bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrophoresis on Cellulose Acetate and Chromatography on DEAE-Sephadex A-50 Compared in the Estimation of Creatine Kinase Isoenzymes
Authors: Yasmineh Walid G , Hanson Naomi Quast 
Published: January 2020

Abstract
We have compared two methods for separating the isoenzymes of creatine kinase in serum and measuring their activity: chromatography on diethylaminoethyl-. Sephadex A-50, with both continuous and discontinuous gradient elution, and electrophoresis on cellulose acetate. Results by continuous and discontinuous gradient elution correlated well both for tissue extracts and sera. Electrophoresis on cellulose acetate is evidently less sensitive than the chromatographic method for detecting and measuring low activities of the isoenzyme designated MB. We describe how the isoenzymes may be separated by discontinuous gradient elution from microcolumns of the Sephadex and their activity rapidly quantitated by the Rosalki method [J. Lab. Clin. Med. 69, 696 (1967)], with a centrifugal analyzer.
Separation of Creatine Kinase Isoenzymes in Serum by Ion-Exchange Column Chromatography (Mercer's Method, Modified to Increase Sensitivity)
Authors: Nealon Daniel A , Henderson Arthur R 
Published: January 2020

Abstract
We describe our experience with Mercer's method [Clin. Chem. 20, 36 (1974)] for separating isoenzymes of creatine kinase (EC 2.7.3.2) in serum by ion-exchange chromatography. By using diethylaminoethyl cellulose rather than diethylaminoethyl Sephadex in the column and by changing the ionic strength of the eluting buffer, we could detect a significant proportion of the MB isoenzyme of serum creatine kinase at normal activities of creatine kinase in serum, even in the absence of cardiac disease.
Improved Biuret Procedure for Routine Determination of Urinary Total Proteins in Clinical Proteinuria
Authors: Rice Eugene W 
Published: January 2020

Abstract
This communication describes and evaluates an improved routine methodology for quantitating clinical proteinuria. Based on investigations of Piscator and of Savory et al., a modified Tsuchiya's reagent (ethanolic HCl-phosphotungstic acid) is used to precipitate proteins at 56 °C, followed by biuret spectrophotometry at 540 nm. The accuracy of the proposed procedure was assessed by comparisons with results obtained by using an ultrafiltration membrane that retains solutes with an average molecular weight in excess of 10 000 for separating of urinary proteins before they are measured with the biuret reaction. Precision of the method (coefficient of variation) is typically 2-3%.
Use of Nucleic Acid Hybridization for Specific Detection of Submicrogram Quantities of DNA, and Its Application to Human Plasma
Authors: Steinman Charles R 
Published: January 2020

Abstract
A technique is described for using radiolabeled RNA complementary to human DNA as a probe for the specific identification of submicrogram concentrations of human DNA by formation of RNA-DNA hybrids. An example is given of its application to the semiquantitation of human DNA in human plasma, a substance that is ordinarily difficult to examine because materials are present that interfere with the usual colorimetric or fluorometric assays. An example is also given of the use of an analogous approach to analyzing rabbit serum for circulating bacterial DNA. Unique to the hybridization technique is a degree of specificity sufficient to identify specific base sequences and hence the origin of the DNA being detected, a point that may be important in the examination of circulating DNA reported to occur in patients with systemic lupus erythematosis. This technique may also be of value in clarifying the presently conflicting data regarding the occurrence of free DNA in the normal human circulation.
Lipase-Triggered Kinetic Assay of Serum Triglycerides
Authors: Bucolo Giovanni , McCroskey Ralph , Whittaker Nadine 
Published: January 2020

Abstract
We describe a kinetic method for assay of serum or plasma triglycerides, by use of an enzymatic hydrolysis and reaction sequence already described [Clin. Chem. 19, 476 (1973)]. The reaction is triggered by addition of lipase, at a time when free glycerol, or pyruvate (or both) are no longer present. In this method, therefore, there is no need for a blank glycerol assay. In the procedure, reagents are used that are available commercially in the form of stable, dry powders; the method for the preparation of the reagents has been changed to achieve improved stability and performance. Stability and recovery of added triglycerides are satisfactory.
pH Dependence of the Binding of Folates to Milk Binder in Radioassay of Folates
Authors: Givas Joan K , Gutcho Sidney 
Published: January 2020

Abstract
We compare the binding of folic acid and N-5-methyltetrahydrofolic acid to milk binder in the pH range 7.4 to 10.1. At pH 7.4 the relative affinities are quite disparate, with folic acid showing the greater affinity for milk binder. As the pH is increased from 7.4 to 9.3, the difference in affinities becomes smaller, and at pH 9.3 the affinities are nearly the same. As the pH is Increased from 9.3 to 10.1, the relative affinities again begin to differ, with N-5-methyltetrahydrofolic acid displaying the greater affinity. These results indicate that at a pH of 9.3 the more stable folic acid may be used as the standard in radioassay of endogenous folates.
Micro-Scale Blood Lead Determinations in Screening: Evaluation of Factors Affecting Results
Authors: Marcus Martin , Hollander Melvin , Lucas Robert E , Pfeiffer Norman C 
Published: January 2020

Abstract
The Delves micro-scale technique for blood lead analysis is an accurate method for screening capillary blood specimens, obtained by fingerstick, for lead intoxication. Results are affected by the age of cup, loop, and hollow-cathode tube and by the spatial relationship between optical tube and cup. Because the glass in many commercially available capillary tubes (used in specimen collection) contains lead and cannot be decontaminated, a lead-free glass tube must be used. A solution of citric acid in ethanol (20 g/liter) effectively cleanses the puncture site. A double-blind study of 207 specimens gave a mean value of 276.6 ± 105.8 µg/liter (1 SD) for the micro-scale method vs. 273.2 ± 99.0 for a macro-scale method. The mean coefficent of variation for the micro-scale method was 5.75% ± 1.9 (SD). We conclude that values of 480 µg/liter or below are not "toxic" (i.e., are significantly less than 600 µg/liter, the value at which therapy is begun). The method is shown to be satisfactory as a screening procedure and for confirming lead analyses done by other methods.
Ultramicro Analysis for Copper, Cadmium, and Zinc in Human Liver Tissue by Use of Atomic Absorption Spectrophotometry and the Heated Graphite Tube Atomizer
Authors: Evenson Merle A , Anderson C Thomas 
Published: January 2020

Abstract
We describe a method of analysis for copper, cadmium, and zinc in a 15-mg (wet weight) sample of human liver by atomic absorption spectrophotometry. The sample is digested with nitric acid (1.0 mol/liter), evaporated, and dilute HNO3 (10 mmol/liter) added. The reconstituted acid mixture is injected into the graphite tube atomizer for analysis of Cu and Cd and aspirated into the airacetylene flame for measurement of Zn. The absorbance for each metal is suppressed with increasing pH. NaNO3, KNO3, KCl, and NaCl (e.g.) quench the Cd absorbance in acid solutions that contain no protein, but not in the presence of protein. Metal ions added to the predigestion human liver sample at 10% and 100% of the intrinsic metal concentrations were, respectively, 93% and 90% accounted for analytically in the case of Cu, 98% and 102% for Zn, and 101% and 93% for Cd. Analysis of a National Bureau of Standards' Bovine Liver Standard Reference Material yielded results corresponding to 99% (Cu), 112% (Zn), and 91% (Cd) of the mean expected concentrations of these metals. The between-run coefficient of variation for the bovine liver material was 6% for Cu, 9% for Zn, and 10% for Cd. For 16 histologically normal samples of human liver, the mean values were: Cu, 26; Zn, 293; and Cd, 6.0 nanograms of metal per milligram dry weight, in agreement with values published previously. The method can be easily and reliably applied to small samples of liver obtained by closed-needle biopsy.
Effect of the Matrix of the Standard on Results of Atomic Absorption Spectrophotometry of Zinc in Serum
Authors: Momčilović Berlslav , Belonje Bartholomeus , Shah Bhagwan G 
Published: January 2020

Abstract
Zinc in pooled human serum, diluted 10-fold with demineralized water, was determined by flame atomic absorption spectrophotometry. Recoveries of zinc added to the serum were calculated by use of standards prepared in water, physiological saline, synthetic serum, or dilute HNO3 (10 ml/liter). The flow rates were essentially the same (9.1 to 9.3 ml/min) for water, diluted synthetic serum or actual human serum, and diluted nitric acid. The mean apparent percentage recoveries (±SD) were the best (102.6 ± 2.5) when the standards were prepared in nitric acid; the values obtained when standards in water were used were too high (111.5 ± 3.9); those with standards prepared in physiological saline (92.0 ± 3.2) or synthetic serum (92.3 ± 2.5) were too low.
Some Aspects of Specimen Collection and Stability in Trace Element Analysis of Body Fluids
Authors: Anand Vir D , White James M , Nino Hipolito V 
Published: January 2020

Abstract
Analyses for trace elements in biological fluids are uniquely susceptible to extreme errors unless special precautions are taken during collection, storage, and analysis. The integrity of the specimen may be compromised before it is analyzed, by contamination during collection and processing or by attenuation of the analyte concentration during storage. If this happens, determined values are not valid even though the method of analysis is extremely sensitive and highly accurate. Obstacles to obtaining precise and accurate analytical data arising from these factors are discussed. We consider control procedures applicable at all stages for ascertaining the sources of error and eliminating them.
The Prostaglandins in Clinical Medicine. A Developing Role for the Clinical Chemist
Authors: Russell Paul T , Eberie Andrea J , Cheng Hsien C 
Published: January 2020

Abstract
We review the ways that prostaglandins might relate to clinical chemistry. Clinical aspects that are discussed include hypertensive diseases, disorders of the gastrointestinal tract, cancer, inflammation and fever, effects on platelets, the respiratory system and asthma, and reproduction. A survey of procedures for the storage, extraction, separation, and quantitation of the prostaglandins is also presented.
Use of Carbon Dioxide- and Oxygen-Tonometered Phosphate— Bicarbonate—Chloride—Glycerol—Water Mixtures for Calibration and Control of pH, pco2 and pO2 Electrode Systems
Authors: Veefkind A H , Van den Camp R A M , Maas A H J 
Published: January 2020

Abstract
Calibration of pH, pco2, and po2 electrode systems of modern blood—gas analyzers, designed with one sample cuvet for measurement, is mostly performed separately with buffer solutions and gas mixtures. We describe the development of solutions of known pH, pco2 and po2 for doing such calibrations simultaneously, containing phosphate, bicarbonate, and chloride in glycerol—water mixtures as solvent. A method is suggested for computing the relation between pH and log pCO2 of these solutions in equilibrium with carbon dioxide gas. It is demonstrated that a solution of phosphate (Na2HPO4, KH2PO4, each 25.mmol/liter), bicarbonate (NaHCO3, 30 mmol/ liter), and chloride (NaCI, 30 mmol/ liter) in glycerol-water mixture (3/7 by vol) and equilibrated with CO2 in air (4 vol/100 vol) and CO2 in nitrogen (8 vol/100 vol), respectively, makes possible accurate and simultaneous calibration of the pH, pco2, po2 electrodes of a Corning Model 165 blood—gas analyzer. Similar solutions may also be used for quality—control of blood—gas measurement.
Preparation of a Modified Glucose Oxidase Reagent for the Polarographic Determination of Glucose with the Beckman "Glucose Analyzer"
Authors: Fischl Joseph , Federman Doža , Talmor Nira 
Published: January 2020

Abstract
In this modification, glucose oxidase, 140-180 U/ml, is dissolved in acetate buffer (pH 6):ethanol (96%):glycerol (80:10:10 by vol). Iodine and molybdate are used as catalysts, formaldehyde and mercuric iodide as preservatives, and octanol as an antifoaming agent. The reagent is suitable for use in the Beckman "Glucose Analyzer," it is stable at room temperature for at least six months, it is sensitive, it has a lubricating effect, and its cost is less than a fifth as much as the "Certified" Beckman reagent. It is not suitable for the measurement of glucose in samples containing maltose, cellobiose, gentiobiose, starch, and glycogen.
Improved Radioimmunoassay of Plasma Cortisol
Authors: Donohue John , Sgoutas Demetrios 
Published: January 2020

Abstract
We report a simplified radioimmunoassay procedure for determination of plasma cortisol. The method offers the advantage that tracer, antibody, and assay buffer are added in a single step with the use of semi-automated equipment. Thus, critical pipetting procedures are minimized, and assay time is reduced to 4 h. No prior extraction or chromatographic purification of cortisol is required. The procedure is simple, reliable, and accurate. For either between-assay or within-assay determinations, the coefficients of variation are about 6%. Our results compare well with those obtained from a procedure that included extraction and chromatographic purification of cortisol in several plasma samples. Conditions for optimizing the assay are also discussed.
Procedure for Calibrating the Technicon Colorimeter I
Authors: Black John C , Furman William B 
Published: January 2020

Abstract
We describe a rapid method for calibrating the Technicon AutoAnalyzer colorimeter I. Test solutions of bromphenol blue are recommended for the calibration, in preference to solutions of potassium dichromate, based on considerations of the instrument's working range and of the stray light characteristics of the associated filters.
Gas—Liquid Chromatographic Measurement of Guanidino Acids
Authors: Patel Harini , Cohen Burton D 
Published: January 2020

Abstract
We present a method for separating and measuring guanidino acids by gas—liquid chromatography. Compared to ion-exchange techniques, this system is faster, more sensitive, requires smaller sample volumes, is independent of colorimetric reactions, and permits simultaneous determination of both amino and guanidino acids. N-Trifluoroacetyl-n-butyl esters are formed and then are separated by using a column containing a mixed silicone liquid phase coated on Chromosorb W-HP. Analytical recoveries from plasma ranged from 86 to 112% and were optimal when purification and derivatization were done without prior protein precipitation. Speculations as to the cause of this interference by protein include coprecipitation, protein-binding, and cyclization of the guanidines in the acids used for denaturation. Evidence presented suggests that all three occur: ultrafiltrability is diminished in the presence of protein and nuclear magnetic resonance demonstrates cyclization of some of these esters.
Rapid Separation of Plasma Creatine Kinase Isoenzymes by Batch Adsorption on Glass Beads
Authors: Henry Philip D , Roberts Robert , Sobel Burton E 
Published: January 2020

Abstract
To separate the MM and MB creatine kinase (EC 2.7.3.2) isoenzymes in small plasma samples, we developed a simple, rapid ion-exchange batch-adsorption procedure with "DEAE Glycophase" glass beads (Corning). All separative steps are performed in a single test tube and can be completed within a few minutes. Results of measurements of isoenzymes in plasma samples from patients with acute myocardial infarction were compared to those obtained with an independent quantitative assay method previously reported. Additional measurements were performed on standard plasma samples containing mixtures of MM and MB isoenzyme purified from human myocardium. Results by the two independent assay procedures agreed well, as did measured isoenzyme activities and activities predicted from the amounts of isoenzyme added. Activities in the fractions containing separated isoenzymes were measured by a direct kinetic fluorometric assay. MB activities in normal plasma averaged 1.6 ± 0.28 U/liter (mean ± SD).
Evaluation of the Revised Serum Calcium Procedure Used with the Du Pont Automatic Clinical Analyzer
Authors: Sage Gloria Welt , LeFever David , Henry John Bernard 
Published: January 2020

Abstract
We evaluated a revised serum calcium method (o-cresolphthalein complexone) used with the Du Pont aca. Our results correlated well with those obtained by atomic absorption spectrometry. Within-run and day-to-day coefficients of variation were 0.5 and 1.5%, respectively. Color produced and calcium concentration are linearly related and the relation is not affected by hemolysis, lipemia, or icterus.
Direct Method for Measuring Lipoprotein-X in Serum
Authors: Neubeck Wolfgang , Seidel Dietrich 
Published: January 2020

Abstract
We describe a fast and easy method for routine quantitation of the abnormal lipoprotein, lipoprotein-X. The procedure is based on densitometry of precipitation areas obtained for it after serum electrophoresis in agar gel followed by precipitation with polyanions. The coefficient of variation was less than 3% in one series. Results were linearly related to concentration in the range 0.063 to 6.3 g/liter.
Relative Usefulness of Measuring Polyamines in Serum, Plasma, and Urine as Biochemical Markers of Cancer
Authors: Russell Diane H , Russell Shauna D 
Published: January 2020

Abstract
Serial samples of plasma and serum were collected in the morning and afternoon from cancer patients, along with 24-h urine specimens. Values for serum and plasma samples taken at the same time from the same patient differed little, suggesting that either procedure is acceptable for polyamine analysis. Increases in concentrations of putrescine and spermidine in serum and plasma correlate well with such increases in 24-h urine samples. Spermidine concentrations in sera were consistently about 10-fold lower than corresponding urine values. Putrescine concentrations were 10to 100-fold different. The variation in putrescine values may be due to its more active metabolism by diamine oxidase, an enzyme known to be present in serum. Concentrations of polyamines in serum and urine increased in response to effective chemotherapy.
Molar Absorptivities of β-NADH and β-NAD at 260 nm
Authors: Hald Erich , Lehmann Paul , Ziegenhorn Joachim 
Published: January 2020

Abstract
To determine the molar absorptivities of β-NADH and β-NAD at 260 nm, we purified the reduced form of the coenzyme by repeated anion-exchange chromatography. A NADH preparation was so obtained for which the 260 nm/340 nm absorbance ratio was 2.265. When calculated with εβ-NADH340 = 6.22 x 103 for β-NADH at 260 nm and 25 °C, a molar absorptivity of 14.1 x 103 liter · mol-1 · cm-1 resulted from this quotient. By use of the lactate dehydrogenase or glycerol-3-phosphate dehydrogenase assay, respectively, and referring to the new absorption coefficient for NADH at 260 nm, the molar absorptivity of β-NAD at 260 nm and 25 °C was established to be 17.4 x 103 liter · mol-1 · cm-1. The values observed are lower than those reported thus far.
Rate of Decrease in Serum Ethchlorvynol Concentrations after Extreme Overdosage—A Case Study
Authors: Pochopien Donald J 
Published: January 2020

Abstract
Ethchlorvynol is a commonly abused sedative hypnotic. I report here a seven-day study of serum ethchlorvynol concentrations in a patient who had received an extreme overdose. These concentrations were correlated with the patient’s response to stimuli. Serum ethchlorvynol concentrations were logarithmically related to time, a fact that can be useful in predicting when a patient’s serum ethchlorvynol concentration will return to a therapeutic concentration. In this case the decrease was about 35% per 24 h.
Comparison of Electrophoresis on Citrate Agar, Cellulose Acetate, or Starch for Hemoglobin Identification
Authors: Hicks Edward J , Hughes Blossie J 
Published: January 2020

Abstract
We compare and discuss three electrophoretic methods for identifying hemoglobins S, A, C, F, and D or G. Electrophoresis on citrate agar gel was more sensitive than electrophoresis on cellulose acetate for detecting hemoglobins S and F, a fundamental consideration in designing cord-blood screening programs for detecting hemoglobin S carriers. Electrophoresis on starch gel is evidently an acceptable method for subtyping hemoglobins AA, CC, AS, SS, AC, and SC, and is more sensitive than cellulose acetate for identifying hemoglobin A1A2. Costs for the citrate agar gel, cellulose acetate, and starch gel procedures are presented.
Practical Applications of Radioimmunoassay Theory. A Simple Procedure Yielding Linear Calibration Curves
Authors: Fernandez Alberto A , Loeb Harold G 
Published: January 2020

Abstract
The fundamental equation describing radioimmunoassays under equilibrium conditions has been recast into a "working equation" in a form more directly applicable to the requirements of the analytical laboratory. Plotting total counts over counts bound vs. ligand concentration, which is conveniently linear over most of its course, is shown readily to yield quantitative data relative to binding site concentration and the equilibrium constant and to provide a means for deriving apparent labeled ligand concentration. Such data are helpful in establishing optimum assay conditions and can serve a continuing quality-control function. The working equation also characterizes the binder and tracer reagents used in the assay. The determination of working-equation parameters has been illustrated for the vitamin B12 assay. Data are presented for seven different assay procedures, involving more than 600 calibration curves and 100 different lots of binding agent and tracer reagent, showing a Consistently High Correlation Coefficient (R&gt; 0.990), between ligand concentration and the response variable.
Erythrocyte Protoporphyrin in the Detection of Iron Deficiency
Authors: McLaren Gordon D , Carpenter John T , Nino Hipolito V 
Published: January 2020

Abstract
Any decrease in the availability of iron for incorporation into the heme moieties of hemoglobin results in an increase in the erythrocyte protoporphyrin concentration. Our aim was to compare protoporphyrin concentrations, determined spectrophotometrically, with body iron stores, as assessed from the amount of iron demonstrable by Prussian blue staining of bone marrow aspirates. The mean protoporphyrin concentration (175 µg/dl) in the erythrocytes of a group of patients with markedly decreased stainable marrow iron or no iron Was Significantly Greater (P &lt; .001) than the mean concentration (76 µg/dl) in a comparable group with adequate bone marrow iron stores, except in the presence of certain interfering conditions. These results suggest that the erythrocyte protoporphyrin test may be a useful addition to the methods now available for assessing disorders of heme synthesis, the most common of which is iron deficiency.