bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunoturbidimetric techniques for quantifying apolipoproteins CII and CIII.
Authors: Rifai N , Silverman L M 
Published: January 2020

Abstract
Immunoturbidimetric assays for determination of serum apolipoproteins CII and CIII (apo CII and CIII) were developed for use on the Cobas-Bio centrifugal analyzer with commercially available antisera and reference sera. Within-run and between-run imprecision (CVs) for apo CII was respectively 3.3 and 6.2%, and for apo CIII 2.75 and 5.2%. Addition to sera of as much as 50 g of hemoglobin or 0.15 g of bilirubin per liter did not interfere with determinations of apolipoproteins. Concentrations of apo CII and CIII were measured in sera from 40 normolipidemic and hyperlipidemic subjects by these immunoturbidimetric methods (x) and by radial immunodiffusion assays (y). Apo CII and CIII gave slopes of 0.93 and 0.86, y-intercepts of 7.4 and 9.5 mg/L, and correlation coefficients of 0.96 and 0.94, respectively. Reference intervals for the two apolipoproteins were established with sera from 100 normolipidemic subjects. The distribution of apo CII and CIII among the various lipoprotein fractions for normal subjects differed significantly (p less than 0.005) from that for hypertriglyceridemic subjects.
Estradiol receptors in human breast carcinomas assayed by use of monoclonal antibodies.
Authors: Duffy M J , O'Siorain L , Waldron B , Smith C 
Published: January 2020

Abstract
Our aim here was to compare a new enzyme immunoassay for estradiol receptors (ER) in breast cancer with a standard assay involving radiolabeled estradiol. A significant correlation was obtained between the standard binding assay and immunoassay (rs = 0.945, p less than 0.001, n = 100). Immunoreactive ER were also found in endometrial carcinomas but not in lung carcinomas, malignant melanomas, or basal cell carcinomas. Patients with breast cancers containing immunoreactive ER survived significantly longer after operation than patients whose tumor lacked immunoreactive ER. This immunoassay for ER is simpler than the binding assay and requires less time and tissue.
Two automated procedures for N-acetyl-beta-D-glucosaminidase determination evaluated for detection of drug-induced tubular nephrotoxicity.
Authors: Goren M P , Wright R K , Osborne S 
Published: January 2020

Abstract
We automated two procedures for determination of urinary N-acetyl-beta-D-glucosaminidase (NAG; EC 3.2.1.30) concentrations and evaluated their reliability for detecting drug-induced tubular damage in children receiving cisplatin, methotrexate, or ifosfamide. Results for 174 patient specimens correlated well (r = 0.98), but NAG concentrations determined by the m-cresolsulfonphthaleinyl (MCP) procedure were about 40% lower than those obtained with p-nitrophenyl-N-acetyl-beta-D-glucosaminide substrate. Dialysis and assay of 50 specimens disclosed no evidence of activators or inhibitors of enzymatic activity. Drugs and metabolites added to urine had negligible effect on NAG determinations; however, NAG was unstable in alkaline urine (pH greater than 8) associated with methotrexate therapy. Both procedures detect tubular damage equally well and neither requires laborious sample treatment. The MCP procedure, being more sensitive and not requiring a sample blank, is better suited for rapid automated assays. Comparisons of clinical data obtained by the two procedures require standardization against human NAG.
Assay of circulating 1,25-dihydroxyvitamin D involving a novel single-cartridge extraction and purification procedure.
Authors: Hollis B W 
Published: January 2020

Abstract
By use of a single-cartridge system, 1,25-dihydroxyvitamin D [1,25(OH)2D] is extracted and purified from a plasma or serum sample. Proteins are removed and 1,25(OH)2D is liberated from the sample with acetonitrile. The acetonitrile extract is applied to the nonpolar octadecylsilanol silica cartridge, in which 1,25(OH)2D is retained while polar compounds are eluted. Then by "phase-switching" on the same cartridge, 1,25(OH)2D is sufficiently resolved from other vitamin D metabolites and extraneous lipophilic compounds to allow its quantification by radioreceptor assay according to an established procedure. Mean (and SD) values for 1,25(OH)2D in serum of 29 normal, 27 chronic renal failure, and nine pregnant subjects were 28.2 (11.3), 10.9 (5.2), and 47.3 (12.9) ng/L, respectively. Results compared well with those of an established radioreceptor procedure. This procedure offers the advantage of a single rapid purification step not involving "high-performance" liquid chromatography or evaporation, under nitrogen, of polar solvents such as acetonitrile or methanol.
Can nutritional criteria help predict outcome in hospitalized patients?
Authors: Prabhakaran V M , Pujara S , Mills A J , Whalen V W 
Published: January 2020

Abstract
The following nutritional criteria were evaluated for their usefulness in predicting outcome in a prospective study of 66 randomly selected hospitalized patients with a variety of diagnoses: total protein, albumin, and transferrin concentrations in serum, creatinine height index, weight height index, phenylalanine/tyrosine ratio (Phe/Tyr), concentration of branched-chain amino acids in serum, and ratio of essential to nonessential amino acids in serum. The cases were followed from admission to discharge, and were classified into the following three groups: 43 "well"; 14 with "complications" but recovered; and nine "dead". Statistical analysis (Scheffe's s-test) demonstrated the means of "well" and "dead" groups to be different for total protein, albumin, transferrin, and Phe/Tyr. In individual patients the nutritional criteria, even for those with fatal outcome, were poor indicators of outcome. These nutritional criteria are useful in identifying hospitalized groups that are at maximum risk (i.e., death), but are much less useful for individual patients.
Lentil-lectin-reactive alpha-fetoprotein in the differential diagnosis of benign and malignant liver disease.
Authors: Buamah P K , Harris R , James O F , Skillen A W 
Published: January 2020

Abstract
Affinity chromatography of serum on lentil lectin bound to Sepharose 4B has been used to identify different forms of alpha-fetoprotein in serum of patients with liver disease. We studied eight patients with non-malignant liver disease, finding that 7-15% of the serum alpha-fetoprotein bound to the lectin. In contrast, for 15 patients with malignant liver disease, 25-83% of the serum alpha-fetoprotein bound to the lectin. Evidently, this simple technique can be used effectively to differentiate these two conditions.
Nephelometric assay of apolipoprotein A-I with a centrifugal analyzer.
Authors: Hanson N Q , Freier E F 
Published: January 2020

Abstract
We developed an automated immunonephelometric assay for quantification of human apolipoprotein A-I (apo A-I) with a fluorescence light-scattering microcentrifugal analyzer. The presence of polyethylene glycol and Tween 20 in the reaction mixture ensures maximum exposure of the antigenic sites of the apoprotein so that immune complex formation occurs more rapidly (reaction is complete within 2 min) and to a greater extent. Lipemia and hemolysis do not interfere with the measurement of apo A-I. The method requires only 10 microL of specimen and is fast and easy to perform. Results vary linearly with apo A-I concentrations to 2.5 g/L. Assay precision (CV) was 3.1% for a specimen with an apo A-I concentration of 1.45 g/L, and the lower limit of detection was 0.15 g/L. Values for a candidate Reference Material agree well with those reported in an international survey (Clin Chem 1985;30:223-8).
Inaccurate measurement of a polymeric IgA myeloma protein by nephelometric and fluorometric instrumentation.
Authors: Levinson S S , Goldman J O , Markyvech L , Nathan L E 
Published: January 2020

Abstract
The concentration of IgA in a serum was 5.99 g/L as assayed nephelometrically with reagent from one company, but varied between 5 and 3 g/L (for sixfold and 36-fold dilutions, respectively) without giving a definitive answer when assayed with reagent from another source. Immunofixation electrophoresis indicated an IgA lambda monoclonal protein of 45 g/L. Radial immunodiffusion showed two components, having a total concentration of 41 g/L. By fluorometry the IgA was 3.1 g/L. Increasing the dilution caused the (dilution-corrected) lower values to increase. Although the most frequent cause of such discrepant findings is an IgA2 myeloma, which occurs in about one of every 100 myeloma cases, Ouchterlony double diffusion indicated the major component to be IgA1. A polymer, Mr 670,000, was identified by column chromatography. Contrary to the usual behavior of polymers assayed with radial immunodiffusion, which underestimates their concentration, this polymer reached equivalency in agreement with its true concentration as assayed by the Mancini-Heremans technique.
Detection of complement activation in immune complex diseases: six methods compared.
Authors: Sun T , Stagias J 
Published: January 2020

Abstract
We compared the performance of six complement tests: electrophoresis, immunofixation, immunoelectrophoresis, and nephelometric quantifications of C3, C4, and C3d. We used 123 blood samples from 60 control subjects and 63 patients with immune complex diseases: systemic lupus erythematosus, idiopathic thrombocytopenic purpura, rheumatoid arthritis, acquired immunodeficiency syndrome, renal diseases, vasculitis, cryoglobulinemia, Gram-negative bacteremia, Hashimoto's thyroiditis, rheumatic heart disease, malaria, and chronic active hepatitis. Immunofixation and quantification of C3d were better for detecting complement activation, their sensitivity rates (90.5% and 89.3%, respectively) being higher than those of the other tests studied. Immunofixation is a relatively simple and inexpensive test, provides good resolution of protein bands, and yields results that are easily quantified with a densitometer. Nephelometry of C3d provides more rapid and accurate quantitative results than immunofixation, but commercial reagents are not yet available. The causes of false-positive results in complement tests and the mechanisms of complement activation in AIDS are also discussed.
Artefactual increase in serum thyrotropin concentration caused by heterophilic antibodies with specificity for IgG of the family Bovidea.
Authors: Bartlett W A , Browning M C , Jung R T 
Published: January 2020

Abstract
A 19-year-old white woman presented with symptoms compatible with mild hyperthyroidism and biochemical evidence suggestive of autonomous thyrotropin (TSH) secretion. Intensive investigation of the pituitary-thyroid axis suggested that the basal concentrations of TSH were artefactually increased owing to heterophilic antibodies in the patient's serum with a broad specificity for immunoglobulin class G of the family Bovidea. These heterophilic antibodies complexed with the ovine antisera to human thyrotropin that are used in the RIA system, in particular blocking the binding of TSH but also partly blocking interaction with the second antibody. When TSH was measured immunometrically or by an RIA with TSH-specific antisera of rabbit origin, the concentrations measured were within the appropriate reference intervals. The blocking effect can be overcome by including large quantities of non-TSH-specific ovine IgG in assay incubation mixtures. Interference of this type is generally not appreciated and its incidence is poorly characterized, but it may have implications for any method in which antibodies are used as reagents.
Homogeneous, liposome-based assay for total complement activity in serum.
Authors: Bowden D W , Rising M , Akots G , Myles A , Broeze R J 
Published: January 2020

Abstract
This is a rapid, homogeneous, liposome-based assay for total complement activity in human serum. Liposome-encapsulated enzyme is unmasked by the action of complement on liposomes carrying surface-bound immune complexes. The amount of unmasked enzyme, proportional to the concentration of added complement, is quantified by measuring the absorbance of enzymically produced product at 410 nm. Complement activity in serum samples is extrapolated from a standard curve generated from dilutions of a guinea pig serum containing a known activity of complement. Interassay CVs were less than 7.0% and intra-assay CVs less than 2.8% for serum pools with complement activities spanning the normal range. Test results correlate as well with those of the hemolytic complement test (r = 0.80) as the latter correlates with itself (r = 0.82), and also correlate reasonably with measurements of complement components C3 (r = 0.62) and C4 (r = 0.74). Values for a normal population are reported. Advantages of this test include stability of reagents, speed, accuracy, simplicity, and avoidance of radioisotopes.
Characterization of lysosomal acid phosphatase from normal and malignant mammary tissue.
Authors: Podhajcer O L , Filmus J E , Mordoh J 
Published: January 2020

Abstract
Acid phosphatase (EC 3.1.3.2) isoenzyme 3 was purified from normal and malignant human mammary tissue and its properties in each were compared. The relative molecular mass of each was 53 000, as measured by sodium dodecyl sulfate gel electrophoresis. Several phosphomonoesters are good substrates for the isoenzymes, whereas organic and inorganic pyrophosphates and phosphoryl choline are hydrolyzed very slowly or not detectably. The optimum pH for interaction of these isoenzymes with p-nitrophenyl phosphate as substrate ranges from 3.5 to 4.5. L-(+)-Tartrate is a very strong inhibitor, Ki = 0.028 +/- 0.04 mmol/L (mean +/- SE), as are mercuric and fluoride ions in low concentrations. We conclude that type 3 isoenzymes obtained from normal and malignant tissue are very similar, though the malignant tissue appears to have a greater proportion of this type than does normal tissue.
Three methods compared for determination of pancreatic and salivary amylase activity in serum of cystic fibrosis patients.
Authors: Wolf R O , Hubbard V S , Gillard B K , Kingman A 
Published: January 2020

Abstract
We evaluated three methods for serum amylase (EC 3.2.1.1) isoenzymes to determine whether they are interchangeable and to test their ability to discriminate between cystic fibrosis patients with and without pancreatic insufficiency. One method involved salivary amylase inhibitor (O), and two were polyacrylamide gel electrophoresis separations differing in method of detection--either direct zymogram (G) or gel slicing followed by activity estimates per slice (W). Results for percentage pancreatic amylase differed significantly. Reproducibility for percentage pancreatic amylase was high, moderate, and low (r = 0.95, 0.53, and 0.02) for methods G, O, and W, respectively; moderate (r = 0.60) among the three methods; and moderate between pairs. Therefore, this result for a subject must be considered relative to the method used in its determination. The clinical diagnosis of pancreatic insufficiency was verified by 77.8%, 83.3%, and 94.4% correct classification rates for methods O, W, and G, respectively. Evidently, method G is the most efficient and may be the method of choice for measuring serum amylase isoenzymes in cystic fibrosis.
Protein markers of nutrition status as related to sex and age.
Authors: Sachs E , Bernstein L H 
Published: January 2020

Abstract
We assessed age- and sex-related variation in those proteins commonly measured to evaluate protein catabolic losses in patients in acute care. We determined concentrations of iron and iron-binding capacity, transferrin, albumin, prealbumin, and retinol-binding protein in sera from 158 healthy blood donors and 48 hospitalized patients, then grouped the data according to age (by decade) and sex. There was no significant variation in either category. For the total nondiseased population the concentrations of three proteins (means SD, and range) were: transferrin, 2760, 510, 1740-3780 mg/L (population CV 18.5%); prealbumin, 296, 49, 200-390 mg/L (CV 16.6%); retinol-binding protein, 60, 127, 35-85 mg/L (CV 21.2%). Prealbumin and retinol-binding protein concentrations were highly correlated (r = 0.803). Because prealbumin can be easily monitored and its assay is subject to few interferences, we conclude that determination of prealbumin is suitable for assessing the existence and severity of nutritional metabolic deficits.
Substrate-Leash Amplification with Ribonuclease S-Peptide and S-Protein
Authors: Ehrat Markus , Cecchini Douglas J , Giese Roger W 
Published: January 2020

Abstract
p 1628, Fig. 6: Although faint, there is a band at the origin in lane g.
p 1656: The accompanying figure should be substituted for the Figure 2 shown on page 1656, a figure that was to have been deleted. The figure legend is unchanged.
p 1705: The second paragraph in the left column should replace the third paragraph of the Discussion. Thus the authors find it "likely...that the principal alkali-labile oxalate precursors in urine are ascorbate and some of its metabolites...."
p 1927: The name of the author of a book review, Robert Rej, was omitted.
p 2014: On line 7, the 95 percentile interval for plasma ammonia should be 16-53 µmol/L, as correctly stated in the Abstract.
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Assay performance and tracer properties for two analog-based assays of free triiodothyronine.
Authors: Wilkins T A , Midgley J E , Stevens R A , Caughey I , Barron N 
Published: January 2020

Abstract
We determined binding characteristics of the triiodothyronine (T3) analog tracer used in the Amerlex and Amerlex-M FT3 radioimmunoassay for the three endogenous binding proteins in serum: thyroxin-binding globulin (TBG), thyroxin binding prealbumin (PA), and albumin. Both T3 and its analog bind to the same sites on TBG and PA. However, the analog has significantly lower association constants (1.0% and 3.8%, respectively, of T3 binding affinity) and it binds to different sites on albumin. Analog binding is characterized by two (weak) specific binding sites [K = 0.46 (SD 0.03) X 10(5) L/mol]; T3 is bound at about 28 very weak, nonspecific sites [K = 0.41 (SD 0.03) X 10(4) L/mol]. Sera from healthy subjects with a wide range of concentrations of binding proteins showed no interference from analog binding in the FT3 assay. In contrast, in vitro studies of albumin binding revealed a weak dependence of both assays on albumin concentration (0.05 pmol of FT3 per gram of albumin per liter), an interference probably unimportant for most laboratory samples. Nonesterified fatty acids (NEFA) and the T3 analog apparently bind to different sites on albumin; thus the Amerlex FT3 assay is insensitive to moderately increased concentrations of NEFA in serum.
Graphical comparisons of interferences in clinical chemistry instrumentation.
Authors: Glick M R , Ryder K W , Jackson S A 
Published: January 2020

Abstract
Instrument- and analyte-specific interferences can be produced by adding known concentrations of potentially interfering substances to serum from healthy volunteers. Analytical results are expressed as a percentage of the original (unaffected) result. Graphical displays of the transformed data document the conditions under which erroneous results would be probable for specimens containing the additive. If several analytical systems are available, one can make an informed choice of which to use for a particular analysis by comparing the appropriate graphical information. Comparisons of such displays of data from newer systems being considered for purchase may facilitate decisions regarding laboratory instrumentation.
Circulating antibodies to mouse monoclonal immunoglobulins in normal subjects--incidence, species specificity, and effects on a two-site assay for creatine kinase-MB isoenzyme.
Authors: Thompson R J , Jackson A P , Langlois N 
Published: January 2020

Abstract
With a two-site CK-MB assay, we screened serum samples from 1008 blood donors for the presence of antibodies to mouse monoclonal immunoglobulin. These antibodies were capable of cross-linking the labeled antibody with the solid-phase antibody in the two-site assay, thus generating a falsely high apparent CK-MB concentration. In 92 (9.12%) of the blood donors tested, apparent CK-MB concentrations of 10-1000 micrograms/L decreased to less than 3 micrograms/L when re-assayed with non-immune mouse serum (10 mL/L) included in the assay reagent. We tested the ability of non-immune sera from other animal species to lower the concentration of apparent CK-MB in 58 of the 92 samples. Bovine and ovine serum were almost as effective as mouse serum; feline, canine, and rabbit serum were less effective. Of the samples tested, 12% (1.1% of the original population screened) showed apparent CK-MB values that either were not depressed by bovine serum or were only partly depressed. We discuss the possible etiology of these antibodies in normal subjects and recommend that all mouse monoclonal two-site assays should contain non-immune mouse serum (or a suitable "irrelevant" mouse monoclonal antibody) to prevent false-positive results.
Direct ultraviolet method for enzymatic determination of uric acid, with equilibrium and kinetic data-processing options.
Authors: Dilena B A , Peake M J , Pardue H L , Skoug J W 
Published: January 2020

Abstract
We developed and evaluated a direct ultraviolet method for the enzymatic determination of uric acid in serum, plasma, or urine, without deproteinization of sera and plasma. Equilibrium and nonlinear curve-fitting kinetic options are evaluated and compared, and results of the proposed method are compared with those of a candidate Reference Method. All data-processing options yield a linear relation for absorbance and concentration of uric acid between 0.1 and 2 mmol/L; with the equilibrium option, results are linear to 5 mmol/L. For 100 plasma samples, results correlate well between the proposed method (y) and a reference method (x): y = 0.99x - 0.002 mmol/L. Between-run imprecision is about 2.3%, and interference by hemolyzed, icteric, or lipemic specimens or specimens containing high concentrations of xanthine or paraproteins is minimal. The kinetic option with a data-processing range of 100 s or longer yields results that correlate well with the equilibrium method: y = 1.006x + 0.002 mmol/L (n = 118). For 20 urine samples processed by the proposed (y) and a reference (x) methods, y = 1.04x + 0.038 mmol/L.
A sensitive and practical immunoradiometric assay of thyrotropin.
Authors: Helenius T , Tikanoja S 
Published: January 2020

Abstract
We describe a two-site immunoradiometric assay for thyrotropin (TSH) in serum, based on use of two monoclonal antibodies directed against two separate antigenic determinants on the TSH molecule. One antibody is immobilized on polystyrene beads; the other is radioiodinated by a modified Chloramine T method. The detection limit of the assay is 0.02 milli-int. unit/L. The working range (CV less than 10%) is from 0.1 to greater than 50 milli-int. units/L. The log mean concentration of TSH in sera collected from 100 euthyroid subjects between 08:00 and 11:00 hours was 1.9 milli-int. units/L, the range 0.4-5.4 milli-int. units/L. Values for hyperthyroid patients and thyroid-cancer patients being treated with thyroxin were much lower than those for euthyroid persons. Results by this new assay correlated excellently with those by our conventional radioimmunoassay (r = 0.99) and also with a sensitive immunofluorometric TSH method (Delfia TSH) (r = 0.99).
Evaluation of "HemoCue," a new device for determining hemoglobin.
Authors: von Schenck H , Falkensson M , Lundberg B 
Published: January 2020

Abstract
Hemoglobinometry according to the International Committee of Standardization in Hematology (ICSH) suffers from imprecision related to high sample dilution and from potential errors owing to sample turbidity. We have evaluated a new instrument, "HemoCue," that measures hemoglobin at two wavelengths as azide methemoglobin, without dilution. The HemoCue method is superior to the ICSH method: by correction for turbidity, it avoids false hemoglobin readings that may arise from hyperlipemia or some large M-component of the immunoglobulin M class. We find the equipment suitable for use in outpatient units.