bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two-dimensional gel electrophoresis method for investigation of human plasma proteins: detection of subtle changes during filtration leukapheresis.
Authors: Lonberg-Holm K , Bagley E A , Nusbacher J , Heal J M 
Published: January 2020

Abstract
Special problems are associated with analysis of human plasma proteins by standard "high-resolution" two-dimensional gel electrophoresis methods in which isoelectric focusing is followed by electrophoresis in sodium dodecyl sulfate/polyacrylamide gels (SDS-PAGE). Individual plasma proteins are often separated into overlapping groups of multiple spots, and identification of individual spots is further confounded by genetic variation. Analytical recovery of components of high molecular mass is also low or variable. These problems may be reduced or overcome by use of a "low-resolution" method consisting of electrophoresis of native proteins at pH 8.6 in an agarose gel followed by SDS-PAGE without added reducing agent. About 60 proteins can be resolved, most as single spots. About 25 of these proteins have been "mapped," and tentatively identified. We have examined 119 plasma samples taken from six donors who were undergoing filtration leukapheresis and 10 donors who were undergoing centrifugation leukapheresis or plateletpheresis. In all cases, passage of blood through a nylon filter induced a significant increase in a doublet of spots tentatively identified as complement component C3c. This was detected in the effluent from the filter throughout the first 30 min of filtration, and to a lesser extent in the venous blood. These spots were not induced by the centrifugation procedures. One filtration donor also showed increased acute-phase proteins 24 h after the procedure.
On the use and computation of likelihood ratios in clinical chemistry.
Authors: Albert A 
Published: January 2020

Abstract
The clinical relevance of likelihood ratios (L-values) for revising the physician's diagnostic probabilities has been recognized. However, the calculation of L-values, particularly in the case of quantitative or mixed quantitative-binary test results, raises problems that have not yet been addressed. Based on a very general assumption that yields a simple functional form for the likelihood ratio, a method is developed that allows such calculations regardless of the nature and the number of clinical laboratory tests to be interpreted simultaneously. Hence the notion of predictive value (posterior probability) is extended from binary or dichotomized tests to quantitative tests, and from univariate to multivariate clinical laboratory results. The simplicity and flexibility of this approach eliminates difficulties in computation arising from the addition of new data to an existing data base. It is hoped that this method will now allow L-values to be reported along with the original test results in daily laboratory practice.
Measurement of plasma estradiol-17 beta by solid-phase chemiluminescence immunoassay.
Authors: Kim J B , Barnard G J , Collins W P , Kohen F , Lindner H R , Eshhar Z 
Published: January 2020

Abstract
We describe a simple, solid-phase chemiluminescence immunoassay for the measurement of estradiol-17 beta in extracts of peripheral venous plasma. The method has similar sensitivity, specificity, precision, and accuracy to a conventional radioimmunoassay with a tritiated antigen. An immunoglobulin G fraction od monoclonal antibodies to estradiol-6-carboyxmethyl oxime-bovine serum albumin is passively adsorbed onto the walls of polypropylene tubes. The labeled antigen is estradiol-6-carboxymethyl oxime-aminobutylethyl isoluminol. After the binding reaction (1 h at 22 degrees C), the solution is removed by aspiration (400 microliters). Sodium hydroxide (5 mol/L, 300 microliters) is added and the mixture incubated for 30 min at 37 degrees C. Luminescence is initiated by oxidation of the label with microperoxidase/hydrogen peroxide and the signal integrated for 10 s. The light yield is inversely proportional to the concentration of estradiol in the standard or sample.
A colorimetric assay for releasable plasminogen activator.
Authors: Campbell E E , Shifman M A , Lewis J G , Pasqua J J , Pizzo S V 
Published: January 2020

Abstract
We describe an equilibrium assay for measuring release of plasminogen activator form blood-vessel walls and report data from 125 individuals free of overt thromboembolic disease. Excess human plasminogen is added to the euglobulin fraction of plasma obtained before and after venous occlusion at mean systolic pressure. To measure plasmin generation in these samples, we used the chromogenic plasmin substrate D-Val-Leu-Lys-p-nitroanilide, which liberates p-nitroaniline upon cleavage. Releasable plasminogen activator in 24 subjects was determined by this colorimetric assay and by the radiocasein assay previously reported by this laboratory (Am. J. Clin. Pathol. 76,403-409, 1981), and the results were compared. The correlation coefficient was 0.97. The colorimetric assay offers several advantages over the radiocasein assay: shorter incubation (6 vs 16 h) and no preparation or quantification of a radioactive substrate and its cleavage products.
Application of response surface methodology to the assay of gamma-glutamyltransferase.
Authors: London J W , Shaw L M , Theodorsen L , Stromme J H 
Published: January 2020

Abstract
Response surface methodology (RSM) offers an empirical approach to the study of clinical enzyme assays. Variables such as pH, which are difficult to characterize by using theoretical enzyme kinetics, are easily included in RSM formulations. In this investigation, we studied with RSM the change in the measured activity of gamma-glutamy-transferase (EC 2.3.2.2) as a function of changes in concentrations of donor (gamma-glutamyl-3-carboxy-4-nitroanilide) acceptor (glycylglycine), and pH. The study defined large ranges for these variables over which maximum enzyme activity is obtained: donor 6.6 to 10.2 mmol/L, acceptor 129 to 250 mmol/L, and pH 7.8 to 8.5. The RSM regression polynomial was as accurate as a previously determined enzyme kinetic equation for predicting the transferase activity from given reagent substrate concentrations. Although not yielding a mechanistic understanding of an enzyme assay, RSM studies do produce an operational understanding of how an assay functions.
Creatine kinase isoenzymes in neonate plasma by cellulose acetate electrophoresis: albumin and adenylate kinase artifacts.
Authors: Massey T H , Barta J S 
Published: January 2020

Abstract
Patterns of creatine kinase (CK, EC 2.7.3.2) isoenzymes were studied in apparently healthy one- to 10-day-old neonates, by use of a sensitive fluorescent staining method with Sclavo CK-F/6001 reagent. Mean activities of CK3 (MM, 105 U/L), CK2 (MB, 6.8 U/L), CK1 (BB, 11 U/L), adenylate kinase (EC 2.7.4.3) anodal to CK3, and a fluorescent albumin artifact were found. Pooled plasma from neonates is recommended as a control because it defines the albumin artifact and approximates the activity of CK2 that must be observed after proper staining before a diagnosis of myocardial infarction can be made.
Theoretical and mathematical conditions for use of linearization methods for saturation-type radioassay data.
Authors: Shaw W 
Published: January 2020

Abstract
The algebraic equivalency of nine different methods for the linearization of saturation-type radioassay data was previously demonstrated mathematically to hold under the assumption that the antibody is saturated with ligand. Although compete saturation with antibody never occurs, a good approximation to a saturation condition occurs when the product of the labeled ligand and the affinity constant is 100 or more. The mathematical basis for determining when methods for the linearization of saturation-type radioassay data are valid is derived from a development of the first-order mass action law applied to ligand-antibody reactions.
Multiple myeloma protein with three light chains.
Authors: Sun T , Erichson R B , Lien Y Y , Wu C H 
Published: January 2020

Abstract
A case of immunoglobulin G (kappa) myeloma showed, in addition to the monoclonal IgG(kappa) arc, two kappa chains in the serum. The urine specimen contained 7.75 g of kappa chains per liter. The electrophoretically fast-moving kappa chain in serum was shown by immunoelectrophoresis and Ouchterlony immunodiffusion to be a complex of kappa chains and alpha 1-antitrypsin. This complex, which was detected only transiently in the patient's blood, was composed of a monomeric kappa chain bound to the antitrypsin by a disulfide bond. The predisposing factor for the formation of this complex is unclear, but patients showing this complex usually have kappa type myeloma protein and excrete kappa chain in urine at more than 1 g/L. The relationship between chemotherapy and formation of the kappa chain-antitrypsin complex needs further investigation.
Analytical artifacts in radioimmunoassay of L-thyroxin in human milk.
Authors: Mallol J , Obregón M J , Morreale de Escobar G 
Published: January 2020

Abstract
Previous results are contradictory regarding the concentration of thyroxin in human milk. Using a sensitive radioimmunoassay, we have found a lack of parallelism between the standard curve for thyroxin and the curve for serial dilutions of whole human milk, skimmed milk, or ethanol extracts of milk. Nonspecific binding also indicated the presence of analytical artifacts. Thus we have separated thyroxin from other milk components by means of a strongly basic Bio-Rad anion-exchange resin with quaternary ammonium exchange groups attached to a styrene divinyl benzene copolymer lattice, radioimmunoassaying the fractions eluted with an equivolume mixture of acetic acid and water. Parallelism with the standard curve was good, and results were the same whether or not the resin eluate was further purified by paper chromatography. The range of thyroxin concentration in 21 samples of human milk was 0.29-2.00 micrograms/L (mean 0.71, SD 0.40, microgram/L). Such concentrations are unlikely to afford protection to the developing brain of a breast-fed athyreotic baby, as previously claimed.
A micro-assay for estrogen receptor in breast tumor with use of 125I-labeled estradiol.
Authors: Van N T , Fritsche H A , Trujillo J M 
Published: January 2020

Abstract
The concentration of estrogen receptor protein in breast-tumor tissue is generally expressed in units of femtomoles of estradiol bound by the receptor per milligram of cytosol protein. The sensitivity of the estrogen receptor radioligand assay is therefore related to the specific activity of the steroid label used for the binding assay, the amount of the receptor protein in the volume of cytosol used, and the protein concentration in the cytosol. In this paper, we discuss factors affecting the sensitivity of the estrogen receptor assay and present various approaches for optimizing the assay. We also describe a procedure that involves a radioiodinated estradiol of high specific activity, a micro-technique for preparing tumor cytosol, and a micro-assay procedure with which the estrogen receptor protein can be measured in as little as 50 mg (wet weight) of tissue.
Comparison of calculated and measured free thyroid hormones in serum in health and in abnormal states.
Authors: Fresco G , Curti G , Biggi A , Fontana B 
Published: January 2020

Abstract
To evaluate a theoretical model for calculating free thyroid hormones, based on the law of mass action, we compared values for both calculated and measured free thyroxin and free triiodothyronine in a group of normal subjects. To determine whether the concentrations of circulating free hormones were also predictable from equilibrium considerations in abnormal states, we compared calculated and measured free thyroid hormone values in an additional population including pregnant women and hyperthyroid, hypothyroid, and "sick euthyroid" patients. Predictions based on the model were accurate in all these states except pregnancy, where there was some discrepancy between calculated and measured values for both hormones. In pregnant women with large abnormalities in thyroid-hormone-binding proteins, euthyroidism was accompanied by significantly lower free hormone concentrations, leading us to conclude that, in pregnancy, equilibrium may be reached at concentrations lower than those in other healthy subjects. Values for calculated and measured free thyroid hormones in "sick euthyroids" showed no discrepancy; however, we cannot exclude the possibility that non-dialyzable compounds are present that interfere with the hormone-protein binding.
Results by fluorescent immunoassay for phenytoin compared with those by enzyme immunoassay, liquid chromatography, and discrete analysis (Dupont aca).
Authors: Gonzalez G , Cid-Amador A , Steele B , Castro A 
Published: January 2020

Abstract
We describe the Ames Fluorescent Enzyme Immunoassay procedure for the detection of phenytoin in serum, and compare the results with it with those by enzyme immunoassay(EMIT), "high-pressure" liquid chromatography, and the Dupont aca. Sera from 48 patients who were receiving phenytoin were promptly analyzed in duplicate by EMIT, frozen, then assayed within four weeks by the other three methods. Correlation was good between results by the fluorescent immunoassay and the other methods. The fluorescent immunoassay procedure is sensitive and requires a small sample volume (100 microliters). Sample reading time can be shortened from 30 to 15 s as the technician becomes more proficient, with no sacrifice of accuracy. The procedure is fast, easy to perform, specific, sensitive, and inexpensive; involves no radioactivity; and requires no temperature control. It is the current method of choice for detection of phenytoin in serum, in terms of precision and accuracy.
A simple, fully enzymic bioluminescent assay for triglycerides in serum.
Authors: Björkhem I , Sandelin K , Thore A 
Published: January 2020

Abstract
In this fully enzymic bioluminescent assay, triglycerides are cleaved by lipase (EC 3.1.1.3) and carboxylesterase (EC 3.1.1.1), and the glycerol obtained is phosphorylated with ATP and glycerol kinase (EC 2.7.1.30). The ATP consumed in the latter reaction is determined by the firefly luciferin-luciferase reaction, and corresponds to the concentration of triglycerides. All the enzymic reactions and the bioluminescent reading can be performed in the same test tube. The precision (CV) of the assay varied between 1 and 7% at different concentrations with a fully enzymic method based on spectrophotometry (r = 0.98).
Liquid-chromatographic determination of pentobarbital in plasma with use of a resin column and an alkaline mobile phase.
Authors: Gupta R N , Smith P T , Eng F 
Published: January 2020

Abstract
We describe a liquid-chromatographic method involving a new, nonsilica column (XAD-2, Hamilton Co.) for pentobarbital in plasma. Plasma is extracted with chloroform after addition of the internal standard, 5-ethyl-5-p-tolyl-barbituric acid. Acidic drugs are back-extracted into alkali, then chromatographed on the resin-base reversed-phase column. The use of alkaline mobile phase allows enhanced sensitivity and detection of barbiturates at 240 nm. The within-run CV for 10 samples was 1.9%, the between-run CV 1.8%. Ten commonly used barbiturates are separated isocratically in less than 15 min. Other commonly prescribed acidic drugs do not interfere with determination of pentobarbital.
Improved direct determination of alpha- and gamma-tocopherols in plasma and platelets by liquid chromatography, with fluorescence detection.
Authors: Lehmann J , Martin H L 
Published: January 2020

Abstract
Tocopherols extracted from plasma with methanol or from platelets with chloroform/methanol were injected in methanol on a reversed-phase (C18) "high-performance" liquid-chromatographic column and eluted with water/methanol (2/98, by vol) at a flow rate of 1.4 mL/min. A "high-performance" spectrophotofluorometer was used for detection. Analytical recoveries ranged from 89 to 106%. The response was linear to at least 0.3 micrograms of either tocopherol (alpha- or gamma-) applied to the column, and the limit of detection was 0.1 ng. The method was used to measure tocopherols in plasma and platelets from human subjects, and some values are presented.
Enzyme immunoassay with flow-amperometric detection of NADH.
Authors: Eggers H M , Halsall H B , Heineman W R 
Published: January 2020

Abstract
Using phenytoin as a model analyte, we demonstrate that an enzyme-coupled immunoassay based on flow-injection analysis and amperometric detection of NADH is both feasible and practical. Good agreement with a routine clinical laboratory procedure for phenytoin was obtained for patients' serum samples. The electrode must be protected to prevent fouling by proteins in the analytical sample. The optimum detection range for NADH was at 0.01 of the concentrations of NADH generated during the several minutes required for each analysis. This suggests that the electrochemical technique should be extendable to the determination of species at concentrations in the microgram per liter range.
Radial partition immunoassay.
Authors: Giegel J L , Brotherton M M , Cronin P , D'Aquino M , Evans S , Heller Z H , Knight W S , Krishnan K , Sheiman M 
Published: January 2020

Abstract
In radial partition immunoassay, radial chromatography is used for performing an immunoassay. We describe the application of this technology to the measurement of digoxin in serum by enzyme immunoassay, with the entire testing procedure carried out on glass-fiber filter paper. A sample is applied to a small central area of the filter paper, where it reacts with the antibody to digoxin immobilized there. Subsequently, enzyme-labeled digoxin is applied to react with remaining antibody sites. After incubation, substrate for the enzyme is applied to the center of the reaction area and washes out any unbound label to the periphery of the paper. This step also initiates the enzyme reaction, which is quantified by front-surface fluorescence. A microprocessor-controlled automated instrument has been developed to process the filter paper matrix through the above sequence, and calculate the final result. Total testing time for digoxin is less than 7 min.
Development of the Biostator Glucose clamping algorithm.
Authors: Clemens A H , Hough D L , D'Orazio P A 
Published: January 2020

Abstract
The "glucose clamping" technique has been proposed as a method for the early detection of a beginning derangement of glucose homeostasis and thus for the possible prevention of maturity-onset diabetes. This technique interrupts the physiological glucose-insulin relationship by placing a patient's blood glucose concentration under an investigator's control, for quantification of the pancreatic beta-cell response during hyperglycemic clamps and of sensitivity of body tissue to exogenous insulin during normoglycemic clamps. We report the development of a glucose clamping algorithm for use with the Biostator glucose-controlled insulin-infusion system (Horm. Metab. Res., Suppl. 8: 23-33, 1977). This algorithm adds simplicity and precision to the glucose clamping procedure and reduces operator effort to a minimum. We describe the early development of the algorithm with a model system and report evaluations made during animal studies and preliminary investigations with human subjects.
Rapid enumeration of T lymphocytes by a flow-cytometric immunofluorescence method.
Authors: Ip S H , Rittershaus C W , Healey K W , Struzziero C C , Hoffman R A , Hansen P W 
Published: January 2020

Abstract
Combined with current advances in microprocessor-controlled flow cytometers, monoclonal antibodies provide a rapid means of phenotyping individual cell surface markers for a large number of clinical samples accurately and reproducibly, which may provide useful information in diagnosing disease and monitoring patients. We have developed a one-step flow-cytometric immunofluorescence procedure for enumerating E-rosette lymphocytes from whole blood by using the monoclonal antibody OKT11. This antibody recognizes the sheep erythrocyte receptor on the lymphocyte surface and can block sheep E-rosette formation. The flow cytometer we use, an Ortho Spectrum III, distinguishes lymphocytes from other leukocytes by measuring the narrow forward and right-angle light-scattering properties of the cells. The instrument further differentiates T lymphocytes frm non-T lymphocytes by measuring the green fluorescence signal of the OKT11-positive lymphocytes. In a typical sample, 1500--2500 lymphocytes are counted in 25 s. In a study of 158 patient samples, ranging from 1% to greater than 90% E-rosette-positive lymphocytes, the correlation coefficient between the manual E-rosette count and the flow immunofluorescence measurement is 0.943.
Automated intelligent microscopy (AIM) and its potential application in the clinical laboratory.
Authors: Deindoerfer F H , Boris W B , Gangwer J R , Laird C W , Tittsler J W 
Published: January 2020

Abstract
The microscope is the most ubiquitous instrument in the clinical laboratory. We discuss improvements in its use, in terms of "front-end" automation of specimen handling and "back-end" automation of image analysis: automated intelligent microscopy. Examples of spatial and spectral differentiation illustrate the potential of this automated version of microscopy as a useful tool with very powerful analytical capabilities for the clinical laboratory.
A computer-based maintenance reminder and record-keeping system for clinical laboratories.
Authors: Roberts B I , Mathews C L , Walton C J , Frazier G 
Published: January 2020

Abstract
"Maintenance" is all the activity an organization devotes to keeping instruments within performance specifications to assure accurate and precise operation. The increasing use of complex analytical instruments as "workhorses" in clinical laboratories requires more maintenance awareness by laboratory personnel. Record-keeping systems that document maintenance completion and that should prompt the continued performance of maintenance tasks have not kept up with instrumentation development. We report here a computer-based record-keeping and reminder system that lists weekly the maintenance items due for each work station in the laboratory, including the time required to complete each item. Written in BASIC, the system uses a DATABOSS data base management system running on a time-shared Digital Equipment Corporation PDP 11/60 computer with a RSTS V 7.0 operating system.
Analytical problems facing the development of electrochemical transducers for in vivo drug monitoring: an overview.
Authors: Pinkerton T C , Lawson B L 
Published: January 2020

Abstract
Even though significant progress has been made in the development of electrodes for the in vivo detection of catecholamines, oxygen, and various cations, there has been little research on the feasibility of continuously monitoring drugs in whole blood by electrochemical sensing devices. Electroanalytical problems associated with the development of such electrochemical transducers include the need for increased sensitivity and specificity, decreased biological matrix interferences, more rapid response times, improved miniaturization, and more reliable calibration procedures. We present a critical evaluation of potentiometric, conductometric, and amperometric techniques, with a brief review of basic principles and recent advances in ion-selective electrodes, chemical-sensing field-effect transistors, amperometric enzyme electrodes, and electrochemical immunosensors.