bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum Albumin: Recent Progress in the Understanding of Its Structure and Biosynthesis
Authors: Peters Theodore
Published: January 2020

Volume 23

p 6: In the sequence shown in Fig. 1, residue 467 should be Ser, residue 468 should be Glu (see Letters section, July issue, for details).

p 29: Column 1: The structure of the diazonium salt of "Variamin Blau B" is [see pdf for equation] i.e., it is the diazonium salt of N-(p-methoxyphenyl)- p-phenylenediamine (C. No. 37 255).

pp 60-62: The last terms of the equations in abstract and text should read "0.0138" instead of "1.380," and "0.0037" instead of "0.37." In Table 2, move the decimal two places to the left for all values under b (columns 3 and 5). On lines 20 and 21 of column 2, p 62, change "-2.32" to "0.0232" and "-0.62" to "0.0062."

p 175: Into line 8 of the second paragraph of column 2, insert (after "0.20 mmol/liter;"): "maleate dehydrogenase, 2000 U/liter,". In column 2 of Table 1 of this paper, "6.?" should read "6.7".

p 729: In Table 2, column 2, the fourth and fifth years from the top should read "1967" rather than "1976," and footnote" should read "Values shown are differences in C from the immediately preceding calibration." The conclusions of the author are unaffected by these changes.

p 1184: Caption to Table 1 should read "Six" (not "Five") samples, and in the sublegend, second line, "fivefold" should read "0.2-fold"—i.e, four parts were diluted with one part of water.
Evaluation of the Harleco Micro CO2 system for measurement of total CO2 in serum or plasma.
Authors: Lam C W , Tan I K
Published: January 2020

In the Harleco Micro CO2 System a volumetric procedure is used to measure total CO2 content in a small volume (0.10 ml) of serum or plasma. CO2 gas is released by mixing specimen and acid, either manually or with a "Micro CO2 Shaker." Within-batch CV's by manual and machine shakings were, respectively, 7.7 and 5.6% for a total CO2 value of 8 mmol/liter, decreasing to 2.0 and 1.4% for a value of 45 mmol/liter. Between-batch CV's were 8.0 and 7.1% at low total CO2, decreasing to 2.4 and 2.0% at high total CO2. Measurements were linear for values from 5 to 60 mmol/liter. Analytical recoveries at low and high concentrations were 97.7 to 98.9%. Correlation coefficients for results obtained with the Technicon "SMA Plus" autoAnalyzer and the Radiometer ABL 1 blood gas analyzer were 0.992 and 0.996, respectively. The Harleco Micro CO2 System appears to be a quick, reliable, and inexpensive method for measuring serum or plasma total CO2.
Selective staining of alpha1-antitrypsin (alpha1-protease inhibitor) with Schiff's reagent after separation from serum by analytical isoelectrofocusing in polyacrylamide gel.
Authors: Hercz A , Barton M
Published: January 2020

After electrofocusing serum from human and various animals in the pH range 4.0-6.0, only the isoproteins of antitrypsin stain with Schiff's reagent. As an additional advantage, this staining provides information about the relative contents of the Schiff-positive carbohydrates of various antitrypsins.
Variability among commercially available digoxin radioimmunoassay kits in cross reactivity to dihydrodigoxin.
Authors: Kramer W G , Kinnear N L , Morgan H K
Published: January 2020

We evaluated four commercially available 125I-digoxin radioimmunoassay kits with regard to their ability to cross react with the digoxin metabolite dehydrodigoxin. We prepared dihydrodigoxin serum samples in digoxin-free serum over the concentration range 0.4 to 5.0 microgram/liter and assayed them with each kit according to the manufacturer's instructions. The metabolite was able to displace the 125I-labeled digoxin derivative from the antibody supplied with all four kits. However, the extent of the cross reactivity depended on the kit, ranging from essentially zero to a high degree of interference. Dihydrodigoxin is the only metabolite of digoxin to have been quantitiated in human serum, and may comprise up to 30% of total glycosides. Over the clinical and therapeutic range of serum digoxin concentrations, enough dihydrodigoxin can be produced to interfere in the determination of serum digoxin concentrations by this method. We suggest that laboratories evaluate their specific kit with regard to cross reactivity to this metabolite.
Automated procedure for kinetic measurement of total triglycerides (as glycerol) in serum with the Gilford System 3500.
Authors: Lehnus G , Smith L
Published: January 2020

An automated procedure is used on the Gilford 3500 Computer-Directed Analyzer to measure serum triglycerides indirectly by using aqueous glycerol standards. Most enzymatic methods require long hydrolysis or awkward saponification. The method of Bucolo and David [clin. Chem. 19, 476 (1973)], in which lipase and glycerol kinase are used, is modified. The kinetic procedure described eliminates the need for a serum blank. It uses "Eskalab" bulk reagents and reduces both time and cost per test by measuring the decreasing NADH concentration from the glycerol kinase reaction at 340 nm after enzymatic hydrolysis at room temperature. The change in absorbance of the standard during a 14-s measuring time is used in the ratiometric calculation of the unknowns. The use of a stable aqueous standard that can be reliably and accurately prepared makes this method ideal for the traceability desired by many organizations. Reagent blank drift did not affect the results. A correlation coefficient of 0.991 for comparison with the manual endpoint method and a typical CV of 2.25% show this method to be accurate and reliable.
Quantitative metabolic profiling based on gas chromatography.
Authors: Gates S C , Sweeley C C
Published: January 2020

The quantitative metabolic profiles of volatilizable components of human biological fluids, particularly urinary organic acids, is reviewed, with emphasis on the use of gas-chromatography/mass spectrometer/computer systems. Various definitions of metabolic profiling are considered and techniques for obtaining such profiles are discussed. The role of computer processing of such data is examined, and statistical techniques for treating quantitative metabolic profiles are suggested.
Evaluation of a kinetic method for simultaneous determination of conjugated and unconjugated bilirubin.
Authors: Landis J B , Pardue H L
Published: January 2020

This paper describes a fast kinetic method for the simultaneous determination of unconjugated and conjugated bilirugin in the same reaction solution. A stopped-flow mixing system with a stabilized photometer and small computer is used to mix sample and reagent rapidly and to record 250 data points during a 700-ms reaction time, and a regression program is used to resolve these kinetic data into the concentrations of unconjugated and conjugated bilirubin. Data are reported for synthetic single and two-component samples and for serum samples. Kinetic results for synthetic mixtures and serum samples are compared with results obtained by a conventional two-step procedure. Regression equations show good linearity between kinetically determined absorbance changes and concentration, good agreement between taken and found values for total, unconjugated, and conjugated bilirubin for synthetic samples in human serum albumin, and a good correlation between kinetic and equilibrium results for these species in sera. Regression slopes for kinetic vs. equilibrium assay results for total, unconjugated, and conjugated bilirubins in sera were 1.01 +/- 0.05, 1.04 +/- 0.03 and 0.91 +/- 0.04, respectively, with intercepts of 6.6,--2.7, and 3.8 micromol/liter, and standard errors of estimate of 28, 14, and 20 micromol/liter. These data reflect uncertainties in both the kinetic and equilibrium methods.
Enzymic fluorometric continuous-flow assays for blood glucose, lactate, pyruvate, alanine, glycerol, and 3-hydroxybutyrate.
Authors: Lloyd B , Burrin J , Smythe P , Alberti K G
Published: January 2020

We describe enzymic fluorometric methods of automated analysis for glucose, lactate, pyruvate, 3-hydroxybutyrate, glycerol, and alanine in perchloric acid extracts of blood. Unmodified Technicon AutoAnalyzer II apparatus is used. The usual concentrations of all these metabolites can be measured in as little as 0.1 ml of blood from a fasting subject. Within-batch and between-batch coefficients of variation ranged from 0.4 to 4.4% for all metabolites except 3-hydroxybutyrate, for which CV's were higher for low concentrations. Analytical recovery of added metabolites ranged from 92 to 98%. Glucose, lactate, alanine, and 3-hydroxybutyrate are stable in perchloric acid extracts for at least 13 days at room temperature, and a year at -20 degrees C; pyruvate shows a 6--8% loss after 3 days and 52% by one year at -20 degrees C; glycerol concentrations were stable at -20 degrees C for at least 13 days. Blank fluorescence is found in perchloric acid extracts of blood, necessitating blank runs for pyruvate, 3-hydroxybutyrate, glycerol, and alanine. The systems are simple to use, relatively inexpensive to operate, and are recommended for any laboratory with high throughput of samples.
Enzymic micro-assay for blood glutamine.
Authors: Stahl A , Frick A , Imler M , Schlienger J L
Published: January 2020

Blood glutamine is hydrolyzed by glutaminase; the resulting ammonia is dialyzed out and measured by use of a continuous-flow colorimetric microassay. Concentrations in the range of 10 to 1300 micromol of glutamine per liter can be determined in a 40-microliter sample. With slight modifications, higher concentrations, up to 5 mmol/liter, can be measured. Assay conditions and the qualities of the microtechnique were made optimal. Usual values obtained with this method for arterial and venous blood in man are, respectively, 443 +/- 140 and 466 +/- 142 micromol/liter (mean +/- 2 SD). Corresponding values for rats are 320 +/- 92 and 340 +/- 108 micromol/liter. Fasting causes a decreased blood glutamine.
High-performance liquid-chromatographic determination of free nicotinic acid and its metabolite, nicotinuric acid, in plasma and urine.
Authors: Hengen N , Seiberth V , Hengen M
Published: January 2020

We report a liquid-chromatographic procedure for determining free nicotinic acid and a metabolite, nicotinuric acid, in plasma and urine. Five-tenths milliliter of urine or deproteinized plasma is evaporated and the residue analyzed isocratically by reversed-phase ion-pair chromatography, with measurement of the eluted nicotinic acid and nicotinuric acid at 254 nm. Nicotinic acid, nicotinuric acid, and the internal standard (isonicotinic acid) have retention times of 7.8, 8.4, and 6.8 min, respectively, in plasma, and 12.3, 13.1, and 10.8 min in urine, because of double column length. Day-to-day reproducibilities (CV) for nicotinic acid and nicotinuric acid within 7.5% are attainable for the concentration ranges 0.1--20 mg/liter, equivalent to 0.81--162 micromol of nicotinic acid and 0.55--11 micromol of nicotinuric acid per liter for plasma; in urine for the range 0.5--100 mg/liter, equivalent to 4--810 micromol of nicotinic acid and 2.8--555 micromol of nicotinuric acid per liter. Metabolites of nicotinic acid such as nicotinamide, N-methylnicotinamide, 2-hydroxypyridine-5-carboxylic acid, and other structurally related substances do not interfere.
Increased D-glucaric acid excretion by jaundiced patients.
Authors: Herzberg M , Wiener M H
Published: January 2020

The urinary excretion of D-glucaric acid, a catabolite of glucuronic acid, is considered to be a reliable index of the state of hepatic microsomal enzyme activity. Because enzyme activity may be altered in liver disease, we examined the effect of liver disease on the excretion of this metabolite and its correlation with liver function tests. We studied 89 patients with nonhemolytic jaundice, 39 with viral hepatitis, 33 with obstructive jaundice, six with cirrhosis, and 11 patients with jaundice of mixed etiology. Glucaric acid excretion was significantly increased in all these patients as compared to controls, most pronounced in the obstructive jaundice group. No correlation was found between glucaric acid excretion and concentrations of bilirubin, albumin, globulin, aspartate aminotransferase, alkaline phosphatase, cholesterol, or gamma-glutamyltransferase in serum, even though the concentrations of these analytes did vary with the type of liver disease. We suggest that this increase in glucaric acid excretion is an indication of normal or even increased glucuronidation (UDP-glucuronosyltransferase activity), which occurs in liver disease.
Use of polyethylene glycol in radioimmunoassay of human placental lactogen.
Authors: Ermshar C L , Gusseck D J
Published: January 2020

We describe a rapid radioimmunoassay for human placental lactogen in biological fluids, with use of polyethylene glycol to separate free from antibody-bound placental lactogen. The standard curve obtained, easily fitted to a logit-log transformation, is useful over a concentration range of 6 to 400 ug/liter. Within-assay variability is 1.97%, between-assay variability 2.20%. The relation is linear when lactogen added is plotted against that accounted for analytically, the actual recovery being 100.26%.
A method of assessing serum triiodothyronine concentrations that is independent of subject's age and variations in concentrations of binding proteins in serum.
Authors: Mardell R , Gerson M
Published: January 2020

Pairs of values for serum triiodothyronine and serum triiodothyronine binding capacity were represented as maps of points for euthyroid populations (including subjects who were pregnant or were receiving estrogens) in the age groups 18-50, 51-64, 65-79, and greater than 80 years (504 subjects) and thyrotoxic populations in the same age groups (207 subjects). For each age group the two populations were effectively separated bythe technique. Statistical analysis by the method of principal components justified the combination of all the age-related maps into a single map, allowing the assessment of serum triiodothyronine regardless of age or concentration of binding proteins in serum. The overlap of the combined populations was less than 1%. The method proposed is superior to a calculation of free triiodothyronine index in several respects.
A sensitive manual enzyme immunoassay for thyroxine.
Authors: Schall R F , Fraser A S , Hansen H W , Kern C W , Tenoso H J
Published: January 2020

We describe an immunoassay for thyroxine in serum. In the assay specific antibody covalently bonded to latex particles is used, along with horseradish peroxidase as the label, and o-phenylenediamine as the chromogen. The flexible protocol is designed for manual execution. Performance is similar to that of the highest-sensitivity thyroxine radioimmunoassays. Results correlate well with radioimmunoassay (r = 0.99, slope = 0.93, y-intercept = 2.4 microgram/liter for 201 samples) and an automated enzyme immunoassay (r = 0.97, slope = 0.99, y-intercept = 4.7 coefficients of variation are less than 7.2% over the entire useful range of the assay (20--240 microgram/liter). The limit of detection is less than 94 pg/tube at 20 microgram/liter. Only D-thyroxine is known to interfere with serum assays. This assay has no discernible protein effect from 40 to 80 g of protein per liter, unlike many thyroxine radioimmunoassays. Serum preservatives known to be peroxidase inhibitors do not adversely affect assay performance because of the 56-fold dilution in the final assay mixture. Hemolyzed serum and EDTA-treated plasmas are unsuitable for this assay.
Column-chromatographic separation of isoenzymes of aspartate aminotransferase.
Authors: Sampson E J , Miller S A , McKneally S S , Whitner V S , Hannon W H , Burtis C A
Published: January 2020

We describe a column-chromatographic method for separating the mitochondrial and cytoplasmic isoenzymes of aspartate aminotransferase in human serum. Bed height of the ion exchanger, pH, and salt concentrations in the eluting buffers are shown to be variables affecting the separation of the isoenzymes. Under the optimized conditions selected for this study, a 30% increase in volume was observed in one fraction, associated with changing the salt concentration of the eluting buffer and attributed to a contraction of the DEAE-Sephadex A-50. Elution profiles (enzyme activity vs. fraction number) were examined with highly purified mitochondrial and cytoplasmic isoenzymes of human origin in bovine serum albumin and human serum. Recovery of the enzyme in the eluted fractions averaged 102% (SD, 2.0%) for specimens prepared from the purified isoenzymes and 104% (SD, 10.7%) for 38 human serum specimens. The separation technique showed linearity to catalytic concentrations in excess of 200 U/liter (reaction temperature 30 degrees C) for each isoenzyme. Additional information is presented regarding among-day precision and the effect of specimen dilution.
A non-barbital buffer for immunoelectrophoresis and zone electrophoresis in agarose gels.
Authors: Monthony J F , Wallace E G , Allen D M
Published: January 2020

We describe buffer for both immunoelectrophoresis and zone electrophoresis procedures in agarose gels, Tricine [N-tris(hydroxymethyl)methylglycine] and Tris [2-amino-2-(hydroxymethyl)-1,3-propanediol] being the main components. This buffer eliminates the procurement cost and inventory control associated with formulation of barbital buffers. We compare it with other common buffer formulations.
Enzyme immunoassay for gentamicin.
Authors: Standefer J C , Saunders G C
Published: January 2020

We describe a gentamicin assay in which a peroxidase-gentamicin conjugate competes with gentamicin for binding to a gentamicin antibody adsorbed to a polystyrene solid phase. The assay can be completed in 30 min and requires 50 microliter of diluted serum. The precision and accuracy are equivalent to that of a radioimmunoassay technique and the reagents are stable for several months.
Proteinuria: accuracy and precision of laboratory diagnosis by dip-stick analysis.
Authors: James G P , Bee D E , Fuller J B
Published: January 2020

We studied and compared results of two urine dip-stick procedures for protein with those of quantitative measurements of total protein and albumin in urine. Sensitivity, specificity, and predictive value of "normal" and "abnormal" dip-stick results, assay efficiency, technologist precision, and method association were determined. Precision was poor, attributable largely to variation within each technologist. Relative to a defined measure of precision, technologist performance appears to be uniform within each product. Patients' urinary protein concentrations of less than 200 mg/liter can be distinguished from concentrations greater than 3000 mg/liter with confidence by dip-stick procedures. Urin samples with low albumin/total protein ratios were frequently falsely negative by dip-stick assays.
Serum galactose determination with centrifugal analyzers.
Authors: Gabrielli M
Published: January 2020

I describe a rapid quantitative centrifugal analysis for galactose in blood. The technique involves galactose dehydrogenase. As compared to the manual (o-toluidine) method for galactose determination, analysis time (4 min 45 s on the GEMSAEC, 4 min 10 s on the CentificCHEM) and sample volume (5 microliter) were considerably reduced. Sample deproteinization is eliminated. A modified commercial kit was also tested. Results by the procedure correlate well with those by the more classical methods and analytical recovery is about 100%. The method is applied to the determination of galactose in intravenous galactose tolerance tests. Results of actual tests are reported.
Determination of 3-methoxy-4-hydroxyphenylpyruvic acid, 3,4-dihydroxyphenylethylene glycol, and 3,4-dihydroxyphenylmandelic acid in urine by mass fragmentography, with use of deuterium-labeled internal standards.
Authors: Muskiet F A , Fremouw-Ottevangers D C , Nagel G T , Wolthers B G , de Vries J A
Published: January 2020

We report the determination of 3-methoxy-4-hydroxyphenylpyruvic acid, 3,4-dihydroxyphenylmandelic acid, and 3,4-dihydroxyphenylethylene glycol in urine, by use of gas chromatography/mass spectrometry in combination with a simple purification method and deuterium-labeled internal standards. Normal excretion values in terms of creatinine, expressed as a function of age, are given, together with results obtained for patients with neuroblastoma, pheochromocytoma, or parkinsonism treated with L-DOPA + peripheral decarboxylase inhibitor, and for a patient receiving dopamine. We were unable to identify 3, 4-dihydroxyphenyllactic acid in urine. The results obtained and their relation to other catecholamine metabolites and catecholamine-precursor metabolites in urine are discussed.
Radioimmunoassay of serum myoglobin: evaluation and modification of a commercial kit and assessment of its usefulness for detecting acute myocardial infarction.
Authors: Kubasik N P , Guiney W , Warren K , D'Souza J P , Sine H E , Brody B B
Published: January 2020

We evaluated a modified procedure for a commercially available myoglobin radioimmunoassay kit (Nuclear Medical Systems). Within-run and run-to-run precision was acceptable. Normal ranges were established and paralelism studies performed. Clinical usefulness was assessed in 100 consecutive patients admitted to our coronary-care facility. The determinations were done daily, along with creatine kinase and its isoenzymes, and lactate dehydrogenase and its isoenzymes. Fifty of the 100 patients ultimately were shown to have had acute myocardial infarction. Myoglobinemia was present in most of the patients with acute myocardial infarction, but information on its presence was less usefull clinically than was detection of creatine kinase isoenzyme MB.
An improved enzyme immunoassay for progesterone in human plasma.
Authors: Joyce B G , Wilson D W , Read G F , Riad-Fahmy R
Published: January 2020

We describe an enzyme immunoassay for progesterone in which we use a progesterone-11alpha-hemisuccinyl-horseradish peroxidase conjugate as the "label" and an antiserum raised in rabbits to a progesterone-11alpha-hemisuccinyl-bovine serum albumin conjugate. In this assay, antibody-bound and free steroid are separated by using a second antibody precipitation procedure. The assay has a lower limit of sensitivity of 10 pg/assay tube and satisfies the usual criteria of specificity, precision, and accuracy. Results obtained with a comparison radioimmunoassay and our procedure agreed well (r = 0.98). Eighty samples can be assayed per day. It is not only well suited for surveys where accurate determination of progesterone concentrations in small plasma aliquots is required, but also for monitoring ovulation induction in patients attending infertility clinics.
An enzymatic radioassay for gentamicin.
Authors: Case R V , Mezei L M
Published: January 2020

An enzymatic, radiochemical assay procedure for measuring serum gentamicin by use of gentamicin 3-acetyl-transferase and [acetyl-14C]acetyl-Coenzyme A is described and evaluated. The enzyme stoichiometrically and quantitatively transfers a radioactive label to the analyte during a 10-min incubation at 37 degrees C. The labeled gentamicin is then absorbed onto phosphocellulose paper discs, which are washed to remove unreacted [acetyl-14C]-acetyl-Coenzyme A and counted in a liquid scintillation counter for 1 min each. The assay detects gentamicin in concentrations as low as 0.2 mg/liter and gives a linear response to concentrations as high as 20 mg/liter. Sisomicin, a structural analog of gentamicin, is measured by the procedure, and tobramycin and netilmicin are slightly reactive. No other interferents were found among other aminoglycosides, other antibiotics, or substances endogenous to serum. Results by the new method are compared to those by radioimmunoassay and a microbiological method.
Atomic absorption spectrophotometry of chromium in serum and urine with a modified Perkin-Elmer 603 atomic absorption spectrophotometer.
Authors: Kayne F J , Komar G , Laboda H , Vanderlinde R E
Published: January 2020

Modification of a Perkin-Elmer 603 atomic absorption spectrophotometer by adding a high-intensity tungsten-halogen lamp for background correction significantly improved the detection limit for elements that have analytical wavelengths in the near-ultraviolet and visible regions. Chromium in human serum and urine can be measured, with a simplified sample-handling technique, in concentrations of less than 0.1 microgram/liter. For comparison, the mean value for chromium in the serum of eight men was 0.14 microgram/liter.
Polystyrene tube immunoradiometric assay for human alpha1-fetoprotein, and its use for mass screening.
Authors: Grenier A , Morissette J , Valet J P , Bélanger L
Published: January 2020

We describe a two-site immunoradiometric assay for human alpha1-fetoprotein, with use of antibody-coated polystyrene tubes as solid phase. The sensitivity, precision, and simplicity of this system make it eminently suitable for mass-screening purposes. We currently use it for neonatal detection of hereditary tyrosinemia in the Province of Quebec; measurements are made on blood spotted and dried on paper. This system could be well suited for other mass surveys, such as prenatal screenings for fetal abnormalities.
The 4-hydroxybenzoate/4-aminophenazone chromogenic system used in the enzymic determination of serum cholesterol.
Authors: Meiattini F , Prencipe L , Bardelli F , Giannini G , Tarli P
Published: January 2020

A single reagent, containing cholesterol oxidase, cholesterol esterase, peroxidase, 4-hydroxybenzoate, and 4-aminophenazone, is used in determining serum cholesterol. Analysis time is 15 min, and the standard curve is linear to 6.0 g/liter. Analytical recovery of cholesterol was 100.1 +/- 0.4%. Within-run precision (CV) was less than or equal to 1.4 1.4%, between-run less than or equal to 4.8%. Comparison with results by a Liebermann Burchard method [Clin. Chim. Acta 5, 637 (1960)] gave a linear regression of y = 1.08x--0.05, with a correlation coefficient (r) of 0.985. Comparison with the Roeschlau enzymic method [J. Clin. Chem. Clin. Biochem, 12, 226 (1974)] gave y = 1.02x + 0.01 (r = 0.958). Comparison with the enzymic method of Allain et al. [Clin. Chem. 20, 470 (1974)] gave y = 1.01x--0.00 (r = 0.995). The following substances do not interfere up to the indicated concentrations (mg/liter): hemoglobin (5000), bilirubin (100), reduced glutathione (150), l-cysteine (400), urea (3000), creatinine (200), uric acid (200), d-glucose (10000), L-ascorbic acid (50), acetylsalicylic acid (500), L-DOPA (10), ergothioneine (1000), 2,5-dihydroxybenzoic acid (20), and 3,4-dihydroxybenzoic acid (10). Stored in an amber-colored bottle, the working reagent is stable for three months at 2--8 degrees C and for three weeks at 25 degrees C.
Anion-exchange chromatography of erythrocytic and muscle adenylate kinase and its effect on the serum creatine kinase isoenzyme assays.
Authors: Klein B , Jeunelot C L
Published: January 2020

We determined the elution profile of erythrocytic and muscle adenylate kinases (EC 2.7.4.3) in the Roche chromatographic creatine kinase procedure and studied the interference these enzymes would cause in the isolation and assay of serum creatine kinase (EC 2.7.3.2) isoenzymes. Both adenylate kinases co-elute with the creatine kinase MM fraction and do not interfere with the isolation or assay of the MB fraction.
Multilayer Film Elements for Clinical Analysis: General Concepts
Authors: Curme Henry G , Columbus Richard S , Dappen Glenn M , Eder Thomas W , Fellows Williams D , Figueras John , Glover Clyde P , Goffe C A , Hill Doyle E , Lawton William H , Muka Edward J , Pinney Jack E , Rand Royden N , Sandford Kari J , Wu Tal W
Published: January 2020

vol. 24

p 1335. In this paper, the equation, p 1340, relating Dt to Dr after integration should read

See Equation in the PDF File

In Table 3, the concentration units are mg/liter, not g/liter, and the day-to-day SD in glucose concentration at 999 mg/liter glucose is 15.1 mg/liter, not 1.51 mg/liter. In Table 4, p 1341, the concentration of Hypaque is expressed in mg iodine/L (mg I/L).

p 1343. Table 3 was inadvertently omitted from this paper. It is as follows.

See Table in the PDF File

The table numbers for Tables 3–6 in the paper as printed should each be increased by one.

p 1627. In Table 6, the numbers in the first line should read 580, 2260, 2210, and +50. The "+50" in the second line should be deleted.
Method for screening urinary steroids by gas chromatography.
Authors: Trocha P , D'Amato N A
Published: January 2020

Numerous methods are available for measuring urinary steroids in evaluating endocrine dysfunctions. Measurements of these particular steroids, or groups of them, usually involve tedious isolation methods, corrections for interferences and losses of the steroid, and (or) expensive reagents. We show how gas-liquid chromatography provides a rapid, sensitive, and direct method for several steroid metabolites in urine. Androstanol, androsterone, etiocholanolone, dehydroisoandrosterone, pregnanediol, pregnanetriol, 11-keto-17-ketosteroids, and the 11beta-hydroxy-17-ketosteroids can be identified and quantified.
Measurement of free and free-plus-peptide hydroxyproline fractions in plasma.
Authors: Husdan H , Leung M , Oreopoulos D , Rapoport A
Published: January 2020

Plasma hydroxyproline fractions--free-plus-peptide and free--were determined by a method involving centrifugal ultrafiltration and the procedure of Kivirikko et al. [Anal. Biochem. 19, 249 (1967)]. Within- and between-day precision (CV) for the combined fractions was 4--5% and 2.8--6%, respectively. Mean analytical recoveries of free hydroxyproline were 95.2% (87--109%) in the normal range, and 97% (91--108%) in the above-normal range. Normal ranges for plasma hydroxyproline fractions, based on data for 11 men and 19 women, were free-plus-peptide, 7.5--25.3; free, 4.9--22.7; and peptide (calculated), 0.1--5.1 mumol of hydroxyproline per litre, respectively. These ranges showed no sex-related differences and were gaussian in distribution. A factor was derived to transform data on concentrations in ultrafiltrate into plasma concentrations.
P-Nitrophenol-alpha-D-glucopyranoside as substrate for measurement of maltase activity in human semen.
Authors: Chapdelaine P , Tremblay R R , Dubé J Y
Published: January 2020

Hitherto, seminal plasma maltase has been measured with maltose as substrate; this method is time consuming and lacks specificity. The use of a synthetic substrate, p-nitrophenol-alpha-D-glucopyranoside, allows accurate and rapid determination of this activity. When maltase is added to the incubation medium (the substrate and reduced glutathione in potassium phosphate buffer, pH 6.8), maintained at 37 degrees C, hydrolysis of the original substrate to p-nitrophenol goes at a constant rate during 4 h. Under optimal conditions of incubation, the Michaelis constant of the reaction, calculated by the Hanes method, was 2.92 +/- 0.84 (SD) X 10(-3) for six different semen samples. Isomaltase appeared to be absent from seminal plasma. The enzyme is stable to freezing and slow thawing and can be stored for at least 26 days at -80 degrees C. Its molecular weight is 259 000. Tris(hydroxymethyl)aminomethane (pH 6.8) exerts a noncompetitive inhibition on the enzyme activity. In 68 men 23 to 45 years old, whose semen analyses were normal, the seminal plasma maltase activity was 467 +/- 135 (SD) mU/g of protein. It was generally decreased in patients with infertility disorders.
Methods compared for determining zinc in serum by flame atomic absorption spectroscopy.
Authors: Kelson J R , Shamberger R J
Published: January 2020

We compared two methods for determination of serum zinc by flame atomic absorption spectroscopy. The first involved 10-fold dilution of serum with water; the second, deproteinization of serum with trichloroacetic acid. Analytical recovery of Zn2+ added to serum averaged 99.3 and 99.9%, respectively, by the two methods, but measured concentrations were consistently greater by the second method [mean difference, 118 +/- 27 (SD) mug/liter]. For the analysis of 55 sera, measured concentrations were also greater by the second method [mean difference, 91 +/- 28 (SD) mug/liter]. We dialyzed serum to remove most of the zinc and measured analytical recovery of increasing amounts of Zn2+ added to this dialyzed serum or, conversely, of zinc in a mixture of increasing volumes of dialyzed serum in a Zn2+ standard. Recovery results for the dilution method showed an interference by an unidentified, but nondialyzable serum component(s). Recovery was not improved by use of (a) a "high-solids" burner, (b) a diluent containing 1-butanol, or (c) a Mn2+ internal standard.
Determination of uric acid on continuous-flow (AutoAnalyzer II and SMA) systems with a uricase/phenol/4-aminophenazone color test.
Authors: Klose S , Stoltz M , Munz E , Portenhauser R
Published: January 2020

This report describes a new specific colorimetric procedure for uric acid assay with AutoAnalyzer II and SMA (Technicon) systems, made specific by the application of uricase. Hydrogen preroxide, formed in this reaction, effects the oxidative coupling of 4-aminophenazone and 2,4-dichlorophenol under the catalytic influence of peroxidase. The red dye formed is measured at 505 or 520 nm. A sample blank measurement is not necessary, and the reagents show very good stability. The test shows linearity up to 714 mumol of uric acid per liter. Results of thie method correlate very well with those by the uricase-ultraviolet and uricase--catalase methods. There is no interference by hemoglobin, bilirubin, lipemia, and various drugs, except a minor interference by alpha-methyldopa. Interference from ascorbate is eliminated by ascorbate oxidase. This method can be regarded as a considerably improved routine test for uric acid on continuous-flow systems in clinical laboratories as compared with the commonly used phosphotungstate method.
A practical radioimmunoassay of thyroglobulin.
Authors: Bodlaender P , Arjonilla J R , Sweat R , Twomey S L
Published: January 2020

We describe a reliable and convenient double-antibody radioimmunoassay for human thyroglobulin that can be performed within two days. Analytical recoveries were quantitative and immunological equivalence between several sources of human thyroglobulin was demonstrated. Cross reactivity with either thyroxine or triiodothyronine was insignificant. The between-day coefficient of variation in the 5--100 mug/liter range was 10%. The range observed for 68 normal individuals was 2--61 microgram/liter.
Radioimmunoassay of alpha-fetoprotein, with special reference to iodination and purification techniques.
Authors: Schiller H S , Kulchinski L , Luthy D A
Published: January 2020

We report a relatively simple and convenient method for iodinating human alpha-fetoprotein and for purifying the 125I-labeled material. The label is incorporated into human alpha-fetoprotein enzymatically by use of lactoperoxidase. Before each assay the labeled material is purified over two successive short columns: Sepharcryl S-200 Superfine and cellulose. This procedure removes both free iodine and "damaged" fetoprotein. With the purified material we developed a sensitive and reliable radioimmunoassay for alpha-fetoprotein in serum and amniotic fluid.
Individual character of variation in time-series studies of healthy people: II. Differences in values for clinical chemical analytes in serum among demographic groups, by age and sex.
Authors: Williams G Z , Widdowson G M , Penton J
Published: January 2020

Assessment of the significance of an observed set of serum chemical values for determining a person's state of health requires comparison with a set of defined reference values. We tested the assumption that a reference group of individuals, categorized by age and sex, gives a narrower range of variation than does a larger mixed population. If this were true, the demographic set would be a more sensitive reference than is the customary "normal range" for interpretation of values occurring in the individual. The ratio, R, of intra-personal to inter-personal (group) standard deviations was similar for defined age/sex classes and the overall group for 16 serum constituents. When the "raw" intra-individual variation (biological plus analytical variation) was adjusted to remove the average analytical component, the resulting R was less than 80 for all constituents except creatine kinase, which indicates that these are all particularly strong "discriminators" of individuality. These results imply the need for individual rather than population-based reference ranges, even if the latter are from persons of similar age and the same sex.
Analytical performance and comparability of the determination of triglycerides by 12 Lipid Research Clinic laboratories.
Authors: Ahmed S , Lippel K , Bachorik P , Albers J , Williams J , Cooper G
Published: January 2020

Twelve Lipid Research Clinic laboratories performed automated fluorometric triglyceride analyses on four control serum pools of known concentration by a modified Hantzsch reaction. The analyses were done during a two-year period, with use of common standards, methodology, and quality-control procedures. Estimates of analytical bias, variability, and short- and long-term trends for each instrument and for the entire group of LRC instruments are presented. High accuracy, precision, and interlaboratory comparability were achieved through rigorous standardization and control of the entire analytical procedure. Individual instrument biases varied from an average of 4.9% below to 1.0% above reference values. Between-run variability was often less than within-run variability and interlaboratory variation was substantially less than intralaboratory variation. The total standard deviation for all instruments ranged from 37 to 63 mg/liter. Only 5 to 14% of this variation was due to differences among instruments. The among-instruments standard deviation ranged from 12 to 17 mg/liter; the between-run, within-instrument standard deviation ranged from 29 to 46 mg/liter, and within-run standard deviation from 27 to 40 mg/liter. The significance of the results for long-term collaborative studies is discussed.
High-performance liquid-chromatographic determination theophylline in plasma.
Authors: Peng G W , Gadalla M A , Chiou W L
Published: January 2020

A high-performance liquid-chromatographic method is reported for monitoring theophylline in plasma. Samples are deproteinized with 2.5 volumes of acetonitrile and the supernates chromatographed on a reversed-phase column. Absorption at 275 nm is monitored. One can accurately measure 1.5 mg of theophylline per liter, in as little as 10 microliter of plasma, and only about 7 min is required per sample. No interference was found in plasma samples from asthmatic patients. This method is particularly useful for routine therapeutic monitoring of both pediatric and adult patients.
Automated serum albumin determination by use of the immediate reaction with bromcresol green reagent.
Authors: Gustafsson J E
Published: January 2020

It has been demonstrated recently that the reaction of serum samples with bromcresol green reagent proceeds in two steps, albumin being responsible for the immediate reaction and other serum proteins for the slower one. I show here that the immediate reaction, used for albumin determination, can be automated. Two different automated systems are described: the LKB 2086 Reaction Rate Analyzer and the multichannel analysis system LKB 2480 Prisma. With the first system, 60 (or 120) samples per hour were run with a within-day standard deviation of 0.3 g/liter; with the second system, a feed rate of 150 samples per hour was used (SD, 0.3 g/liter, within-day). Comparison with other methods gave the following equations: y (LKB 2086) = 1.44 + 0.97 X (immunodifussion) (n = 43; r = 0.98) and y(Prisma) = 2.04 + 0.96x (manual method) (n = 73; r = 0.98). Thus albumin determinations can be done reliably, quickly, and simply at low reagent and labor cost.
Evaluation of a radiometric method for determination of total and unsaturated iron-binding capacities and serum iron.
Authors: Fudge A N , Fraser C G
Published: January 2020

We describe an evaluation of the "RES-OMAT FE-59" radiometric kit (Mallinckrodt Australia Pty. Ltd.) for determination of total iron-binding capacity and unsaturated iron-binding capacity; serum iron may be calculated from total iron-binding capacity and unsaturated iron-binding capacity. Values obtained on patients' sera were compared with those obtained by continuous-flow analysis; correlation coefficients were 0.92, 0.93, and 0.88 for total iron-binding capacity, unsaturated iron-binding capacity, and iron, respectively. Precision between-run and within-run was almost identical and compares very favorably with that reported by Dixon [Ann. Clin. Biochem. 10, 127 (1973)] and that achieved in inter-laboratory surveys. Analytical recovery averaged only 83.5%, but results of analyses of sera with assigned or consensus values showed good accuracy. Satisfactory performance cannot be achieved with lyophilzed bovine quality-control materials. The kit has significant technical advantages over colorimetric methods and good short- and long-term analytical performance.
Pitfalls of the alcohol dehydrogenase procedure for the emergency assay of alcohol: a case study of isopropanol overdose.
Authors: Vasiliades J , Pollock J , Robinson C A
Published: January 2020

We describe a case of ethanol and isopropanol ingestion that resulted in coma. The concentration of ethanol and isopropanol was 0.90 and 1.65 g/liter in serum and 3.12 and 5.34 g/liter in gastric contents. With an enzymatic (alcohol dehydrogenase) method for ethanol determination we obtained erroneous analytical results. Because of partial cross reactivity with isopropanol, ethanol concentration was overestimated and total alcohol (i.e., the contribution of isopropanol) was underestimated. This was recognized by measuring serum osmolality. Differences between measured and calculated serum osmolality that are not accounted for by the serum ethanol concentration as determined by an enzymatic ethanol method must be further investigated by specific methods to see if other alcohols are present.
Performance evaluation of multi-channel analyzers by use of linearly-related survey specimens.
Authors: Caragher T E , Grannis G F
Published: January 2020

Sets of specimens having quantitative linear inter-relationships for 25 analytes were prepared and used in a small survey of results with multi-channel analyzers. Instrument calibration was evaluated by linear regression analysis of the analytical results, with calculation of the x- and y-intercepts and slopes. The average intercepts and slopes agreed quite well with those expected on the basis of specimen preparation, but the results from individual laboratories and from particular kinds of instruments demonstrated a variety of analytical biases. We conclude that performance of multi-channel analyzers can be evaluated effectively by such use of linearly related specimens in an inter-laboratory survey.
Parathyrin radioimmunoassay: diagnostic utility of antisera produced against carboxyl-terminal fragments of the hormone from the human.
Authors: Di Bella F P , Kehrwald J M , Laakso K , Zitzner L
Published: January 2020

Antisera directed toward the carboxyl-terminal region of human parathyrin (parathyroid hormone), for use in daignostically applicable radioimmunoassays of the hormone in serum, are scarce, largely because of the lack of suitable immunogens of human origin. We produced four antisera in goats and guinea pigs by immunization with recently discovered carboxyl-terminal fragments of human parathyrin extracted from parathyroid tumors. Here, we report results of radioimmunoassays of nearly 200 normal and pathological sera with one of these antisera; we observed almost complete differentiation between concentrations of parathyrin in serum of healthy normal subjects and patients with primary, secondary (due to chronic renal failure), or "ectopic" hyperparathyroidism (due to nonparathyroid cancer). The availability of a new immunogen should now make possible the deliberate production of large quantities of diagnostically applicable parathyrin antisera directed toward the carboxyl-terminal region of human parathyrin. This should, in turn, lead to more widespread availability of this useful radioimmunoassay.
Purification of human prostatic acid phosphatase by affinity chromatography and isoelectric focusing. Part I.
Authors: Vihko P , Kontturi M , Korhonen L K
Published: January 2020

The main isoenzyme of human prostatic acid phosphatases was purified by affinity chromatography on L(+)-tartrate linked to agarose and by isoelectric focusing. The enzyme was a single protein when examined by polyacrylamide gel electrophoreses, either as a native protein or in the presence of sodium dodecyl sulfate. The analytical recovery of enzyme activity was 19%. The specific activity was 40 18 mumol/(min X mg) for hydrolysis of 5.5 mmol/liter p-nitrophenyl phosphate at pH 4.8 and 37 degrees C. The purification factor was as great as 1900. The molecular weight of the enzyme as measured by gel filtration was 109 000 and by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate 54 000, indicating that the enzyme had been isolated in the dimer form. By this method we have achieved the best purification of human prostatic acid phosphatase so far.
Direct assays of lactate, pyruvate, beta-hydroxybutyrate, and acetoacetate with a centrifugal analyzer.
Authors: Hansen J L , Freier E F
Published: January 2020

Methods are described for direct assays of lactate, pyruvate, beta-hydroxybutyrate, and acetoacetate in plasma with the GEMSAEC centrifugal analyzer. The methods for lactate, beta-hydroxybutyrate, and acetoacetate are kinetic and ratiometric, eliminating the need for specimen-blank assays. The pyruvate method is an end-point assay, because endogenous lactate dehydrogenase interferes in a kinetic pyruvate assay. The methods are precise and accurate and 1-min of analysis time is adequate for each assay. Rapid assessment and monitoring of metabolic acidosis is possible with these methods, as is illustrated by examples.
Spurious underestimation of results for digoxin radioimmunoassay with a commercial kit.
Authors: Witherspoon L R , Shuler S E , Garcia M M
Published: January 2020

Estimates of digoxin in serum with a commercial redioimmunoassay kit (Schwarz/Mann) occasionally result in more counts in the patient's "bound" fraction than in the "bound" fraction for the zero standard. This phenomenon has been investigated in 26 serum samples obtained from patients who were ingesting known amounts of digoxin. The problem appears to relate to environmental differences in at least the zero standard and affects results when serum digoxin concentrations are less than 0.8 microgram/liter. Apparently dose estimates are more accurate with other methods or by calculating results after omitting the zero standard.
Determination of serum alpha-tocopherol (vitamin E) by high-performance liquid chromatography.
Authors: De Leenheer A P , De Bevere V O , Cruyl A A , Claeys A E
Published: January 2020

We report a fast, simple high-performance liquid-chromatographic assay for serum alpha-tocopherol, with use of a reversed-phase column and tocol as internal standard. Only 200 microliter of serum is required. Isocratic elution of the n-hexane extract is done within 6 min; total analysis time is less than 1 h. Within-day precision (CV) was 2.3% for 24 samples of a normal plasma pool (mean concn, 10.1 mg/liter). Day-to-day precision (CV) was 3.2%, measured for 20 days for a specimen with a concentration of 10.8 mg/liter. Analytical recovery of alpha-tocopherol from fortified serum was 89 to 100%. The lower detection limit of alpha-tocopherol is estimated to be 0.6 mg/liter. The specificity of the procedure was verified by spectrophotometry, gas-liquid chromatography, and combined gas chromatography/mass spectrometry of an eluate collected from the column.