bluuebunny/crossref_metadata_2025 huggingface dataset:
Automated Determination of Serum Oxytocinase Activity
Authors: Peeters J A B M
Published: January 2020

An automated kinetic method is described for determination of oxytocinase activities in the sera of pregnant women. The reaction mixture consists of serum in phosphate buffer and the substrate L-cystine-bis-p-nitroanilide. The absorbance increase, due to the appearance of the reaction product, p-nitroaniline, is recorded during 2 min. With this method, 25 determinations per hour can easily be done.
A Linear Absorbance Converter for Continuous-Flow Colorimeters
Authors: Walker Leonard , Amador Elias
Published: January 2020

The photocell transmittance output from continuous-flow colorimeters can be converted into linear absorbance by means of a simple solid-state circuit. The circuit includes a field effect transistor operational amplifier and a logarithmic operator, plus several stabilizing circuit networks. The working range is 1.2 absorbance units, which for most applications is an improvement of 50% over the unmodified colorimeter, at wavelengths of 420 to 700 nm. The output can drive the conventional AutoAnalyzer recorder, or a 2-input, low-cost recorder such as the Heath Kit IR-18M.
A Computer Program for Calculating Blood Acid-Base Parameters on an Olivetti "Programma 101" Desk Computer
Authors: Hardt Jørgen
Published: January 2020

A computer program is presented for a desk calculator, to be used in calculating Pco2, standard bicarbonate, and base excess. The computer simulates the readings from the Siggaard-Andersen nomogram [Scand. J. Clin. Lab. Invest. 14, 598 (1962)].
Identification and Biochemical Significance of Substituted Furans in Human Urine
Authors: Mrochek J E , Rainey W T
Published: January 2020

The normal urinary chromatographic pattern on the high-resolution UV-Analyzer exhibits approximately 20 major peaks and more than 100 minor peaks. Three of the major chromatographic peaks, observed in most urinary samples from both normal and pathologic subjects, have recently been identified as 5-hydroxymethyl-2-furoic acid, 2-furoylglycine, and 2,5-furandicarboxylic acid. A related compound, 5-hydroxymethyl-2-furoylglycine, was also identified in the urine of a leukemic patient who was excreting an abnormal amount of the free acid. The compound 5-hydroxymethyl-2-furoic acid and its glycine conjugate have not, to our knowledge, been previously reported in human urine, and the excretion of 2-furoylglycine and 2,5-furandicarboxylic acid by all humans is not generally recognized. The four identified compounds seem to be biochemically interrelated, and a mechanism for their formation from uronic acids is postulated. Analytical techniques and results utilized in the identification of these compounds are discussed. High-resolution (m/Δm ≈ 20,000) mass spectrometric data obtained from three independent laboratories are presented for 5-hydroxymethyl-2-furoic acid, illustrating the accuracy and precision that can be expected for a random sample submitted to a well-equipped facility.
Kinetic Method for Determining Acid Phosphatase Activity in Serum with Use of the "CentrifiChem"
Authors: Fabiny-Byrd Diane L , Ertingshausen Gerhard
Published: January 2020

Acid phosphatase activity is determined by splitting 1-naphthyl phosphate, concurrently diazotizing the released 1-naphthol with Fast Red TR, and measuring the resulting color. The test is performed in the presence and absence of tartrate. Reaction rates can be continuously monitored, and their difference is proportional to acid phosphatase activity that is inhibited by tartrate. Results for sera with normal and increased acid phosphatase activities are presented and three different methods for acid phosphatase are compared. The kinetic blank used in the reaction eliminates all nonenzymatic contributions to substrate splitting.
Evaluation of a New Radioimmunoassay Method for Carcinoembryonic Antigen in Plasma, with Use of Zirconyl Phosphate Gel
Authors: Chu Tsann Ming , Reynoso Gustavo
Published: January 2020

A radioimmunoassay of carcinoembryonic antigen in plasma is described and evaluated. The assay can be easily performed and implemented in a clinical laboratory. Assessed by Rodbard’s statistical quality-control procedure, the assay is shown to be highly sensitive, precise, and reproducible.
Determination of Copper in Fingernails by Atomic Absorption with the Graphite Furnace
Authors: Barnett William B , Kahn Herbert L
Published: January 2020

Two atomic absorption techniques, acid digestion followed by conventional flame analysis and direct analysis of solid samples with the graphite furnace, were compared for the determination of copper in fingernails. Nail samples, from 11 persons, containing between 5 and 50 µg/g of copper, were analyzed by both methods. There was good correlation between results of the two. The furnace requires less sample preparation, has good sensitivity, and solid samples may be directly analyzed.
Modified Method for Estimating the Phosphatidyl Choline:Sphingomyelin Ratio in Amniotic Fluid, and Its Use in the Assessment of Fetal Lung Maturity
Authors: Sarkozi Laszlo , Kovacs Hanna N , Fox Howard A , Kerenyi Thomas
Published: January 2020

Phospholipids of amniotic fluid were extracted, separated by thin-layer chromatography, detected with acidified ammonium sulfate, and charred; the phosphatidyl choline and sphingomyelin fractions were quantitated by transmission densitometry. The densities were recorded as integrator trace units. We used commercially available precoated plates and a solvent system to eliminate the interference of phosphatidyl serine. The procedure used for visualization eliminated the irritating and corrosive effects of the 50% sulfuric acid spray used in other methods. Omission of the acetone precipitation step decreased assay time without loss of accuracy. In 117 amniotic fluid samples obtained before delivery of infants who subsequently did not develop respiratory distress syndrome (RDS) the geometric mean density ratio of phosphatidyl choline: sphingomyelin was 3.1, range 1.8 to 8.6. In three pre-delivery amniotic fluid samples, density ratios of less than 1.5 were found. Those infants developed RDS.
Photometric Assay of Dopamine-β-Hydroxylase Activity in Human Blood
Authors: Nagatsu Toshiharu , Udenfriend Sidney
Published: January 2020

We describe a simple, rapid, and sensitive procedure for measuring dopamine-β-hydroxylase activity in human blood. The assay is based on the enzymatic conversion of tyramine to octopamine [1-(p-hydroxyphenyl)-2-aminoethanol], which is then oxidized to p-hydroxybenzaldehyde and determined photometrically. Activities are assayed on 2-20 µl of human serum or plasma obtained from fingertip blood samples. The method should prove useful in clinical studies, including the field of pediatrics.
Rapid Lipid-Staining Procedure for Paper Electrophoretograms
Authors: Naito Herbert K , Lewis Lena A
Published: January 2020

We describe a rapid, reliable staining procedure for lipoproteins on paper electrophoretograms. Staining time, is 2.5 h in an acetone-water (1:1, by vol) solution of Oil Red O dye (0.4 g/liter). Results agree well with those obtained by the conventional overnight staining technique
Semiautomated Enzymatic Method for Determining Serum Triglycerides by Use of the Beckman "DSA 560"
Authors: Mourad Nabeeh , Zager Ronald , Neveu Peter
Published: January 2020

Triglycerides are hydrolyzed to glycerol and fatty acids with alcoholic potassium hydroxide, and total glycerol (that originally present plus that released by hydrolysis) is determined enzymatically, with use of a Beckman "Discrete Sample Analyzer 560," at the rate of 120 samples per hour. Absorbance decrease is measured at 340 nm, and the final results are printed out directly, in milligrams per 100 ml. Results of this procedure were compared with those obtained by a manual method. Standard deviations for more than 200 determinations of commercial normal and abnormal quality-control reference sera during the course of a year were 2.00 and 2.31 mg/100 ml (C.V, 1.6 and 2.4%)
Use of Ferric Ammonium Sulfate in Serum Cholesterol Determination
Authors: Feng Hsien-wen , Pi Chung-miu , Wang Rong-bor , Chen Li-chuen
Published: January 2020

Ferric ammonium sulfate, which has advantages over ferric chloride in that it is not deliquescent and does not evolve hydrogen chloride upon addition of sulfuric acid, was used in the ferric chloride—sulfuric acid method for serum cholesterol determination. Comparable results are obtained with these iron salts
Radioassay of Serum Folate, with Use of a Serum Blank and Nondialyzed Milk as Folate Binder
Authors: Tajuddin Mohammed , Gardyna Henry A
Published: January 2020

Serum folate determination by this method requires incubation of 0.1 ml of serum (or standards) with nondialyzed milk and then with tritium-labeled folate. A serum blank corrects for nonspecific binders present in the serum. Unbound folate is removed with hemoglobin-coated charcoal. The standard deviation of the results is ±0.2 µg/liter, and more than 90% of folate added to the serum is accounted for analytically. Serum folate concentrations as determined by this method agree with those obtained by microbiological assay (Lactobacillus casei), and our method is faster, simpler, and more accurate than other radioassay methods
Improved Manual and Automated Colorimetric Determination of Serum Glucose, with Use of Hexokinase and Glucose-6-Phosphate Dehydrogenase
Authors: Coburn Holly J , Carroll James J
Published: January 2020

A previously reported assay for serum glucose, in which hexokinase and glucose-6-phosphate dehydrogenase were used, was improved to replace the light-sensitive phenazine methosulfate with "diaphorase," providing a one-reagent system. The assay system was automated for use with standard AutoAnalyzer equipment and evaluated at 40 and 60 samples per hour with a 2:1 sample-to-wash ratio. Sensitivity, precision, accuracy, and sample interaction were quite satisfactory at both sample rates. The assay benefits from the inherent advantages of the reaction mechanism: sensitivity, specificity, NADP regeneration, and freedom from dialysis
Biological Activity of a Semisynthetic Flavonoid, O-(β-Hydroxyethyl)rutoside: Light-Scattering and Metabolic Studies of Human Red Cells and Platelets
Authors: ten Cate J W , van Haeringen N J , Gerritsen J , Glasius E
Published: January 2020

The effect of O-(β-hydroxyethyl)-rutoside (HR) on human erythrocyte and platelet functions is reported. Only high concentrations of the compound distinctly inhibited red cell and platelet aggregation induced by ADP and epinephrine. Lower concentrations of HR inhibit [14C8]adenosine incorporation into red cells as well as into platelets. Inhibition occurs at both 0°C and 37°C, presumably because diffusion of [14C8]adenosine is hindered. Phosphorylation of [14C8] adenosine by the platelets is not inhibited by HR. The inhibition of red cell aggregation is reversed by washing the cells with plasma. Collectively, these findings indicate an effect of the compound at the site of the membrane, independent of cellular metabolism
Use and Interpretation of Common Statistical Tests in Method-Comparison Studies
Authors: Westgard James O , Hunt Marian R
Published: January 2020

We have studied the usefulness of common statistical tests as applied to method comparison studies. We simulated different types of errors in test sets of data to determine the sensitivity of different statistical parameters. Least-squares parameters (slope of least-squares line, its y intercept, and the standard error of estimate in the y direction) provide specific estimates of proportional, constant, and random errors, but comparison data must be presented graphically to detect limitations caused by nonlinearity and errant points. t-test parameters ( bias, standard deviation of difference) provide estimates of constant and random errors, but only when proportional error is absent. Least-squares analysis can estimate proportional error and should be considered a prerequisite to t-test analysis. The correlation coefficient (r) is sensitive only to random error, but is not easily interpreted. Values for r, t, and F are not useful in making decisions on the acceptability of performance. These decisions should be judgments on the errors that are tolerable. Statistical tests can be applied in a manner that provides specific estimates of these errors
Cooperative Survey of "SMA" Analyzers in Wisconsin—A Method of Improving Interlaboratory Performance
Authors: Laessig Ronald H , Schwartz Thomas H , Paskey Toni A
Published: January 2020

A state-wide cooperative quality-control program for automated multichannel analytical systems is described. The survey benefits participating laboratories by providing, through regular comparison, a means of improving interlaboratory precision. A common lot of reference material used for a large group of similar multichannel analyzers is shown to significantly improve their precision. The study delineates components of interlaboratory variation resulting from the inconsistency of the reference materials and from the inherent precision of the analyzers. Errors in the assay values of commercial controls and reference sera, as well as problems of homogeneity in these products, are documented. These errors make some form of regular interlaboratory comparison an essential element of a total quality-control program
Computer-Controlled Instrument System for Sequential Clinical Chemical Testing. II. Evaluation of Instrumental Performance
Authors: Toren E Clifford , Mohr Stephen A , Busby Michael G , Cembrowski George S
Published: January 2020

The instrumental system described [Clin. Chem.19, 1114 (1973)] is evaluated in manual, partially automated, and totally automated modes to measure system and individual component performance. Excellent accuracy and precision were observed, hence the system is judged suitable for most analytical applications. Results are: wavelength accuracy and reproducibility in automated mode: ±0.004 nm and ±0.1 nm, respectively; photometric accuracy and precision: ca. 0.8% relative and ±0.007 A, respectively, in both the manual and automated modes; and ratemeter accuracy and precision: ±0.4% relative and ±0.873 (SD) mV/min (or mA/ min), respectively, for standard synthetic ramps and ±1.2% relative and ±2.2 (SD) mV/min, respectively, under actual laboratory conditions for rates in the range of 1 to 200 mV/min. Automated experiments are made without human intervention after the samples are loaded.
Isoenzymes of Liver Alkaline Phosphatase in Serum of Patients with Hepatobiliary Disorders
Authors: Rhone Douglas P , White Florence M , Gidaspow Helene
Published: January 2020

The isoenzymes of alkaline phosphatase (ALP; EC 3.1.3.1) present in the [unknown]sera of 116 patients with hepatobiliary disease were studied by electrophoresis on cellulose acetate. Individual liver isoenzyme bands were identified and quantitated by densitometric scanning. The occurrence and magnitude of increase of the isoenzyme bands of liver ALP (α2 alone or α1 and α2) are related to diagnosis. Of the cases studied, 30% showed only the α2 band of liver ALP. A couplet of liver isoenzyme bands (α1 and α2) was seen in 70% of the cases studied. The isolated α2 band occurred in 26 of 36 patients with viral hepatitis and in two patients with hepatic infarction. Most patients with other liver diseases showed the α1 and α2 couplet. The serum pattern of liver ALP is related to total ALP, age, ABO blood group, and serum bilirubin concentration. The α1 band is markedly increased in patients with granulomatous hepatitis and carcinoma metastatic to the liver. The findings are related to previous work, and their implications are discussed.
Rapid Method for Measurement of Oxygen in Human Blood
Authors: Butts William C , Kenny Margaret A , McCoubrey Pamela G
Published: January 2020

The "Lex-O2-Con" (Lexington Instrument) for measuring oxygen in blood is technically simpler to use and three times as rapid as the traditional Van Slyke instrument. Results obtained with both instruments for 90 blood samples from 18 patients were satisfactory (r = .997). The coefficient of variation for the Lex-O2-Con instrument was 0.6%.
Improved Method for Determination of Triglycerides in Serum
Authors: Neri Bruce P , Frings Christopher S
Published: January 2020

We describe a new method for determination of serum triglycerides that is based on the original method of Fletcher [Clin. Chim. Acta22, 393 (1968)]. We have modified Fletcher’s reagents so that it is possible to saponify serum triglycerides in 5 min at room temperature (about 24 °C) instead of 60-70 °C for 15 min and to produce the final color in 15 min at 60-70 °C instead of 30 min at 50 ° C. The new reagents are stable for at least two months. The correlation coefficient obtained for the two methods (n = 107 sera) was 0.98. When the t test and F test were applied to these data, no significant difference in accuracy and precision was found at the 95% confidence level. The coefficient of variation (day-to-day) for the new method is 7.0%.
Radioimmunoassay of Insulin in Serum and Plasma
Authors: Feldman Jerome M , Chapman Barbara A
Published: January 2020

Paired serum and plasma samples from subjects were analyzed to determine if there was a difference in the insulin content of serum and plasma. Although there was no difference in the serum and plasma insulin concentrations in the samples as a group, there were differences in the serum and plasma insulin concentrations in individual subjects. Recovery of radioimmunoassayable insulin from clotted or heparinized blood is less than the recovery from serum or plasma, apparently because of association of insulin with the blood cells. Serum and plasma insulin concentrations are not altered when blood stands at room temperature for as long as 4 h. Storage at -20 °C for 28 months results in similar decreases in the insulin content of serum (74%) and plasma (76%). We conclude that one should consistently use either serum or plasma for insulin measurements in individual patients.
NADH Preparations as They Affect Reliability of Serum Lactate Dehydrogenase Determinations
Authors: Berry Arnold J , Lott John A , Grannis George F
Published: January 2020

We observed large variations in the activity of lactate dehydrogenase (EC 1.1.1.27) in serum when random lots of NADH were used in its determination. The imprecision, caused by variable amounts of lactate dehydrogenase inhibitor in the NADH preparations, was greatly lessened by using only a single lot of NADH; reliability was improved further by selecting an NADH preparation having a negligible amount of inhibitor. A method is described for assessing the quality of commercial NADH preparations, so as to have a satisfactory reagent and to maintain continuously comparable results over an extended period of time. The results have possible relevance for proposed governmental regulation of commercial kits and reagents used for clinical laboratory testing, and for improved intraand inter-laboratory comparability of lactate dehydrogenase determinations.
A New Micromethod for Determination of Protein in Cerebrospinal Fluid and Urine
Authors: Pesce Michael A , Strande Carl S
Published: January 2020

We developed a new micro-scale procedure for determination of protein in cerebrospinal fluid and urine. The sample (50 µl) is mixed with a trichloroacetic acid—Ponceau S dye solution. The proteins, together with a proportional amount of dye, are precipitated and the red precipitate is dissolved in dilute sodium hydroxide solution, giving a violet-colored solution. This color, linearly proportional to the amount of protein present (up to 150 mg/dl), is measured spectrophotometrically at 560 nm. By varying the sample size alone, protein concentrations up to 1500 mg/dl can be measured. The detection limit for the method is 2 mg/dl of sample. Precipitation of the proteins is independent of temperature and albuminbinding compounds, and is not appreciably affected by the albumin—gamma globulin ratio.
Proposed Standard Method for Measuring Lipase Activity in Serum by a Continuous Sampling Technique
Authors: Tietz Norbert W , Repique Eliseo V
Published: January 2020

A method is presented for measuring lipase activity in serum by use of either triolein or olive oil as substrate. The method requires 3 to 8 min for each measurement and 5 to 8 min for initial set-up. The reaction mixture is maintained at the optimum pH of 8.8 by automatic addition of sodium hydroxide (10 mmol/liter) with a " pH-Stat." Amount of sodium hydroxide delivered per unit time reflects lipase activity. When reaction conditions—such as pH, substrate concentration, emulsifier concentration, and type and concentration of added bile salts—were made optimal, the reaction kinetics were zero order. Data presented indicate that adding sodium glycocholate prevents inactivation of lipase and does not lead to activation of this enzyme. Comparative studies, in which triolein and olive oil, respectively, are used as substrates show that triolein is the superior substrate for lipase, but olive oil can be substituted for triolein for routine clinical laboratory use. The suggested upper limit of normal is 200 and 160 U/liter for triolein and olive oil substrates, respectively.
Increased Lactate Dehydrogenase Isoenzyme-5 (LD5) Activity Evidently Caused by Persistent Diaphragmatic Pressure on a Congested Liver
Authors: Henderson A R , Kostuk W J , Griffiths J C
Published: January 2020

A patient with congestive cardiac failure owing to severe bradycardia had a transvenous cardiac pacemaker inserted, resulting in complete alleviation of the cardiac failure. Later, however, the pacer became displaced high into the superior vena cava, where it ceased to pace the heart but instead stimulated the right phrenic nerve. Consequently the rapid movement of the right hemidiaphragm pressing on the dome of an increasingly congested liver, for about one week before hospital admission, was associated with an unusually elevated LD5 (lactate dehydrogenase, EC 1.1.1.27) activity in the serum.
Preparation of Amine Salts of Thymolphthalein Monophosphate and Their Use for Measuring Phosphatase Activity
Authors: Erikson John M , Biggs Homer G
Published: January 2020

An easy and quick preparation of amine salts of thymolphthalein monophosphate is described. All of the salts prepared are stable, nonhygroscopic, soluble powders. The 2-amino-2-methyl-1,3-propandiol salt is preferred for use as a substrate for measuring phosphatase activities because of its high solubility and easy preparation.
Serum Thyroxine: Results Compared for a Commercial Radioimmunoassay and a Commercial Competitive Protein Binding Analysis
Authors: Kubasik Norman P , Sine H E , Murray Martin H
Published: January 2020

Two commercial isotopic methods for measuring serum thyroxine—radioimmunoassay and competitive protein binding analysis—have been compared with regard to recovery of thyroxine added to sera, within-run and run-to-run reproducibility, and results for patients’ sera. For the latter the relationship is expressed by the equation CPBA = 082 RIA + 0.33. The correlation coefficient was 0.92.
Counting of Beta and Gamma Emitters Used in Clinical Radioimmunoassays and Competitive-Binding Assays by Liquid Scintillation Counters
Authors: Helman Edith Zak , Ting Philip
Published: January 2020

Although liquid scintillation (LS) counters were originally designed to count low-energy beta emitting isotopes, they can also be used to count gamma emitters used in radioimmunoassay. This is made possible by placing the gamma emitter inside a "Microfuge" tube suspended from a LS vial cap into a scintillator fluid containing an electron density increaser. Efficiencies of 71% are obtained for 125I by this method, comparable to that obtained with Nal (TI) crystal gamma counters. Efficiencies for other clinically important isotopes used in radioimmunoassay—131I, 57Co, 60Co, 51Cr, 59Fe—by the Microfuge method are 15-19%; therefore, for these isotopes a LS "Mini-Vial" method is suggested, in which smaller volumes may be used. The dual capability of LS counters to count both beta and gamma emitters extends its usefulness in the clinical laboratory.
Simple Radioimmunoassay of Five Unconjugated Ovarian Steroids in a Single Sample of Serum or Plasma
Authors: Powell John E , Stevens Vernon C
Published: January 2020

A simplified radioimmunoassay procedure is described for determination of free ovarian steroids in plasma or serum. Ether extracts were chromatographed on a Sephadex LH-20 column equilibrated with benzene—methanol (85:15 by vol) and estrone, estradiol, estriol, progesterone, and 17α-hydroxyprogesterone were resolved from each other. With relatively specific antibodies, all five hormones were specifically assayed directly after the single chromatographic procedure. Procedures for additional purification are described when specific antibodies are not available. A mechanized chromatographic apparatus was used to purify 12 serum extracts simultaneously, permitting up to 120 determinations per day by a single worker. Assay reliability criteria were satisfactory for all assay systems, and steroid values obtained from subjects in different physiological states agreed with previously reported concentrations.
Australia Antigen Content of Commercial Quality-Control Sera
Authors: Simon R G , Langhofer L A , Hendricks E J
Published: January 2020

Australia Antigen (HB Ag) content of 30 chemistry control sera and six other control sera was determined by radioimmunoassay. 23 of the 36 sera were found to be strongly HB Ag positive. We conclude that greater than normal care must be exercised in handling these serums and that better methods must be used to prepare control serum.
Additional Observations on Hydrochlorothiazide Interference with Measurement of Total Urinary Placental Estrogens
Authors: Acosta A Arnaldo , Madeira Linda B , Besch Paige K , Buttram Veasy C
Published: January 2020

The diuretic, hydrochlorothiazide, which enjoys widespread clinical use, decreases the apparent assay values for total urinary estrogens by directly interfering with formation of the Kober chromogen. Urine from patients receiving this medication may give a falsely low total estrogen value. Chlorothiazide, a closely related diuretic, does not so interfere.
Some Drugs and Other Substances That Interfere with Protein Determination
Authors: Pashley D H , Schuster G S , Palmer P , Sharawy M M
Published: January 2020

We show that a variety of substances may interfere positively, to different extents, with the determination of protein by either the Lowry procedure or absorbance at 280 nm, or both. Some of these substances may interfere in concentrations that could be present in clinical laboratory specimens or in research samples.
Modified Glucose Oxidase Method for Determination of Glucose in Whole Blood
Authors: Meites Samuel , Saniel-Banrey Karen
Published: January 2020

We have modified an ultramicro method for determining glucose with glucose oxidase—peroxidase—odianisidine. Capillary blood is diluted in isotonic NaF (17.6-17.8 g/ liter), the cells are removed, and glucose is determined after a 20-min incubation with enzyme-containing reagent. Increasing the enzyme concentration fourfold nullifies interference from ascorbic acid and hemolysis, while greatly decreasing interference from bilirubinemia. If necessary, bilirubin is removed completely by coprecipitation with protein. Interference from uric acid is minimized by incorporating it into the standards. Several other suspected interferences proved inconsequential. Isotonic NaF does not inhibit the enzymes used, and preserves glucose in blood for at least 2 h. Avoiding protein precipitation and shortening the incubating time significantly lessens analytical time without affecting precision.
An Approach to the Measurement of Total Lipid Glycerol in Serum
Authors: Horney Donald L
Published: January 2020

Serum phospholipids that derive from glycerol are hydrolyzed to diglycerides and by-products in the presence of phospholipase C (phosphatidylcholine cholinephosphohydrolase, EC 3.1.4.3). The diglycerides produced are saponified, together with the triglycerides present, to glycerol and salts of fatty acids. Measuring the glycerol produced yields a measure of the total lipid glycerol in serum, and is useful for the estimation of the phospholipid and total lipid content of serum.
Biochemical Properties of Human Prostatic Acid Phosphatase
Authors: Lam K W , Li Olivia , Li C Y , Yam L T
Published: January 2020

The electrophoretic pattern (in polyacrylamide gel) for acid phosphatases in the prostate gland was compared with that for other tissues. Isoenzyme 2 predominates in the prostate. The isoenzyme was isolated from the prostate and its biochemical properties were compared with those of acid phosphatases isolated from spleen. Isoenzyme 2 has a molecular weight of about 100,000. Its optimum pH is between 5 and 7, unlike other lysosomal enzymes. Its substrate specificity is not very much different from those of the most active isoenzymes of acid phosphatase in other tissues. Our results contraindicate the use of a specific substrate in the analysis of prostatic acid phosphatases. Determination of the isoenzyme pattern is a new approach in the specific analysis of prostatic acid phosphatases.
Accurate Micromethod for Estimation of Both Medium- and Long-Chain Fatty Acids and Triglycerides in Fecal Fat
Authors: Massion Charles G , McNeely Michael D
Published: January 2020

An accurate, precise photometric assay has been developed for both medium-chain and long-chain fatty acids and triglycerides, in which very small aliquots of fecal emulsion are used. Feces are collected in a paint can and agitated on a commercial paint-can shaker. Homogenization is improved by substituting isopropanol for ethanol and adding bile salts as an emulsifying agent. This collection and processing technique, combined with a spectrophotometric microscale assay, produces a semiclosed system that reduces manipulation of the fecal sample to a minimum, greatly increasing its acceptance by technical personnel. Special glassware is not required and batch processing of samples is convenient. The micromethod of analysis is also readily adaptable to studies of the fecal lipid excretion of small laboratory animals.
Determination of Serum Calcium by Use of an AutoAnalyzer I-II Hybrid
Authors: Jacklyn C L , Freeman C D , Gray M E , MacAulay M A
Published: January 2020

A hybridized system is described for the continuous-flow determination of serum calcium. The analysis is based on the cresolphthalein colorimetric procedure as described for use with the SMA 12/60 (Technicon Corp.). The hydraulic features of the AutoAnalyzer II are used with modules of the AutoAnalyzer I. This combination gives both the ease of operation and hydraulic improvements inherent in the AutoAnalyzer II system and provides an emergency alternative to the SMA 12/60, with which results are shown to be comparable.
An Automated Procedure, with Use of Ferrozine, for Assay of Serum Iron and Total Iron-Binding Capacity
Authors: White J M , Flashka H A
Published: January 2020

In this procedure of analysis for iron in serum and measurement of iron-binding capacity, the Beckman Model 560 DSA and ferrozine are used. The analysis rate is 120 samples per hour. Interferences were investigated and a procedure was devised for masking high concentrations of copper. A modified procedure was used to prepare samples for the assay of total iron-binding capacity. This procedure is more rapid and requires smaller amounts of sample than many methods now in use.
Free Calcium in Serum. II. Rigor of Homeostatic Control, Correlations with Total Serum Calcium, and Review of Data on Patients with Disturbed Calcium Metabolism
Authors: Ladenson Jack H , Bowers George N
Published: January 2020

Two hundred and fifteen measurements of free (ionic) and total calcium were performed on sera from 184 patients in whom some disturbance in calcium metabolism was suspected. The correlation coefficient between free and total calcium was 0.94, but a scattergram indicated that free calcium concentration cannot be predicted from knowledge of total calcium concentration. In "normal" individuals the correlation coefficient was only 0.45. Homeostasis of free and total calcium was examined by making periodic measurements in seven normal individuals over a period of eight months; the variability around the individual’s mean value was 1.2% for free calcium and 1.9% for total calcium. Free calcium, as properly measured by the ion-specific electrode, is a better measure of calcium status than is total calcium in the disease states studied, which were mostly hyperparathyroidism, multiple myeloma, and renal failure.
Measurement of Hexoses and Pentoses, Singly or in Combination, with o-Anisidine
Authors: Goodwin Jesse F , Yee Hugh Y
Published: January 2020

Hexoses and pentoses can be measured either singly or in combination, with an o-anisidine reagent. It has the advantages of a fast reaction rate and relatively little interference from hexoses (Amax = 660 nm) in the measurement of pentoses. A simple subtraction of absorbance attributable to glucose at the maximum for pentoses (465 nm) is sufficient for satisfactory pentose estimation in urine. The method has been automated, and results compare favorably with those from an automated procedure for the measurement of serum glucose in which hexokinase is used, and also with those from a colorimetric aniline method for measurement of pentoses in urine. Interferences and procedural variables are discussed. Urinary pentose and hexose values for normal infants are reported.
Evaluation of an Automated Creatininase Creatinine Procedure
Authors: McLean Monty H , Gallwas Jerry , Hendrixson Mark
Published: January 2020

We have evaluated an automated method for determining serum creatinine by use of the enzyme creatininase. The method has been adapted to the Beckman DSA-560 and measures the Jaffé-positive chromogens present in serum before and after enzymatic hydrolysis of creatinine. The precision and linearity of the method are acceptable, and the results correlate well with those obtained by other accepted techniques. The method offers the advantages of automation, enhanced specificity, micro-scale sample volume, and direct serum analysis.
Principles of Competitive Binding Assays (Saturation Analyses). I. Equilibrium Techniques
Authors: Zettner Alfred
Published: January 2020

The principles of competitive binding assays are reviewed, with emphasis on the differentiation of equilibrium vs. sequential saturation techniques. Three methods of equilibrium analysis are outlined that differ from each other in the relative concentrations of labeled ligand and binder used in the incubation system. The linearization of dose-response curves through the use of the logit plot is discussed. The importance of the knowledge of the effective affinity constant K for optimization of the assays is stressed, and two methods of estimating K are demonstrated with a digoxin-antidigoxin-antiserum system.
Semiautomated Method for Analysis of 11-Deoxy-17-Oxo Steroids in Urine. A Preliminary Report
Authors: Moore John W
Published: January 2020

A method is described for the automated analysis of urinary 11-deoxy-17-oxo steroids from hydrolyzed conjugate extracts. Steroid conjugates are extracted manually on an Amberlite XAD-2 column and hydrolyzed with β-glucuronidase at 62°C for 90 min. After addition of alkali, the samples are transferred to the AutoAnalyzer where the steroids are extracted into isooctane and estimated colorimetrically by a modified Zimmerman reaction.
Radioimmunoassay of Serum Estrogen
Authors: Jiang Nai-Siang , Ryan Robert J , Albert A
Published: January 2020

Radioimmunoassay of serum estrogen (sum of estrone and estradiol-17β) in 0.5 ml of human serum is described. After dilution of the serum, the estrogens are adsorbed on a Sephadex G-15 column in the presence of dilute HCl and then eluted with benzene. After evaporation of the benzene eluate, the estrogens are dissolved in bovine serum albumin (5 g/ liter solution, at pH 8.0). An aliquot of this solution is used for the assay. Serum estrogen concentrations (mean ± SD) were 69 ± 23 pg/ml in 105 normal men and 199 ± 146 pg/ml in 26 fertile women. In 109 postmenopausal women, estrogen was undetectable in seven sera, but in the remaining 102 it was 52 ± 30 pg/ml of serum.
Assay of "Soluble Fibrinogen" in Bloodstain Extracts as an Aid to Identification of Menstrual Blood in Forensic Science: Preliminary Findings
Authors: Whitehead P H , Divall G B
Published: January 2020

Bloodstain saline extracts were prepared and "soluble fibrinogen" in the extract was measured by the hemagglutination inhibition technique. Total protein in the extract was also measured. Menstrual bloodstain extracts contained higher concentrations of "soluble fibrinogen" than did capillary bloodstain extracts. The two types of stain were better differentiated by calculating soluble fibrinogen as a percentage of the total protein in the extract. Extracts of capillary blood plus semen stain, and of capillary blood plus vaginal secretion stain, contained higher proportions of soluble fibrinogen than did blood alone. The results are interpreted and their use for aiding the identification of menstrual bloodstains in forensic science is discussed.
Nonutility of Measurement of Serum Gamma-Glutamyl Transpeptidase Activities in Diagnosis of Myocardial Disease
Authors: Cook Virginia P , Carter N Kent
Published: January 2020

We have examined the usefulness of measuring gamma-glutamyl transpeptidase activity in serum, in diagnosing myocardial damage. Abnormalities in gamma-glutamyl transpeptidase activity were compared with those observed for aspartate aminotransferase, lactate dehydrogenase isoenzymes, creatine kinase, alanine aminotransferase, and alkaline phosphatase. Such measurements were made for 12 consecutive days on 22 patients admitted to the coronary care units. Serum gamma-glutamyl transpeptidase activity was not increased in all cases studied, but when it was increased, the electrophoretic band of the lactate dehydrogenase isoenzyme originating from the liver also showed abnormal activity. We conclude that the changes observed in gamma-glutamyl transpeptidase activity primarily reflect liver involvement, as in congestive heart failure, rather than myocardial disease.
Development of an Analytical System Based Around a Miniature Fast Analyzer
Authors: Burtis C A , Johnson W F , Mailen J C , Overton J B , Tiffany T O , Watsky M B
Published: January 2020

A modified version of a previously described miniature Fast Analyzer [Clin. Chem. 18, 753 (1972)] was used as the basis for developing a compact, potentially portable, analytical system. This system includes an automated and versatile sample-reagent loader, a miniature Fast Analyzer, several plastic rotors and their cleaning station, and a portable data system. The sample-reagent loader combines a unique turntable assembly and two "Micromedic" pipets to quickly (5 min per rotor), accurately, and precisely obtain, transfer, and dispense small volumes of sample (1 to 10 µl of sample, 50 µl of diluent) and reagent (20 µl of reagent, 50 µl of diluent) into their respective cavities in a 17-cuvet rotor. The loader uses separate sample and reagent carousels, which allows operation of the system in either the single-sample—multiple-chemistry, multiple-sample— single-chemistry, or multiple-sample—multiple-chemistry analytical modes. The miniature Fast Analyzer rotates a loaded 17-cuvet rotor through a stationary optical system at speeds up to 5000 rpm. The resulting centrifugal force is used to mix and to transfer the discrete aliquots of sample(s) and reagent(s) into their respective cuvets. The ensuing reactions are monitored photometrically, and the data are processed in real time by either a portable Data Processor [Clin Chem. 18, 762 (1972)] or an on-line computer. A major improvement to the analyzer has been the addition of a temperature-control system that allows the temperature of the spinning rotor to be monitored and controlled to within ±0.2°C. After completion of an analytical run, the rotor is automatically washed and dried in the rotor cleaning station. Many of the standard clinical analyses, including most of the NADH-linked enzymatic analyses, have been adapted for use with this system.
Use of High-Pressure Liquid Chromatography for Monitoring Nucleotide Concentration in Human Blood: A Preliminary Study with Stored Blood Cell Suspensions
Authors: Brown Phyllis R , Parks R E , Herod Jane
Published: January 2020

The development of high-pressure liquid chromatography has made available a new technique for monitoring nucleotide concentrations in biological materials sensitively, accurately, and rapidly. Because there appears to be a correlation between ATP concentrations and viability of stored blood, a preliminary study was carried out on blood cell suspensions to evaluate the technique for possible use in blood banks, clinical laboratories, and research on preservatives for blood.
Automated Reaction-Rate Method for the Direct Determination of Total Serum Cholesterol by Use of the "CentrifiChem" Parallel Fast Analyzer
Authors: Slickers K A , Edwards L , Daly J , Ertingshausen G
Published: January 2020

The direct procedure for determining serum cholesterol described by Wybenga et al. [Clin. Chem. 16, 980 (1970)] can be used to assay 29 samples in 10-min reaction time by using the "CentrifiChem" parallel fast analyzer (Union Carbide). Commercial reference serum was used for standardization. Correlation of results with those obtained by the method of Abell et al. [J. Biol. Chem. 195, 357 (1952)] for 54 samples yielded a regression line with a slope (m) of 0.897 and a y-intercept (b) of 231 mg/liter; the correlation coefficient (r) was 0.971. Compared with the manual procedure of Parekh and Jung [Anal. Chem. 42, 1423 (1970)] for 146 samples, the corresponding values were m = 0.991, b = 27 mg/ liter, and r = 0.981. Compared to serum extracts assayed with the "AutoAnalyzer" (Standard Technicon Methodology N-24a), 186 samples gave corresponding values of m = 0.990, b = 92 mg/ liter, and r = 0.979. No bias significant at the 95% confidence level existed versus any of the three methods. Sera containing abnormally high bilirubin concentrations (>50 mg/liter) or abnormally high triglyceride content (>5,000 mg/liter) did not give significantly different cholesterol values on the CentrifiChem as compared with values obtained with either the AutoAnalyzer or the Parekh and Jung method.
Determination of Gold in Drugs and Serum by Use of Anodic Stripping Voltammetry
Authors: Schmid G M , Bolger G W
Published: January 2020

Gold is determined in aqueous gold-containing drug solutions, 8 x 10-8 to 1 x 10-5 mol/liter, and in such drugs in serum, 2 x 10-6 to 1 x 10-5 mol/ liter, by electrodeposition onto a carbon paste electrode at -0.3 V vs. a saturated calomel electrode and subsequent stripping at constant current. Aqueous solutions are prepared for electrodeposition with a ceric perchlorate—hydrogen peroxide treatment. Serum samples are in addition treated with nitric and chloric acids. Variation coefficients are 16 to 2.5%, depending on concentration and deposition time.
Purification of Progesterone Antiserum for Radioimmunoassay, by Chromatography on QAE-Sephadex A-50
Authors: Bodley Frank H , Chapdelaine Alcide , Roberts Kenneth D
Published: January 2020

Antibodies were generated in sheep after administration of the antigen, progesterone-11α-succinyl-bovine serum albumin. This antiserum was purified 10-fold by treatment with "Aerosil" and column chromatography on "QAE-Sephadex A-50." In addition to an increased specific activity (cpm progesterone bound/g of protein) the purified antibody fraction was less cross-reactive with pregnenolone and desoxycorticosterone than was the crude antiserum. A sensitivity of 10 pg of progesterone was obtained with the purified antibody preparation, compared to 25 pg for the crude antiserum. This method of purification of antisera was devised in order to concentrate the antibody fraction before covalent coupling to insoluble supports such as activated arylamine-glass particles.
Determination of 3-Methoxy-4-Hydroxyphenylethylene Glycol, a Noradrenaline Metabolite, in Cerebrospinal Fluid and Urine
Authors: O’Keeffe R , Brooksbank B W L
Published: January 2020

We describe a sensitive, accurate method for quantitative determination of 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) in cerebrospinal fluid and urine. The method entails enzymatic hydrolysis of conjugated MHPG, acetylation of the phenolic group, thin-layer chromatographic purification, and estimation of total MHPG as the acetyl heptafluorobutyryl derivative by gas—liquid chromatography with electron capture detection and with use of aldrin as internal standard. Results obtained by this method compare favorably with those by other published procedures. Precision, calculated as the mean ± SD of the percentage differences between duplicate estimations, was 8.4 ± 8.0% for cerebrospinal fluid (3 ml) or 6.9 ± 6.6% for urine (2 ml). Total MHPG in lumbar cerebrospinal fluid specimens from 49 individuals ranged from 6.1 to 19.7 ng/ml, with no significant difference between the mean for control subjects and that for patients with affective disorders.
Application of an Automated Determination of Isoenzyme-5 of Lactate Dehydrogenase to the Diagnosis of Hepatic Disease
Authors: Nathan Lawrence E , Feldbruegge Donald , Westgard James O
Published: January 2020

We have examined the clinical usefulness of measuring the activity of LD-5 (the slowest-moving isoenzyme of lactate dehydrogenase) in serum, after its column chromatographic separation, on the Du Pont ACA. Primary and secondary diseases of the liver were readily identified. LD-5 and alanine aminotransferase activities correlated well in hepatitis and LD-5 and alkaline phosphatase activities in metastatic disease of the liver. LD-5 activity was elevated in cases of congestive heart failure, muscle trauma, and cirrhosis (when associated with active inflammation or alcoholic hepatitis). The test proved most useful for the early identification of hepatitis and tumor involvement of the liver.
A "Reagentless" Fluorometric Method for Creatine Kinase Activity in Serum
Authors: Lau Herbert K Y , Guilbault George G
Published: January 2020

A "reagentless" fluorometric method is described for the analysis of serum creatine kinase (CK) activity. The method is based on the use of silicone rubber pads, upon which are placed all the reagents for assay of CK. The rate of formation of NADH fluorescence at 460 nm is measured and equated to CK activity. The method is simple, rapid, inexpensive, and as little as 3 µl of serum is needed.
Radioimmunoassay of Thyroxine in Unextracted Serum, by a Single-Antibody Technique
Authors: Dunn Ralph T , Foster Lowell B
Published: January 2020

A radioimmunoassay procedure for thyroxine (T4) is described, for which only 25 µl of serum is required. The antibody, commercially available, is produced in rabbits in response to injections of a T4—albumin conjugate. Native T4—binding proteins are denatured by heating 25 µl of serum in 0.2 ml of a glutamate buffer in a boiling water bath. After a 1-h incubation of heat-treated serum with I125-T4 and T4 antibody, "free" and "bound" T4 are separated by use of hemoglobin-coated charcoal. The method has excellent sensitivity, is rapid, and possesses significant advantages over a standard competitive protein binding method with which it is compared.
Effect of Various Diluents on the Activity of Several Enzymes Present in Serum
Authors: Fendley Ted W , Hochholzer Jane M , Frings Christopher S
Published: January 2020

We have evaluated the effect of diluting serum with water or NaCl solution (8.5 or 9.0 g/liter) before assaying by a manual method for creatine kinase (EC 2.7.3.2), alkaline phosphatase (EC 3.1.3.1), lactate dehydrogenase (EC 1.1.1.27), and aspartate aminotransferase (EC 2.6.1.1) activity. The t test and the F test show no significant difference in the accuracy and precision of the assays at the 95% confidence level when 100 different samples were compared for each enzyme activity after use of the three diluents.