bayer P M , Foo Y , Keller H , Koller P U , Leinberger R , Weidemann G , Rosalki S B 
Published: January 2020

Abstract
In the Reflotron Amylase dry-reagent carrier system (Boehringer Mannheim GmbH) a new substrate is used for determining total amylase (EC 3.2.1.1) activity:indolyl-alpha-D-maltoheptaoside. The procedure shows low imprecision (median CV less than 3.2%), and results for sera, plasma, and capillary and venous blood (y) correlate well with those of a conventional alpha-amylase method involving p-nitrophenyl (PNP)-maltoheptaoside substrate (x) (for 209 blood samples: y = 0.981x + 9.7; r = 0.994). Correlation was also excellent with a method involving maltotetraose as substrate (r = 0.987). Attachment of an indoxyl residue rather than a PNP group to the maltoheptaoside did not affect the substrate response to pancreatic or salivary isoenzyme activity. Therefore, the relative proportion of these isoenzymes did not affect the correlation between the Reflotron Amylase reagent carrier and the alpha-amylase PNP-maltoheptaoside method. With a reaction time of less than 3 min, this system is especially suitable for amylase determination in situations where a prompt result is required.
IgG heavy-chain subclass typing of myeloma paraproteins by isoelectric focusing immunoblot analysis.
Authors: Fasullo F J , Fritsche H A , Liu F J , Hamilton R G 
Published: January 2020

Abstract
The objective of this study was to develop a clinical laboratory method for subclass typing of human immunoglobulin G (IgG) paraproteins. Serum proteins were isoelectrically focused (IEF) in a mini-gel and passively blotted by capillary diffusion onto untreated nitrocellulose. Unreacted sites on the nitrocellulose were blocked with bovine serum albumin and the bound IgG was detected with peroxidase-conjugated anti-human IgG1-4 monoclonal antibodies from WHO/IUIS clones. The IEF immunoblot specificity was demonstrated by analysis of documented IgG, IgA, and IgM myeloma proteins of known subclass and light-chain composition. IEF immunoblots of sera from 18 myeloma patients who had an above-normal total IgG concentration produced IEF immunoblot patterns composed of five to 10 discrete bands (pI range 6.0 to 8.4). In contrast, no detectable IgG bands were observed with sera containing IgA and IgM paraproteins. The observed subclass frequencies of IgG paraproteins were 56% IgG1 (10/18), 28% IgG2 (5/18), 11% IgG3 (2/18), and 5% IgG4 (1/18). IEF immunoblot analysis permits the monitoring of changes in the pI and subclass of an IgG paraprotein over the course of a myeloma patient's therapy program.
Short-term and long-term variability of indices related to nutritional status. I: Ca, Cu, Fe, Mg, and Zn.
Authors: Gallagher S K , Johnson L K , Milne D B 
Published: January 2020

Abstract
Five free-living women (ages 28-38 y) and five women (ages 23-44 y) residing in a metabolic unit and eating a constant diet were assessed for variation in indices related to mineral nutrition. Blood was sampled once a month for five months, once a week for five weeks, and once a day for five days to assess analytical and biological variability. Analytical variability was determined by using concurrently run duplicate control samples prepared from plasma or serum pools. Of the measured indices, serum ferritin varied most, with intra-individual variance of 4.72% to 18.0%. Much of this variance may have been because of changes in iron status or in the analytical technique used. Intra-individual month-to-month variance for other indices ranged from 17% for superoxide dismutase (EC 1.15.1.1) to 1.5% for calcium. Correction for long-term analytical variation indicated that most of the variance was associated with the biological component. The higher biological variabilities of some indices, including ferritin or superoxide dismutase, need to be considered when nutritional status is being evaluated or when serial observations are made over a protracted period in clinical studies or trials.
Diagnostic test for mucopolysaccharidosis. I. Direct method for quantifying excessive urinary glycosaminoglycan excretion.
Authors: Whitley C B , Ridnour M D , Draper K A , Dutton C M , Neglia J P 
Published: January 2020

Abstract
This direct method for quantifying excessive urinary glycosaminoglycan excretion exploits the specific binding of 1,9-dimethylmethylene blue (DMB). The procedure obviates cumbersome and labor-intensive procedures for separating glycosaminoglycans from other constituents of urine. Pediatric pharmaceutical formulations (except heparin), in concentrations expected in urine, do not interfere with spectrophotometry, nor does protein. Results can be expressed in terms of urinary creatinine; thus the test is applicable to very small urine specimens (0.1 mL), such as those obtainable from neonates. In a pilot study, results of the direct DMB test for 48 urine specimens agreed with the clinical diagnosis, and quantitative measurements correlated moderately (r = 0.76) with results of a commonly used procedure (carbazole-borate reactivity after precipitation with cetylpyridinium chloride). The present method was also used to assess metabolic correction in a patient with Hurler's syndrome after treatment by bone-marrow transplantation. This quantitative method surmounts the major technical problems of developing mass screening programs for infants, thus offering the potential for earlier diagnosis and treatment of mucopolysaccharidosis diseases.