bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved radiochemical assay for carnitine and its derivatives in plasma and tissue extracts.
Authors: Pace J A , Wannemacher R W , Neufeld H A 
Published: January 2020

Abstract
We describe the measurement of carnitine and short-chain and long-chain acylcarnitines in perchloric acid extracts of liver and muscle. [1-14C]Acetyl-CoA is used, and labeled acetylcarnitine is measured with a sensitivity of less than 1 to 50 nmol of L-carnitine per 50-microliter sample. Samples frozen at -20 degrees C lost no carnitine during several months. Analytical recovery of carnitine (5 nmol) added to 50-microliter perchloric acid extracts of liver was 103 +/- 2%. This method may be suitable for clinical applications such as screening patients with muscle and metabolic disorders.
Sensitive gas-chromatographic determination of fluphenazine in human plasma.
Authors: Franklin M , Wiles D H , Harvey D J 
Published: January 2020

Abstract
We describe a method for quantitative determination of fluphenazine in human plasma, based on gas chromatography of its trimethylsilyl derivative and the use of a structurally similar internal standard. We determined its concentrations in plasma of four patients who were receiving the drug intramuscularly as its decanoate, in doses ranging from 12.5 to 250 mg; the concentrations in the plasma of these patients ranged from 0.25 to 11.8 microgram/liter. The precision (CV) of the method over the range 2 to 17 microgram/liter was 6.8% when fluphenazine was extracted from 5 ml of plasma. Of 18 other drugs tested, only thioridazine and the cis and trans forms of flupenthixol interfere with the determination.
Automated metabolic profiling of organic acids in human urine. II. Analysis of urine samples from "healthy" adults, sick children, and children with neuroblastoma.
Authors: Gates S C , Sweeley C C , Krivit W , DeWitt D , Blaisdell B E 
Published: January 2020

Abstract
Normalized median, minimum, and maximum values (analytical concentration factors) are given for 134 organic acids in urine of nine adult control subjects, five juvenile control subjects, and five children with neuroblastoma. The organic acids, separated by anion-exchange chromatography, were analyzed by a gas chromatograph-mass spectrometer-computer system. Sixty substances in this fraction are positively identified, and, of these, mean absolute concentrations are listed for 20. An additional 81 substances, sought but not found by this method, and 16 other substances found in a subset of these urines by another analytical method, are also listed. Measured retention indices on 5% OV-17 and a selected discriminating ion are given for each of the total of 231 compounds. Results are compared for the three groups of subjects, and the value of normalizing the data is discussed.
Evaluation of a glassy-carbon electrode for amperometric detection of selected methylxanthines in serum after their separation by reversed-phase chromatography.
Authors: Lewis E C , Johnson D C 
Published: January 2020

Abstract
We examined the relative merits of direct-current, pulse, and differential pulse amperometry at a flow-through, glassy-carbon electrode used in monitoring column chromatography. We give a rapid, simple procedure for determining theophylline (1,3-dimethylxanthine) in 20--100 microliter of blood serum. Interference by 1,7-dimethylxanthine, a metabolite of caffeine, is compared for photometric and amperometric detection, and some advantages of combined photometric and amperometric detection are discussed.
Negative-ion mass spectrometry of amphetamine congeners.
Authors: Mårde Y , Ryhage R 
Published: January 2020

Abstract
Negative-ion chemical ionization mass spectrometry with a conventional combined gas chromatograph-mass spectrometer has been used for the analysis of amphetamine-like compounds. Ammonia was used as the reagent gas, which gives rise to few but specific sample-fragment ions, such as (M--1)- as the base peak, m/z 91, and a smaller peak corresponding to the end part of the side chain. Five reference compounds and a urine sample from an overdose case were analyzed. Comparative positive-ion chemical ionization reference spectra were also recorded.
Measurement of three aminoglycosiee antibiotics with a single radioimmunoassay system.
Authors: Ashby C D , Lewis J E , Nelson J C 
Published: January 2020

Abstract
A versatile radioimmunoassay procedure has been developed to specifically assay gentamicin, tobramycin, or amikacin. Iodinated derivatives of these three antibiotics were prepared by a modified Bolton and Hunter procedure. A single reagent system composed of a pool of three very specific antisera was used in the procedure. The antisera combination did not alter the specificity of the procedure. Validation of the assay of the three antibiotics included studies of parallelism, accuracy, precision, reproducibility, and method comparison with other radioimmunoassay procedures involving single antiserum systems. We discuss the application of this multiple assay capability to other procedures involving use of immunochemicals.
Neonatal thyroxine screening by use of a single-tube solid-phase radioimmunoassay.
Authors: Bell A B , Coleman L H 
Published: January 2020

Abstract
Filter paper discs saturated with dried blood can be used in the Immunotube solid-phase thyroxine radioimmunoassay. This assay utilizes polypropylene tubes to which antibody to thyroxine is covalently bound. The filter paper standards and samples are placed in the tubes, followed by an assay buffer that contains I125-labeled thyroxine and compounds to displace thyroxine from its binding proteins. After incubation, bound and free thyroxine are separated by aspirating or decanting the disc and buffer from the tube. The test can be used with 0.32 cm (1/8 inch) or 0.64 cm(1/4 inch) discs, and gives quantitative results that correlate well with those for serum samples. The intra-assay coefficient of variation is less than 10%. The assay may readily be mechanized with existing disc-punching equipment, and results of its use in mass screening programs are described.
Is serum cholinesterase activity a predictor of succinyl choline sensitivity? An assessment of four methods.
Authors: Evans R T , Wroe J 
Published: January 2020

Abstract
Four methods for measuring serum cholinesterase activity have been applied to sera of normal individuals and of patients shown to be sensitive to short-acting muscle relaxants of the succinyldicholine type. They have been assessed according to their ability to differentiate between sensitive and insensitive individuals on the basis of enzyme activity measurements alone. The method described, based upon that of Dietz et al. [Clin. Chem. 19, 1309 (1973)], in which propionylthiocholine is used as substrate, is best for this purpose, being capable of identifying over 90% of affected individuals with no false positives. Acetylcholine and butyrylthiocholine are slightly inferior substrates in this respect, and benzoylcholine gives little useful information.
Non-equilibrium enzyme immunoassay of gentamicin.
Authors: Mattiasson B , Svensson K , Borrebaeck C , Jonsson S , Kronvall G 
Published: January 2020

Abstract
We describe a fast, accurate non-equilibrium enzyme immunoassay for serum gentamicin. With use of isokinetic conditions an assay takes a total of 12 min, including regeneration of the immunosorbent. The coefficient of correlation between the present method and conventional microbiological assays was 0.98.
Interlaboratory Comparison of Lead and Cadmium in Blood, Urine, and Aqueous Solutions
Authors: Paulev Poul-Erik , Solgaard Poul , Tjell Jens Christian 
Published: January 2020

Abstract
Analysis for lead and cadmium in biological liquids (blood and urine) is difficult. Results of such analyses from five laboratories are compared for samples with known additions of lead and cadmium. The data, evaluated in terms of inter- and intralaboratory reproducibility and accuracy, suggest that laboratories should voluntarily participate in quality control programs. Users of routine laboratories are advised to use their own quality control program.
Simultaneous gas-chromatographic analysis for diazepam and its major metabolite, desmethyldiazepam, with use of double internal standardization.
Authors: Greenblatt D J 
Published: January 2020

Abstract
Electron-capture gas-liquid chromatography was used for simultaneous quantitation of plasma diazepam (I) and its major metabolite, desmethyldiazepam(II). Because concentrations of I can greatly exceed those of II after single doses of I, two benzodiazepine-analog internal standards were added to all samples, thereby allowing reliable quantitation of high concentrations of I and low concentrations of II. After extraction at neutral pH with benzene (containing isoamyl alcohol), the organic extract is evaporated and the residue is reconstituted in a small volume of solvent and chromatographed on a 3% OV-17 column. The sensitivity limits are 2 to 3 ng of I or II per milliliter of original sample, with a CV for identical samples of less than 5%. The applicability of the method to single-dose pharmacokinetic studies of I in humans is illustrated.
Interlaboratory comparison of lead and cadmium in blood, urine, and aqueous solutions.
Authors: Paulev P E , Solgaard P , Tjell J C 
Published: January 2020

Abstract
Analysis for lead and cadmium in biological liquids (blood and urine) is difficult. Results of such analyses from five laboratories are compared for samples with known additions of lead and cadmium. The data, evaluated in terms of inter- and intralaboratory reproducibility and accuracy, suggest that laboratories should voluntarily participate in quality control programs. Users of routine laboratories are advised to use their own quality control program.
A one-tube micromethod for radioimmunoassay of plasma cortisol.
Authors: Ellis G , Morris R 
Published: January 2020

Abstract
A micro-scale method is presented for measurement of cortisol. Serum or plasma, 2 microliter, is diluted with buffer and the solution heated at 60 degrees C in the presence of high-affinity antibody and [3H] cortisol. Corticosteroid-binding globulin in the serum is denatured, releasing cortisol and making it available to the antibody, which is stable during the incubation. After cooling, ammonium sulfate solution is added, followed by a toluene-based scintillant that does not dissolve in the aqueous phase. The vial is shaken to extract the free cortisol into the scintillant. Antibody bound cortisol remains in the aqueous phase and does not produce any scintillation. The amount of [3H] cortisol that is free at the end of the incubation, and which therefore gives rise to the measured counts, is related to the concentration of cortisol in the original serum, and may be calculated from a standard curve. The assay is sensitive and precise. Ranges are presented for normal and pathologic subjects.
Modification of the choriogonadotropin beta-subunit radioimmunoassay for determination of urinary choriogonadotropin.
Authors: McCready J , Braunstein G D , Helm D , Wade M E 
Published: January 2020

Abstract
The choriogonadotropin beta-subunit radioimminoassay has been used extensively to measure human choriogonadotropin in the sera of pregnant women and individuals with trophoblastic and nontrophoblastic tumors. Unmodified, this method cannot be used to measure choriogonadotropin in urine because of interfering substances. We circumvented the non-parallelism between the standards and serial dilutions of urine containing choriogonadotropin by adding pooled urine from men to the standard tubes and limiting the volume of urine to 100 microliter. This modified assay has a sensitivity of 3 int. units/liter of urine and is specific for choriogonadotropin concentrations of 40 int. units/liter of urine. Analytical recovery of choriogonadotropin added to urine ranged from 96 to 105%. The within-assay CV was 7.6%; the between-assay CV was 11.8%. Concentrations of choriogonadotropin in concurrently collected serum and urine samples from pregnant women correlated well. The test can be performed within 24 h by using the double-antibody method for separating bound from free hormone, or in 3 h with a dioxane method. The assay is about 20-fold more sensitive than the 2-min or 2-h slide and tube pregnancy tests, and seven-to 12-fold more sensitive than the radioreceptor assay.
Trace elements in scalp-hair of persons with multiple sclerosis and of normal individuals.
Authors: Ryan D E , Holzbecher J , Stuart D C 
Published: January 2020

Abstract
Scalp-hair samples from 40 multiple sclerosis patients and 42 controls were analyzed by neutron activation analysis, with a SLOWPOKE reactor as the neutron source. Ag, Al, As, Au, Ba, Br, Ca, Cl, Cu, l, K, Mg, Mn, Na, S, Sb, Se, Sr, V, and Zn were determined in samples of about 0.1 g. Highly significant differences (99% confidence) were observed between the two groups in concentrations of Cu, l, Mn, S, Se, and V.
Mechanized micro-scale determination of protein in platelet pellet sonicates.
Authors: Haff A C 
Published: January 2020

Abstract
With the method described here, samples can be assayed at the rate of 40/h, with increased reproducibility. As described, the method covers an analytical range of 1 to 7 g/liter, but it can be readily adapted to measure different ranges of concentration in other protein preparations.
Immobilized-enzyme membrane sandwich reactor used in automated micro-scale assay of plasma uric acid.
Authors: Kamoun P , Douay O 
Published: January 2020

Abstract
We describe the automated microassay of plasma uric acid by use of an immobilized uricase-membrane sandwich reactor. Hydrogen peroxide, formed when uric acid is oxidized, oxidatively couples two molecules of p-hydroxyphenylacetic acid in the presence of peroxidase to produce a highly fluorescent compound. The specificity of the uricase reaction is coupled with a significantly lower cost of analysis.
Effect of diluent temperature on creatine kinase values found for lyophilized controls and reference sera.
Authors: Feld R D , Brown L F , Neri B P , Witte D L 
Published: January 2020

Abstract
We report the effect of temperature of diluent on creatine kinase activity in several lyophilized controls. Creatine kinase activity was significantly greater when the lyophilized control was reconstituted with diluent at 4 degrees C as compared to 25 degrees C. This is an additional source of variation in creatine kinase controls.
Should blood samples for assay of plasma renin activity be chilled?
Authors: Emanuel R L , Williams G H 
Published: January 2020

Abstract
Collecting blood on ice for renin determination reportedly may produce falsely high results. To assess the probability of this occurring under actual collection conditions, we measured renin activity in duplicate aliquots of plasma from blood samples from 25 hypertensive patients, both supine and upright, and in 10 supine normotensive controls. One aliquot of the blood was collected on ice and processed at 4 degrees C, the other at room temperature. The two aliquots showed no significant differences in renin activity. If anything, values for samples collected at room temperature were higher. Repeat determination on the same specimens stored at--20 degrees C for nine and 12 months revealed no significant changes in results for any samples, although the amount of angiotensin I found in the sample before incubation at 37 degrees C significantly increased. We conclude that it makes little difference at what temperature one collects blood for renin determination, but because of the wide fluctuations in "room" temperature we recommend that blood samples be collected on ice.
Creatine kinase isoenzyme of high relative molecular mass in serum of a cancer patient.
Authors: Yuu H , Takagi Y , Senju O , Hosoya J , Gomi K , Ishii T 
Published: January 2020

Abstract
We describe an atypical serum creatine kinase isoenzyme in the serum of a woman with cancer of the left breast. This isoenzyme migrated toward the cathode, closely following the MM isoenzyme on agarose gel electrophoresis. Its relative molecular mass was estimated to be about 325,000, fourfold that of normal creatine kinase. It is more heat-stable and is inhibited more by urea than the normal MM isoenzyme. Isoenzyme monomer B activity was observed to be 20 U/liter in the serum, as measured with use of an antibody against the M monomer. On anion-exchange column analysis, creatine kinase activity was observed only in the MM fraction, in spite of the fact that B activity was observed in the patient's serum. Results of the immunological investigation make it unlikely that the atypical isoenzyme is linked to immunoglobulin or beta-lipoprotein. It may have been present as the result of modification of normal creatine kinase by the therapeutic radiation the patient was receiving.
Effect of membrane potential on dialysis of calcium in a continuous-flow system.
Authors: Staley M J , Farrance I 
Published: January 2020

Abstract
Electical potentials across the membrane in a modified AutoAnalyzer dialyzer (Technicon) have been determined under various conditions and related to the dialysis of 45Ca. The results suggest that anomalies in the diffusion of calcium from protein and nonprotein containing streams could be due to factors other than "Donnan equilibrium effects."
Assay of an antitumor protein, neocarzinostatin, and its antibody by fluorescence polarization.
Authors: Maeda H 
Published: January 2020

Abstract
I evaluated use of the fluorescence polarization technique to measure neocarzinostatin, a proteinaceous antitumor antibiotic, and its antibody, in serum. The antigen (neocarzinostatin), labeled with fluorescein isothiocyanate, was allowed to interact with its antibody in a cuvet, in the instrument, yielding an increase in the fluorescence polarization value. Antibody content was determined in the presence of a definite amount of the labeled antigen, fluorescence polarization values increasing in parallel with each addition of antibody. Antigen content was determined with a known amount of antibody, which reacted at first with an unknown amount of antigen in samples, followed by addition of a definite amount of the labeled antigen (competition). I used the method to determine a pharmacokinetic parameter, the apparent volume of distribution for neocarzinostatin in rabbits, using drug-injected rabbit sera. I evaluated precision, accuracy, and reproducibility, using various samples or possible interfering substances such as bilirubin and hemoglobin, and also compared results for antigen with those by single radial immunodiffusion assay. The present assay is fast (less than 2 min), sensitive (less than 10 nmol/liter can be detected), and simple (there is no separation step before readout of the results).
Analytical precautions in measurement of blood cyanide.
Authors: Rodkey F L , Robertson R F 
Published: January 2020

Abstract
Solutions of KCN in 0.1 mol/liter NaOH, stored for six months at 4 degrees C, were unchanged as determined by silver titration and color development with pyridine-pyrazalone reagent. At room temperature the cyanide concentration of such solutions decreased by 0.079% per day (half life = 880 days) and the extent of color development changed in direct proportion to the change in silver titer. Rubber stoppers adsorb (or dissolve) HCN when in contact with this gas. The cyanide tends to come out of the stopper long after the source of the gas is removed. Rubber stoppers and expired air contaminated by HCN must be carefully avoided during cyanide analysis. Expired air contains HCN, generally in larger amounts for persons who smoke.
Microchromatographic methods for hemoglobin A2 quantitation compared.
Authors: Brosious E M , Wright J M , Baine R M , Schmidt R M 
Published: January 2020

Abstract
On 20 consecutive work days during four weeks, one technologist performed 24 microchromatographic determinations of hemoglobin A2 (Hb A2) by each of four methods: the Efremov procedure requiring Tris/HCl buffer, the original Huisman technique with use of glycine developer, and two commercial test kits in which a modified glycine developer is used. The bloood samples tested were obtained from 12 adults with no hematological abnormality and from 12 beta-thalassemia carriers previously diagnosed by familial and hematologic studies. Results by the first method and the two commercial kits (one from Helena Laboratories and one from Isolab, Inc.) did not differ significantly in precision for either the normal or beta-thalassemia trait samples. For both sample types, the second method yielded larger coefficients of variation than those obtained with the other methods. Moreover, the second method was the only one with which values overlapped for normal samples and samples with above-normal Hb A2 concentrations.
Use of a programmable calculator in processing and interpreting serum cholinesterase phenotypes.
Authors: Brown P , McQueen M J , Patterson M C 
Published: January 2020

Abstract
Cholinesterase phenotyping is done at 25 degrees C with use of benzoylcholine as substrate and dibucaine, fluoride, chloride, and succinyldicholine as inhibitors. We wrote a diagnostic program in modified BASIC language for the processing and interpretation of these cholinesterase phenotypes. We used the HP 9830A calculator. The diagnostic aspect of the program uses 646 words, a further 86 words being used to run this program. The traditional and the programmed reporting procedures were duplicated for 296 consecutive patients, with no case of disagreement between the two reporting methods as to the appropriate phenotype. The programmed system requested nine repeat analyses more than did the traditional method. Seven of these were due to the tight limits set in the program for the fluoride inhibitor numbers. These tight limits were set to ensure that there was as limited an overlap as possible between the phenotypes E1uE1u and E1uE1f. The remaining two repeats were due to the restrictions placed on the succinyldicholine inhibitor numbers that would be acceptable before a patient was designated as having the relatively rare phenotype, E1aE1f.
Immobilized-enzyme nylon-tube reactors for routine determination of urea and citrulline in serum.
Authors: Sundaram P V , Igloi M P , Wassermann R , Hinsch W , Knoke K J 
Published: January 2020

Abstract
A continuous-flow clinical analyzer for the routine estimation of urea is described that makes use of an immobilized-enzyme nylon-tube reactor as part of a flow-through system (a Technicon AutoAnalyzer I). Results of blood-urea analyses by use of the immobilized urease are compared with determinations made with the diacetyl monoxime method and the urease solution method. Clinical trials carried out routinely with the immobilized enzyme nylon tube reactor give reliable and reproducible results with high precision and low cost. The reactors are stable to intermittent or continued use for at least four months or for 2000 tests. A method is described in which differential colorimetry is used for determining citrulline in blood and which makes use of the immobilized urease, albeit indirectly.