bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combined gel filtration, biuret/copper method compared with an immunochemical method for urinary protein measurement.
Authors: Peele J D , Gadsden R H , Loadholt C B 
Published: January 2020

Abstract
We compared an immunochemical method specific for plasma proteins with a chemical method, in which interfering substances are separated by gel filtration and "total" urinary protein is determined by the biuret reaction followed by reaction of protein-bound copper with diethyldithiocarbamate after a second gel filtration to remove nonprotein-bound copper. More than 250 24-h urine samples were analyzed by each method. There was linear agreement and a correlation of 0.96 between the two methods, but urinary protein values determined by the immunochemical method, especially for patients with multiple myeloma, were lower than by the chemical method.
Biochemical characterization of the tartrate-resistant acid phosphatase of human spleen with leukemic reticuloendotheliosis as a pyrophosphatase.
Authors: Lam K W , Yam L T 
Published: January 2020

Abstract
A tartrate-resistant acid phosphatase was isolated from a human leukemic spleen by freeze-thawing in saline and purified by repeated chromatography on carboxymethyl-cellulose. The purified enzyme has a molecular weight of 64 000. It catalyzes the hydrolysis of inorganic and organic pyrophosphate as well as the phenolic ester of monoorthophosphate, with optimal activity between pH 5 and 6. However, there is no activity toward mono-orthophosphate esters of aliphatic alcohols. The present data have identified its catalytic function as a pyrophosphatase. However, it has properties different from the pyrophosphatase previously observed in normal animal tissues.
A semi-automated fluorometric method for total estrogens in pregnancy urine.
Authors: Frye R , Fong P F , Johnson G F , Rock R C 
Published: January 2020

Abstract
We report a continuous-flow fluorometric method for total urinary estrogens that involves the Kober reaction, with extraction of the reaction product into dichloroethane containing trichloroacetic acid as described by Hahnel and Jones [Clin. Chim. Acta 16, 185 (1967)]. The dichloroethane extraction gives greater stability to the Kober color and sharper separation of aqueous and organic phases. The analytical system is adjusted to give maximum response to estriol 16alpha,beta-D-glucuronide, the principal estrogen conjugate in urine from late pregnancy, when calibrated with estriol standards. An initial 20-fold dilution of the sample with water increased analytical recovery of estriol conjugates from urine while maintaining adequate fluorescent response. Glucose interference was reduced by dilution and eliminated by treatment with sodium borohydride. Urinary protein up to 20 g/liter did not interfere. Total estriol, as determined by gas-liquid chromatography, comprises about 70% of total urinary estrogens in late pregnancy as measured by our continuous-flow fluorometric method. A reference range is presented based on 209 randomly collected urine specimens in which total urinary estrogens are expressed as a ratio to creatinine.
High-pressure liquid-chromatographic method for determination of gentamicin in plasma.
Authors: Peng G W , Gadalla M A , Peng A , Smith V , Chiou W L 
Published: January 2020

Abstract
A rapid, specific method for measuring gentamicin in plasma by high-pressure liquid chromatography was developed. After deproteinization, gentamicin in the supernate was dansylated and extracted into ethyl acetate. The organic extract was chromatographed on a microparticulate reversed-phase column, which was eluted with aqueous acetonitrile. Use of the dansyl derivative enables fluorometry, for more sensitive quantitation. Various factors that could affect the assay sensitivity were investigated. With 0.2-ml plasma samples, the method can accurately measure as little as 1 mg of gentamicin per liter. We encountered no interferences from plasma supplemented with various drugs or plasma of patients who were on therapy with other drugs. This method can also separate gentamicin C1 from C1a and C2, all of which are present in various ratios in commercial dosage forms. This method is also applicable to gentamicin determination in urine.
Effect of incubation with Mg2+ on the measurement of alkaline phosphatase activity.
Authors: Rej R 
Published: January 2020

Abstract
Human serum incubated with 2-amino-2-methyl-1-propanol (860 mmol/liter) and magnesium ion (270 mumol/liter) at pH 10.35 showed greater alkaline phosphatase (EC 3.1.3.1) activity than if an equal amount of magnesium ion was added at the time of measurement. The apparent increase is due in part to a slight lability of serum alkaline phosphatase in 2-amino-2-methyl-1-propanol, which is prevented by the inclusion of magnesium. For some sera, however, a portion of this increased activity is real rather than artifactual. Use of serum rather than 4-nitrophenylphosphate to initiate the reaction produced relatively low activities and, in some cases, markedly nonlinear (increasing) rate progress curves. The behavior of some commercial lyophilized control sera differed significantly from that of patients' sera, in particular exhibiting a marked lability in the presence of 2-amino-2-methyl-1-propanol. Incubation of these labile materials with Mg2+ slightly improved their stability; addition of Zn2+ plus Mg2+ markedly stimulated and completely protected their alkaline phosphatase activity.
Adaptation to the centrifugal analyzer of an enzymatic method for the measurement of lactate in plasma and cerebrospinal fluid.
Authors: Alderman J A , Cross R E 
Published: January 2020

Abstract
A fully enzymatic method for measurement of l(+)-lactate has been adapted for use with a centrifugal analyzer. The procedure is based on a two-point fixed-time kinetic approach for elimination of static interferences, and commercially available reagents are used. Specimen collection and preservation are simplified by the use of standard evacuated tubes containing sodium fluoride. Under these conditions lactate is stable for as long as seven days at 4 degrees C, and deproteinization is unnecessary. The method is extremely simple and ideally suited for emergency and routine use. Determinations may be performed on plasma or cerebrospinal fluid. Sensitivity and precision are excellent, linearity extends to 8.0 mmol/liter, and results compare well with those obtained using the manual enzymatic procedure.
Methaqualone metabolites in human urine after therapeutic doses.
Authors: Kazyak L , Kelley J A , Cella J A , Droege R E , Hilpert L R , Permisohn R C 
Published: January 2020

Abstract
We measured five principal metabolites of methaqualone in the urine of seven volunteers after single and multiple doses of the drug. Urine, collected for up to 72 hours after the last dose, was analyzed for methaqualone and its principal metabolites by high-resolution capillary-column gas chromatography. The major biotransformation of methaqualone under therapeutic conditions occurred through benzylic and para-hydroxylation of the o-tolyl moiety. Methaqualone itself was present in concentrations of no more than 1 mg/liter, if it could be detected at all. The observed physiological effects ant total urinary excretion of metabolites reflected the cumulative nature of the parent drug when it was administered in multiple doses. No clear relationship was found between appearance of a specific metabolite and time after ingestion of the drug, although higher amounts of 2-methyl-3-(2'-hydroxymethylphenyl)-4(3H)-quinazolinone were noted in those individuals who tolerated the drug less well.
Improved colorimetry of urinary 3-methoxy-4-hydroxyphenylacetic acid (homovanillic acid).
Authors: Knight J A , Haymond R E 
Published: January 2020

Abstract
Homovanillic acid is an important metabolite of dopamine, and a high proportion of patients with neuroblastoma excrete increased amounts of it in their urine. When this diagnosis is suspected, both homovanillic acid and vanilmandelic acid should be measured, because such a combined measurement reportedly leads to detection of 95% of cases. Although rapid and reliable chemical methods are available for vanilmandelic acid, the same is not true for homovanillic acid. We report here a colorimetric method for homovanillic acid that reasonably fills this void and that can be used in most clinical laboratories. In addition, we present normal values determined for children of various age groups.
Removal of an endogenous antigen from an antibody to increase its effective affinity constant, as illustrated by triiodothyronine assay.
Authors: Oliver L K , Cano C 
Published: January 2020

Abstract
Antisera to triiodothyronine were shown to contain large quantities of the hormone, well in excess of normal circulating concentrations. Extracting the triiodothyronine from the antiserum with alkaline ethanol yielded an antibody of increased affinity. Use of this antibody in a radioimmunoassay resulted in a fourfold increase in sensitivity as compared with the unextracted material.
Semi-automated vs. visual reading of urinalysis dipsticks.
Authors: Peele J D , Gadsden R H , Crews R 
Published: January 2020

Abstract
Semi-automated reflectance readings of urinalysis dipsticks showed better precision than visual readings in the case of artificially prepared urine samples containing glucose, ketone, and protein. Actual pathological specimens containing glucose, protein, and nitrite also showed that instrumental readings were better than visual. Results of repeated visual readings spread over three different color blocks for certain concentrations of glucose, ketone, and protein, whereas repeated instrumental readings were never spread greater than two color blocks. Subjectivity can be reduced by semi-automated dipstick urinalysis.
Measurement of carbamazepine and its epoxide metabolite by high-performance liquid chromatography, and a comparison of assay techniques for the analysis of carbamazepine.
Authors: Mihaly G W , Phillips J A , Louis W J , Vajda F J 
Published: January 2020

Abstract
We describe a modified high-performance liquid-chromatographic method for the simultaneous analysis of carbamazepine andits biologically active metabolite, carbamazepine-10, 11-epoxide. Concentrations of both these compounds in the plasma of 35 epileptic patients receiving chronic carbamazepine therapy are presented. Concentrations of carbamazepine in plasma were related to those of carbamazepine-10, 11-epoxide (r - 0.495, P less than 0.05). Total daily doses of carbamazepine were better correlated with plasma concentrations of carbamazepine-10, 11-epoxide (r = 0.714, P less than 0.001) than of carbamazepine (r = 0.269, P greater than 0.05). Close correlations were found between results of the three assay procedures we used to measure plasma carbamazepine concentrations: high-performance liquid chromatography, gas-liquid chromatography, and enzyme immunoassay. Correlation coefficients exceeded 0.97 and regression slopes were near unity, indicating that all three procedures were individually specific for the quantification of plasma carbamazepine.
Use of gel filtration to examine the distribution of calcium among serum proteins.
Authors: Toffaletti J , Savory J , Gitelman H J 
Published: January 2020

Abstract
Gel filtration of serum by use of dextran bisacrylamide beads ("Sephacryl S-200," fractionation range: 5000-250 000 daltons), separates the serum proteins into three distinct peaks. We used an eluent containing (per liter) 140 mmol of sodium, 1.10 mmol of calcium, 0.50 mmol of magnesium, and 10 mmol of 2-([2-hydroxy-1, 1-bis(hydroxymethyl)ethyl]amino)ethanesulfonate buffer (pH 7.43 at 37 degrees C) to provide the physiological conditions necessary to maintain the equilibrium of bound calcium in serum. We examined the calcium binding by each of the three protein groups. Calculating the calcium bound per gram of protein in each peak, we found that proteins in the first peak (alpha2-macroglobulin, IgM, haptoglobins) bind about the same amount of calcium per gram as does albumin. The proteins of the second peak (largely IgG and IgA) bind less calcium than does albumin, which is the protein accounting for 90% or more of the third peak. We also were able to calculate intrinsic association constants for calcium/albumin under physiological conditions.
Some aspects of sodium nitroprusside reaction with human erythrocytes.
Authors: Spiegel H E , Kucera V 
Published: January 2020

Abstract
Sodium nitroprusside is an excellent agent for lowering blood pressure in hypertensive emergencies, for producing controlled hypotension during anesthesia, and for treating acute myocardial infarction and chronic heart failure. Toxic effects of this drug have been reported and above-normal cyanide and thiocyanate concentrations have been observed in the blood of a small proportion of subjects receiving nitroprusside. Nitrite, syanide, and thiocyanate are major decomposition products of nitroprusside, resulting from an in vitro reaction with human blood. On the basis of the conversion mechanism, we suggest that, in the cyanide/thiocyanate cycle, only cyanide is directly responsible for any acute toxicity attributed to sodium nitroprusside. In this work, the extent of cyanide production by erythrocytes in vitro was studied. The rate of detoxification of cyanide by human liver in vitro was experimentally determined and data from a search for a possible inhibitor of the nitroprusside/hemoglobin reaction are presented. Also, the possible mechanism of the nitroprusside/hemoglobin reaction is discussed.
Calorimetric enzymic measurement of uric acid in serum.
Authors: Rehak N N , Janes G , Young D S 
Published: January 2020

Abstract
Uric acid in serum was determined calorimetrically with a batch type microcalorimeter, by measuring the heat evolved during a coupled uricase/catalase enzymic reaction in tris(hydroxymethyl)aminomethane HCl buffer (pH 9.0 at 30 degrees C). Heat evolution and concentration are linearly related through the physiological range of serum uric acid concentrations and the method is free of interferences of the sort encountered with spectrophotometric methods. Precision and accuracy are good (CV, 2%) and the results correlate well with those obtained by a mechanized colorimetric uricase/peroxidase system.
Delta check tables for the Technicon SMA 6 continuous-flow analyzer.
Authors: Wheeler L A , Sheiner L B 
Published: January 2020

Abstract
To provide a data base for the establishment of a method to detect potentially incorrect SMA 6 test results, we analyzed 2970 pairs of SMA 6 results. For each test result, as well as for the urea nitrogen/creatinine ratio and the anion gap, we estimated to probability density function of the amount of change since the most recent test of the same type. We made separate estimates for each of three ranges of the current test result and two ranges of time-spacing between the tests. Tables of nonparametric estimates of selected points from each of the six distributions for each test result and calculated quantity were developed. These tables could be used to identify unlikely test results, either manually or with a laboratory computer.
Simultaneous spectrophotometry of Fe2+ and Cu2+ in serum denatured with guanidine hydrochloride.
Authors: Williams H L , Johnson D J , Haut M J 
Published: January 2020

Abstract
We show how iron and copper ions may be simultaneously measured in 0.2 ml of serum after using guanidine hydrochloride to cause their release from protein. Sensitive reagents for iron (2,4,6-tripyridyl-s-triazine) and copper (disodium 2,9-dimethyl-4,7-diphenyl-1, 10-phenanthroline disulfonate) facilitate such measurement. We eliminated spectral interference between the two metal-ion complexes by selective use of pH. Results compare well with those obtained by accepted methods in which the concentrations of these ions are measured independently.
Extraction and measurement of circulating angiotensins I and II.
Authors: Barrett J D , Eggena P , Sambhi M P 
Published: January 2020

Abstract
We describe a method for simultaneous extraction of angiotensins I and II from human blood. Blood was diluted with 10 volumes of isotonic saline containing ammonium ethylenediaminetetraacetate, and the angiotensin peptides were extracted by cation-exchange chromatography. The dilution effectively inhibits in vitro production of angiotensin I, conversion of angiotensin I to angiotensin II, and degradation of the peptides. Analytical recovery of exogenous angiotensin I or II added to whole blood in physiological concentrations was essentially complete. The extraction procedure removes blood and plasma components that interfere with radioimmunoassay of angiotensin, thus eliminating the need to correct for nonspecific interference. Circulating angiotensins I and II, measured in patients with essential hypertension before and after a week of diuretic administration, increased in parallel with plasma renin activity.
Biological variability in aspartate aminotransferase activity in serum of healthy persons, and effect of in vitro supplemantation with pyridoxal 5-phosphate.
Authors: Horder M , Bowers G N 
Published: January 2020

Abstract
Aspartate aminotransferase (EC 2.6.1.1) activities in sera from nine healthy individuals were monitored during two weeks, both with and without first supplementing the serum with pyridoxal phosphate. Pyridoxal phosphate supplementation caused a mean increase of 39% (range, 33-55%) in measured activity. The biological variability during the two-week period was independent of pyridoxal phosphate supplemantation. The intra-individual variability (CV) was 5.3% and 5.1% with and without pyridoxal phosphate supplementation, respectively; the corresponding inter-individual variability was 13.2% and 13.6%. We conclude that the reference interval will be insensitive to intra-individual fluctuations in aspartate aminotransferase activity in serum, whether or not the serum is supplemented with pyridoxal phosphate.
Differential serum amylase determination by use of an inhibitor, and design of a routine procedure.
Authors: O'Donnell M D , FitzGerald O , McGeeney K F 
Published: January 2020

Abstract
We describe a new method for measuring pancreatic and salivary-type amylases in serum that requires no electrophoresis or chromatography. An inhibitor protein (from wheat) with a 100-fold greater specificity for human salivary than for human pancreatic amylase was used to analyze mixtures of the two enzymes. The concentration of pancreatic and salivary amyalase was determined in 141 normal sera (72 men and 69 women). Statistically significant differences were found for serum pancreatic amylase between mean and women, higher values being shown in women. No sex-related difference was found for the salivary component of serum amylase. With this method, the increase in serum amylase activity in pancreatitis was shown to be attributable to the pancreatic component. In mumps, the increase is attributable to the salivary component. In pancreatic insufficiency, serum pancreatic amylase activities were significantly lower than in the controls. Our method is simple and rapid; our results agree well with those of other authors who used chromatographic or electrophoretic methods.
Micro-scale method for theophylline in body fluids by reversed-phase, high-pressure liquid chromatography.
Authors: Orcutt J J , Kozak P P , Gillman S A , Cummins L H 
Published: January 2020

Abstract
We describe a micro-scale method for determining serum theophylline. The chromatography system includes a muBondapack C18 column and acetonitrile, 70 ml/liter of sodium acetate buffer (10 mmol/liter, ph 4.0) as the mobile phase. Test serum or plasma, 30 mul, is mixed with an equal quantity of a solution containing the internal standard, beta-hydroxyethyltheophylline in acetonitrile/sodium acetate buffer (20 mmol/liter, pH 4.0), 7/43 by vol. After the precipitate is removed by centrifugation, the mixture is chromatographed and the amount of theophylline calculated from the ratio between peak heights for theophylline and the internal standard. Advantages include easy sample preparation, involving only addition of internal standard and centrifugation before injection, long column life, and the suitability of the internal standard, which is adjusted to a peak height equivalent to 20 mg of theophylline per liter for easy computation of results.
The Gallium Melting-Point Standard: A Determination of the Liquid—Solid Equilibrium Temperature of Pure Gallium on the International Practical Temperature Scale of 1968
Authors: Thornton Donald D 
Published: January 2020

Abstract
The sharpness and reproducibility of the gallium melting point were studied, and the melting temperature of gallium in terms of IPTS-68 was determined. Small melting-point cells designed for use with thermistors are described. Nine gallium cells including three levels of purity were used in 68 separate determinations of the melting point. The melting point of 99.99999% pure gallium in terms of IPTS-68 is found to be 29.7714 ± 0.0014 °C; the melting range is less than 0.0005 °C and is reproducible to ±0.0004 °C.
Acetaminophen in Serum and Plasma Estimated by High-Pressure Liquid Chromatography: A Micro-Scale Method
Authors: Blair Doyce , Rumack Barry H 
Published: January 2020

Abstract
We describe a capillary-sampling method for serum or plasma acetaminophen by cation-exchange chromatog-raphy. As little as 1.5 ill of plasma or serum and an equal volume of the internal standard (N-butyryl-p-aminophenol) were run, with a precision of ±5 % between duplicates. Acetaminophen and the internal standard chromato-graphed in 32 and 50 min, respectively, distinct from in-trinsic plasma peaks and peaks caused by other medica-tions.
Some problems associated with assay of 25-hydroxycalciferol in human serum.
Authors: Mason R S , Posen S 
Published: January 2020

Abstract
Methods available for the assay of 25-hydroxycalciferol in human serum are evaluated and compared to one another. Ethanol was chosen for use in the initial extraction procedure and rat-kidney cytosol as the binding protein, although good alternative methods are also available. We used silicic acid for chromatography and found this an essential step. Reproducibility was increased when, after "bound" and "free" material were separated, an aliquot of the supernate was pipetted into the counting vial instead of the entire supernatant fluid being decanted. Beta-lipo-protein added to the assay system was of no advantage; added bovine serum albumin interfered with the assay by giving rise to high blank values. With ethanol extraction, silicic acid chromatography, rat kidney cytosol and separation on dextran-coated charcoal, sera from normal subjects showed a mean 25-hydroxycalciferol concentration of 28.5 microng/liter (range, 13.1 to 43.9) during the fall season. Coefficients of variation for a control serum were 4.9% (intra-assay) and 10.9% (interassay).