bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Improved Fluorometric Methods Used to Quantitate Plasma Catecholamines
Authors: Manger William M , Steinsland O S , Nahas G G , Wakim Khalil G , Dufton S
Published: January 2020

Comparative studies reveal that the ethylenediamine and the trihydroxyindole method when employed as suggested are suitable for assessing sympatho-adrenal activation under various stressful conditions that are accompanied by release of catecholamines into the circulation. Both methods are very accurate in quantitating epinephrine or norepinephrine that has been added to plasma or whole blood, although recovery from blood is less, owing mainly to some association of catecholamines with formed elements, primarily erythrocytes. Use of sodium thiosulfate in the ethylenediamine procedure minimizes association of catecholamines with formed elements. If blood samples are cooled in ice water when collected, association of catecholamines with blood cells can be further reduced. In the trihydroxyindole method, unless tubes containing blood samples are immediately immersed in ice water, a significant amount of catecholamines will disappear from plasma, because of this association of catecholamines with cells.
Determination of Urinary Formaldehyde Following Administration of Methenamine Salts
Authors: Greenfield W , Berg R , Moore R
Published: January 2020

Earlier studies on formaldehyde determination in the urine of subjects receiving methenamine salts have given questionable results. A modification of the Tannenbaum and Bricker procedure was utilized to evaluate formaldehyde production from 3 methenamine salts and methenamine base. Formaldehyde production was studied in vitro and in vivo.
Chemical Composition of Peripheral Nerves
Authors: Anghinah Abrao , De Jorge Francisco Bastos , Aisen Julinho
Published: January 2020

The present paper presents normal values for the contents of water, sodium, potassium, calcium, magnesium, phosphorus, chloride, copper, and iron in peripheral nerves (tibialis, fibularis profundus, and ulnaris) in individuals without any neurological condition. This study constitutes a basis for the interpretation of other data, still being gathered, relating these normal values with those obtained for peripheral nerves under pathological conditions.
Automated Fluorometry as Applied to the Assay of Individual Estrogens in Purified Urinary Extracts
Authors: Strickler Herbert S , Stanchak Patricia J
Published: January 2020

Using the Kober-lttrich fluorescence procedure, automated fluorometry was applied to the assay of individual estrogens and their 3-methyl ether derivatives in the purified urinary extracts of nonpregnant women. The values obtained by using this new automated scheme were compared with those obtained by the manual time-decay modification of the Slaunwhite-Engel fluorescence method; the comparison shows excellent correlation. A ratio of the corrected peak reading at 546 mµ. excitation to the corrected peak reading at 490 mµ. excitation was used not only to follow the effect of introducing additional purification stages in the development of assay procedures, but also to follow impurity levels in sample analyses. The same assembly of modules can be used for samples dissolved in acidified water, 70% methanol, and, with a simple change of manifold, in 1 N sodium hydroxide. This fully automated assay provides precise conditions in all stages.
A Colorimetric Method for the Determination of Serum Arginase Activity
Authors: Loeb Walter F , Stuhlman Robert A
Published: January 2020

A detailed description of a method for the determination of serum arginase activity is presented. Arginase activity is demonstrated by the decrease in arginine concentration in a reaction mixture, as determined by a modification of the method of Sakaguchi. The reaction is linear until inhibited by the increasing concentration of ornithine. The cellular distribution of arginase is reviewed to determine its role in diagnosis and in the evaluation of biologic systems.
Simultaneous Determination of Urinary Estriol, Pregnanediol, and Pregnanolone by Gas-Liquid Chromatography
Authors: Baynton Robert D , Campbell Donald J
Published: January 2020

A simplified method for following the urinary excretion of estriol, pregnanediol, and pregnanolone during the course of pregnancy is presented. The procedure has been used successfully in a large hospital laboratory. An important advantage is that the estrogen and progesterone metabolites are measured simultaneously, and separate extraction and gas-liquid chromatography is not required. The urine specimen is hydrolyzed enzymatically, extracted, and the steroids are converted to trimethylsilyl ethers. Temperature-programmed gas-liquid chromatography is carried out on a 2% neopentyl glycol succinate column using a hydrogen flame ionization detector.
Thyroxine-Binding Prealbumin in Thyrotoxicosis and Hypothyroidism
Authors: Vergani C , Stabilini R , Agostoni A
Published: January 2020

The serum concentrations of thyroxine-binding prealbumin (TBPA) have been determined quantitatively by an immunochemical method in patients with thyrotoxicosis and hypothyroidism. Low levels of TBPA were found in all patients with untreated thyrotoxicosis. Normal values were found in 8 of 10 cases of untreated hypothyroidism.
Comparison of Dumas and Kjeldahl Methods for Determination of Nitrogen in Feces
Authors: Stitcher Joseph E , Jolliff Carl R , Hill Robert M
Published: January 2020

The present study was undertaken to compare the nitrogen content of human feces as determined by the Kjeldahl technic and the micro-Dumas method as utilized in the automated Coleman nitrogen analyzer. The standard deviation between duplicate determinations of the same sample was 0.06% nitrogen in the case of the nitrogen analyzer and 0.02% nitrogen for the Kjeldahl method. The standard deviation between the average values obtained by each method for each sample was 0.07% nitrogen. The agreement between the two methods seemed to be independent of the nitrogen content. The apparent recovery of nitrogen by the nitrogen analyzer was found to be greater than that recovered by the Kjeldahl procedure. Factors which may be involved in this difference in recovery between the two methods are discussed.
Simultaneous Spectrophotometric Determination of Diphenylhydantoin and Phenobarbital in Biologic Specimens
Authors: Wallace Jack E
Published: January 2020

A rapid, accurate method for determining diphenylhydantoin and phenobarbital in a single biologic sample is described. Separation of the two drugs after their initial chloroform extraction from the specimen is not required. After extraction, diphenylhydantoin is converted to benzophenone by pemanganate oxidation. Phenobarbital is determined by differential absorption between pH values of 12.0 and 10.5. Final quantitation in each case is carried out by ultraviolet spectrophotometry. Barbiturates do not interfere with the diphenylhydantoin analysis or vice versa. The method is sensitive enough for detecting subtherapeutic amounts of each compound with a high degree of specificity.
Aldolase
Authors: Pinto Patrick V C , Kaplan Alex , Van Dreal Paul A
Published: January 2020

Two commercial kits for the measurement of serum aldolase activity by a spectrophotometric (UV) method were evaluated. Neither was satisfactory in their present forms, since aldolase activity was not rate-limiting in one, and side reactions utilizing NADH occurred in the other.

A study was made of the optimum concentrations of substrate, NADH, buffer, and coupled enzymes (triosephosphate isomerase and α-glycerophosphate dehydrogenase) in the procedure utilized by one kit, and a method based upon these findings is proposed. The key feature of the proposed method is an increase in the amount of the auxiliary enzymes, GDH/TIM, so that aldolase becomes the rate-limiting enzyme. The proposed method also differs from the kit procedure in the concentrations of substrate and NADH, in the choice of buffer, volume of reaction mixture, and in the order of adding solutions to the reaction mixture.
A Simple and Rapid Procedure for the Determination of α Amino-nitrogen and Ammonia in Urine
Authors: Clarkson T W , Ferraio L
Published: January 2020

The ninhydrin-colorimetric procedure for the determination of urinary α amino-nitrogen has been simplified by the use of the Conway microdiffusion unit to remove ammonia from the sample. In this way, urinary ammonia is measured, and at the same time an ammonia-free urine sample is ready for α amino-nitrogen analysis. Values for total and free α amino-nitrogen in normal urine samples were found to be similar to those previously reported by more complicated procedures.
Automated Determination of Free Amino Groups in Serum and Plasma Using 2,4,6-Trinitrobenzene Sulfonate
Authors: Palmer D W , Peters T
Published: January 2020

A simple automated method is described for determining the level of total free amino acids in the blood. The method utilizes the AutoAnalyzer, and is based on the formation of colored complexes by uniting free amino groups with 2,4,6-trinitrobenzene sulfonate (TNBS). Proteins do not interfere because the free amino acids are first separated by dialysis. Characteristics of the reaction and potential clinical applications of the procedure are discussed.
Ammonium Sulfate Precipitation of Conjugated Estrogens in Pregnancy Urine: Rapid Assay and Glucose Effects
Authors: Pinkus Geraldine S , Pinkus Jack L
Published: January 2020

Ammonium sulfate precipitation of total estrogens in pregnancy urine effectively removes many substances that interfere with estrogen assays. From systematic study of the precipitation technique we define optimum conditions for isolating free and conjugated estrogens. Solutions of the precipitated estrogens are directly analyzed. Glucose effects on these assays are negligible. Urinary estrogens are minimally exposed to acid or alkali before analysis by the Ittrich procedure, thus protecting the labile fraction that may be significant in complicated pregnancies
Automated Enzymatic Method for L-Lactate in Blood
Authors: Mann George V , Shute Elizabeth
Published: January 2020

An automated method for measuring L-lactic acid in whole blood is de-scribed. The method uses a Somogyi procedure for deproteinizing and stabilizing the sample, the lactic dehydrogenase derived from yeast coupled with potassium ferricyanide for the determination. Results by this method compare favorably with those obtained by manual and automated procedures in which lactic dehydrogenase from muscle is used
An Automated System for Kinetic Multiple-Point Determinations Exemplified by Serum Lactic Dehydrogenase Determination
Authors: Fasce Charles F , Rej Robert
Published: January 2020

A fully automated procedure is presented for kinetic determinations and for use of the AutoAnalyzer in their study; serum lactic dehydrogenase has been used to illustrate such an application. The LDH-catalyzed oxidation of L-lactate by NAD in separate, unequal time-delay coils is determined by measuring the natural fluorescence of reduced coenzyme. The normal range for LDH activity by this method was 63-169 U/liter at 37°C.
Calculation of Normal Ranges by Methods Used for Resolution of Overlapping Gaussian Distributions
Authors: Gindler E Melvin
Published: January 2020

Distribution of a quantity, e.g., concentration of a serum constituent, in a typical general hospital population is considered. It is assumed that the distribution within any subpopulation is Gaussian and that adjacent subpopulations overlap somewhat, presenting overlapping Gaussian distributions. Bhattacharya’s procedure for resolving such overlapping distributions, based upon differentiation of the Gaussian distribution equation, is applied to the determination of the apparent normal range as well as, in some cases, an abnormal range. Gaussian probability paper is used for estimating the normal range and the conditions discussed under which this method may be expected to give a valid estimate. Use of the chi-square test to evaluate the long-term constancy of clinical laboratory data distribution, normal and abnormal, is also considered.
A Serum Reference Standard for Automated Total Protein and Albumin Procedures
Authors: Keyser J W , Cawson M
Published: January 2020

Preparation of a stable pool of concentrated serum, suitable for use as a reference standard in automated total protein and albumin procedures, is described.
Simplified Procedure for Determination of Estrogen in Pregnancy Urine
Authors: Grannis George F , Dickey Richard P
Published: January 2020

Determination of total estrogen in pregnancy urine has involved hydrolysis, extraction of estrogen, development of color, and extraction of chromogen prior to absorbance measurements. The necessity for each of these steps was evaluated and a more simple procedure was developed which requires only extraction of estrogen and development of color. The new procedure should be useful for prenatal screening and monitoring of high-risk pregnancies.
Development of Normal Values for Use in Multitest Biochemical Screening of Sera
Authors: O’Kell Richard T , Elliott Joseph R
Published: January 2020

Age- and sex-related "normal" values were calculated for data obtained by screening 8015 patients’ sera with the Technicon SMA 12/60 at the time of hospital admission. Calcium, phosphorus, total protein, and albumin concentrations decrease with age; glucose, urea nitrogen, cholesterol, and lactic dehydrogenase concentrations increase. Uric acid concentration increases with age in women. Mean values for calcium, glucose, urea nitrogen, and uric acid concentrations are greater in men. Serum glutamic-oxaloacetic acid transaminase activity is most frequently abnormal, total protein concentration least frequently. Alkaline phosphatase and bilirubin results were unremarkable.
Improved Accuracy in Automated Fluorometric Determination of Plasma Triglycerides
Authors: Noble Robert P , Campbell Frank M
Published: January 2020

Accuracy of the automated fluorometric measurement of triglyceride by the technique of Kessler and Lederer is limited by the instability of the baseline. Concentration of the alcoholic KOH reagent was modified, and the pump tube manifold altered to provide on-stream mixing of the KOH reagent, which overcame this difficulty. A relatively inexpensive fluorometer with the solid-state photomultiplier microphotometer, modified to provide dual-scale sensitivity, was used to increase precision of measurements. Analytical results for 30 serum samples, taken from three pools of frozen serum, show the accuracy of the measurements to be ±8 mg/100 ml and the standard deviation ±9 mg/100 ml for a single determination.
Problem of the Unit of Reference in Expressing Biomedical Data
Authors: Barak Anthony J
Published: January 2020

This paper reviews various bases used by investigators in the biomedical field for expressing analytical data obtained from biological tissues. The advantages of certain units of reference in certain research situations and the pitfalls of other modes of expression are discussed. I suggest that authors express their data using several bases when no particular one is fully adequate. Use of wet weight, DNA, and total protein (as polypeptide) as bases would add new dimensions to the data and may suggest new possibilities for further experimental investigation.
Comparison of the Weber-Schalm Method with the Ducci-Watson Modification of the Malloy-Evelyn Method for Serum Bilirubin Determination
Authors: Perrelli W Vincent , Watson C J
Published: January 2020

Unconjugated bilirubin, conjugated bilirubin, and mixtures of various proportions of each were dissolved in depigmented human serum. These, together with normal and pathologic native human sera, were analyzed for conjugated, unconjugated, and total bilirubin by the Weber-Schalm method. Results were compared with the determination of "prompt direct reacting bilirubin" and of total bilirubin by the Ducci-Watson modification of the Malloy-Evelyn method. Comparisons show that the Weber-Schalm method more accurately measures conjugated bilirubin concentrations in serum in which the bilirubin is mostly conjugated, but that it gives falsely high values for unconjugated bilirubin in serum in which more of the bilirubin is in the unconjugated form. The two methods gave statistically identical total bilirubin values for the native serum tested. A method is described for correcting the unduly low values for prompt, direct reacting bilirubin in terms of percentage of conjugated bilirubin.
An Improved Reagent System for the Measurement of Serum Uric Acid
Authors: Jung D H , Parekh A C
Published: January 2020

The reagent is modified as follows: Serum chromogens are destroyed by trisodium phosphate. The use of phosphotungstic acid eliminates the tungstate and sulfate anions, a frequent cause of turbidity. Triethanolamine, added to the carbonate—urea mixture, provides unusual stability of the color through its buffering action. Only 0.2 ml of serum is required. The method is highly reproducible and accurate; analytical results agree closely with those obtained by the uricase or cyanide—urea method.
An Improved Method for Preparation of Feces for Bomb Calorimetry
Authors: Lovelady Hubert G , Stork Emmett J
Published: January 2020

As a preliminary to bomb calorimetry, weighed, homogenized fecal slurries are prefrozen and lyophilized. Advantages of this method over the method of drying in a vacuum oven include: more moisture is removed from the sample initially, drying time is reduced from 48 h to 16 h, grinding is eliminated and objectionable odors are eliminated during sample processing.
A New Saccharogenic Micromethod for Measurement of Amylase Activity in Biological Fluids
Authors: Lorentz Klaus , Oltmanns Detlef
Published: January 2020

To determine serum amylase activity we have quantitatively measured the glucose and maltose hydrolyzed from soluble starch by colorimetrically measuring the reduction of colorless triphenyltetrazolium chloride to a red formazan, which is dissolved in methanol. The method is suitable for use with microsamples of all biological fluids, and is specific for the final products of starch digestion. Values found for sera from 55 apparently healthy blood donors ranged from 0.15 to 1.55 (mean, 0.83; standard deviation, ±0.4) mg of glucose per ml per h, corresponding to 7.5 to 78 Somogyi units.
Urinary Excretion of Folic Acid Activity in Man
Authors: Cooperman Jack M , Pesci-Bourel A , Luhby A Leonard
Published: January 2020

Urinary excretion of folic acid activity was studied in healthy adults and children before and after intravenous administration of 2.5, 5, 10, 20, 40, or 80 /1g of pteroylglutamic acid per kg of body weight. Activity was measured by three improved microbiological assays that use Lactobacillus casei, Streptococcus fecalis, or Pediococcus cerevisiae. Activity excreted under normal dietary conditions was about 1% of the dietary folate intake. Excre-tion of urinary folic acid activity was appreciably increased after admin-istration of 10 big or more of pteroylglutamic acid per kg body weight. At the latter doses, there was a linear relationship between L. casei and 8. fecalis assayable folic acid activity in urine and the administered dose. Less than 1% of the activity excreted after the above doses of pteroylglu-tamic acid was detectable by P. cerevisiae assay. More than 90% of the 24-h urinary excretion occurred within 6 h after each subject received pteroyl-glutamic acid. Intercomparison of the three assays showed that the urinary folic acid activity after intravenously administered pteroylglutamic acid was due to pteroylglutamic acid or a closely related derivative. The excre-tion by children and adults was proportionately the same
A Specific Colorimetric 5′-Nucleotidase Assay Utilizing the Berthelot Reaction
Authors: Belfield Alan , Ellis Graham , Goldberg David M
Published: January 2020

A sensitive calorimetric assay for 5′-nucleotidase activity is described, which requires 40 µl of serum. Adenosine, formed by hydrolysis of 5′-adenylic acid, is deaminated enzymatically and the ammonia determined with the Berthelot reaction. β-Glycerophosphate is added to suppress hydrolysis of 5′-adenylic acid by alkaline phosphatase. The reaction is optimal at pH 7.9 in 0.05M Michaelis' barbital buffer containing 10 mmoles of MgCl2 per liter. In the Berthelot reaction the MgCl2 causes a precipitate, which is removed without decreasing color yield by adding EDTA. Inhibition of the Berthelot reaction by serum and constituents of the reaction mixture is predictable and can be compensated by a correction factor
A New "Bilirubinometer"1 and Its Use in Estimating Total and Conjugated Bilirubin Serum
Authors: Jackson S H , Hernandez A H
Published: January 2020

The prototype "Bilirubinometer" previously reported by Jackson [Clin. Chem. 11, 1051 (1965)] has been modified for commercial production. A method for the determination of conjugated (direct-reacting) bilirubin with this instrument is described.
Phenotyping of Hyperlipoproteinemias
Authors: Winkelman James , Wybenga Donald R , Ibbott Frank A
Published: January 2020

The stability of serum specimens collected for cellulose acetate electrophoresis of lipoproteins has been studied for each of the hyperlipoproteinemia phenotypes. In general, samples kept at room temperature for three days are still suitable for analysis. On longer standing, artifacts can cause misinterpretation of strips, or render them completely unreadable. If specimens are stored at refrigerator or freezer temperatures, deterioration is retarded but the period of stability after they are returned to room temperature is unaltered. A second freeze-thaw cycle makes specimens unsuitable for analysis. Samples can be stored at refrigerator temperatures for at least 28 days and at freezer temperatures for at least 14 days if one freeze-thaw cycle is used.
Phenotyping of Lipemias by Ultrafiltration and Nephelometry of Serum Lipoproteins
Authors: Werner Mario , Montgomery Carolyn K , Jones Albert L , Nussenbaum Siegfried
Published: January 2020

Nephelometry of serum before and after ultrafiltration through cellulose membranes affords a simple and rapid physical method for separately estimating pre-β-lipoproteins and chylomicrons in their native state. The method was rigorously evaluated through correlative studies with chemical analyses, electron microscopy, and electrophoresis. Together, the data indicate that this technique, combined with the determination of cholesterol as an estimate of β-lipoprotein concentration, allows the phenotyping of hyperlipemias.
Miniature Photometers for Liquid Chromatography
Authors: Thacker L H , Pitt W Wilson , Katz S , Scott Charles D
Published: January 2020

A series of miniature photometers has been developed for use as on-stream detectors in systems for liquid chromatography. All of the detectors feature dual-beam, dual-wavelength operation without mechanical or electrical switching of either wavelength or signal. The two types of detectors originally developed—ultraviolet (254 and 280 nm) and colorimetric (any two choices of visible wavelengths)—have been integrated into a single modular instrument that can be converted from ultraviolet to use with visible wavelengths by substituting source and filter modules. Both straight-through vertical quartz tube flow cells of 3-mm i.d. and Z-cell modules with 10-mm light pathlengths are available. A single-unit power-source and rangeswitching box is used with any configuration of the detector.
Rapid Separation of the Components of Nucleic Acids and Urine by High-Resolution Liquid Chromatography
Authors: Burtis A C , Munk M N , MacDonald F R
Published: January 2020

The improved separations of nucleic acid components obtained with two recently developed liquid chromatography systems are presented. An ion-exchange system operating at 3000 lb/in.2, developed for use with pellicular ion-exchange resins, separates the 2',3'-ribonucleotides of the four common bases in 55 min, the 5'-deoxynucleotides in 10 min, a mixture of four dinucleotides in 30 min, and a mixture of AMP, ADP, and ATP in 3.5 min. The difficult separation of the mono-, di-, and triphosphates of the four nucleosides requires 2.5 h with the pellicular anion-exchange resin. The four bases, or their nucleosides, are separated in less than 15 min with pellicular cation-exchange resin. The system has been modified to allow separation of more than 90 uv-absorbing constituents in human urine. A versatile, nonpulsating system, operated at 5000 lb/in.2, separates the ribonucleosides in less than 5 min on small-particle, conventional cation-exchange resin. Resins from three separate sources performed comparably, but parameters such as pH, temperature, and linear velocity must be optimized for each. Both systems are designed with a minimum of dead volume and use a sensitive uv photometer. The 0.02 absorbance unit full-scale sensitivity and 1-cm pathlength of the uv photometer allow analysis of picomole quantities of nucleic acid components.
Lipids of Commercial Serum Products Offered as Controls or "Standards" for Cholesterol and Triglyceride Determinations
Authors: Witter R F , Kuchmak M , Williams J H , Whitner Virginia S , Winn Carole L
Published: January 2020

The cholesterol and triglyceride content of commercial control products (usually sera), purchased from six manufacturers, were measured. In addition, total fatty acid and qualitative neutral lipid composition of the total lipids were measured by gas—liquid and thin-layer chromatography, respectively. Cholesterol values we found by the Abell—Kendall method differed from the values given for six of the 12 assayed products by 6 to 37 mg/100 ml; triglyceride values, determined by a modified Carison procedure, differed from the means given for two of the four assayed products by 14 to 17 mg/100 ml. Neutral lipids present in total lipids in 13 of 15 lyophilized samples, and fatty acid composition of the latter in 12, closely resembled those of freshly drawn human serum, indicating that the lipids had not deteriorated grossly. The lipids of one lyophilized product from a bovine serum source included an appreciable amount of linolenic acid, which is not found in human serum; a second contained an unknown lipid-solvent material. Some decomposition of the lipids was noted in a filtered liquid sample. These results strongly support the use of commercial lyophilized preparations as control sera, but not as secondary serum standards.
A Discussion of the Linearity between the Measured Voltages of Ion-Selective Electrodes and the Ionic Concentrations in Whole Blood
Authors: Neff G W
Published: January 2020

The ion-sensitive electrodes used to measure Na+, K+, and Cl- in biological fluids have output voltages that are logarithmically related to ionic activity. This measured voltage also is linearly related to ionic concentration for the Na+ and Cl- electrodes. Furthermore, the K+ electrode, which must be corrected for its Na+ sensitivity in whole blood or plasma, exhibits a linear characteristic between measured voltage and K+ concentration in which the constants of the straight-line equation are each a linear function of the Na+ concentration. The linear relationships are discussed and fitted to data for pure electrolyte solutions, plasma, and whole blood.
Direct Potentiometric Determination of Potassium and Sodium in Blood, Plasma, and Serum
Authors: Miyada Don S , Inami Kazuko , Matsuyama George
Published: January 2020

A potentiometric analyzer, developed to directly measure potassium and sodium concentrations, was evaluated on aqueous solutions, whole blood, serum, and plasma. The analyzer consists of three electrodes—sodium, potassium, and reference—mounted in a flow-cell configuration, and a modified digital pH meter, which displays the ion concentrations directly. Volume of the cell is about 100 µl. The electrodes equilibrate to each new sample in less than a minute. Calibrated with aqueous standard solution, the system yields essentially the same values for whole blood and the corresponding plasma, and results agree with those obtained for the same samples of plasma by flame photometry.
The In Vitro Sensitivity of Erythrocyte Aggregation to Quinine: Assessment by a Serial Blood Sedimentation Procedure
Authors: Robbins R C , Harbin James E
Published: January 2020

A serial erythrocyte sedimentation procedure is based on maintaining blood in vitro in thermal (body temperature) and flow equilibrium, as changes in sedimentation rate are evaluated at 20-min intervals. Each measurement was made 1 h after the determination was begun. We thus confirmed in vitro the clinically observed effects of quinine on blood cell aggregation. A delayed effect of quinine on aggregation corresponded to in vivo observations that aggregation is first affected 3 to 12 h after the drug is administered. Quinine’s greatest effect (p < 0.01) on erythrocyte sedimentation in vitro was at 200 min with 2 mg of quinine per 100 ml of blood, 220 min with 1 mg/100 ml, and 240 min with 0.5 mg/l00 ml.
Evaluation of the Microzone System for Simultaneous Electrophoresis of 16 Sera
Authors: Fingerhut Benjamin , Ortiz Antonia
Published: January 2020

We investigated the feasibility of using the "Microzone" electrophoresis system to produce 16 instead of eight electrophorograms on a single cellulose—acetate membrane by placing eight specimens at the left of center, rotating the cellulose—acetate membrane and supporting bridge 180° horizontally, and again applying eight samples to the left of center. The membrane, now with eight samples each on anodic and cathodic sides, is electrophoresed according to the usual recommended procedure. There was a statistically demonstrated association between sample application position and results (for 96 samples). This technique is nevertheless useful for determining albumin/globulin ratios and for screening large numbers of samples. Sera with borderline or abnormal results should be rerun by the usual technique.
Isolation of Urinary 17-Ketosteroid Conjugates by Ammonium Sulfate Precipitation
Authors: Pinkus Geraldine S , Pinkus Jack L
Published: January 2020

Ammonium sulfate precipitation of urinary 17-ketosteroid conjugates is a rapid, effective method for isolating and purifying them. Negligible quantities of pigment are produced during acid hydrolysis of solutions of the precipitated conjugates. Despite elimination of nonspecific chromogenic material, colorimetric determinations of Zimmerman chromogens with use of the Allen correction of absorbances [J. Clin. Endocrinol 10, 71 (1950)] gave comparable 17-ketosteroid values for solutions of the precipitate and for urines. Recoveries of urinary 17-hydroxysteroid conjugates were variable when the ammonium sulfate procedure was used.
Improved Method for Measurement of delta-Aminolevulinic Acid Dehydratase Activity of Human Erythrocytes
Authors: Burch Helen B , Siegel Abraham L
Published: January 2020

We have evaluated and modified a current method for estimating δ-aminolevulinic acid dehydratase (5-aminolaevulinate hydro-lyase, EC 4.2.1.24) activity in blood, so as to adequately control the pH of the enzyme-substrate solution at the optimum throughout the incubation period. This has improved the sensitivity and reliability of the assay. Also, N-ethylmaleimide has been substituted for a potentially hazardous mercury salt, used to remove sulfhydryl groups before color development with a modified Ehrlich’s reagent.
Hepatitis-Associated Antigen (HAA). II. A Survey of Antisera from Different Sources and Species
Authors: Boenisch Thomas , Katz Gerson
Published: January 2020

Thirty-two antisera against the hepatitis-associated antigen (HAA) were studied for titer and specificity. Titers were expressed in milligrams of the antigen precipitated by one milliliter of the antiserum. Specificity was investigated by Ouchterlony double diffusion against 40 HAA-positive sera and a serum pool consisting of about 200 HAA-positive specimens. Antiserum titers ranged from 0.04 mg/ml to 4.52 mg/ml. With some antisera, titers of 0.11 mg/ml or lower gave questionable or falsely negative results for specimens with high antigen concentrations, with use of counter-electrophoresis. By the classic criterion of spur formation in Ouchterlony double diffusion, antibody specificities were not different among the antisera studied. A relatively high number of falsely negative reactions was obtained with some antisera in double diffusion, which could not be explained by excess of either antigen or antibody. Several of our observations and those of others are cited to offer tentative explanations.
Rapid Solubility Test for Detection of Hemoglobin S
Authors: Matusik Jean E , Powell James B , Gregory David M
Published: January 2020

We have devised a rapid screening test for use in detecting sickling hemoglobins. This test depends on the insolubility of sickling hemoglobins in 2.24 molar phosphate buffer. Sickling hemoglobins form a turbid suspension in this test, in which positive and negative results, respectively, appear very much like those for the "Sickledex" test.
Evaluation of Pneumatic-Tube System for Delivery of Blood Specimens
Authors: Steige Harold , Jones James D
Published: January 2020

Blood specimens from normal individuals and patients (with and without blood dyscrasias) were sent through a 1,423-m pneumatic-tube system that included two monitoring devices, three switches, and 67 bends (62 with a 152-cm radius and 5 with a 76-cm radius), and then returned to the central laboratory. Each specimen was thus subjected to twice the trauma it usually would receive during transit. After transit, these specimens and duplicates kept in the laboratory were analyzed in the same manner for serum or plasma Na, K, Cl, CO2, Ca, Pi, LDH, urea, uric acid, glucose, creatinine, total protein, fibrinogen, hemoglobin, and bilirubin. Filling the tubes completely with blood and using a foam-rubber-Iined vinyl insert to hold the specimen tubes in the carrier decreased the differences attributable to transportation. Allowing the blood to clot before transport did not alter the results. Increases attributable to transport occurred only in hemoglobin, LDH, and K. Values were altered considerably less when the transported aliquot made only one leg of the trip via pneumatic tube. The alterations observed for the remaining analyses were within laboratory error. The pH of whole blood and the mean for PCO2 were not significantly altered, while the mean value for PO2, was increased 1.7 (0.5 to 4.5) mm Hg on transport.
Modified Manual or Automated o-Toluidine System for Determining Glucose in Serum, with an Improved Aqueous Reagent
Authors: Yee Hugh Y , Jenest Edward S , Bowles Fred R
Published: January 2020

A manual and automated method has been developed in which a new "aqueous" o-toluidine reagent is used that is compatible with standard tubing throughout the system. Citric acid, boric acid, and thiourea are incorporated, to increase absorbance readings. The sampling rate is 50/h, and the sample volume is 0.12 ml. Measurements may be made at either 630 or 385 nm.
Differentiation of Urinary N-Acetyl-p-Aminophenol from Endogenous Phenolic Compounds
Authors: Imashuku Shinsaku , LaBrosse Elwood H
Published: January 2020

An unknown spot, observed on two-dimensional paper chromatograms of extracts of human urine, was identified as N-acetyl-p-aminophenol (APAP), a drug metabolite. This finding suggests that APAP is clearly separable from other endogenous phenolic compounds in urine by a two-dimensional paper chromatographic method. This simple technique is feasible for the specific routine analysis of APAP in urine.
Accuracy in Clinical Chemistry
Authors: Caraway Wendell T
Published: January 2020

Improved accuracy of clinical laboratory measurements requires a broad range concept of quality control. Items considered include standardization, precision, specificity, recovery studies, interlaboratory comparisons, and long-range stability of laboratory performance.
An Assay and Screening Procedure for Serum Glutamic Oxaloacetic Transaminase
Authors: Itoh Hajime , Srere Paul A
Published: January 2020

A clinical method for measuring serum GOT activity and its application as a screening test for GOT are described. Results for sera, compared by two popular methods, correlated well. This method may be suitable for routine use as a screening test in the blood bank.
Molecular Heterogeneity of Human Serum Cholinesterase
Authors: LaMotta Rudolph V , Woronick Charles L
Published: January 2020

The evidence is described that serum cholinesterases are a group of discrete isoenzymes, differing primarily in molecular size but also kinetically. A number of genetically determined variants have been described which probably differ by virtue of structural modifications. The clinical importance of the measurement of serum cholinesterase activity is discussed.
Simplified Measurement of Monoglycerides, Diglycerides, Triglycerides, and Free Fatty Acids in Biological Samples
Authors: Marzo A , Ghirardi P , Sardini D , Meroni G
Published: January 2020

A sensitive (5 to 100 µg) and reproducible (±3.54% SD) method is described for determining monoglycerides, diglycerides, triglycerides, and free fatty acids. After these lipid classes are separated from extracts of plasma or tissues by a single thin-layer chromatographic development, they are eluted into concentrated H2SO4 at 200°C. The resulting color is stable for more than six days.
Effects of Treatment on Tyrosine Tolerance in Thyroid Disease
Authors: Williams Trevor , Besser Gordon M
Published: January 2020

A widely used assay technique for plasma tyrosine determination has been found to give rise to large errors. It was modified to improve accuracy, and the relationship between the values derived by the modified and unmodified procedures was studied. The plasma tyrosine concentrations in thyrotoxic and hypothyroid patients during oral tyrosine loading are reported. Tyrosine tolerance in thyrotoxicosis reverts to normal after successful treatment. In hypothyroidism, most patients had normal tyrosine tolerance before and after treatment.
Normal Clinical Chemical Values for Pregnant Women at Term
Authors: Elliott Joseph R , O’Kell Richard T
Published: January 2020

Results for clinical chemical determinations on serum of 20 to 39-year-old pregnant women at term were compared (SMA 12/60) with those for nonpregnant women in the same age group. Sera from the pregnant group had higher mean uric acid and cholesterol concentrations; higher mean alkaline phosphatase, lactic dehydrogenase, and glutamic oxaloacetic transaminase activities; and lower mean glucose, urea nitrogen, protein, and albumin concentrations. All differences are significant (P <0.001). Phosphorus and bilirubin concentrations did not differ significantly for the two groups. The increase in alkaline phosphatase activity in the pregnant group is evidently due to a heat-stable fraction, which does not correlate (at term) with number of weeks gestation, infant sex, infant weight, or placental weight. Forty women who had high concentrations of serum uric acid showed no signs of toxemia of pregnancy and delivered normal infants.
A Simplified Alkaline Phosphotungstate Assay for Uric Acid in Serum
Authors: Carroll James J , Coburn Holly , Douglass Roberta , Babson Arthur L
Published: January 2020

An alkaline phosphotungstate procedure was developed in which the phosphotungstic acid reagent is used both as protein-precipitating and oxidizing reagent. The procedure requires only a 0.2-ml sample and fewer reagents and manipulations than similar procedures, but yields results equivalent to those obtained by Henry’s alkaline phosphotungstate procedure. Recovery, precision, and linearity were good over a wide range of uric acid concentrations. Standardization was easy with use of aqueous albumin standards or of commercial calibration reference sera.
Comparison of Laboratory Test Results for Assessing Thyroid Function in Normal Subjects and Treated and Untreated Hyper- and Hypothyroid Patients
Authors: Lee Norman D , Catz Boris , Margolese M S , Pileggi Vincent J
Published: January 2020

Various indexes of thyroid status were measured in sera from normal men and women, normal women who were using oral contraceptives, hyper- and hypothyroid patients, and hypothyroid patients being successfully managed with various forms of replacement therapy. Total circulating thyroxine concentrations were measured by three methods as well as the thyroxine-binding capacity of the serum inter-alpha globulin, "free" thyroxine, and "free" thyroxine index. Our purpose was to compare the various measurements, and to assess their diagnostic usefulness. The most significant finding was that, of 197 hypothyroid patients, all of whom possessed total circulating thyroxine concentrations within normal limits, 28% showed subnormal "free" thyroxine concentrations.
Design of an Analog Converter for Use in Colorimetry
Authors: Lapidus Berton M , Tetrud James W , Karmen Arthur
Published: January 2020

A simple analog circuit, incorporating commercially available components, has been used to convert the output of a colorimeter photocell into units directly related to concentration. The converter is useful for analyses that obey Beer’s law approximately, with continuous-flow automatic analyzers or other colorimetric systems. The results obtained by analog conversion agree within 1% with the photocell output read out in the usual manner.
Determination of Serum and Urine Amylase with Use of Procion Brilliant Red M-2BS Amylopectin
Authors: Sax Sylvan M , Bridgwater Anna B , Moore John J
Published: January 2020

We describe a sensitive, precise assay of serum or urine amylase activity, with use of a new substrate, Procion Brilliant Red M-2BS—Amylopectin. After 0.2 ml of serum or urine is incubated with substrate for 10 min at 37°C, ethylene glycol monomethyl ether is added to precipitate proteins and larger substrate particles. Clarity and chromogenicity of the final solution are not sensitive to small changes in temperature or concentrations of the various reagents. No interferences necessitating preparation of specimen blanks have been encountered. Human salivary amylase, assayed by a reference saccharogenic method, is used for calibration. When read against the resulting curve, normal sera and urines give activities comparable to those obtained with the reference method. Human pancreatic extract, sera and urines from pancreatitis patients, and macroamylasemia serum show higher activities by the proposed method.
β-Glycerophosphate and Thymolphthalein Monophosphate Compared as Substrates for Determining Alkaline Phosphatase Activity in Serum
Authors: Dalal Fram R , Akhtar Mohammed , Shin Kwang Hi , Winsten Seymour
Published: January 2020

β-Glycerophosphate and sodium thymolphthalein monophosphate were compared clinically and methodologically as substrates for alkaline phosphatase assay. The relative simplicity of the thymolphthalein procedure, its adaptability to semi-automated and micro methods, and its apparent clinical reliability indicate that it is a better substrate for serum alkaline phosphatase assay than is β-glycerophosphate.
Automated Immunoprecipitin Technique for Analysis of the Third Component of Complement (C'3) in Human Serum
Authors: Killingsworth L M , Savory John , Teague Perry O
Published: January 2020

An automated continuous-flow procedure has been developed for measuring C'3 in human serum, by reaction with specific antiserum. The procedure is standardized with pooled human serum, appropriate dilutions of which had previously been measured for C'3 by a reference method. C'3 values obtained by this new automated procedure correlate with values obtained by radial immunodiffusion. The precision (CV) of this method is 1.65%.
Micromethod for Measuring Pentoses by Use of an Aniline Reagent
Authors: Goodwin Jesse F
Published: January 2020

Aniline, in an acetic acid solution containing borate and thiourea, reacts with pentose sugars to yield a highly colored chromogen that absorbs maximally at 480 nm. The reagent may be used to measure pentoses in dilute protein solutions and serum without first removing protein. Bilirubin and hemoglobin do not interfere extensively with the method, but this interference is substantially decreased if a protein-free filtrate is used. An optimal procedure is presented for the measurement of pentoses in the presence of glucose, involving use of glucose oxidase and the aniline reagent. The method is easy to perform, sensitive, and reproducible.
Determination of Serum Ionic Calcium with an Ion-Selective Electrode: Evaluation of Methodology and Normal Values
Authors: Li Ting-Kai , Piechocki Joseph T
Published: January 2020

Ionized calcium in serum has been determined potentiometrically by using a calcium ion-selective electrode in a flow-through configuration. For 397 normal human adults the mean value for serum ionic calcium was 1.22 ± 0.09 (2 SD) mmol/liter. Factors affecting the measurement—such as the procedure for sample collection, sample storage, the preparation of standard solutions, the type of resin employed, and the choice of the reference electrode filling solution—were examined. Magnesium ions in physiological concentrations cause a slight depression of the electrode's response to calcium ions, indicating an interference by magnesium in the method. Under the conditions used, the relative standard deviation (CV) of the method is 0.8%.
Varieties of Human Serum Lipoprotein Pattern: Evaluation by Agarose Gel Electrophoresis
Authors: Papadopoulos N M , Kintzios J A
Published: January 2020

A previously reported agarose gel electrophoretic technique for the determination of serum lipoprotein patterns has been modified for analysis of a large number of samples for screening and epidemiological purposes. In addition, we demonstrate the varieties of lipoprotein patterns that can clearly be distinguished and visually evaluated for practical applications in the clinical laboratory.
Trace-Element Analysis in Clinical Chemistry
Authors: Schroeder Henry A , Nason Alexis P
Published: January 2020

Present knowledge of human bodily contents and concentrations in blood, urine, and hair of 11 essential trace elements and 17-22 nonessential inert or toxic trace elements is reviewed and summarized. Analyses of trace elements are applicable as diagnostic aids and indices for therapy in a number of clinical conditions. Techniques are not difficult, and analyses will probably become more or less routine for many diseases in which primary or secondary abnormalities are manifest. Trace elements play fundamental roles in human metabolism.
Rapid Automated Analyses Performed in Parallel
Authors: Hatcher D W
Published: January 2020

The analytical concept of monitoring chemical reactions simultaneously in a number of discrete samples is explored. A new class of analyzers based on this concept has been introduced. One such system uses centrifugal force to transfer and mix reagent and sample in a multiple-cuvet rotor. A second, completely new system (CHAMP) is introduced here. In both systems, data signals can be generated at 3.3-ms intervals. Thus, these devices are potentially very fast and can be interfaced directly with a computer, which facilitates their integration into computerized information systems of hospitals.
Rapid, Reliable Method for Measuring Serum Lipase Activity
Authors: Yang Jeun-Sing , Biggs H G
Published: January 2020

The method of Dirstine et al. [Clin. Chem. 14, 1097 (1968)] has been modified to increase sensitivity and decrease manipulations. The modifications permit a 10-min incubation, and a single analysis can be completed in 30 min, or five concomitant assays can be done in an hour. Stability of the substrate has been increased by increasing the emulsifier concentration. Recovery of the fatty acid products has been improved by adding electrolyte to the copper reagent and by using combined organic solvents. Pancreatin was added to human serum to provide samples with increased activities, with behavior identical to that of pathological sera with increased lipase activities. Normal values for 100 adults, 50 women and 50 men, ranged between 21 and 171 units, with a mean of 63 units. Within-day precision for 21 assays (mean activity, 641 units) was ±16 units (SD). Between-days precision for 36 assays was ±18 units (SD), with a mean of 636 units.