bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.
Radioimmunoassay of calcitonin in the plasma of rhesus monkey and man.
Authors: Hargis G K , Reynolds W A , Williams G A , Kawahara W , Jackson B , Bowser E N , Pitkin R M 
Published: January 2020

Abstract
We describe a radioimmunoassay for rhesus monkey and human immunoreactive calcitonin, in which a selected goat anti-human calcitonin antiserum, 131I-labeled synthetic human calcitonin tracer, and purified synthetic human calcitonin standards were used. The mean basal concentration of calcitonin in normal monkey plasma (254 microgram/liter) was not significantly different from that in normal human plasma (217 microgram/liter). The data indicate that the method is sensitive (lower limit of detection, 5 ng/liter), specific, accurate, and reproducible (coefficient of variation, 1-11% over a wide range of concentrations). Monkey calcitonin response to changes in plasma calcium concentration is similar to that in man, with significant correlation between calcium and calcitonin concentrations. Use of this radioimmunoassay for monkey and human calcitonin allows the monkey to be used in further studies of factors regulating secretion, function, and metabolism of calcitonin under various experimental conditions that would not be feasible in man.
Serum estradiol-17 beta as determined by mass fragmentography and by radioimmunoassay.
Authors: Zamecnik J , Armstrong D T , Green K 
Published: January 2020

Abstract
We describe the preparation of [2,4,16,16-2H4]estradiol-17 beta. The method for quantitative determination of subpicomole amounts of estradiol-17 beta (trimethylsilyl ether derivatives) by gas-liquid chromatography-mass spectrometry with multiple ion detector and with [2H4]estradiol-17 beta as the carrier is presented and characterized. Values for serum samples, as measured by radioimmunoassay and by mass fragmentography, agreed well.
Evaluation of an aqueous fluorometric continuous-flow method for measurement of total urinary estrogens.
Authors: Hammond J E , Phillips J C , Savory J 
Published: January 2020

Abstract
Measurement of urinary estrogen excretion is used extensively to monitor fetal welfare in utero, allowing the fetus at risk to be identified. We evaluated a direct all-aqueous fluorometric method adapted to a continous-flow (AutoAnalyzer I) system, using a spectrofluorophotometer for detection. In this method, which is based on a modified Kober reaction, NaBH4 is used to eliminate the known negative interference of glucose. The mean analytical recovery was 98%. Urines from 15 men showed no blank fluorescence. Comparison studies of the fluorometric method (x) and a manual method based on the Kober/Ittrich reaction (y) yielded the equation y = 1.53x + 4.38 (r = 0.9235). The incomplete correlation can be explained by erratic extraction in the manual Kober/Ittrich procedure (mean recoveries were 57%). A day-to-day precision (CV) of 5.2% can be achieved with the automated method. Samples are analyzed at a rate of 20 per hour, but this rate can be doubled, if necessary, without significant carryover problems. We conclude that the automated fluorometric method is accurate, precise, and inexpensive and therefore the method of choice for measuring urinary estrogens.
Albumin activation of urinary amylase as determined with the Du Pont aca.
Authors: Garber C C , Carey R N 
Published: January 2020

Abstract
Protein activation of urinary alpha-amylase (EC 3.2.1.1) activity was observed during an evaluation of the Du Pont aca procedure for the determination of urinary alpha-amylase. This activation effect became constant for urinary albumin concentrations exceeding 1.50 g/liter. It is recommended that urinary alpha-amylase be analyzed with sufficient albumin added to maximize this effect. The aca alpha-amylase procedure is compared to an amyloclastic method for both serum and urine analysis. Expected ranges are presented for the aca method for serum and urinary amylase, amylase clearance, and the amylase clearance/creatinine clearance ratio.
Screening for urinary oligosaccharides: application to a mentally handicapped population and to patients with some other diseases.
Authors: Purkiss P , Hughes R C , Watts R W 
Published: January 2020

Abstract
The method for screening urinary oligosaccharides described in the accompanying paper [Clin. Chem. 24, 669 (1978)] has been applied to a large group of mentally handicapped patients as well as to patients with cystic fibrosis, malignant disease, and schizophrenia. The cause of the mental handicap was unknown in most cases. The primary object of the study was to investigate a possible link between some diseases and urinary complex carbohydrates. Our results show that abnormalities that are detectable in this way do not contribute significantly to the overall incidence of mental handicap, nor are they expressed in the other diseases studied.
Bis(2-ethylhexyl)phthalate concentrations in the serum of hemodialysis patients.
Authors: Lewis L M , Flechtner T W , Kerkay J , Pearson K H , Nakamoto S 
Published: January 2020

Abstract
Bis(2-ethylhexyl) phthalate is extracted from artificial kidneys, both in vivo and in vitro. Perfusion of whole blood through arterial-,venous tubing (that supplied with the dialyzer) for 1 h in vitro yielded 3.23 mg of the compound, while similar perfusion of the tubing plus the artificial kidney yielded 6.10 mg. Its mean concentration after dialysis in patients undergoing hemodialysis was 751 microgram/liter of serum. Patients who had undergone more than 50 hemodialysis treatments showed significantly higher postdialysis concentrations than patients who had undergone fewer. Uptake of bis(2-ethylhexyl) phthalate by the blood during a dialysis session followed two patterns. One set of patients showed a maximum concentration at 3 h, the second set showed a steady increase until the end of dialysis. Bis(2-ethylhexyl) phthalate appeared to be rapidly cleared from blood, most being removed within 5 to 7 h of completion of dialysis.
Urinary polyamine excretion during the menstrual cycle.
Authors: Osterberg S , Rosén S , Heby O 
Published: January 2020

Abstract
Urinary polyamines were measured by a fluorometric thin-layer chromatographic technique in samples collected daily throughout a single menstrual cycle by each of 13 healthy women. Polyamine excretion fluctuated considerably, but excretion of putrescine, spermidine, and spermine combined was consistently greatest during menstruation, sometimes extending into the early follicular phase of the cycle. Enhanced excretion of polyamines was also noticed in many individuals at the approximate time of ovulation.
A stable blood product for pH-blood-gas quality control.
Authors: Steiner M C , Shapiro B A , Kavanaugh J , Walton J R , Johnson W 
Published: January 2020

Abstract
We describe how to prepare, store, and use a hemolyzed blood product for simultaneous pH, pCO2, and pO2 quality control. Tonometry of the blood product with two oxygen and two carbon dioxide concentrations resulted in consistent and reproducible values during 38 weeks. The resulting pH values were consistent and reproducible, demonstrating the metabolic acid-base stability of the blood product. We conclude that the proper preparation, storage, and use of the product results in consistent, reproducible, and economical quality control for pH, pCO2 and pO2 blood measurements.
Improved iodination of peptides for radioimmunoassay and membrane radioreceptor assay.
Authors: Heber D , Odell W D , Schedewie H , Wolfsen A R 
Published: January 2020

Abstract
Generally applicable methods for iodinating and purifying small peptide radiolabels for radioimmunoassay and membrane radioreceptor are described in detail. Resulting improvements in radioreceptor assay and radioimmunoassay, as well as results of analyses of specific activity, separation from unlabeled peptide, and storage characteristics, are presented for luliberin, corticotropin, melanotropin, and calcitonin.
Evaluation of the JET technique for extracting drugs from urine.
Authors: Lantz R K , Eisenberg R B 
Published: January 2020

Abstract
A rapid extraction method preliminary to analysis for drugs in urine is described. Extraction columns containing purified cotton fiber (JETUBE, Manhattan Instrument Co., Santa Monica, Calif.) are shown to give high (approximately 90-97%) extraction efficiencies for some commonly prescribed or abused drugs, notably phenobarbital, amphetamine, morphine, and methadone. Analysis time, extraction efficiency, convenience, and eluate purity with a modified JET procedure are shown to be superior to results obtained with XAD-2 resin columns.
Multi-laboratory comparison of three heparin-Mn2+ precipitation procedures for estimating cholesterol in high-density lipoprotein.
Authors: Albers J J , Warnick G R , Wiebe D , King P , Steiner P , Smith L , Breckenridge C , Chow A , Kuba K , Weidman S , Arnett H , Wood P , Shlagenhaft A 
Published: January 2020

Abstract
Plasma high-density lipoprotein is commonly estimated by measuring the cholesterol remaining in plasma supernatant solutions after other lipoproteins, which contain apolipoprotein B, are precipitated with heparin and Mn2+. The method (method I) now in use by the Lipid Research Clinics, in which Mn2+ is at 46 mmol/liter final concentration, is reasonably accurate, but precipitation and sedimentation of lipoproteins other than high-density lipoproteins is often incomplete. We evaluated two modifications of method I. In method II, the Mn2+ concentration was doubled; the second modification (method III) included the increased Mn2+ concentration in a combined heparin Mn2+ reagent, decreased sample volume (2 ml), and a shorter incubation time (10 min at room temperature). The percentages of samples with turbid supernates (i.e., incomplete sedimentation) by methods I, II, and III were 9, 3, and 2%, respectively. Among non-turbid supernates, the percentages of samples containing measurable apolipoprotein B (incomplete precipitation) were 79, 19, and 16%, respectively. We conclude that method III is the most convenient and accurate of the three procedures.
Interlaboratory comparisons of nickel analyses in urine by atomic absorption spectrometry.
Authors: Adams D B , Brown S S , Sunderman F W , Zachariasen H 
Published: January 2020

Abstract
Two interlaboratory surveys of urine nickel analyses were performed in which eight or nine urine samples were distributed to laboratories in seven nations for measurements of nickel concentrations by atomic absorption spectrometry. In both surveys, wide discrepancies were observed in the values for urine nickel concentrations that were obtained in different laboratories by various analytical methods. This finding documents a serious need for improvement in the proficiency of nickel analyses. Nonetheless, excellent interlaboratory concordance was found in the rankings of urine samples in order of increasing nickel concentrations. Analytical techniques that involved preliminary wet or dry ashing and extration steps before flameless atomic absorption spectrometry were generally superior to techniques for direct analysis of urine by flameless atomic absorption spectrometry in respect to (a) analytical sensitivity, (b) recovery of added nickel, (c) interlaboratory precision, and (d) interlaboratory concordance of ranking of urine samples in order of increasing nickel concentrations.
Analysis for carbamazepine in serum by electron-capture gas chromatography.
Authors: Schwertner H A , Hamilton H E , Wallace J E 
Published: January 2020

Abstract
We describe an analytical method for determining carbamazepine in serum by electron-capture gas chromatography. A single-step extraction is followed by formation of the N-pentafluorobenzamide derivative with pentafluorobenzoyl chloride. For quantitation either of two internal standards may be used: 10-methoxy carbamazepine or 7-chloro-5,11-dihydrodibenz[b,e] [1,4]-oxazepine-5-carboxamide (Squibb Compound No. 10996). The procedure requires 0.5 ml of serum. Analytical recoveries are 96%. Coefficients of variation routinely are less than 2% for concentrations of carbamazepine that are within the therapeutic range.