bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum Beta-Lipoproteins of Normal,Atherosclerotic, and Lipemic Individuals
Authors: Gottfried Sidney P , Pope Russell H , Friedman Nathan H , Akerson Irving B , Mauro Salvatore Di
Published: January 2020

1. Serum lipids, cholesterol, and lipoproteins were determined on 8 normal 7 atherosclerotic, and 8 lipemic individuals in the fasting state. Serum lipids and cholesterol were determined chemically, the lipoprothins by paper electrophoresis. Serum lipoproteins were also performed after incubating at 6.5° and 37° for 24, 48, and 72 hours, and changes in the physical appearance of the serum, and in the concentration and mobility of the β-lipoproteins were observed. In 12 of the above cases, serum protein patterns were noted with the lipoprotein patterns.

2. In many cases a visible turbidity appeared upon incubating at 37°, never upon incubating at 6.5°. Inmost cases this turbidity appeared after incubating for 48 hours, and tended to occur more frequently in atherosclerotic sera than in normal sera.

3. The concentration of β-lipoproteins decreased upon incubating either at 6.5°orat 37°, the decrease being of the same order of magnitude for normal, atherosclerotic, or lipemic sera.

4. Incubating at 37°increased the mobility of the β-lipoproteins (except when a turbidity appeared), the peak shifting from between the β- and γ-globulins to between the β- and γ-globulins. Incubating at 6.5° had no effect on the mobility of the β-lipoprotein.

5. When a turbidity appeared upon incubating at 37°, the mobility of the β-lipoproteins decreased, the peak shifting toward the origin. As the turbidity became marked, a sixth protein fraction appeared, of slower mobility than the γ-globulin. This protein fraction first appeared to form at the expense of the β- and γ-globulins and then at the expense of the α-globulins, all of which decreased. It is considered that the turbidity is due to the formation of "denatured" proteins and lipoproteins which are characterized by a decrease in mobility.

6. No consistent changes were noted in the concentration, stability and mobility of the α-lipoproteins upon incubating at either 6.5° or 37°.
Estimation of Lipid Fractions of Blood Plasma
Authors: Kibrick Andre C , Skupp S J
Published: January 2020

The Allen volumetric method for plasma fat has been modified by calibration to include the percentage of olive-oil recovery. The values obtained from calibration with mercury are corrected for the 125 per cent recovery of the oil. The validity of the entire procedure has been discussed.

A simple system of estimating the lipid fractions of plasma has been described. Total lipids are the total of Allen fat + (25 x lipid P). Neutral fat is Allen fat-cholesterol-cholesterol fatty acids. Total fatty acids are X neutral fat + cholesterol fatty acids + (0.64 x phospholipids).

The values of total fatty acids have been compared with those obtained by oxidation with dichromate and by determining the esterified fatty acids with iron perchlorate.

The values of neutral fat found in 13 apparently normal individuals are shown to range from 0 to 88 and to give an average value of 28 mg./100 ml.
Estimation of Lipid Fractions of Blood Plasma
Authors: Kibrick Andre C , Skupp S J
Published: January 2020

On page 320 (Vol. 1, 1955), the second and third sentences in the last paragraph should read, "It is interesting that most of the values are quite low. Among the few high values is Number 8, a man about 45 years old who proved to be an alcoholic and may have had some liver dysfunction."
Plasma Amino Acids in Young and Older Adult Human Subjects
Authors: Ackermann Philip G , Kheim Teofil
Published: January 2020

Nineteen amino acids were determined in the plasma of young and older individuals by the chromatographic procedure of Moore, Spackman, and Stein (7,8). Of the essential amino acids, valine, methionine, isoleucine, leucine, phenylalanine, and lysine were found to be lower in older subjects. In all, 11 of the 19 amino acids studied showed lower values in these individuals, indicating some differences in protein metabolism between the elderly and younger adults.
The Oxidation of Glutathione by Serum
Authors: Rony Hugo R , West Michael , Zimmerman Hyman J
Published: January 2020

Studies of serum glutathione reductase activity in this laboratory prompted an attempt to demonstrate glutathione oxidase in the serum. The oxidation of reduced glutathione in the sera of patients with various diseases does not differ from normal sera. Preheating the serum and addition of cytochrome c does not effect the oxidizing capacity of the serum. The ability of serum to oxidize reduced glutathione appears to represent autoxidation, not the effect of an oxidizing enzyme.
Application of Atomic Absorption Spectrophotometry in the Determination of Calcium in Serum
Authors: Zettner Alfred , Seligson David
Published: January 2020

Atomic absorption spectrophotometry (AAS) was applied to the determination of serum calcium. A special diluent was developed to abolish the effect of absorption depressors. This made possible measurement of calcium in directly diluted serum samples without prior removal of any serum constituents. Values obtained by AAS on calcium oxalate precipitates from serum were identical with those found by the direct dilution technique.
A Photometric System for Automatically Reading Concentration
Authors: McKay D K , Seligson D , Jewett W R
Published: January 2020

Spectrophotometric or colorimetric data are normally obtained in some type of photometric unit and must be dealt with mathematically to provide a final result expressed in concentration. Such mathematical operations are time-consuming, require data transfer, and are subject to human error. A photometric system has been devised which can be adjusted to perform calculations automatically and provide direct readout of concentration. This system combines logarithmic conversion of %T with control of both m and b constants in the straight-line equation, y = mx + b, in which y is absorbance, m is slope, x is concentration, and b is the blank correction. The system also provides linearizing compensation for those reactions which do not follow the Beer-Lambert law. The calibration procedure for the system is described, as is the linearization of nonlinear standard curves.
Serum Cholesterol
Authors: Boutwell Joseph H
Published: January 2020

The chromogenic reaction of cholesterol with iron-sulfuric acid-acetic acid has been modified to increase its sensitivity, precision, and stability. This has been done by carrying out the reaction isothermally (at room temperature), at the same time avoiding exposure to fluorescent light or sunlight. Optimal conditions for maximal yield of chromogen have been established, as a result of which the sensitivity is increased greatly over previous methods. The modified chromogenic reaction is applied to fractions obtained by a modified Abell extraction schema which allows the accurate and precise measurement of the total cholesterol of serum using 0.1-ml. samples.
Method for the Determination of Vitamin E (Total Tocopherols) in Serum
Authors: Martinek Robert G
Published: January 2020

The use of tripyridyltriazine has been investigated as a chromogenic reagent for the colorimetric determination of vitamin E in serum. The advantages of using this re-agent have been elucidated. Comparison is made with a method employing terpyridyl.
Micromethod for the Rapid Determination of Serum Protein-Bound Iodine and Total Serum Iodine
Authors: Gardiner Eli , Burns Arthur
Published: January 2020

A modification is presented of the chloric acid method for the rapid determination of serum protein-bound iodine and total serum iodine requiring less than 0.5 ml. serum for duplicate determinations. The time required for the entire procedure is less than two hours. By adjusting the amounts of reagents used and by varying the time of digestion, the need for constant and continuous supervision is eliminated.
A Study of Variables Affecting the Ion-Exchange Resin Uptake of I131-Labeled Triiodothyronine from Human Serum
Authors: Lee Norman D , Pileggi Vincent J , Segalove Milton
Published: January 2020

When serum is incubated with I131-labeled triiodothyronine and then equilibrated with the anion-exchange resin IRA-400 in the formate cycle, a fraction of the total radioactivity is bound to the resin. Resin uptake values are reproducible and have been correlated with alterations in the thyrometabolic status of patients. A study of a number of fundamental variables in this test yielded the following observations. Resin uptake values were found to be linearly related to serum thyroxine concentration over a limited range; no comparable relationship could be shown for triiodothyronine. Of the specific thyroxine-binding proteins in serum, only the interalpha globulin fraction could be shown to be involved. It was also observed that the radioactivity ultimately bound to resin had been initially associated with serum protein and was continuously being translocated to resin as equilibration time was extended. This continuous translocation was multiphasic with respect to time and probably represented the result of several equilibrium compartments, each involving one or more different protein species. Consequently, these findings indicated that those proteins which bound triiodothyronine nonspecifically had a distinct role in determining resin uptake values.
Simultaneous Determination of Calcium and Magnesium of Serum by a Single Chelometric Titration
Authors: Jackson Sanford H , Brown Florence
Published: January 2020

Titration of a trichloracetic acid filtrate of serum with EDTA is carried out at pH 9.8 using an excess of Calmagite indicator. Successive photometric readings of percentage transmission, made with an EEL titrator, are plotted against the volume of EDTA added. There is very little change at first while calcium is being complexed; the reading then decreases rapidly while magnesium is being titrated, followed by a flattening of the curve at completion of the titration. Hence, two sharp "breaks" are obtained in the titration curve, the first corresponding to the amount of calcium and the second to the amount of magnesium.
Estimation of Bilirubin Using Acetamide
Authors: Boutwell Joseph H
Published: January 2020

A study of the effect of acetamide as an accelerator of the reaction between free bilirubin and diazotized sulfanilic acid (DSA) has led to its use in a method for serum bilirubin which is simple, sensitive, linear over a wide range, and which requires neither excessive dilution nor protein precipitation. The conditions necessary for greatest sensitivity and for linearity have been established with regard to the pH of coupling and photometry, the concentration of DSA, the minimizing of turbidities, and the effect of protein.
Primary Hyperparathyroidism
Authors: Nicholas H O , Chamberlin James Allen
Published: January 2020

This paper presents the final results obtained by this laboratory during a 3½-year investigation of primary hyperparathyroidism. The project involved establishment of a routine test procedure for more reliable diagnosis of this condition; a study of the incidence of renal lithiasis in hyperparathyroidism, and, finally, the subject of the present paper-the obtaining of data to construct a nomogram for estimation of diffusible serum calcium from the total serum calcium and the albumin and globulin levels.
Adaptation of a Photoelectric Colorimeter to a Computer Program for Calculating and Storing Data in a Clinical Chemistry Laboratory
Authors: Mckay Donald K , Lotito Lawrence A , Seligson David , Wogrin Conrad A
Published: January 2020

In order to facilitate data processing in the clinical laboratory, a system was devised for colorimetric analysis in which the necessary calculations for hemoglobin measurement were performed automatically using analog and digital computer programs singly and combined. The technics described are essential steps toward an over-all system for obtaining, calculating, storing, and retrieving data in a clinical laboratory.
Comparison of Technics for Estimation of Albumin by Determination of Its Dye-Binding Capacity and by Paper Electrophoresis
Authors: Goodwin Jesse F
Published: January 2020

Values for serum albumin obtained by the methyl orange and 2-(4’-hydroxyazobenzene) benzoic acid (HABA) dye-absorption methods have been compared with values obtained by Spinco Procedure B paper-electrophoresis system. A good correlation of albumin values has been found by the three methods in serums with albumin/globulin ratios ranging from 0.19 to 3.00. Modifications of the dye-absorption procedures are presented which permit use of reagents ordinarily employed for automatic analyses on small numbers of specimens. A decrease in ionic strength of the methyl orange buffer tends to increase the sensitivity of this procedure. Temperature affects the HABA dye/albumin reaction. Bilirubin, free hemoglobin, and lipid interfere with both dye procedures. Means for eliminating most of these interferences have been presented. The methyl orange procedure appears to be superior to the 2-(4 -hydroxyazobenzene) benzoic acid method for estimating albumin in icteric serum and serum containing macroglobulins. Albumin values of serum containing abnormal proteins were compared with values obtained by paper electrophoresis and both dye procedures. Estimation of albumin by the two dye procedures appears to be simple, precise, and fairly specific.
Determination of Exogenous Galactose in Blood using "Specially Purified" Glucose Oxidase
Authors: Waldstein Sheldon S , Dubin Alvin , Newcomer Albert , McKenna Charles H
Published: January 2020

A method is described for the determination of exogenous galactose in blood by a modification of the Nelson-Somogyi hexose procedure in which glucose oxidase is used to eliminate interfering glucose. The use of "specially purified" glucose oxidase (SPGO) achieves low, regular blanks and satisfactory replicates, and enhances accuracy, in contrast to the results obtained with crude enzyme preparations. The ready availability of SPGO makes the method satisfactory and practical for the clinical laboratory.
False Positive Reaction Due to Methocarbamol in the Screening Test for Vanilmandelic Acid (VMA)
Authors: Campbell D J , Sherbaniuk R , Rigby J
Published: January 2020

Methocarbamol, a widely prescribed muscle relaxant, gives a positive result for increased vanilmandelic acid excretion with the useful screening test devised by Gitlow for evidence of pheochromocytoma. Evidence for the presence of this drug can be obtained from a positive color reaction with the 5-hydroxyindoleacetic acid test, used in the screening for carcinoid tumor.
A Colorimetric Method for Determination of Serum Chloride
Authors: Schoenfeld R G , Lewellan C J
Published: January 2020

A procedure is outlined for the determination of body fluid chloride levels from as little as 0.2-ml. of fluid. The results are highly reproducible and compare very favorably with the widely used method of Schales and Schales. The color produced is quite stable, and the interference of extraneous compounds has been found to have no effect on the accuracy of the method.
Direct Automated Determination of Glucose by a Glucose Oxidase-Peroxidase System
Authors: Getchell Gloria , Kingsley George R , Schaffert Roscoe R
Published: January 2020

A simple, accurate, automated method for the determination of glucose in plasma, urine, and spinal fluid, which does not require dialysis or protein-free filtrates is presented. Only unusually high uric acid levels in the plasma interfere with the procedure described.
Evaluation of Procedures for Urinary Calcium
Authors: Fales Frank W
Published: January 2020

In a comparative study of urinary calcium methods, many of the recently proposed procedures proved either impractical or invalid in our hands. A preliminary isolation of the calcium as the oxalate, followed by perchloric acid oxidation of the oxalate seemed to be the simplest procedure whereby urinary calcium could be put in a state suitable for chelometric titration. The isolated calcium could also be titrated with considerable precision and accuracy by a modified procedure with a derivative automatic titrator which is available commercially.

It was suggested from our observations that too little attention has been directed towards the problems imposed by the occurrence of calcium precipitates in urine. An untreated 24-hr. urine specimen is not suitable for direct analysis of calcium by chelometric titration, by colorimetric analysis, by emission flame photometry, or by atomic absorption flame photometry because these methods do not give a true measure of the calcium in the precipitate. Boiling for 5 min. with 1 part concentrated nitric acid to 25 parts urine proved a suitable means for completely dissolving the calcium precipitate.
Enzymatic Method for Determination of Vanillyl Mandelic Acid
Authors: Rosano Carmen L
Published: January 2020

An enzymatic method is described for the measurement of vanillyl mandelic acid (VMA). The method utilizes an L-mandelic acid dehydrogenase preparation from Pseudomonas fluorescens A-312 to catalyze the transformation of VMA to vanillin. The method is specific for VMA because only the final product, vanillin, will absorb maximally at 350 mµ. The results compare favorably with the method of Pisano et al.(2).
Clinical Applications of Infrared Spectroscopy
Authors: Klein Bernard , Weissman Milton
Published: January 2020

The precise identification of some clinically important sugars as their phenylosazones has been accomplished by infrared absorption spectroscopy. Tentative band assignments have been suggested.
Complexometric Titration of Calcium and Magnesium by a Semiautomated Procedure
Authors: Jones James D , McGuckin Warren F
Published: January 2020

A semiautomatic procedure for the direct estimation of both serum calcium and magnesium is described. The indicator used, Eriochrome blue SE (EBSE), has the advantage of stability and freedom from interference by naturally occurring substances. The procedure requires 3-5 min. per sample and is very reproducible. The values obtained agree with those obtained by back-titration of excess chelator and are consistently 0.3 mg./100 ml. less than those obtained by a standard oxalate precipitation method.
Use of Halogenated Acetates and Formaldehyde as Plasma Additives in Inhibiting Heat Denaturation of Plasma Proteins
Authors: Dawson Donald , Zajtchuk Rostik , Allen J Garrott
Published: January 2020

Halogenated acetates alone and in combination with dextrose and formaldehyde will protect against heat denaturation of plasma proteins even when plasma is heated for 10 hr. at 60°. Application of this principle would afford reclamation of plasma from outdated blood bank blood.

Changes in protein patterns were observed by paper electrophoresis. Other measurements of denaturation were pH, absorbance at 610 mµ, and viscosity. The chemical reaction between the additives and plasma are considered, and estimations of toxicity are given.
Spectrophotometric Determination of Microgram Quantities of Copper in Biologic Materials
Authors: Stoner Ramon E , Dasler Waldemar
Published: January 2020

A procedure for the determination of microgram quantities of copper in biologic material is described. The sample is wet-ashed with a nitric acid-perchloric acid mixture. The copper is extracted from an alkaline solution of the ash with a solution of diphenylcarbazide in benzene. Absorbance of the red complex is read at 540 mµ. The copper in as little as 0.5 ml. of serum can be determined and the method is suitable for routine determinations. The use of microcells makes possible the analysis of 0.1 ml. of serum.
Cystine in Human Serum Proteins
Authors: Reiner Miriam , Sullivan Michael X
Published: January 2020

1. The amount of cystine was determined in a number of serum protein fractions separated by the procedure of E. J. Cohn. In albumin, the average value was 6.40 per cent for cystine; for γ-globulin the average value was 1.94 per cent; the other fractions tested were mixtures and varied according to the different globulins present. Globin from human hemoglobin contained 1.90 per cent cystine.

2. Separated fractions from three types of multiple myeloma cases have been presented showing abnormal fractions in the α-, β-, and γregions. The percentage of cystine was determined, and except for the fraction from the "gamma" type of myelomas, which contained 6.15 per cent cystine, the anomalous protein fractions contained about the same amount found in separated fractions of normal serum.
Urinary Peptides
Authors: Balikov Bernard , Castello Robert A
Published: January 2020

A simple method for the assay of urinary peptides has been presented. This method involves the reaction of a biuret reagent on a tungsticacid filtrate of Permutit-treated urine. Some possible interfering substances have been investigated and the precision of the method has been determined. Using this procedure, normal values have been assessed for adults on 24-hour urine collections.
Quantitative Nephelometric Microdetermination of Alpha-Globulins in Serum and Cerebrospinal Fluid
Authors: Saifer Abraham , Zymaris Michael C
Published: January 2020

1. A micronephelometric method is presented for the quantitative determination of total α-globulins in both serum and cerebrospinal fluid. The method is based on the relatively specific interaction of this protein fraction with the cationic detergent, Octab, at pH 6.65 in collidine-NaCl (.08M) buffer.

2. The various Cohn's protein fractions (Method 6) (25) were investigated with the nephelometric procedure. In comparison with normal serum, Fractions IV-6, IV-1, and IV-4, respectively showed the greatest detergent reactivity per milligram of α-globulin.

3. The variations of such factors as the concentrations of reagents, protein/detergent ratio, and salt concentration were reinvestigated.

4. Analysis of 14 normal and 33 pathologic sera gave excellent checks with the total α-globulin values obtained with the Tiselius electrophoretic method.

5. Application of the procedure to the analysis of the α-globulin content of cerebrospinal fluid required the addition of standard serum to 0.5-ml. aliquots of spinal fluid for stoichiometric results.
International Biochemical Trial 1954
Authors: Wootton I D P
Published: January 2020

There are two conclusions to be drawn from this trial. In the first place, this problem is universal and no country taking part maintains an acceptable standard of laboratory precision. Secondly, inspection of Fig. 1 shows that the ratio 37B/37A is significantly more constant for most constituents than are the corresponding absolute values. This implies that laboratories can compare two solutions more accurately than they can determine the absolute value of a constituent. It follows that estimations should be made whenever possible by comparing an unknown with a standard solution, a measure that would immediately eliminate one source of error.
Glutamine and Glutaminase in Blood
Authors: Iber Frank L , Bruton Joseph
Published: January 2020

A convenient and accurate procedure for the determination of glutaminase activity and glutamine in blood has been described.

Kidney homogenate from rats made acidotic by feeding NH4CL was used as a glutaminase source and the Conway microdiffusion method was used to determine ammonia.
Clinical Chemistry Work-Load Control Factors
Authors: Finch Edmund P , Owen Seward E , Byers Walter E
Published: January 2020

An analytic study of work-load factors in clinical chemistry shows that there are many elements involved. An average of 6.3 to 6.5 tests per man hour were obtained when clinical chemistry and urinalyses were combined. For clinical chemistry alone the tests per man hour averaged 3.1 in a hospital servicing patients with chronic diseases and 4.7 in a general hospital. The breakdown of a standard laboratory man hour in clinical chemistry included 49.3 minutes for the collection and determinative tests; the remaining time included vacations, training, personnel needs, nontechnical duties, and other items.
Activation of the Kinin-Forming System during Therapy with Cyclophosphamide
Authors: Cuschieri A
Published: January 2020

Venous blood kininogen is significantly decreased during therapy with cyclophosphamide in cases of advanced breast cancer. The maximum decrease in plasma kininogen coincided with onset of maximal leukopenia in the peripheral venous blood. In vitro studies showed that both human whole blood and mononuclear cell suspensions liberate free kinin when incubated with cyclophosphamide, but plateletfree human plasma does not. Evidently, the kinin-forming system is activated during therapy with cyclophosphamide, and this may account for some of its reported side effects. The in vitro studies suggest that this activation results from damage to peripheral blood leukocytes by the cyclophosphamide, with the release of intracellular proteases.
Differing Methodology and Equations Used in Quantitating Immunoglobulins by Radial Immunodiffusion—A Comparative Evaluation of Reported and Commercial Techniques
Authors: Berne Bernard H
Published: January 2020

Differing methods of plotting have been used to describe the results of radial immunodiffusion (RID). Two, logarithm of antigen concentration (log c) vs. precipitin-ring diameter (d) (Fahey) and log c vs. area (A or d2) (Mancini), are linear while rings are enlarging. Another, c vs. A (or c vs. d2), becomes linear when enlargement ceases at equivalence (Mancini). Because of methodological inaccuracy, I could not experimentally determine whether log c = d or log c = d2 is appropriate; either one or both semilogarithmic graphs may be linear as precipitin circles enlarge. I could confirm the c = d2 linearity at equivalence. Because smaller circles cease growth first, intermediate readings produce plots that are partially curved and partially straight. Commercial RID plates produce linear and curved plots of log c vs. d and of c vs. d2. They often create too small a diameter range for great accuracy. I conclude that semilogarithmic plots are of questionable value. For greatest accuracy plates should be designed for measurement at equivalence. At this time, a straight-line graph of c = d2 will include a maximal diameter range.
Simultaneous Automated Estimation of Noradrenaline and Dopamine in Brain Tissue
Authors: Waldmeier P , De Herdt P , Maitre L
Published: January 2020

A method is described for the simultaneous automated fluorometric estimation of noradrenaline and dopamine in brain extracts. It is based on a slight modification of the automated method for dopamine published recently. Interference of noradrenaline in the estimation of dopamine, and vice versa, is low (0.8 and 1.4%, respectively). Interferences of other catechols and related compounds have also been studied. Samples can be processed at a rate of 30 per hour, and the limit of sensitivity for both amines is about 2 ng/ml of brain extract.
Relative Affinity of Hemoglobin S and Hemoglobin A for Carbon Monoxide and Oxygen
Authors: Rodkey F Lee , O'Neal John D , Collison Harold A , Uddin David E
Published: January 2020

The relative affinity constants of hemolysates from individuals with hemoglobins A, S, or AS have been measured at 37 and 26 ° C. Observed values of all hemoglobin types were the same at both temperatures, K37 = 230, K26 = 296. Control measurements on whole blood containing Hb A gave values of K37 = 222. The small but significant difference between K37 values measured in whole blood and in hemolysates may be a result of the greater increase of MetHb in the hemolysates during the in vitro equilibration.
Statistical Quality Control and Routine Data Processing for Radioimmunoassays and Immunoradiometric Assays
Authors: Rodbard David
Published: January 2020

Numerous methods are available for the graphical display of radioimmunoassay dose—response curves, for curve-fitting and dose interpolation, for statistical quality control, and for automation and computerization of data processing. The relative merits of these approaches are discussed. Minimal requirements for radioimmunoassay data-processing systems are presented. The features of an "ideal" system are discussed.
Evaluation of an Enzymatic Procedure for Determination of Serum Cholesterol with the Abbott ABA-100
Authors: Witte David L , Barrett II David A , Wycoff Delane A
Published: January 2020

A previously reported direct enzymatic method for cholesterol [ Clin. Chem. 20, 470 (1974)] was critically evaluated in the clinical laboratory. Other methods compared to this enzymatic procedure were: (a) the manual Abell—Kendall procedure, giving a regression slope (proportional sensitivity) of 0.998 and a negative bias of 9.7 mg/dl in the enzymatic procedure; (b) Lipid Research Clinic procedure, giving a regression slope of 1.005 and a negative bias of 8.8 mg/dl in the enzymatic procedure; and (c) the SMA 12/60 (Technicon) method, giving a regression slope of 0.881 and a negative bias of 20.8 in the enzymatic procedure. Replicate analyses of pooled serum by the enzymatic procedure demonstrated the following inter-run precision: mean = 178 mg/dl, SD = 4 mg/dl, CV = 2.2%. Bilirubin caused a slight positive interference (1 mg of bilirubin per deciliter appears as 1-2 mg of cholesterol). Hemolysis, lipemia, and a series of steroid drugs caused no interference. A group of 465 normal subjects was tested by the enzymatic procedure. This population had a mean cholesterol of 203 mg/dl. The 2.5 percentile was 130 mg/dl, and the 97.5 percentile was 316 mg/dl.
New Method for Determination of Aminolaevulinate Dehydratase Activity of Human Erythrocytes as an Index of Lead Exposure
Authors: Tomokuni Katsumaro
Published: January 2020

I describe a new method for measurement of aminolaevulinate dehydratase (EC 4.2.1.24) activity of human erythrocytes. In this method, the amount of substrate δ-aminolevulinic acid consumed (instead of the amount of porphobilinogen formed) is determined colorimetrically. In the incubation mixture, the δ-aminolevulinic acidpyrrole produced by the condensation of δ-aminolevulinic acid with ethyl acetoacetate is separated from porphobilinogen by extraction with ethyl acetate, without resorting to ion-exchange column chromatography. The pyrrole-containing extract is treated with a modified Ehrlich's reagent. Activity of the enzyme is expressed as micromoles of δ-aminolevulinic acid consumed per minute per liter of erythrocytes. Enzyme activity is more accurately estimated by the present method than by the usual method in which porphobilinogen is measured.
Evaluation of a Gilford "Automatic Enzyme Analyzer" Modified to Assay 60 Samples per Hour
Authors: Morell Samuel A , Bach Daniel A , Ayers Valborg E
Published: January 2020

A Gilford 3400 Automatic Enzyme Analyzer has been modified to assay 60 samples per hour in modes 1 and 2 (28 and 61 seconds of incubation) or 30 samples per hour in mode 3 (187 seconds of incubation). The calculation cycle was reduced threefold to print activity based on ΔA/20 s, rather than ΔA/60 s. Linear ranges at 30 and 37 °C for lactate dehydrogenase, aspartate aminotransferase, and alkaline phosphatase were determined with control sera at rates of 60 samples per hour and for creatine kinase activated by dithiothreitol at 30 samples per hour. AutoAnalyzer end-point assays of patients' sera were correlated with the Gilford U/liter values. Application of the Micromedic pipette to the Gilford AEA system provided a convenient mean to study the linear range, precision, and accuracy of an enzyme assay.
Use of a Laser-equipped Centrifugal Analyzer for Kinetic Measurement of Serum IgG
Authors: Buffone Gregory J , Savory John , Cross R E
Published: January 2020

Use of a visible laser in an Aminco "Rotochem" centrifugal analyzer enables light-scattering measurements to be made with this instrument. The modification is technically simple, inexpensive, and requires no fundamental changes in basic instrument design. The laser-modified analyzer has been applied to the measurement of IgG in serum. A two-point kinetic analysis is used to quantitate IgG from a standard curve: protein concentration vs. change in intensity of the scattered light during a fixed time interval. Fourteen 20-µl samples can be simultaneously determined in 1.9 min. No sample blank corrections are required. Within-run precision studies, based in each case on 56 replicate measurements, yielded coefficients of variation of 3.8% and 4.8% for normal and abnormal pools, respectively.
Automated Method for Determining Serum Thiocyanate, to Distinguish Smokers from Nonsmokers
Authors: Butts William C , Kuehneman Martha , Widdowson Graham M
Published: January 2020

A chemical test to distinguish smokers and nonsmokers is important in many epidemiologic studies. We have developed an automated method for determining serum thiocyanate by use of the reaction between thiocyanate and ferric ions to form a colored complex. Our data show that this method distinguishes cigarette smokers and nonsmokers: of 197 healthy individuals studied, 1.8% false-positive and 6.7% false-negative results were obtained when 85 µmol of SCN- per liter was the critical value used to distinguish the two populations.
Rapid, Efficient Procedure for Extraction of Drugs for Toxicological Analysis
Authors: Ehrsson Hans , Knapp Daniel
Published: January 2020

The method involves extraction of nonionized acidic drugs and iodide ion pairs of amines by column chromatography. A yield of about 90% is obtained for acetylsalicylic acid and amphetamine.
Separation and Quantitation of Coproporphyrin and Uroporphyrin in Urine
Authors: Sobel Charles , Cano Carlos , Thiers Ralph E
Published: January 2020

Coproporphyrin and uroporphyrin are separated from urine and from each other by absorption onto, and selective elution from, an anion-exchange resin. The two compounds are separated by using solvents differing in both polarity and pH. The porphyrins are then quantitated with an Aminco-Bowman Spectrophotofluorometer equipped with an ellipsoidal mirror and a red-sensitive photomultiplier tube. Porphyrins can be determined in 1 ml of urine from a normal individual.
Computer Simulation and Optimization, as Exemplified by the Enzyme-Coupled Aminotransferase (Transaminase) Assays
Authors: London Jack W , Yarrish Robert , Dzubow Leonard D , Garfinkel David
Published: January 2020

We have constructed a computer model, based on experimental data and the known properties of the enzymes involved, of the aspartate aminotransferase and alanine aminotransferase assays by the coupled-enzyme procedure of Henry et al. [Amer. J. Clin. Pathol. 34, 381 (1960)] to assay sera from normal persons and persons with liver disease or myocardial infarct. Observed inhibitions of aminotransferase activity were included in the models. When the computer models are combined with an optimization procedure, substrate concentrations that result in maximum enzyme activity for individual sera are obtained. Aminotransferase activity is not much affected by rather large changes in these concentrations around the optimum. The optimal concentrations we computed are close to those currently accepted. The computer methods involved may be applied to other assays, and factors other than reagent concentration may be optimized.
Comparison of Visualization Methods Used to Measure the Lecithin/Sphingomyelin Ratio in Amniotic Fluid
Authors: Olson E B , Graven S N
Published: January 2020

Amniotic fluid lecithin/sphingomyelin ratios are commonly determined after these phospholipids are separated by thin-layer chromatography and made visible by one of several methods. Here, we comprehensively survey the experiences of other authors with these visualization methods, and we have evaluated the available techniques. We report standard curves of dipalmityl lecithin and sphingomyelin made visible by six of these methods. Bromthymol blue in ammonia vapor or charring with either sulfuric acid:water (1:1 by vol) or potassium dichromate (10 g/liter) in sulfuric acid:water (7:3 by vol) produces spots of similar intensity for both phospholipids. However, iodine vapor, a phosphomolybdic acid dip, or charring with ammonium sulfate, produces more intense sphingomyelin spots. We recommend that (a) visualization methods be used that produce similar spot intensities for both phospholipids so that the ratio determined reflects the actual relative amounts of lecithin and sphingomyelin, and (b) if clinical predictions are made based on interpretation tables provided in the literature, the visualization method on which the ratio interpretation tables are based gives results that correlate with the actual ratio.
Fully Automated, All-Enzymatic Triglyceride Method Adapted to the GEMSAEC Centrifugal Analyzer, with Use of an Aqueous Triolein Standard
Authors: Chong-Kit R , McLaughlin P
Published: January 2020

We describe a completely automated enzymatic method for estimating serum triglycerides with a centrifugal analyzer (ENI-GEMSAEC). Accuracy and precision (CV, 2 to 4.8%) and the upper limit of linearity (400 mg/100 ml) are monitored by use of newly developed, clear, aqueous triolein standards. A modified computer program (FOCAL 8) is used for data manipulation and correcting absorbance to zero reaction time. Results cornpare well with those obtained by an automated fluorometric procedure and a manual enzymatic procedure.
Factors Contributing to Intra-Individual Variation of Serum Constituents: 4. Effects of Posture and Tourniquet Application on Variation of Serum Constituents in Healthy Subjects
Authors: Statland Bernard E , Bokelund Henning , Winkel Per
Published: January 2020

We studied the effects on 18 serum constituents of posture and prolonged tourniquet application. The subjects were 11 healthy men, ages 20-25 years. The assays were performed on the AutoChemist Multi-Channel Analyzer (AutoChem Instrument AB, Lidingö, Sweden). To compensate for the within-hour variation in these constituents, we drew blood samples at 1100 h and 1130 h on several days. The 1100-h sample was taken after the subjects had been sitting erect for 60 min. The 1130-h sample followed different posture regimens: Control day: sitting for 15 min; experimental days: after (a) being supine for 30 min, (b) standing for 30 min, and (c) sitting erect for 30 min. The 1130-h/ 1100-h ratios for the three experimental days were compared with those for the control day. Significant differences (P <.05) were found for serum potassium, calcium, total protein, albumin, aspartate aminotransferase, and acid phosphatase under condition a; for phosphate ion, total protein, total lipid, cholesterol, and alkaline phosphatase under condition b; and for aspartate aminotransferase under condition c. The effect of a 3-minute tourniquet application was similarly studied. The ratio of the "prolonged tourniquet application day" differed significantly from the control day with regard to serum potassium, total protein, iron, total lipid, cholesterol, aspartate aminotransferase, and bilirubin. Significance of posture and tourniquet time in blood-sampling and their effect on total intra-individual variation are discussed.
Gas—Liquid Chromatography of Phenylalanine Metabolites in Urine and Sera of Hyperphenylalaninemic and Phenylketonuric Patients
Authors: Kitagawa Teruo
Published: January 2020

Gas—liquid chromatographic methods are described for measuring phenylalanine metabolites in urine and serum. These were studied in controls and in various types of hyperphenylalaninemics. The plasma phenyllactic acid concentration increased as the serum phenylalanine concentration increased. The 24-h urinary excretion of both phenylalanine and phenyllactic acid depends upon their respective concentrations in serum.
Optimizing Nephelometric Measurement of Specific Serum Proteins: Evaluation of Three Diluents
Authors: Killingsworth Lawrence M , Buffone Gregory J , Sonawane Meena B , Lunsford Glennie C
Published: January 2020

Three diluents were studied, to determine which is the best for the automated immunochemical measurement of specific serum proteins. Nine serum proteins (orosomucoid, α1-antitrypsin, α2-macroglobulin, haptoglobin, transferrin, C3, IgG, IgA, and IgM) were measured in physiological saline (9 g NaCI/liter), tris(hydroxymethyl)aminomethane buffer (0.01 mol/liter; pH 7.4), and physiological saline containing polyethylene glycol ("PEG 6000," 40 g/liter). Criteria were: reaction rate, analysis rate, carryover between samples, steady-state approximation, precision, and correlation with other methods. Saline containing polyethylene giycol is the best of the three diluents for use in continuous-flow nephelometric analysis of serum proteins.
Measurement of Ceruloplasmin from Its Oxidase Activity in Serum by Use of o-Dianisidine Dihydrochloride
Authors: Schosinsky Karl H , Lehmann H Peter , Beeler Myrton F
Published: January 2020

We have developed a new method for determination of serum ceruloplasmin from its oxidase activity, in which o-dianisidine dihydrochloride is used as substrate. o-Dianisidine dihydrochloride is more stable than is the more widely used p-phenylenediamine substrate, and forms a stable product that is measured at 540 nm. Correlation was good between results of this method and those obtained with both a p-phenylenediamine substrate method (r = 0.98) and a radial immunodiffusion procedure (r = 0.97). There is little or no interference from reducing or colored components of serum. The coefficient of variation (day-to-day) for the method was 4.2%. A normal range of 62-140 U/ liter has been determined by the reported method.
Simple Enzymatic Determination of Polysaccharide (Glycogen) Content of Animal Tissues
Authors: Murat J C , Serfaty A
Published: January 2020

For determination of (chiefly) glycogen content, tissue homogenates in citrate buffer are mixed with exo-1,4-α-glucosidase (EC 3.2.1.3). Liberated glucose is estimated with a Beckman Glucose Analyzer. This method was checked with commercial glycogen (from oysters) and with fish (carp) tissues. Comparative measurements were made with the classic Good-Kramer-Somogyi method [J. Biol. Chem. 100, 485 (1933)]. The described method, suitable for small samples of tissue, such as those obtained by biopsy, seems to be simple and accurate, but gives values 5 to 10% higher than those given by the classic KOH-ethanol method.
Frequency of Clinical Toxicology Test-Ordering (Primarily Overdose Cases) and Results in a Large Urban General Hospital
Authors: Lundberg George D , Walberg Clifford B , Pantlik Violet A
Published: January 2020

We report one year's analytical data from a clinical toxicology laboratory of a large urban hospital. The laboratory was designed to perform tests on seriously ill patients believed to be suffering from possible drug overdose. The data describe the types and numbers of tests requested and percent positive. Barbiturates, ethanol, a "hypnotic screen," phenothiazines, and salicylates were the leading requests and positive findings among the 63 drug determinations studied. The mechanism of organizing a laboratory along "patient-focused" lines is described and the clinician—laboratory interface is discussed. We believe that these data could be of value to anyone contemplating offering a clinical toxicology service for the first time or in assisting in the reorganization of their present service.
Rapid Gas Chromatographic Method for Quantitation of Ethchlorvynol ("Placidyl") in Serum
Authors: Evenson M A , Poquette M A
Published: January 2020

A rapid, simple, and sensitive method for quantitation of ethchlorvynol by gas chromatography has been developed. Instrument response is linear to a concentration of 200 mg/liter (2.0-ml sample of serum). Day-to-day (20 days) precision of a 15 mg/liter serum pool was 0.85 mg/liter (SD) and 5.6% (CV). For 30 samples analyzed by both the gas chromatographic method and a colorimetric method, the correlation plot had a slope of 0.989, x and y intercepts near zero, and a correlation coefficient of 0.997. Mean recovery of ethchlorvynol added to serum was 87%. Subsequently, all standards were prepared in serum, to compensate for the nonquantitative yield and to help assure accuracy. Sera from healthy controls and from hospitalized patients contain no endogenous interfering substances, nor did any of a series of commonly prescribed drugs interfere.
Use of Fluorescamine ("Fluram") to Detect Amphetamine in Urine by Thin-Layer Chromatography
Authors: Klein Bernard , Sheehan Joan E , Grunberg E
Published: January 2020

A "Fluram" (fluorescamine; 4-phenylspiro[furan-2(3H)-1'-phthalan]-3,3'-dione) spray reagent will detect as little as 250 ng of amphetamine in an extract of amphetamine-containing urine, after it has been separated by thin-layer chromatography. The fluorescence is stable for about 20 h and can be renewed by respraying. Fluram spray does not interfere with reagent sprays used to detect other drugs of abuse. Amphetamine on the thin-layer plate can be measured by extracting the fluorescent area of silica gel and measuring the fluorescence in a fluorimeter. Recovery of 1.0 µg and 2.0 µg of amphetamine averaged 69% and 67%, respectively.
Fluorometric Determination of Propoxyphene
Authors: Valentour James C , Monforte Joseph R , Sunshine Irving
Published: January 2020

We report a sensitive fluorometric method of analysis of propoxyphene in biological materials. 4-Chloro-7-nitrobenzo-2,1,3-oxadiazole is reacted with propoxyphene to produce highly fluorescent derivatives, thus enabling quantitative determination of propoxyphene in whole blood, urine, or tissue after either therapeutic use or overdose.
Isolation of Drugs and Drug Metabolites from Biological Fluids by Use of Salt-Solvent Pairs
Authors: Horning M G , Gregory P , Nowlin J , Stafford M , Lertratanangkoon K , Butler C , Stillwell W G , Hill R M
Published: January 2020

Simple rapid procedures based on salt-solvent pairs have been developed for the isolation of drugs and drug metabolites from urine, plasma, and breast milk. The best overall recovery of drugs (84-104%) was obtained by using ammonium carbonate—ethyl acetate extraction. Internal standards were added to the biological samples before the isolation procedure was begun; standards labeled with stable isotopes were preferred. The isolated drugs were quantitated by selective ion detection, with use of an LKB 9000-PDP 12 in electron impact mode, a Finnigan 1015-PDP 8/1 in chemical ionization mode, and an atmospheric pressure ionization mass spectrometer. Sensitivity of detection was in the nanogram to picogram range.
Thin-Layer Chromatographic Differentiation of Amphetamine from Other Primary-Amine Drugs in Urine
Authors: Bussey Robert J , Backer Ronald C
Published: January 2020

We describe a thin-layer chromatographic procedure for distinguishing among amphetamine, mescaline, 4-methyl-2,5-dimethoxyamphetamine (STP), 3,4-methylenedioxyamphetamine (MDA), phenylpropanolamine, chlorphentermine, β-phenylethylamine, benzocaine, and procaine. These compounds may be encountered in urine-screening programs, and all except MDA are well separated from amphetamine (a fact not previously established) as well as from each other. They are revealed by sequentially spraying with ethanolic phenylacetaldehyde—ninhydrin and aqueous sodium phosphate. The resulting yellow spots fluoresce green on heating. The aromatic amines fluoresce poorly. MDA is distinguished from amphetamine by overspraying with chromotropic acid. Detection limits and Rf values are reported. Fluorescence spectra of the aliphatic amines are similar.
Radioimmunoassay of Calcitonin in Human Plasma
Authors: Silva Omega L , Snider Richard H , Becker Kenneth L
Published: January 2020

A sensitive, specific radioimmunoassay of calcitonin is described, suitable for measuring the hormone in peripheral plasma of normal man. With this assay we have demonstrated that calcitonin is detectable under ba sal conditions and the concentrations respond to induced and spontaneous hypercalcemia and induced hypocalcemia. The mean value for basal calcitonin of normal men was 182 pg/ml (range 63-450); patients with hypercalcemia of various etiologies had a statistically significant higher mean value of 510 pg/ml (range 110-2700). In calcium-infusion studies, concentrations of both total calcium and ionic calcium correlated well with plasma calcitonin (0.77 and 0.84, respectively). These findings strongly suggest that calcitonin is of physiologic importance in man.