bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous radioassay of serum vitamin B12 and folic acid.
Authors: Gutcho S , Mansbach L 
Published: January 2020

Abstract
The radioassays of vitamin B12 and folic acid can be carried out in a single tube to give the simultaneous assay of both vitamins in 100 microliter of serum. Release of bound vitamins from their endogenous binders and the destruction of these binders are effected by a heating step at pH 9.3. The subsequent binding reactions with hog intrinsic factor and milk binder protein proceed advantageously and simultaneously in the same tube at pH 9.3. A single set of dual reagents replaces two sets of reagents that would normally be used for separate radioassays. Complete separation of bound radioactivities, [57Co]cyanocobalamin and 125I-labeled folate derivative, is obtained in a dual-channel gamma counter with no requirement for any correction for spill-over of counting data. Analytical results are comparable to those found for previously developed individual radioassays. The simultaneous assay has decreased technical time of analysis for these interrelated vitamins by about 50%.
Evaluation with the centrifugal fast analyzer of a chemical activation procedure for creatine kinase MB isoenzyme.
Authors: Bostick W D , Mrochek J E 
Published: January 2020

Abstract
The differential activation method for the determination of the "myocardial" isoenzyme of creatine kinase (MB) is based on the computed difference in activity of serum aliquots activated by the combination of dithiothreitol and glutathione (skeletal plus myocardial creatine kinase) and by glutathione alone (skeletal creatine kinase). The unique ability of the Centrifugal Fast Analyzer to perform analyses in parallel is used to precisely measure (CV = 0.1-1.5%) the activity of the two chemically activated aliquots. Statistical considerations concerning the reliability of this difference estimation are discussed with respect to both the precision of the rate measurements and to the relative amount of isoenzyme MB present. Another potential source of error in the analysis of the two differently activated aliquots, namely variation in lag phases, is circumvented by use of a linear-search FOCAL software package. This program searches the data for a linear segment of maximum slope, automatically rejecting those data that appear in lag or depletion regions of the curve representing the progress of the reaction. Correspondence of the results obtained with those of comparison techniques (chromatography and electrophoresis) are discussed.
Determination of morphine by electron capture gas-liquid chromatography.
Authors: Nicolau G , Van Lear G , Kaul B , Davidow B 
Published: January 2020

Abstract
We describe a micromethod for determining as little as 0.1 microgram of morphine per liter of human urine. The procedure is about 20-fold more sensitive than are currently used gas-liquid chromatographic methods. It is particularly suitable for use as a confirmatory method for large-scale radioimmunoassay screening tests. The procedure involves extraction of morphine from urine and analysis of its heptafluorobutyryl derivative by gas-liquid chromatography with electron capture detection. Morphine can be determined by this procedure over a range of 0.1-200 microgram/liter of urine, 2 pg of the pure derivative being the lowest amount detectable. Urine samples from patients receiving methadone were analyzed by thin-layer chromatography, radioimmunoassay, and our procedure. The results by our procedure agreed well with those obtained by radioimmunoassay.
Comparison of the Hoesch and the Watson-Schwartz tests for urinary porphobilinogen.
Authors: Pierach C A , Cardinal R , Bossenmaier I , Watson C J 
Published: January 2020

Abstract
A comparison of the Hoesch and the Watson-Schwartz tests shows that the latter, although slightly more complicated, generally yields more concise results and is superior in sensitivity and specificity for porphobilinogen. The recommendation of the Hoesch test for use as a "bedside screening" method seems unrealistic. Before the diagnosis of an "inducible" porphyria is made, a positive Hoesch test requires that indoles, indoleacetic acid, methyldopa, end-stage alcoholic malnutrition, and phenazopyridine HCl be excluded, to avoid misinterpretation.
Quantitative method for estimating myoglobin in urine.
Authors: Markowitz H , Wobig G H 
Published: January 2020

Abstract
A simple, rapid, and quantitative immunochemical technique is described for quantitation of urinary myoglobin. The test is specific for myoglobin in the presence of hemoglobin or tissue constituents, can be completed within 1 h or less, and can detect 1 to 2 mg/liter. Normal urinary myoglobin concentrations are less than this.
Sensitive, optimized assay for serum AMP deaminase.
Authors: Pedersen R C , Berry A J 
Published: January 2020

Abstract
A sensitive, optimized assay for serum AMP deaminase (EC 3.5.4.6) is presented, which is based on a colorimetric indophenol determination of ammonia liberated during the enzyme reaction. An average enzyme activity in serum of 2.7 U/liter (n = 36, range 0-6.2) for healthy adults was established. Both the enzyme and colorimetric reactions were optimized to give an assay sensitivity of 0.2 U/liter of serum, a 98-99% analytical recovery in the normal serum enzyme concentration range, and a CV of 7.9% in-run and 10.6% between-run. This optimization included studies on specific buffer, pH, ionic strength, and potential activators. The Km for the enzyme in serum was determinated to be 1.4 X 10(-3) mol/liter, which agrees well with the value reported for human skeletal muscle enzyme. Above-normal serum AMP deaminase activity may be present in various myopathies and could be useful in detecting carriers of the X-linked dystrophies.
Urinary organic acids quantitated by age groups in a healthy pediatric population.
Authors: Thompson J A , Miles B S , Fennessey P V 
Published: January 2020

Abstract
Urine samples from 92 individuals of a healthy pediatric population ranging in age from less than 24 h to 12 years were analyzed for organic acid content (amino acids excepted). A few samples from adults were included for purposes of comparison. Acids were extracted by using an anion-exchange procedure, converted to trimethylsilyloxime derivatives, and analyzed by gas chromatography with the help of a small computer system. Identifications were confirmed by using a combined gas chromatograph/mass spectrometer/computer system. The data has been tabulated according to five pediatric age groups. Despite large individual variation within age groups, significant differences in amounts of several acids excreted (based on urinary creatinine concentration) have been determined between age groups. Such differences might be due to one or a combination of several factors, including changes with age in creatinine excretion, in physiologic maturity, and in diet. Such data may help to provide a basis for diagnosing metabolic abnormalities in pediatric patients.
Comparison of enzyme immunoassay and gas chromatography for determination of carbamazepine and ethosuximide in human serum.
Authors: Sun L , Szafir I 
Published: January 2020

Abstract
Patients' sera were analyzed for carbamazepine and ethosuximide by enzyme immunoassay (x) and gas chromatography (y), and the results were compared. The correlation coefficients were: for carbamazepine, x vs. y 0.94 (n = 93); for ethosuximide, x vs. y 0.99 (n = 30). These results suggest that the two methods could be used interchangeably. Ten serum samples supplemented with carbamazepine (2.5 to 12.5 mg/liter) and ethosuximide (20.0 to 130.0 mg/liter) were analyzed by both methods. The correlation coefficients were: x vs. y 0.99 (n = 10) for carbamazepine and x vs. y 0.99 (n =10) for ethosuximide.
Improved direct determination of serum cholesterol in low-density lipoproteins with use of polycations.
Authors: Heuck C C , Middelhoff G , Schlierf G 
Published: January 2020

Abstract
The previously described procedure of direct determination of LDL-cholesterol after selective extraction of VLDL and HDL with polycations and a polycation-exchange resin has been improved by using dodecoylated poly(ethyleneimine) instead of poly(ethyleneimine). The acyl derivative has a higher affinity for lipoproteins. Disc-electrophoretic patterns of lipoproteins separated by this procedure correspond to patterns of apolipoproteins in VLDL and HDL, a finding that corroborates the conclusion that the mechanism of the selective binding of certain lipoproteins to lipophilic water-soluble polycations is based on hydrophobic interaction between the polymer and lipids located at the surface of lipoprotein particles. The procedure offers a simple possibility for direct LDL-cholesterol and LDL-triglyceride determination and for the isolation of VLDL and HDL. The mechanism of the reaction has a biochemical correlate in the action of phospholipase A2 on phospholipids.
Serum alkaline phosphatase: normal values by sex and age.
Authors: Eastman J R , Bixler D 
Published: January 2020

Abstract
We report here the normal range of serum alkaline phophatase activity as measured by the method proposed by Hausamen et al. [Clin. Chim. Acta 15, 241 (1967)] with a much larger sample size than used in previous investigations. In the statistical analysis the sample population is subdivided by sex and age, two variables which are known to influence enzyme activity. No statistically significant influence of blood type on enzyme activity was observed. The normal range of enzyme activity is reported in percentiles.
Influence of methotrexate on results by three methods for determining protein in cerebrospinal fluid.
Authors: Zweig M H 
Published: January 2020

Abstract
Because high intravenous and intrathecal doses of methotrexate are used in treatment for various neoplasms, this drug can reach high concentrations in cerebrospinal fluid. At those encountered clinically, it produced significant positive interference with values for cerebrospinal fluid protein as determined with the du Pont aca. A small interference was found with the Folin-Lowry method, and virtually no interference with an automated immunochemical procedure.
Serum Albumin: Recent Progress in the Understanding of Its Structure and Biosynthesis
Authors: Peters Theodore 
Published: January 2020

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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%.