bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonspecificity of Urinary Lead Measurements by Atomic Absorption Spectroscopy
Authors: Segal Robert J
Published: January 2020

Lead measurements by direct AAS at 217 nm on a pooled urine sample gave values of 57 µg/l by the method of standard additions. In contrast, dithizone procedures gave values of 15-20 µg/l. Studies demonstrated that various urine salts and organic compounds contributed to the absorbance at 217 nm. These native urine materials also give a similar absorbance value at 220 nm, a line not related to lead emitted by the lead hollow cathode tube. Thus, correction of the nonlead absorbance was possible by subtracting the A220 from A217. Utilizing this correction, the standard addition procedure gave values of 12 µg/l. The correction technic was also applied to the lead isolation-concentration technic of Kopito and Shwachman (3) which employs bismuth coprecipitation. The simplicity of operations, increased sensitivity and reproducibility obtained by coupling the AAS correction technic with bismuth coprecipitation recommends it as a method for serious consideration.
Serum Cholesterol Assay Using a Stable Liebermann-Burchard Reagent
Authors: Kim Edward , Goldberg Morris
Published: January 2020

A single stable Liebermann-Burchard reagent was prepared and studied for the rapid and accurate determination of total cholesterol in serum. The preparation, stability, and developed spectral character of the proposed reagent were assessed. Reproducibility, recovery, and interference studies on pure standard and patient sera were performed using the Abell-Kendall method as reference. The influence of water, protein, bilirubin, hemoglobin, and other serum constituents was evaluated.
A New Fluorometric Method for the Estimation or Detection of Total and Fractionated Alkaline Phosphatase
Authors: Johnson Roy B
Published: January 2020

A highly sensitive fluorometric method for the assay of total alkaline phosphatase and the detection of its components is described. The commercially available substrate naphthyl AS-MX phosphate, combined in 1 M 2-amino-2-methyl-1-propanol buffer, pH 9.8, is cleaved to the highly fluorescent naphthol AS-MX. Fluorometry requires filters passing 405 mµ primary and 505 mµ secondary. As little as 20 µl. of normal serum per 3 ml. of reaction mixture can be assayed. Alkaline phosphatase components, separated by vertical starch gel (or other methods of) electrophoresis, produce yellow fluorescence under ultraviolet light when incubated at 37° with the same buffer-substrate. After vertical starch gel electrophoresis, all normal serums exhibit at least one component (β-globulin region), but six distinct areas of activity have been located. These correspond to Taswell and Jeffers’ origin, beta-lipoprotein, alpha-2, alpha-beta, and beta (5). Few serums contain all of these; rather there appears to be a correlation between the ones present, their relative activity, and the disease state.
An Automated Fluorometric Procedure for the Enzymatic Determination of Ethanol in Fingertip Blood
Authors: Ellis Fred W , Hill John B
Published: January 2020

An automated fluorometric procedure, using AutoAnalyzer modules and based on the alcohol dehydrogenase reaction, has been developed for the determination of ethanol in fingertip capillary blood samples. Whole blood is measured directly from the finger prick into 0.02-ml. capacity automatic-filling disposable micropipets. The sample is quickly discharged into an AutoAnalyzer cup containing 1.0 ml. of water. This dilution can be placed on the sampler plate for immediate analysis or preserved under refrigeration for future use. The time required for sample flow from sampler to fluorometer cuvet (and recording of results) is 16 min. The coefficient of variation of replicate analyses is approximately 1%. Analyses of blood to which varying amounts of ethanol was added gave a mean recovery of 101%. As described, the method is designed to extend over the ethanol concentration range of 10-300 mg./100 ml. of whole blood. Analysis of undiluted blood or of weaker dilutions of blood samples would permit the accurate determination of as little ethanol in whole blood as 0.2 mg./100 ml. or as much as 600 mg./100 ml.
Altered Pathways of Urinary Corticosteroid Excretion in Liver Disease Studied by a Clinical Laboratory Method
Authors: Bacchus Habeeb
Published: January 2020

A method of sequential extraction of β-glucuronidase-hydrolyzed urine, which permits the assessment of alternative pathways of corticosteroid excretion, was employed to study urine samples from normal subjects and from patients with hepatic cirrhosis. In patients with hepatic cirrhosis there is a decrease in the excretion of methylene dichloride-soluble 17-hydroxycorticosteroids; this decrease is due to significantly lower levels of tetrahydrocortisone, with moderately low levels of tetrahydrocortisol. A significant increase was observed in the levels of 17-OH,20,21-glycols, confined mainly to cortols in the urine of patients with cirrhosis; a less marked increase in this fraction was also observed in patients with fatty metamorphosis of the liver. Urinary 17-ketosteroids were decreased in patients with hepatic cirrhosis. The intravenous infusion of adrenocorticotropin to normal subjects was followed by increased 17-hydroxycorticosteroids in all solvent fractions of the urine. In patients with hepatic cirrhosis similarly treated, there was no significant rise in the level of 17-hydroxycorticosteroids extracted with methylene dichloride, but significant increases in polar 17-hydroxycorticosteroids were found. The relative magnitudes of the alternate pathways of corticosteroid excretion were determined by calculation of the ratios of (1) total ketols to total glycols, (2) polar ketols to total glycols, and (3) less polar ketols to polar ketols; it was shown that in hepatic cirrhosis there are significant alterations in the excretory pathways of cortisol metabolites, with relative decreases in the excretion as tetrahydrocortisone and increases in the excretion as cortols. Based on these data it is clear that values of routine 17-hydroxycorticosteroid and 17-ketosteroid excretion should be evaluated carefully as to whether they represent abnormal adrenal function or alterations in the peripheral metabolism of cortisol. The method is sufficiently simple to be employed in the clinical laboratory.
The Use of the Allen Correction in the Quantitative Determination of Urinary Porphobilinogen
Authors: Loriaux L , Delena S , Brown H
Published: January 2020

The method of Mauzerall and Granick for the quantitative determination of urinary δ-aminolevulinic acid and porphobilinogen was found, in our hands, to give falsely elevated values for porphobilinogen. The use of the Allen correction appears to resolve this problem.
Fluorometric Ultramicrodetermination of Calcium in Biologic Fluids
Authors: Moser George B , Gerarde H W
Published: January 2020

A fluorometric ultramicromethod for the determination of calcium in serum, plasma, spinal fluid, and urine is described. All the reagents, which are premeasured and prepackaged for each determination, are stable indefinitely at room temperature.
Filter Paper Blood Collection and Punching As A Means of Quantification
Authors: Hill John B , Palmer Phyllis
Published: January 2020

Filter paper has been tested as a medium for the collection of blood samples for the subsequent elution and analysis of phenylalanine, tyrosine, glucose, and urea nitrogen. The use of paper did not measurably alter the precision of the above methods.

The paper punch as a means of quantification has been compared with the more commonly used technic of volumetric measurement. The precision obtained with punched spots was found to be similar to that found with measured spots for the above four procedures and for weighed samples.

The hematocrit value was found to have an influence on the volume of blood contained in a punched spot. Differences in spreading through filter paper between 100 individual blood samples tested did not seem to be responsible for a variance in excess of that introduced by the analytic procedures themselves.
A Modified Orcinol Reaction for RNA Determination
Authors: Kamali Mohammad , Manhouri Hamid
Published: January 2020

The Schneider orcinol technic for pentose estimation was modified by replacing ferric chloride with cupric acetate in glacial acetic acid as catalyst, to make the test more sensitive and less DNA-reactive. In addition, data were obtained showing that human plasma contains no detectable nucleic acid by the spectrophotometric determinations applied.
The Automated Thiosemicarbazide-Diacetyl Monoxime Method for Plasma Urea
Authors: Mather Alan , Roland Dorothy
Published: January 2020

Sensitivity and linearity of the diacetyl monoxime reaction for urea is greatly improved by the addition of thiosemicarbazide. Evidence is presented for the high specificity of this composite reagent.
Quantitative Comparative Immunohistology
Authors: Semar Martin , Treser Gerhard , Lange Kurt
Published: January 2020

A quantitative assay for the determination of fluorescence of tissue sections stained with fluorescein-labeled antibodies using a fluorometer is described. Sequential microtome sections were stained with labeled antiserums, washed repeatedly with buffered saline, and digested with 20% (w/v) NaOH at 60° for 12 hr. The fluorescence of the resultant solution is then read in a fluorometer. There is similarity between sequential sections of the same biopsy specimen. Specific blocking procedures reduce the readings of the fluorescence markedly. By comparison with values obtained simultaneously from standard curves of the labeled antiserums used, the amount of bound antibody or specific proteins can be determined quantitatively.
Measurement of Lead in Blood and Urine by Atomic Absorption Spectrophotometry
Authors: Farrelly R O , Pybus J
Published: January 2020

An extraction method for the estimation of lead in red cells is given. The method avoids both acid digestion and/or protein precipitation. It is extremely simple and reliable, and can easily be performed by technicians. A technical error of 4.5 v.g lead per 100 ml of red cells has been obtained. The use of red cells instead of whole blood provides a more accurate measure of exposure to lead as the lead is concen¬trated within the red cells. Normal and toxic ranges are given. As it is frequently required to monitor the lead excretion of patients receiving chelates for therapy, a method for the analysis of urine specimens from patients on this therapy is given.
Glucose Oxidase Method for Continuous Automated Blood Glucose Determination
Authors: Rosevear John W , Pfaff Kenneth J , Service Frederick J , Molnar George D , Ackerman Eugene
Published: January 2020

A glucose oxidase-peroxidase method for continuous automated monitoring of blood glucose has been developed. The response is linear over the range 0-800 mg/100 ml. Sensitivity can be maintained for 24 hr or longer and can be restored by rinsing the analytic system with sulfuric acid to permit studies of longer than 48 hr in duration. A precision of ± 1% can be maintained between rinses for samples containing 100-600 mg of glucose per 100 ml. This method is satisfactorily specific for glucose: The response with other sugars is less than 1% of the response obtained with the same concentration of glucose. Ascorbic acid causes no significant inhibition of the response to glucose. The inhibition by uric acid has been reduced fifty-fold compared to that in other methods. Transit through the sampling catheter and analytic system requires 15 min. Timed from the first detectable response to a change in concentration, 25% of total response is achieved in 30 sec and 90% in 80 sec. Fifty percent of an oscillation with a half-period of 45 sec can be detected; no oscillations this short were observed in records of human blood glucose. Applicability and feasibility of this method have been demonstrated in over 2000 hr of repeated blood glucose recordings in 12 diabetic and 6 normal subjects.
Automatic Calculation of Densitometer Scans of Electrophoretic Strips
Authors: Winkelman James , Wybenga Donald R
Published: January 2020

A system for processing of serum protein electrophoresis is described that utilizes a Disc integrator, automatic digital readout, and programmable desk-top computer. This configuration has proven to be highly efficient and accurate.
A Method for Measurement of Sodium and Potassium in Erythrocytes and Whole Blood
Authors: Bugyi Helen I , Magnier Eugene , Joseph William , Frank Gordon
Published: January 2020

The analysis of concentration of cations in erythrocytes and plasma, in theory, offers a means of identifying disease states in peripheral blood. Technical difficulties associated with cation analysis in erythrocytes and whole blood have resulted in a lack of precision and accuracy. This lack has increased the difficulties of using the analysis of blood in the diagnosis of disease. It is felt that the technic discussed in this paper with its increased precision, in combination with previously mentioned research in the diagnosis of disease, will increase the clinical significance of the analysis of red cells and whole blood for the diagnosis of disease states.
Measurement of Cholesterol in Tissues with Phospho-6-tungstic-12-molybdic Acid
Authors: Negrin A
Published: January 2020

A new spectrophotometric method for the determination of minute amounts of cholesterol in tissues is described. This method is a modification of the Yoshimatsu reaction which is based on the reduction of the yellow aqueous solution of phospho-6-tungstic-12-molybdic acid by a solution of cholesterol in concentrated sulfuric acid. The color of the resulting hydrosol of "molybdenum/tungsten blue" is particularly intense. The conditions for saponification confer virtual specificity for cholesterol. The proposed method is verified by comparison with estimates obtained by Abell’s procedure (9) as well as by the automated methodology of Block et al (8).
Practical Spectrophotometric Standards
Authors: Rand Royden N
Published: January 2020

The Subcommittee on Spectrophotometry of the Standards Committee of the American Association of Clinical Chemists presents a discussion of spectrophotometric standards for use in the routine clinical chemistry laboratory. Numerous surveys have demonstrated the need for regular checks to assure that instruments meet specifications, and that proper technics are employed. Methods for evaluation of linearity, sensitivity, wavelength calibration, stray light, and photometric accuracy are discussed, and the details for testing are given in the Appendix. Criteria of performance for wide-band-width colorimeters and spectrophotometers as well as the more elaborate spectrophotometers are presented.
A Rapid and Simple Thin-Layer Chromatographic Method for Amino Acids in Blood
Authors: Culley William J
Published: January 2020

Simple and rapid thin-layer chromatographic methods, using heel or finger-tip blood, are described that are suitable for screening for inborn errors of amino acid metabolism. Serum is chromatographed without deproteinizing. A variation of this method utilizes blood impregnated on paper discs for chromatography. These methods are much faster, more sensitive, and provide better resolution of amino acids than paper chromatography. Because untreated serum- or blood-impregnated discs are placed directly on thin-layer chromatograms, these methods require considerably less working time than other thin-layer chromatographic methods.
Micromethod for Total Serum Cholesterol that Eliminates Interference by High Bilirubin Concentrations
Authors: Jordan William J , Knoblock Edward C
Published: January 2020

The analysis of pediatric serum for total cholesterol in the presence of high amounts of bilirubin presents special problems. The serum specimens are so small that a direct micro- or ultramicromethod has to be used, and consequently the error owing to bilirubin is impressive. In the proposed method, cholesterol is precipitated, along with other serum lipids, from only 20 µliters of serum as a dextran sulfate—lipoprotein complex. The precipitate is dissolved in molar NaCl, treated with glacial acetic acid, and incubated for 5 min at 70°C. A ferric chloride—sulfuric acid reagent is then added and, after 20 min at room temperature, the color is read at 560 nm. Total cholesterol values obtained by the proposed method are not statistically different from those obtained by the direct method of Pearson et al. Bilirubin added to sera does not affect the results. Agreement was obtained with the stated cholesterol values for Versatol-A and Moni-trol II reference sera to which known amounts of cholesterol and bilirubin had been added by the manufacturer.
Silicic Acid Chromatography of Organic Acids in Blood Cells and Biological Fluids
Authors: Barness Lewis A , Morrow Grant , Nocho Robert E , Maresca Rita A
Published: January 2020

The separation of organic acids and their elution from silicic acid columns and their quantitative measurement by color change of buffered indicator, a technique mechanized by Kesner and Muntwyler, are applicable to the study of biological materials. As little as 25 µg of acid can be measured. Elution times and color yield in terms of peak areas obtained with the commercial apparatus are given for 25 organic acids. Blood, plasma, red cells, and spinal fluid have been analyzed; specimens were either untreated or extracted with ether. The most abundant acids detected were propionic, lactic, hippuric, and acetic. Methylmalonate was measured in body fluids and blood cells of patients with methylmalonic acidemia and pernicious anemia. Concentrations of organic acids in blood and spinal fluid are given.
Blood Volume Changes during Three-Week Residence at High Altitude
Authors: Myhre L G , Dill D B , Hall F G , Brown D K
Published: January 2020

Circulating red blood cell volumes were determined by the carbon monoxide method, and plasma volumes were calculated in four men 20, 29, 71, and 75 years old, and two women 29 years of age before, during, and after exposure to an altitude of 3800 m. In the four youngest subjects there were early increases in hemoglobin concentration during the first days at the stated altitude attributed to decreases in plasma volume. At the same time, hemoglobin concentration decreased and plasma volume increased in the oldest subject. Red cell volumes were slow to change, and it was concluded that 3 weeks or more of exposure to this altitude are required to affect significantly the red cell volume in man.
Use of a Computer Program to Correct for Sample Interaction: A Significant Adjunct to Continuous-Flow Analysis
Authors: Thiers Ralph E , Meyn Jute , Wildermann Robert F
Published: January 2020

A computer program has been developed to correct errors resulting from interaction in continuous-flow analysis. The correction applies to both the unknown samples and the standards of the calibration curve. A reiterative calculation is necessary that is practical only on a computer, but which accurately measures the interaction from the standards of the calibration curve, even though they are themselves rendered inaccurate by interaction. One extra standard is added to the conventional calibration curve. After correction, the calibration curve is independent of the order in which the standards were run. Because interaction is a principal factor limiting the speed of continuous-flow analysis, this program can be used to increase the rate of routine analysis. It has been added to the LABCOM system for use on the LINC-8 computer and has proved effective and valuable in practice
Comparison of Serum Lithium Determinations by Flame Photometry and Atomic Absorption Spectrophotometry
Authors: Levy Arthur L , Katz Eve M
Published: January 2020

Lithium determinations by flame photometry and atomic absorption spec-trophotometry are compared with respect to precision, sensitivity, and the effects of the presence of various concentrations of proteins and cations. Flame photometry gave results closely similar to those obtained by atomic absorption; under the conditions we used, it is more sensitive, slightly less precise, but easier to use. Varying the protein, Na, and K concentrations produces small but demonstrable effects, insignificant for clinical applica-tions. No protein effect was found with flame photometry, in contrast to atomic absorption spectrophotometry, for which protein standards are recommended. Sera from 65 patients receiving lithium therapy were an-alyzed on both instruments; no significant differences were found.
Urinary Excretion of Hydroxyproline after Fractures
Authors: Herzberg Mala , Oberman Z , Khermosh O , Weissman S L
Published: January 2020

Urinary excretion of hydroxyproline was measured in 12 cases of multiple fractures as an index of bone collagen metabolism. Measurements were made for 10 consecutive days after injury; 10 patients with low back pain served as the control group. With three exceptions, the mean daily excretion of hydroxyproline and the day-to-day variations were within the same range in the group with multiple fractures as in the control group.
Progesterone in Nonpregnancy Plasma: An Assay Method for the Clinical Chemistry Laboratory
Authors: Lurie Aron O , Patterson Richard J
Published: January 2020

A simple method for the assay of progesterone in nonpregnancy plasma was designed specifically for the clinical chemistry laboratory. One technician can readily perform 22 assays in less than one work day. Although no chromatographic step was used, the method was highly specific. Repro-ducibility studies indicated that the assay had a coefficient of variation of 7.5% for pregnancy plasma, 11.5% for nonpregnancy plasma. Clinical application of the method to specimens obtained from subjects during the normal menstrual cycle yielded values very similar to those obtained by more laborious and costly assay techniques.
Rapid Assay for Glycogen-Cycle Enzymes in Small Samples of Muscle
Authors: Russell J C , Tougas Diane , Taylor A W
Published: January 2020

A rapid assay is described for the glycogen-cycle enzymes glycogen synthetase and α-glucan phosphorylase (UDP glucose:glycogen α-4-glucosyltransferase, EC 2.4.1.11 and α-1,4-glucan: orthophosphate glucosyltransferase, EC 2.4.1.1) in muscle tissue. UDP glucose-14C and G-1-P-14C are used as substrates for reaction with muscle homogenates, and the rate of incorporation of labeled glucose into primer glycogen is measured. Muscle samples weighing 25 to 75 mg are suitable for assay. We found activities in rat gastrocnemius muscle of 0.37 ± 0.02 µmol of glucose per minute per gram of tissue for synthetase I, 2.84 ± 0.29 µmol per minute per gram of tissue for synthetase D, and 34.5 ± 2.8 µmol per minute per gram of tissue for phosphorylase b. Corresponding values for human muscle tissue for phosphorylase a and b were 12.6 and 10.6 µmol per minute per gram of tissue, and synthetase activity of 0.011 and 0.399 µmol per minute per gram of tissue.
Automated Saccharogenic Assay of Alpha-Amylase Activity in Serum
Authors: Fridhandler Louis , Berk J Edward
Published: January 2020

A saccharogenic amylase assay in which amylopectin is used as the substrate has been adapted for use with the AutoAnalyzer. Results closely matched those obtained with an established manual saccharogenic method.
Prediction of Haptoglobin and α2-Macroglobulin Concentrations from Electrophoretic Patterns of Serum α2-Globulin
Authors: Gault M Henry , Elzer Eleonore , Gabe Alec
Published: January 2020

Cellulose—acetate electrophoretic densitometry patterns for α2-globulin have been analyzed, with sera from 150 patients. The mobility of serum α2-macroglobulin exceeds that of haptoglobin to the extent that certain patterns correlate with abnormal concentrations of one or both of these proteins in serum. The most readily recognizable patterns occur when there is a major increase in one protein and the other remains normal. A very low value for one protein, particularly haptoglobin, can also be recognized. Concentration of these two proteins can be roughly predicted under definable circumstances.
Variations in Blood ATP after Oral Administration of Glucose, in Individuals Diagnosed as Normal, Equivocal, or Diabetic According to the Glucose Tolerance Sum Principle
Authors: Windisch Rita M , Pax P Robert , Bracken Mark M
Published: January 2020

Blood adenosine triphosphate was determined for 35 individuals at various times after they had ingested glucose. They were divided into four groups, categorized according to the "glucose tolerance sum" principle as normal, equivocal, or abnormal. Patients showing glucose intolerance also had supranormal concentrations of ATP as compared to the fasting level. Data are presented which suggest that the increase in ATP is a regulatory mechanism for insulin secretion.
A Source of Error in the Automated Serum Triiodothyronine-Uptake Test
Authors: Mardell R J
Published: January 2020

Variations in the diagnostic efficiency of the automated serum triiodothyronine-uptake test are shown to be caused by a large and variable proportion of radioiodide in the dialysate from a mixture of radioactive triiodothyronine and serum.
Biological and Analytic Components of Variation in Long-Term Studies of Serum Constituents in Normal Subjects
Authors: Harris Eugene K , Kanofsky Paul , Shakarji George , Cotlove Ernest
Published: January 2020

Standard statistical analysis of variance has been used on data from weekly determinations of 15 blood constituents in each of 68 normal subjects, our purpose being to isolate and estimate biological components of observed variation. These components include intra-individual, or "personal" variation, and inter-individual, or "group" variation. The most critical problem, that of separating personal variation from long-term analytic deviations in each individual's data record, was resolved with the aid of concurrent analysis of a constant "pooled" serum. Comparison of isolated personal variation with inter-individual variation indicates that many common blood tests—e.g., magnesium, calcium, total protein, uric acid, serum enzymes, and cholesterol—could contribute to an individually distinctive blood "profile" if substantial improvements were made in analytic precision. Presently, only cholesterol (among older women) and uric acid (in males) appear to possess strong capabilities for distinguishing among normal individuals.
An Automated, Saccharogenic Method for Determining Serum Amylase Activity
Authors: O'Neal Wendell R , Gochman Nathan
Published: January 2020

An automated adaptation of the Somogyi saccharogenic determination of serum amylase is described in which conventional AutoAnalyzer modules are used. Adequate sensitivity with short incubation is achieved by incorporating glucose oxidase and catalase in the substrate to destroy serum glucose during incubation. Maltose and other dialyzable oligosaccharides are measured with the alkaline copper-neocuproine reaction. A simultaneous blank run is performed to determine reducing substances other than glucose in serum. Precision studies and correlation with a manual saccharogenic method are presented. The normal range was determined from data for 49 healthy blood donors.
Assessment of Two Blood-Analyzer Systems Intended for Diagnostic Testing in the Physician's Office
Authors: Logan J E , Sunderland M L E
Published: January 2020

We have assessed the Bio-Dynamics "Unitest System" and the Dow Chemical "Diagnostest." Day-to-day reproducibility and within-day precision of the Unitest uric acid and urea nitrogen kits were beyond acceptable limits of error. For Diagnostest, day-to-day reproducibility of bilirubin was outside these limits for two concentrations of bilirubin, one each for uric acid and cholesterol. The Unitest kit gave falsely high readings for cholesterol such that incorrect diagnoses could result. The Diagnostest cholesterol procedure gave values significantly lower than those obtained with the AutoAnalyzer. With Unitest, low results were found on specimens with supranormal uric acid; with Diagnostest low results were obtained for supranormal concentrations of urea nitrogen. Both systems yielded acceptable results for glucose and hemoglobin. We conclude that personnel not technically trained could not obtain reliable data with these systems.
Simultaneous Measurement of Diphenylhydantoin and Primidone in Serum by Gas—Liquid Chromatography
Authors: Evenson M A , Jones P , Darcey B
Published: January 2020

The need for simultaneous determination of the concentration of diphenylhydantoin (Dilantin) and primidone (Mysoline) in serum is frequently expressed to the clinical chemistry laboratory. Isothermal gas-liquid chromatography (GLC) has been used to develop a rapid, specific method. The method involves a single extraction and no derivative formation. The procedure is simple enough to be used with large numbers of samples. Detection limits for the method are 0.3 µg diphenylhydantoin per ml and 0.1 µg primidone per ml. The mean precision of the method is 6.2% and 4.8%, expressed as the coefficient of variation, for diphenylhydantoin and primidone, respectively. Barbiturates and glutethimide added to serum samples did not interfere with the analysis. The method has been used for more than 500 patients without interferences from metabolites, and meets all criteria for routine and emergency use.
Use of Patient Data for Quality Control of Clinical Laboratory Tests
Authors: Reed Allen H
Published: January 2020

The average-of-normals quality-control method is examined mathematically. Two modifications are proposed. After modification, the essential unchanged feature of the method is the idea of censoring the laboratory test results so that only means of test values inside the normal range are plotted on the quality-control chart. Several limitations of the modified method are discussed, and I conclude that, although censoring does improve the probability of detecting drift, more statistical research and further modifications are needed before the average-of-normals method will be useful for quality control in the clinical laboratory.
Method for Rapid Infrared Microdetermination of Serum Carbonate
Authors: Peterson John I
Published: January 2020

Carbonate is determined in serum by infrared absorption measurement of the carbon dioxide evolved upon acidification. The determination requires 1 min and a 50-µl sample. The method has a coefficient of variation of 2.0% for samples in the normal range.
Method for Simultaneous Direct Estimation of Glucose and Xylose in Serum
Authors: Goodwin Jesse F
Published: January 2020

A direct procedure for measuring serum monosaccharides is presented. Borate intensifies the colors produced when these substances react with o-toluidine, which, in the case of glucose and xylose, have absorption maxima at 480 nm and 630 nm, respectively. Thus, these sugars may be determined singly or simultaneously in a single sample by differential spectrophotometry. An alternative technique in which glucose oxidase and o-toluidine are used is also presented for the estimation of xylose and other pentose sugars in the presence of glucose. These two techniques permit the measurement of a pentose and a hexose other than glucose in protein solutions containing glucose. The techniques have a high degree of correlation and reproducibility. The effects of such variables as reagent concentration, reaction time, and borate concentration on the o-toluidine reaction are presented, along with an evaluation of bilirubin and hemoglobin interference.
Simplified Determination of Serum Iron and Total Iron-Binding Capacity
Authors: O’Malley John A , Hassan Anne , Shiley Judith , Traynor Henry
Published: January 2020

2,4,6-Tripyridyl-s-triazine (TPTZ) is a color reagent for ferrous ion in the pH range 2 to 10, when ascorbic acid is used as the reducing agent. In this range TPTZ and ferrous ion combine in the ratio of two to one. Tris buffer is commonly used to maintain an alkaline pH, but it reacts with other reducing agents, rendering them ineffective. These observations suggested a method for the joint determination of serum iron and total iron-binding capacity (TIBC), all done in a single tube and with one color reagent. The method is compared with those of Peters et al. The standard deviation of the difference between the serum iron methods is less than 6 µg/100 ml, between the TIBC methods, less than 19 µg/100 ml.
Measurement of Polarographically Active Sulfur in Human Serum Fractions Obtained by Paper Electrophoresis
Authors: Homolka Jiří
Published: January 2020

Polarographically active sulfur was distributed among the serum-protein fractions as follows (in percentages): albumin, 63.21; α1-globulin, 3.17; α2-globulin, 7.92; β-globulin, 14.54; α-globulin, 11.16. The results compare well with those obtained by X-ray spectrometry. The same method was applied to sera from patients suffering from malignant processes and some other diseases; the percentage of polarographically active sulfur in fractions of plasma from diseased individuals varied considerably.
Fractionation of Human Urine by Gel Chromatography
Authors: Burtis C A , Goldstein Gerald , Scott Charles D
Published: January 2020

High-resolution anion-exchange chromatography of human urine can resolve more than 150 constituents that absorb ultraviolet light. Prefractionation of urine on Sephadex G-10 helped us identify the constituents and simplified the anion-exchange chromatogram. The material associated with the 13 peaks obtained by gel chromatography was pooled and concentrated into six fractions, which were subsequently analyzed by high-resolution anion-exchange chromatography. Each of these fractions contained from 13 to 63 ultraviolet-absorbing constituents.
Interface Instrumentation between Computer and Spectrophotometer for Reaction Rate Measurements
Authors: Toren E Clifford , Eggert Arthur A , Sherry Arletta E , Hicks G Phillip
Published: January 2020

An instrument interface which generates an output voltage level proportional to rate of change of an input voltage is described. The interface permits direct connection of routine spectrophotometric rate measurements to a real-time laboratory computer system. The form of the voltage level output enables the computer to read rates in the same manner as peaks are read for AutoAnalyzers, permitting the clinical laboratory LABCOM system to compute and report results for rate methods with no software changes. Spectrophotometric rates from about 10 to 0.025 absorbance units per min can be measured with an accuracy and precision of less than 1% relative in measurement times of about 10 to 30 s, respectively. The interface is readily constructed from commercially available components. Test results are presented for simulated rates, lactic dehydrogenase, and alkaline phosphatase.
Lactic Dehydrogenase Inhibitors in NAD
Authors: Babson Arthur L , Arndt Elsa G
Published: January 2020

Commercial samples of nicotinamide adenine dinucleotide (NAD) contain various amounts of one or more lactic dehydrogenase (LDH) inhibitors but not the inhibitor described in the reduced coenzyme, NADH. The kinetic assay for LDH, in which a high concentration of NAD is used, was more seriously influenced by the source of NAD than a tetrazolium-coupled colorimetric procedure that requires much less coenzyme.
Use of Ion-Exchange Resin in Preparing Erythrocytes for Magnesium Determinations
Authors: Hunt B J , Manery J F
Published: January 2020

A rapid, accurate method is described for determining magnesium in red blood cells. Dowex 50 resin was used to separate magnesium from calcium and other cellular constituents. Magnesium in the eluate was titrated with EDTA, with Eriochrome Black T as indicator; the end point was determined spectrophotometrically. Magnesium in the erythrocytes of 17 healthy adults averaged 4.57 ± 0.16 (SD) mEq/liter of packed cells, with a range of 4.32 to 4.88, narrower than reported before in the literature.
Protein-Free Filtrates Obtained by Membrane Ultrafiltration
Authors: Farese Genevieve , Mager Milton
Published: January 2020

Serum was ultrafiltered by centrifugation through size-selective membranes, and the ultrafiltrates were analyzed directly for glucose, urea nitrogen, creatinine, and uric acid. The concentrations obtained were equivalent to their concentration in conventional protein-free filtrates. This procedure eliminates the need for specific precipitating methods required in various analyses, and yields undiluted samples that are free of foreign ions.
An Automated Method for Measuring Creatine Phosphokinase Activity in Serum
Authors: Wright Ronald K , Alexander Roy L
Published: January 2020

We describe a procedure for automating the determination of creatine phosphokinase (CPK) activity in serum by use of the AutoAnalyzer. Enzyme activity is determined by measuring the creatine phosphate formed from the CPK-catalyzed reaction of creatine with adenosine triphosphate (ATP). The sensitivity of the automated procedure was comparable to that of the manual method. By use of the most favorable concentrations of creatine, ATP, and magnesium ion in the substrate, a linear relationship was obtained between enzyme concentration and enzyme activities up to 600 mU, representing a sixfold improvement over that obtained by the manual method. The degree of correlation between results obtained by the manual and automated procedures is shown.
A Quality-Control Program Based on the Use of Desk-Top Digital Computer
Authors: Cohen Eugene L , Hermann George , Sugiura Henry T
Published: January 2020

Programs written for a relatively inexpensive desk-top computer are used to calculate the chemical concentration of any batch of unknowns from a flattened absorbance curve with up to five points produced by single- or dual-channel continuous-flow analyzers and other instrumentation. Any value beyond the limits of the curve is rejected. The programs are then used to evaluate a pooled control serum from previously programmed standard deviation data. The sequence of calculation is such that computation of patient samples stops if the control value lies outside these programmed limits. The system ensures that no patient sample is reported, or even calculated, unless its accompanying control was within acceptable statistical limits. Acceptance of the system by technologists has been outstanding.
A Rapid Extraction and Quantification of Total Lipids and Lipid Fractions in Blood and Feces
Authors: Amenta J S
Published: January 2020

An analytical system for plasma lipids suitable for use in the large and small clinical laboratory is presented. Lipids are extracted into a chloroform— methanol solvent and concentrated into a chloroform phase by a wash with an aqueous CaCl2 solution. This extract is used to estimate total lipids and (after separation by thin-layer chromatography) the major lipid fractions. A single acid dichromate reagent is used for all quantification steps. Normal ranges for the proposed method are presented. The method with minor modifications is also used for quantification of fecal lipids. Lipids in other body fluids can be conveniently analyzed with this flexible method.
A Cause of Apparently Abnormal Urinary 17-Hydroxy Corticosteroids Responses to Metyrapone in Normal Subjects
Authors: Jubiz William , Frailey Jacqueline , Tyler Frank H
Published: January 2020

The metyrapone test is used to evaluate adrenal and pituitary disorders. The response to metyrapone administration can be erroneously interpreted as negative if a method that includes benzene— water partition is used to measure urinary 17-hydroxy corticosteroids. The reason for this is that benzene—water partition excludes most of the tetrahydrodeoxycortisol from the final extract, although this is the urinary steroid metabolite that increases after metyrapone administration.
A Simple Method for Separating Serum Lipoproteins by Electrophoresis on Cellulose Acetate
Authors: Fletcher Margaret J , Styliou Maria H
Published: January 2020

A simple, rapid method is described for separating the serum lipoproteins into clear, discrete, and reproducible bands by electrophoresis on cellulose acetate. Sera of patients with primary or secondary hyperlipidemias show patterns reflecting changes in lipid metabolism. The method would be appropriate for use in screening surveys.
A Fluorometric Ferric Chloride Method for Determining Cholesterol in Cerebrospinal Fluid and Serum
Authors: Solow Elizabeth B , Freeman L W
Published: January 2020

Sensitive or simple methods for the rapid determination of cholesterol in biological fluids have been developed during the past 10 years. Sensitivity has been increased by fluorimetry of the Lieberman—Burchard reaction for cholesterol. Measurement of the reaction of cholesterol with ferric chloride is simpler. Still, there are great differences between the results when different methods are used to measure the microquantities of cholesterol present in small volumes of serum or cerebrospinal fluid. In the proposed method, the simpler ferric chloride technique has been made highly sensitive by use of fluorometry. As little as 100 µl of cerebrospinal fluid, containing less than 1 µg of cholesterol, may be used, and the reaction is stable for as long as 1 h. Interference was negligible from pigments (such as bilirubin and hemoglobin), certain drugs, and ionic substances that might be expected to affect fluorescence.
Application of Fe+2-5-PyridylBenzodiazepin-2-Ones to the Automated Determinations of Serum Iron and Iron-Binding Capacity
Authors: Klein Bernard , Kleinman Norman , Searcy Ronald L
Published: January 2020

An automated procedure has been developed for determining serum iron content and iron-binding capacity with a new iron-chelating ligand, a 5-pyridyl-benzodiazepin-2-one derivative. A simplified manifold and flow system, together with improved reagent combinations, offer distinct advantages over existing automated procedures. The results obtained by automated analysis for serum iron and iron-binding capacity agree excellently with those obtained by the corresponding manual procedure.
Peak Characteristics and Computers in Continuous Flow Analysis
Authors: Evenson M A , Hicks G P , Thiers R E
Published: January 2020

The data output of continuous-flow analyzers is examined, and the characteristics of sample peaks are related to the timing program of the sampler module. Optimal conditions are presented for continuous-flow analyzer performance and for computer acquisition of such data.
The Preservation of Urine Specimens for δ-Aminolevulinic Acid Determination
Authors: Vincent William F , Ullman William W
Published: January 2020

The effect of light exposure and temperature on urinary δ-aminolevulinic acid recovery was studied. Addition of tartaric acid and storage of urine specimens in the dark results in excellent recovery of δ-aminolevulinic acid, even after several days at room temperature. Proper handling and storage of urine collected during surveys of lead poisoning are emphasized.
Diagnostic Application of Metabolic Studies with Isotopes
Authors: Hutterer Ferenc , Sarkozi Laszlo , Roboz John , Bacchin Paolo
Published: January 2020

The mechanism of the maintenance of normoglycemia in chloroform intoxication in rats was studied with isotopes. Metabolic pathways were altered before the concentration of blood glucose changed significantly. Measurement of the incorporation of precursors rather than the determination of the concentration of the metabolic end products (e.g., glucose) may provide more diagnostic information and may more sensitively detect early diseases or disease stages.
Effect of a Chemically Defined Diet on Urinary Excretion of Minerals and Aromatic Compounds
Authors: Young D S
Published: January 2020

A diet of known composition, prepared from pure chemicals, was fed to a healthy man for five days. Urinary excretion of minerals, ultraviolet-absorbing compounds, phenolic acids, indoles, and phenolic amines was determined by use of conventional techniques, high-resolution column chromatography, and thin-layer chromatography. The excretion of compounds during the period of the synthetic diet was compared with that when a self-selected diet was ingested. Institution of the synthetic diet caused a decrease in mineral excretion, and also caused the excretion of many aromatic compounds to decrease markedly. Several additional compounds could be attributed to the flavoring agent in the diet. We conclude that many compounds present in urine samples have a dietary origin primarily, and that it is necessary to feed diets of known composition before satisfactory metabolic studies may be undertaken.
Amphetamines in Human Urine: Rapid Estimation by Gas—Liquid Chromatography
Authors: Schweitzer J W , Friedhoff A J
Published: January 2020

A procedure is described for the quantitative determination of amphetamine and p-methoxyamphetamine and for the semiquantitative determination of methamphetamine, mephentermine, and normephentermine in human urine. An internal reference compound, phenethylamine, is added to 5 ml of urine. The urine is extracted at low pH to remove acidic contaminants, then at high pH with chloroform, in which the amines were acetylated with acetic anhydride. After evaporation, the residue, dissolved in dioxane, is injected onto a column at 215°C, packed with 8% ethyleneglycol adipate on Chromosorb W, 100-120 mesh, except at both ends, where the packing was 8% silicon rubber SE 30 on Chromosorb W, 100-120 mesh. The excretion rate of amphetamines by patients admitted with a diagnosis of amphetamine psychosis was measured.
Quality Control in the Astrup Method for Determining Acid-Base Parameters in Blood
Authors: Russell C D , Roeher H-D
Published: January 2020

We present a method for automatic error screening by digital computer of acid-base data obtained by the Astrup procedure. It is based on the detection of discrepancies between the slope of the line joining the high- and low-pCOCO2, measurements on the Astrup diagram and the known slope for human blood.
Glucose Assay Systems: Evaluation of a Colorimetric Hexokinase Procedure
Authors: Wright Walter R , Rainwater John C , Tolle Lawrence D
Published: January 2020

A colorimetric enzymatic assay system for glucose was evaluated. The system uses hexokinase (ATP:D-hexose 6-phospho-transferase; EC 2.7.1.1) and glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate:NADP oxidoreductase; EC 1.1.1.49) coupled with a PMS-INT reaction (phenazine methosulfate; 2-p-iodophenyl-3-p-nitrophenyl-5-phenyl tetrazolium chloride). The precision, range of linearity, reproducibility of standard curve, and stability of reagents after reconstitution are excellent. The method is specific for glucose in the presence of mannose, fructose, galactose, xylose, and ribose. Uric acid, urea, ascorbic acid, reduced glutathione, or creatinine at abnormally high concentrations do not interfere. Good correlations (with unselected hospital sera) were obtained in parallel assays by ferricyanide (AutoAnalyzer), o-toluidine (manual), and hexokinase (manual) procedures. Results obtained by the neocuproine (SMA-12/30) method in the parallel assays were significantly different from results obtained by the other three procedures.