bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intra-individual variation in commonly analyzed serum constituents.
Authors: Morrison B , Shenkin A , McLelland A , Robertson D A , Barrowman M , Graham S , Wuga G , Cunningham K J 
Published: January 2020

Abstract
Concentrations of 27 commonly estimated serum constituents were measured in blood sampled from 20 apparently healthy volunteers at 0830, 1230, and 1630 hours on each of four days, at weekly intervals. Time-dependent statistically significant (p less than or equal to 0.01) variation was observed in 12 of the constituents. The 15 constituents that showed no statistically significant diurnal variation included the immunoglobulins, other specific proteins, enzymes, cholesterol, calcium, copper, and magnesium. On the different days of the study consistent temporal patterns were observed in urea, creatinine, phosphate, zinc, bilirubin, triglyceride, total protein, and albumin. The magnitude of variation was particularly great in potassium, iron, zinc, and bilirubin. In general, day-to-day changes in concentration exceeded within-day changes, except for potassium, phosphate, and zinc, for which greater changes could be observed within-day than from one day to another at the same time.
Adsorption of organic acids from amniotic fluid and urine onto silica gel before analysis by gas chromatography and combined gas chromatography/mass spectrometry.
Authors: Williams V P , Ching D K , Cederbaum S D 
Published: January 2020

Abstract
We describe a method for adsorbing organic acids from amniotic fluid and urine specimens onto a column of silica gel before analysis by gas chromatography and by combined gas chromatography/mass spectrometry. Analytical recoveries of individual organic acids by our adsorption method compare favorably with those obtained by a more laborious manual extraction with ethyl acetate. Results for specimens of amniotic fluid and urine show that our method gives better recoveries of most of the organic acids. Furthermore, because citric acid is also extracted in our method without extracting significant amounts of sulfate or phosphate, the method is a suitable alternative to methods involving the use of DEAE-Sephadex for concentrating these acids.
Washington University Case Conference. Multiple myeloma and hypercalcemia?
Authors: Ladenson J H , McDonald J M , Aguanno J , Goren M 
Published: January 2020

Abstract
We present a case of multiple myeloma with high values for total calcium. The case discussion focuses on the role of the laboratory in diagnosis and monitoring of multiple myeloma and on the causes of the associated hypercalcemia. We present evidence for calcium binding to the paraprotein as a cause for the "hypercalcemia" in this case and we document a difference in the results for total calcium among various methods when this patient's serum was analyzed.
Modification of the DuPont aca as exemplified by a new procedure for neonatal total bilirubin.
Authors: Fraser A D , Lindsay A L 
Published: January 2020

Abstract
Hemoglobin interferes with determination of total bilirubin by the diazo procedure with the DuPont aca. We compared results by that procedure with those by a manual direct spectrophotometric two-wavelength method. Because the manual method was not inhibited by hemolysis as was the DuPont aca diazo procedure, we reprogrammed our DuPont aca to measure the absorbance of diluted serum samples at 452 and 577 nm with use of DuPont absorbance packs as the sample pack and cuvette. Results correlated well with those by the manual spectrophotometric method, and hemolysis no longer interfered. The method is primarily intended for use with serum from neonates.
Competitive enzyme-linked immunoassay for Factor VIII antigen.
Authors: Yorde L D , Hussey C V , Yorde D E , Sasse E A 
Published: January 2020

Abstract
We describe a competitive enzyme-linked immunoassay for Factor VIII antigen. Binding of anti-factor VIII to solid-phase Factor VIII antigen is competitively inhibited by the free factor VIII antigen that is to be measured. The amount of anti-Factor VIII bound to solid-phase VIII is measured by applying in sequence a heterologous bridging antibody and a soluble antibody/enzyme immune complex. The soluble complex used was rabbit antiperoxidase/horseradish peroxidase. Peroxidase activity is inversely proportional to the Factor VIII antigen concentration in the original test plasma and is measured spectrophotometrically. The assay can be performed in as little as 4 h with only a microtiter plate, antisera, antigen, and a spectrophotometer. It is sensitive to 0.05 units of Factor VIII antigen per milliliter, and reproducibility, linearity, and normal range are similar to those reported for other techniques.
Gas-chromatographic estimation of urinary oxalate and its comparison with a colorimetric method.
Authors: Farrington C J , Chalmers A H 
Published: January 2020

Abstract
We describe a simple, specific gas-chromatographic method for urinary oxalate. Its specificity was evaluated by precipitating the oxalate as its calcium salt from urine, followed by methylation of the oxalate with boron trifluoride/methanol and subsequent gas-chromatographic separation and quantitation of the dimethyl oxalate. [U-14C]Oxalate and n-decanoic acid are used as internal standards. Analytical recoveries ranged from 93.8 to 97.7% for oxalate-supplemented urine. Twenty replicate analyses of urines containing typical concentrations of oxalate gave CVs of 10.0, 9.1, and 8.3% for low, medium, and high concentrations, respectively. Day-to-day precision (CV) for single analyses repeated on 20 days was 8.6% for the low urinary oxalate concentration. The lower limit of detection of urinary oxalate is 25 mumol/L. Results by our method correlated well (r = 0.95) with those by a colorimetric method (Clin. Chim. Acta 36: 127, 1972) but averaged 68.4% of those obtained colorimetrically (n = 75 samples, p less than 0.001). The expected range for our method is calculated to be 80 to 500 mumol of oxalate per 24-h urine (mean +/- 1 SD: 280 +/- 100).
Novel 125I-labeled nortriptyline derivatives and their use in liquid-phase or magnetizable solid-phase second-antibody radioimmunoassays.
Authors: Kamel R S , Landon J , Smith D S 
Published: January 2020

Abstract
Nortriptyline derivatives prepared by reaction with fluorescein isothiocyanate or conjugation to N-acetyl-L-histidine were radioiodinated and the products purified with Sephadex LH-20 columns to obtain two novel nortriptyline radioligands. Antisera were raised in rabbits by immunization with nortriptyline conjugated to succinylated ovine albumin. By use of the iodinated fluorescein derivative we developed a liquid-phase second-antibody radioimmunoassay that gives results correlating closely (r = 0.98) with those by an established radioimmunoassay of similar specificity in the assay of apparent total amitriptyline and its metabolite nortriptyline in serum or plasma from patients being treated with these drugs. With the iodinated N-acetyl-L-histidine derivative we developed a magnetizable solid-phase second-antibody radioimmunoassay. The cross reactivities of amitriptyline and nortriptyline could be made equal by performing the assay at pH 9.0, which makes it possible to measure true total active drug concentrations in patients receiving amitriptyline.
A statistical method for determining normal ranges from laboratory data including values below the minimum detectable value.
Authors: Tsay J Y , Chen I W , Maxon H R , Heminger L 
Published: January 2020

Abstract
Determination of normal ranges from laboratory data containing undectable values is a frequently encountered problem in the radioimmunoassay of peptide hormones. In the past, such determinations usually have been based on the mid-point method or the one-end Winsorized method. A graphic method involving the use of probability paper has also been reported. We propose that the maximum-likelihood estimation is a more appropriate statistical method for the determination of normal range from this type of data (Type I censored data). With this method, the mean and standard deviation, and hence the tolerance limits, can be estimated. We used the maximum-likelihood estimation method to determine the normal range of serum thyrotropin values obtained from 93 healthy subjects, based on a log normal distribution. Although the serum thyrotropin content was undetectable in 14% of the subjects, a normal range could be calculated. Using tolerance limits for 95% coverage of the population with 90% confidence, we calculated the normal range of thyrotropin to be 0.51-5.75 milliunits/L, with a mean value of 1.71 milliunits/L, and predicted that 91.4% of undetectable serum thyrotropin values will fall within the normal range.
Gas-liquid chromatography of undervatized drugs after chromatographic extraction from blood.
Authors: Werner M , Mohrbacher R J , Riendeau C J 
Published: January 2020

Abstract
We have developed an integrated method that overcomes the two main procedural difficulties of gas-liquid chromatography, namely, solvent-solvent extraction and chemical derivatization. Drugs are extracted from serum by column chromatography on granular diatomaceous earth (kieselguhr). Subsequent gas-liquid chromatography of underivatized samples can be performed on either of two liquid phases. A mixed liquid phase, used for quantitative gas-chromatographic assay on patients with a known therapeutic regimen, has enabled quantitation of 12 drugs in serum. Alternatively, a single liquid phase, used with the mixed liquid phase, permits the gas-chromatographic identification of unknown drugs on the basis of the characteristic pattern of the two relative retention times; by this approach more than 40 drugs have been identified in cases of suspected intoxication, both in serum and in gastric aspirate. Besides providing ease of performance and wide applicability, the proposed procedure offers a degree of precision and accuracy that compares favorably with established methods.
Nephelometry of apolipoprotein B in human serum.
Authors: Heuck C C , Schlierf G 
Published: January 2020

Abstract
We studied the development of light scattering in the reaction between anti-apolipoprotein B and apolipoprotein B in intact very-low-density lipoproteins (I) and low-density lipoproteins (II) as well as in lipoproteins treated with lipases, and found considerable differences in the kinetics of the immunoreaction for the two lipoprotein classes. Pre-incubation with triglyceride lipase and cholesterol esterase caused a decrease of final light scattering in I but only minimal changes in the reaction with II. Non-ionic detergent not only decreased the original light scattering in hyperlipemic serum samples, but also accelerated the immunoreaction. Under standardized conditions, results of quantitative nephelometry correlated highly significantly with quantitative determination of apolipoprotein B by radial immunodiffusion, both for normolipemic and hyperlipoproteinemic serum samples. The nonspecific light scattering caused by neutral lipids in intact lipoproteins could be minimized when samples were pre-incubated with lipolytic enzymes.
Rapid fluorometry of estrogens in nonpregnancy urine, with use of chloroform extraction and purification by anion-exchange chromatography.
Authors: Goutte-Coussieu C , Habrioux G , Eichenberger D , Jayle M F 
Published: January 2020

Abstract
We describe a new method of extraction and purification of estrogens in low concentration in urine, involving a rapid enzymic hydrolysis of a 10-mL sample, automatic extraction (in a tube) with CHCl3/ethyl acetate, purification by chromatography on a disposable "mini-column" of AG 1-X2, and fluorometry by continuous flow according to Itrich's procedure [Acta Endocrinol. (Copenhagen) 35, 34 (1960)]. Conditions of hydrolysis, extraction, and purification were studied. Within-day precision (CV) was 7.5%, the mean between-day precision 8.5%. The sensitivity was 6 microgram of total estrogens per liter of urine. The specificity was assessed particularly by comparison with the results obtained by Schöller et al. [Acta Endocrinol. (Copenhagen) 57, suppl. 107 (1966)] and by gas-chromatography-mass-spectrometry. The normal limits as calculated by this technique were identical to values reported by others. The technique is rapid; results are obtained in 3 h. It is quite suitable for routine determinations: 100 assays can be done by a team of three technicians in one working day.
Continuous-flow fluoroimmunoassay of serum gentamicin, with automatic sample blank correction.
Authors: Shaw E J , Watson R A , Smith D S 
Published: January 2020

Abstract
We describe the continuous-flow automation of a quenching fluoroimmunoassay for determination of the antibiotic gentamicin in serum. In the flow system, sample is mixed with fluorescein-labeled gentamicin, followed by antiserum, and after a short incubation the fluorescence is measured. The intrinsic blank signal of each sample is corrected for during its single passage through the system by pumping antiserum discontinuously, so as to divide the final stream into sections corresponding to conventional separate assay and blank mixtures. Analyses time for each sample is 6 min, and 20 samples can be run per hour. Sensitivity, precision, and accuracy are adequate for clinical purposes, and assays of patients' samples correlate satisfactorily with the results of manual quenching and polarization fluoroimmunoassays, and plate diffusion bioassay.
An enzymic and centrifugal method for estimating high-density lipoprotein cholesterol.
Authors: Allen J K , Hensley W J , Nicholls A V , Whitfield J B 
Published: January 2020

Abstract
Enzymic measurement of high-density lipoprotein cholesterol with a centrifugal analyzer is described. We used polyethylene glycol (Mr 6000), final concentration 100 g/L, to precipitate low-density and very-low-density lipoproteins, thereby eliminating the difficulties of the commonly used heparin/Mn2+ precipitation method and facilitating the use of ethylenediaminetetraacetate-stabilized plasma. As measured by rocket immunoelectrophoresis, this final concentration of polyethylene glycol completely precipitates beta-lipoproteins, leaving the alpha-lipoproteins in solution. Between-run reproducibility (CV) was 3.6%, within-run reproducibility (CV) 0.8%. Reagent costs currently are $US 0.13 per test and large numbers of samples can be handled conveniently. Normal ranges were compiled for 539 men and 444 women. The high-density lipoprotein cholesterol for men was 1.20 +/- 0.31 (SD) mmol/L and for women 1.52 +/- 0.38 (SD) mmol/L.
Measurement of alpha-, beta-, and gamma tocopherol in serum by liquid chromatography.
Authors: De Leenheer A P , De Bevere V O , Claeys A E 
Published: January 2020

Abstract
A liquid-chromatographic assay for alpha, beta, and gamma-isomeric tocopherols in human serum is reported. The tocopherols and the internal standard (tocol) are absorbed into a silica gel column and are eluted in less than 10 min with n-hexane/isopropanol (99.4/0.6, by vol) at a flow rate of 1 mL/min. The complete analysis requires no longer than 30 min. Within-day precision (CV) was 1.4% (mean = 13.18 mg/L, n = 24), 7.4% (mean = 0.214 mg/L, n = 14), and 1.3% (mean = 1.01 mg/L, n = 14) for alpha-, beta-, and gamma-tocopherol, respectively. Day-to-day precision (CV) was 4.4% (mean = 9.85 mg/L, n = 10) for alpha-tocopherol, 9.1% (mean = 0.222 mg/L, n = 20) for beta-tocopherol, and 3.8% (mean = 1.00 mg/L, n = 20) for gamma-tocopherol. Extraction recoveries for alpha-, beta-, and gamma-tocopherol averaged 92.4 +/- 2.9% (n = 5), 91.4 4/- 7.6% (n = 5), an 92.0 +/- 4.1% (n = 4), respectively. The smallest injected amount detectable is estimated to be 0.03 micrograms for alpha-, and 0.04 micrograms for beta- and gamma-tocopherol.
Effects of wavelength error and spectral band width on measurement of alkaline phosphatase activity.
Authors: Schifreen R S , Burnett R W 
Published: January 2020

Abstract
We re-examined the effects of wavelength error and spectral band width on the measurement of alkaline phosphatase activity. The methods we studied is relatively insensitive to these two factors, a conclusion we base on both experimental results and theoretical analysis. These findings are in conflict with a recently published report [Lott et al., Clin. Chem. 24, 938 (1978)], and we suggest a possible explanation for this.
Incorporation of a SMAC analyzer into the data-processing procedures of a computer-assisted laboratory.
Authors: Undrill P E , Stroud R E , Paterson N 
Published: January 2020

Abstract
This paper describes the incorporation of a SMAC (Technicon) analyzer into data-processing techniques that have been developed on existing computer hardware during several years. The SMAC system is interfaced directly to a small computer, and suitable peripherals produce a manageable form of result tabulation for subsequent reporting, as well as provide quality-control information to the SMAC operators in real time. The design is such as to facilitate the performance analysis of the SMAC system during its initiation period and during normal service operation.
Radioimmunoassay of "pregnancy-specific"-beta 1-glycoprotein (SP1).
Authors: Kaminska J , Calvert I , Rosen S W 
Published: January 2020

Abstract
A radioimmunoassay for SP1 ("pregnancy-specific" beta 1-glycoprotein) is described in which a sensitivity of 0.1 microgram/L was achieved by use of an antiserum with Ka approximately equal to 1.7 x 10(11) L/mol and delayed addition of a 125I-SP1 tracer (specific acty, 25 Ci/g) that was stable for use in the assay for at least six to seven weeks. We also report an additional anti-SP1 serum, from an early bleeding, that displayed "apparent positive cooperativity" in the IgG but not the IgM fraction.
Comparison of current methods for high-density lipoprotein cholesterol quantitation.
Authors: Warnick G R , Cheung M C , Albers J J 
Published: January 2020

Abstract
We compared six precipitation methods for high-density-lipoprotein cholesterol quantitation with an ultracentrifugation method, the accuracy of which was improved by correcting for 4% manipulative loss in the d greater than 1.063 fractions. For purposes of comparison, the apoprotein B-associated cholesterol (average 56 mg/L) measured by immunoassay in the d greater than 1.063 fractions was subtracted. In 65 plasma samples from men, women, and children, a heparin-Mn2+ procedure with Mn2+ at 46 mmol/L produced results slightly higher (+16 mg/L), while results with Mn2+ at 92 mmol/L averaged slightly lower (-8 mg/L) than the comparison ultracentrifuge method. Results that were about 5% low were obtained by the dextran sulfate 500-Mg2+ (-25 mg/L) and phosphotungstate-Mg2+ (-31 mg/L) methods. A heparin-Ca2+ method produced results 10% high (+58 mg/L). Results by a polyethylene glycol-6000 precipitation method were 12% low (-64 mg/L). Precision was better with the two heparin-Mn2+ and the dextran sulfate 500-Mg2+ procedures, with CVs of 4%, intermediate with phosphotungstate-Mg2+ and polyethylene glycol-6000 (CV 6-7%), and poorest with heparin-Ca2+ (CV 10%). Precipitation by phosphotungate-Mg2+ appeared more sensitive to reagent concentration and temperature variations than either the heparin-Mn2+ or dextran sulfate 500-Mg2+ methods. We conclude that these precipitation methods are not equivalent, but give rise to significant systematic differences in high-density-lipoprotein cholesterol quantitation.
Enzyme immunoassay for serum lidocaine in antiarrhythmic therapy.
Authors: Lehane D P , Wissert P J , Menyharth P , Levy A L , Kukucka M A 
Published: January 2020

Abstract
We have adapted the commercially available EMIT kit [Clin. Chem. 23, 1161 (1977)] to the Gilford System 3500 Analyzer. Sample volume is 10 microliter. We compare reagent blank-corrected absorbance changes at 340 nm between 15 and 55 s for samples and a series of calibrators, and calculate results with use of a logarithmic transformation. Within-run precision (CV) for a serum pool with 4.0 mg of added lidocaine per liter was 2.7% (n = 45); day-to-day precision was 3.3% (n = 15). Analytical recoveries of 2 to 6 mg of lidocaine per liter were 90-102% (average, 97.3%). Results correlated significantly with those by a gas-chromatographic technique. No clinically significant interferences by concomitantly administered medications were observed. The procedure is rapid (42 samples per hour) and is well suited to the fast response required in monitoring lidocaine therapy. Usefulness of the assay data in the management of arrhythmias in the coronary care unit is discussed.
Preparation of cytosol for steroid receptor determinations with the Beckman "Airfuge".
Authors: Heidemann P H , Wittliff J L 
Published: January 2020

Abstract
Preparation of cytosols from several estrogen target organs was compared, with use of the Beckman Airfuge and a preparative ultracentrifuge. The specific estrogen-binding capacities of cytosols prepared with these instruments were indistinguishable. Similarly, the sedimentation profiles of estrogen-receptor species as determined by sucrose gradient centrifugation were identical. We conclude that the Airfuge provides a rapid, accurate, and inexpensive means of preparing cytosols for measurements of steroid receptors in the clinical laboratory.
Elemental composition of platelets. Part II. Water content of normal human platelets and measurements of their concentrations of Cu, Fe, K, and Zn by neutron activation analysis.
Authors: Kiem J , Borberg H , Iyengar G V , Kasperek K , Siegers M , Feinendegen L E , Gross R 
Published: January 2020

Abstract
We determined the elements Cu, Fe, K, and Zn in normal human platelets by neutron activation analysis. The platelets were obtained from seven donors and treated as described in Part I. The elemental composition is expressed on a wet-weight basis for plasma-free platelets. The following results were obtained (+/- values are 1 SD); "Pure" platelets: trapped plasma = 378 +/- 35 mg/g, water content = 715 +/- 15 mg/g, mean weight of the single platelet (by two different methods) = 9.9 +/- 1.1 pg and 11.2 +/- 1.7 pg, K = 4.39 +/- 1.06 mg/g, Zn = 49.23 +/- 10.97 microgram/g, Fe = 12.28 +/- 2.94 microgram/g, and Cu = 1.39 +/- 0.25 microgram/g. "Impure" platelets: trapped plasma = 349 +/- 31 mg/g, water content = 736 +/- 12 mg/g, K = 3.26 +/- 0.78 mg/g, Zn = 35.71 +/- 7.99 microgram/g, Fe = 17.11 +/- 5.10 microgram/g, and Cu = 1.39 +/- 0.21 microgram/g. To our knowledge, no data on Fe and Cu in platelets have hitherto been reported.
Improved liquid-chromatographic determination of propranolol in plasma, with fluorescence detection.
Authors: Jatlow P , Bush W , Hochster H 
Published: January 2020

Abstract
We describe an analysis for propranolol in plasma, with use of reversed-phase "high-pressure" liquid chromatography and fluorescence detection. Pronethalol is used as the internal standard. The procedure, which involves extraction into an organic solvent, evaporation, and clean-up by micro-scale back extraction from hexane into an aqueous phase, is specific and sensitive. The detection limit is less than 6 microgram/L (2.3 X 10(-8) mol/L). Within-day and between-day coefficients of variation are 1.8 and 4.4%, respectively. Commonly used drugs, including procainamide, N-acetylprocainamide, and quinidine, do not interfere.
A simple method for the intravenous fat-tolerance test.
Authors: Redheendran R , Edwards J A , Schnatz J D 
Published: January 2020

Abstract
A simple method for measuring intravenous fat tolerance with an artificial fat emulsion (intralipid) was studied and compared with the currently used method of Carlson and Rossner [J. Lab. Invest. 29, 271-280 (1972)]. The proposed method uses as little as 3 mL of whole blood to follow, by nephelometry, the elimination of intravenously administered fat emulsions. There is a high correlation between the K2 values obtained by the current method for plasma and those obtained by the proposed method (r = 0.903). The latter is simpler, quicker, and more acceptable to patients.