bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal conditions and comparison of lactate dehydrogenase catalysis of the lactate-to-pyruvate and pyruvate-to-lactate reactions in human serum at 25, 30, and 37 degrees C.
Authors: Buhl S N , Jackson K Y 
Published: January 2020

Abstract
We report optimal conditions for assaying highly purified human lactate dehydrogenase isoenzymes with the lactate-to-pyruvate and pyruvate-to-lactate reactions, as they apply to human serum. Interconversion of results between reactions is not practicable. Measurements of lactate dehydrogenase in either reaction direction at 25, 30, or 37 degrees C can be equally reliable if the volume fraction and the resulting deltaA/min is small. However, for interinstrument and interlaboratory comparisons, results from the lactate-to-pyruvate reaction are more reliable.
Comparison of product moment and rank correlation coefficients in the assessment of laboratory method-comparison data.
Authors: Cornbleet P J , Shea M C 
Published: January 2020

Abstract
We have studied the effects of range and distribution of data on product moment and rank correlation coefficients when deviation from a linear relationship was due solely to experimentally produced random error. All correlation coefficients (Pearson r, Spearman rho, and Kendall tau) were markedly influenced by the range of the data, and, for the rank correlation coefficients, the effect of range varied for different data distributions. While correlation coefficients may be useful in assessing whether an association exists between two variables, they are not useful in assessing the degree of random error about the regression line when a strong linear association is presumed to exist between the two variables. Thus, neither product moment nor rank correlation coefficients are of value in analysis of laboraoty method-comparison data. The standard deviation of the residual error of regression should be calculated as a measure of the random error about the regression line.
A micro-scale method for liquid scintillation counting, applicable to radioimmunoassay of steroids and substances of comparable relative molecular mass.
Authors: Grotjan H E , Steinberger E 
Published: January 2020

Abstract
A major expense of radioimmunoassay involving tritiated tracers is that of liquid scintillation counting. We present a micro-scale method that markedly reduces the cost of liquid scintillation counting. The radioimmunoassay is done in 10 X 50 mm tubes. The antibody-bound tracer is precipitated with a second antibody, the precipitate is resuspended in 0.1 ml of water, and 0.3 ml of dioxane is added. One milliliter of a toluene-based scintillation cocktail is added, and the tube is capped and placed in an adapter for liquid scintilation counting. When this method was applied to a double-antibody testosterone radioimmunoassay, it performed comparably to assays counted by the usual method.
Multilayer film elements for clinical analysis: applications to representative chemical determinations.
Authors: Spayd R W , Bruschi B , Burdick B A , Dappen G M , Eikenberry J N , Esders T W , Figueras J , Goodhue C T , LaRossa D D , Nelson R W , Rand R N , Wu T W 
Published: January 2020

Abstract
Using the general concept of a dry multilayer analytical element, we can change chemical procedures and configurations to assay several blood components. In the assay of serum urea nitrogen, urease in the reagent layer catalyzes the hydrolysis of urea. A semipermeable membrane excludes aqueous base, but allows ammonia to diffuse to an underlying indicator layer. For the amylase determination, the enzyme hydrolyzes a dyed-starch substrate coated on top of the spreading layer; this produces small fragments, which diffuse to a registration layer. The increase of absorbance at 540 nm is correlated with amylase activity. Bilirubin complexes with a cationic polymer at the interface between the spreading and reagent layers. The direct reading at 460 nm allows determination of total bilirubin in the range 1 to 500 mg/liter. Tirglycerides are hydrolyzed in the spreading layer, and the resulting soluble glycerol readily diffuses into the reagent layer, where it is phosphorylated and subsequently oxidized by glycerophosphate oxidase to yield dihydroxyacetone phosphate and hydrogen peroxide. Peroxidase catalyzes production of a color commensurate with the hydrogen peroxide produced.
Coupled reactions of immobilized enzymes and immobilized substrates: clinical application as exemplified by amylase assay.
Authors: Barabino R C , Gray D N , Keyes M H 
Published: January 2020

Abstract
We described a partitioned enzyme-sensor system, which incorporates an immoblized substrate and three or more discrete immobilized enzymes. This instrument measures alpha-amylase activity by passing the solution containing alpha-amylase over a column packed with immobilized starch. The resulting oligosaccharides are successively exposed to a column or columns containing immobolized glucose oxidase, catalase, glucoamylase or maltase, and glucose oxidase. The resulting hydrogen peroxide is detected by a three-electrode amperometric cell. All immobilized reagents were immobilized on a particulate, porous alumina to allow rapid and constant flow rate. With use of less than optimum immobilized reagents, alpha-amylase activity has been measured from about 5 to 200 kU/liter with a 50 microliter sample size. Lack of sensitivity is predominantly attributable to the low activity and low stability of immobilized maltase and glucoamylase. We believe that a clinical test using this system is feasible and desirable because the immobilized reagent system should allow for testing of alpha-amylase with excellent precision, convenience to the operator, and low cost.
External quality-control survey of cholesterol analyses performed by 12 lipid research clinics.
Authors: Lippel K , Ahmed S , Albers J J , Bachorik P , Muesing R , Winn C 
Published: January 2020

Abstract
We report accuracy and precision achieved in the automated analysis for cholesterol in a long-term multilaboratory study, presenting and evaluating the significance of data accumulated by 12 Lipid Research Clinics (LRC's) in the analysis of 18 unknown surveillance pools during three years. The average bias for all pools and for 13 autoAnalyzer II (Technicon Instruments Corp., Tarrytown, N.Y. 10591) instruments in the 12 clinics was -0.41% (range -1.2 to +0.3%), as compared to values established by reference methodology. The regression equation relating observed cholesterol values (y) to reference values (x) was: y = 0.35 + 0.977x. The bias varied from pool to pool (-2.3 to +5.3%), positive biases being observed for pools with cholesterol concentrations less than 1.4 g/liter, and negative biases for those pools with higher concentrations. Total standard deviations ranged between 25 and 75 mg/liter, and total CV's for most individual instruments were between 1 and 3%. Of the variability for a particular pool, less than 20% was due to differences among instruments, and within- and between-run variabilities were approximately equal. These trends were the same as those previously observed [Clin. Chem. 23, 1744 (1977)] in the analysis of bench control pools of known cholesterol concentration.
Liquid-chromatographic determination of serotonin in serum and plasma.
Authors: Sasa S , Blank C L , Wenke D C , Sczupak C A 
Published: January 2020

Abstract
Using high-performance liquid chromatography with electrochemical detection, we determined serotonin in plasma from parkinsonian patients being treated with L-3,4-dihydroxyphenylalanine or N-(DL-seryl)-N'(2,3,4-trihydroxybenzyl)hydrochloride plus L-3,4-dihydroxyphenylalanine ("Sinemet") and in serum from a blood bank, from "normal" persons, and a pooled specimen from a hospital clinical laboratory. The values obtained for the two groups of Parkinson's disease patients showed no significant difference. Long-term storage on solid CO2 was xhown to be an adequate technique for preserving samples. The mean (+/-SEAM) normal value obtained for serotonin in serum was 146 +/- 46 microgram/liter (n = 23), a result in harmony with that previously obtained [Clin. Chem. 20, 812 (1974)] by fluorometry. In comparison to other methods for measurement of serotonin in serum or plasma, we believe that the present scheme offers greater selectivity, sensitivity, and precision.
An improved technique for immunofixation of electrophoretograms.
Authors: Karinkanta H H , Nieminen E J 
Published: January 2020

Abstract
Immunofixation coupled with electrophoresis is winning favor as an easy, sensitive, and versatile method for detecting specific protein fractions. Here, we discuss problems which appear when antisera are applied onto the electrophoretic medium (Cellogel or cellulose acetate). Longitudinal slits can be made in the electrophoretic medium without worsening resolution. Such longitudinally slitted electrophoretic membranes can be used in electrophoresis and specific antisera applied simply by pipetting them onto the electrophoretograms. The method has been used successfully in typing immunoglobulins.
Performance of the Du Pont aca ammonia method.
Authors: Doumas B T , Hause L L , Sciacca R D , Jendrzejczak B , Foreback C C , Hoover J D , Spencer W W , Smock P L 
Published: January 2020

Abstract
We evaluated the performance of the Du Pont aca ammonia procedure with regard to (a) linearity, (b) precision, (c) interferences, and (d) effect of anticoagulants. Linearity extends to 2,000 mumol/L. The SD of the method was essentially constant (2 to 3 mumol/L) and independent of the NH3 concentration. Hemoglobin, bilirubin, and lipemia do not interfere. Either EDTA or heparin is suitable as anticoagulant. Recovery of NH3 added to plasma samples averaged 102% (range: 97--107%). We established normal values by measuring NH3 in 188 plasma samples from apparently healthy individuals. The 95% confidence range is from 10 to 35 mumol/L. The aca ammonia method compares very well with that of Kingsley and Tager but correlates less strongly with that of Reinhold and Chung. We describe a protein-based solution with stable NH3 concentration that is suitable as a control material.
Chemical inhibition used in a kinetic urease/glutamate dehydrogenase method for urea in serum.
Authors: Sampson E J , Baird M A 
Published: January 2020

Abstract
We describe a fixed-time-interval, kinetic inhibition method, with use of a competitive inhibitor (l) of the urease/glutamate dehydrogenase reaction to increase the "apparent" Michaelis constant by a factor of (1 + [l]lKl). This allows greater flexibility in selecting an appropriate sample dilution for kinetic determinations of urea in serum (i.e., [S]lKm ratio). Nine compounds were screened as potential inhibitors for this study. Adding 5 mmol of hydroxyurea per liter increases the "apparent" Michaelis constant for the coupled enzyme reaction by 10-fold. We used a sample dilution of 21-fold vs. dilutions of 141- to 350-fold for previously reported kinetic methods. Mean analytical recovery with this method was 100.2%. Reaction rate vs. urea concentration was linear, and complete recovery extended to 30 mmol of urea per liter. Of 22 potential interferents, only fluoride (250 mmol/L) and bilirubin (1 mmol/L, or 580 mg/L) caused greater than 5% interference. We discuss precision and effects of specimen dilution, and compare results for 100 specimens with those by a manual Berthelot-indophenol method, a manual diacetyl monoxime method, and a diacetyl monoxime method adapted to continuous-flow analysis.
Rate nephelometric measurement of rheumatoid factor in serum.
Authors: Finley P R , Hicks M J , Williams R J , Hinlicky J , Lichti D A 
Published: January 2020

Abstract
We describe the measurement of rheumatoid factor in human sera with a rate nephelometer. The National Reference Preparation for Rheumatoid Factors is used to calibrate the assay in International Units. We used Hyland Positive Control, Level I, as a secondary standard. The standard curve is exponential, but is linear when plotted on log-log graph paper. Aggregated immune globulin (IgG) is the antigen used to detect rheumatoid factor (IgM-class antibody to IgG). The rate reaction measures the rate of increase in light-scatter by the antigen-antibody complexes; the reaction takes place in 17 to 20 s. Precision, linearity, and accuracy are excellent. Results agree well with those for a commonly used latex precipitation test. The advantages of speed, quantification in International Units, and superior discrimination of concentration as compared to serological titration provide a more reliable test for use in the diagnosis and treatment of rheumatoid arthritis.
Re-evaluation of turbidimetry of proteins by use of aromatic sulfonic acids and chloroacetic acids.
Authors: Ebina S , Nagai Y 
Published: January 2020

Abstract
From studies on 11 different proteins (including native albumin and albumin with reduced disulfide-bridges) treated with sulfosalicylic, 2-naphthalenesulfonic, toluenesulfonic, dichloroacetic, or trichloroacetic acids, we elucidate the interactions determining the resulting turbidities and other factors affecting turbidities, and we discuss the clinical utility of such turbidimetry. At least three interactions are important in determining turbidity: reduction of positive charges on the protein, hydrogen bonding of the non-ionized chloroacetic acids with the protein, and hydrophobic interaction of the aromatic sulfonic acids with albumin. Turbidity varies appreciably with the species of acid and protein, concentrations of acid, temperature, and standing time after acid is added. We conclude that this technique should be restricted to confirming proteinuria.
An "antibody electrode," preliminary report on a new approach in enzyme immunoassay.
Authors: Boitieux J L , Desmet G , Thomas D 
Published: January 2020

Abstract
We report preliminary experiments on a new, sensitive, and reliable procedure for enzyme immunoassay of various antigens in biological fluids. The method, developed from the biological model "hepatitis B surface-antigen/antibodies," is less time consuming than most immunochemical techniques and eliminates many inconveniences arising from use of isotopes. We use a solid-phase "sandwich" procedure, the antibodies being immobilized on gelatin membranes, and determine antigen concentration with the help of an iodide-sensitive electrode modified by fixing the active membrane onto the crystal sensor. We have established the analytical criteria of the method and compared it with the solid-phase radioimmunoassay for the surface antigen in dilution series. One-tenth microgram of antigen per liter can be reproducibly detected with our method. Use of antibody electrode should easily be extended to assay of other antigens and haptens that usually are determined by radioimmunoassay.
An evaluation of ethylene glycol-based liquid specimens for use in quality control.
Authors: Pope W T , Caragher T E , Grannis G F 
Published: January 2020

Abstract
We investigated the analytical acceptability of ethylene glycol-based control sera by preparing sets of aqueous and ethylene glycol-based specimens that had added uric acid, calcium, creatinine, glucose, urea, sodium, and potassium. Ethylene glycol caused a significant systematic proportional bias in procedures involving dialysis, but had no discernible effect on methods not involving dialysis. The extent of bias was proportional to the concentration of ethylene glycol, was independent of protein concentration, and differed according to the type of dialysis system used. We conclude that ethylene glycol-based control materials can have useful applications in clinical chemistry, but caution must be exercised in their use with analytical systems that employ dialysis.
Multi-channel, probe colorimeter for use with the micr-ELISA test, which makes use of disposable flat-bottom microhemagglutination plates.
Authors: McMurray C H , Blanchflower W J 
Published: January 2020

Abstract
We describe a multiprobe colorimeter that permits the reading of enzyme-linked immunosorbent assays (ELISA) in situ, by use of microhemagglutination plates. The use of dipping probes eliminates interference from meniscus effects and air-bubble entrapment. Detailed validation tests have been done and potential sources of inaccuracy identified.
Method for determining thiocyanate in serum and urine.
Authors: Lundquist P , Mårtensson J , Sörbo B , Ohman S 
Published: January 2020

Abstract
We describe a method for rapid and specific measurement of thiocyanate in serum or urine. We separate thiocyanate from interfering compounds by adsorbing it on an anion-exchange resin that has special affinity for thiocyanate, then eluting with sodium perchlorate. The eluted thiocyanate is quantified by a modified König reaction, sodium hypochlorite being used as the chlorinating reagent. Analytical recovery of thiocyanate added to serum and urine was quantitative; the coefficient of variation was 2.3% for both within-day and between-day precision. Cyanide and certain antibiotics interfere, but may be eliminated by including additional washing steps in the usual procedure. The proposed procedure was compared with another method, based on the oxidation of thiocyanate to cyanide. Agreement was satisfactory, both for serum and urine.
Anaphylaxis in the mouse--a model for using two-dimensional electroimmunodiffusion to study pathological changes in multiple serum proteins simultaneously.
Authors: Quintero S , Crowle A J 
Published: January 2020

Abstract
Two-dimensional electroimmunodiffusion is rarely used in clinical chemistry, because its potentialities are not yet widely appreciated. Studying mouse anaphylaxis, we observed with this technique certain striking short- and long-term pathologic changes in several important serum antigens, which aptly demonstrate its uniqueness and potential clinical usefulness. We present some of these observations here, for illustration. We analyzed sera from CF-1 female mice that had been anaphylactically shocked with chicken conalbumin antigen and bled 45 min to 22 days afterward. In three separate experiments, with samples of serum being analyzed only once each, this technique easily and surely detected quantitative and (or) qualitative changes in several serum antigens. We discuss here the changes in 7S gamma1 immunoglobulin, C3 globulin, hemopexin, and alpha lipoprotein, and explain how some of these changes would have been difficult and others impossible to detect by currently routine tests. We urge the adoption of two-dimensional electroimmunodiffusion for frequent use in the clinical laboratory for diagnosis, prognosis, and monitoring pathological conditions.
Direct determination of mercury in blood by use of sodium borohydride reduction and atomic absorption spectrophotometry.
Authors: Sharma D C , Davis P S 
Published: January 2020

Abstract
A method is presented for the rapid determination of total mercury in blood. The reagent used is alkaline sodium borohydride, and no digestion of the sample is needed. The detection limit and sensitivity are 1.15 and 1.59 ng of Hg, respectively. The method gives reproducible results (the CV ranged from 5.3 to 6.7% for low and high mercury blood samples, respectively), comparable to those obtained by the digestion method. The mean analytical recoveries of added mercuric chloride and methylmercuric chloride were 106.65 and 99.02%, respectively. Other advantages of the method are freedom from contamination encountered with digestion methods and elimination of matrix effects.
Hyperamylasemia and ovarian carcinoma.
Authors: Sandiford J A , Chiknas S G 
Published: January 2020

Abstract
We present a case of advanced ovarian carcinoma associated with high concentrations of serum and urine amylase. Biochemical analysis to elucidate the nature and origin of the hyperamylasemia identified seven amylase isoenzymes, of which five appeared to be distinct from normal salivary and pancreatic amylase. We discuss the nature of amylase isoenzymes produced by malignant tumors.
Isoelectric focusing of serum proteins on modified thin cellulose-acetate membranes.
Authors: Ambler J , Walker G 
Published: January 2020

Abstract
We applied a method previously described for treating cellulsoe acetate gel strips with boron trifluoride in methanol, to make them suitable for isoelectric focusing of proteins, to dry cellulose acetate membranes. The results obtained are shown to compare very favorably. Both wide and narrow pH gradients may be used and coupled either to conventional protein staining or to specific identification by immunofixation. Focusing ordinarily takes 90--120 min, is technically easy, and is economical in the use of ampholytes.
IgD myeloma protein with "unreactive" light chain determinants.
Authors: Cejka J , Kithier K 
Published: January 2020

Abstract
Serum from a patient with multiple myeloma showed a monoclonal protein, classified by immunoelectrophoresis as IgD. Immunofixation electrophoresis and immunoelectrophoresis failed to demonstrate a precipitation reaction between the paraprotein and antisera to immunoglobulin light chains. The light chains of the monoclonal protein, immunologically inaccessible in the intact molecule, reacted with anti-lambda chain antisera only after reduction and alkylation of the paraprotein. Moreover, interpretation of the immunoelectrophoretic patterns was hampered by the presence in patient's serum of free lambda chains having about the same mobility as that of the paraprotein.
Solid-phase radioimmunoassay with protein-A-bearing Staphylococcus aureus cells used to assay a protein (ferritin) and a hapten (digoxin).
Authors: Gauldie J , Tang H K , Corsini A , Walker W H 
Published: January 2020

Abstract
We compared use of protein-A-containing Staphylococcus aureus bacteria with conventional ammonium sulfate precipitation and second-antibody methods of separating bound and free antigen in the radioimmunoassay of a hapten (digoxin) and protein (ferritin) in human sera. In each case, values obtained with the heat-killed, formalin-fixed bacteria correlated well with those found by established methods. No matrix effects were detected in either hapten or protein measurements. Because of the affinity of S. aureus for rabbit IgG, rabbit antisera could be used with a small number of bacteria to detect antigen in the presence of 50-fold excess human IgG. The availability of S. aureus and ease of handling make this reagent a rapid, economical alternative of general applicability in radioimmunoassay.
Extraction and determination of chloroform in rat blood and tissues by gas chromatography-electron-capture detection: distribution of chloroform in the animal body.
Authors: Vogt C R , Liao J C , Sun A Y 
Published: January 2020

Abstract
We have developed a simple, sensitive, and accurate method for the determination of chloroform in rat blood, brain, kidney, liver, and fat. The detection limit is 2.5 ng of chloroform per gram of tissue. Studies of in vivo distribution of chloroform in rat blood and target tissues after intragastric intubation of chloroform/water show that the amount of chloroform accumulated in the different tissues increases with increasing doses. Fat tissue contains the greatest amount of chloroform. The accumulation of chloroform in rat blood and target tissues seems to be maximum 1.5 h after administration, and the apparent chloroform concentration is almost at baseline value 8 h later.
Immunoglobulins in cerebrospinal fluid in various neurologic disorders.
Authors: Bouloukos A , Lekakis J , Michael J , Kalofoutis A 
Published: January 2020

Abstract
We determined the concentrations of immunoglobulins A, G, and M in cerebrospinal fluid of 16 patients suffering from multiple sclerosis, 13 with non-bacterial meningitis, 10 with stroke syndrome, and 13 with epilepsy. The differences in concentrations of immunoglobulins in these groups were remarkable in the patients with multiple sclerosis, meningitis, or stroke syndrome. We propose that the determination of the absolute immunoglobulin content in cerebrospinal fluid is of greater significance than the relative immunoglobulin concentration.