bluuebunny/crossref_metadata_2025_split huggingface dataset:
Creatine kinase in serum: 4. Differences in substrate affinity among the isoenzymes.
Authors: Szasz G , Gruber W 
Published: January 2020

Abstract
The goal of this work was to find out whether it is possible to measure all three creatine kinase isoenzymes under the same reaction conditions in spite of their different kinetic properties. We found the tightest substrate binding for purified human BB, followed by the MB And MM isoenzyme preparations for both creatine phosphate and ADP. An increase in substrate concentration usually resulted in an inhibition. Nevertheless, it was possible with a method optimized for the MM isoenzyme also to measure the BB and MB isoenzymes at a rate of inhibition of only 6 and 3%, respectively. Marked differences in the apparent Km values between purified and native MM isoenzyme in human serum may indicate that the enzyme declined in substrate affinity during the isolation procedure. The use of enzyme preparations for standardization purposes, therefore, is only suitable if their kinetic properties are close to those of the enzyme in serum. Difficulties in the calculation of the apparent Km values are discussed and the graphical procedures of Lineweaver and Burk and of Eisenthal and Cornish-Bowden compared.
Gas-chromatographic method for plasma acetate analysis in acetate-intolerance studies.
Authors: Nielsen L G , Ash K O , Thor E 
Published: January 2020

Abstract
We describe a modified gas-chromatographic method for acetate in serum or plasma, intended for use in the investigation of acetate intolerance in hemodialysis patients. The assay may be adapted for use with a single-column gas chromatograph equipped with a flame ionization detector. The analysis, made isothermally, requires only 0.5 ml of plasma or serum. Only one deproteinizing step is required to prepare the sample for analysis. Additionally, we present preliminary findings of an ongoing acetate-intolerance study.
Preparation of ligand-free human serum for radioimmunoassay by adsorption on activated charcoal.
Authors: Carter P 
Published: January 2020

Abstract
I describe a convenient method for stripping hormones and other ligands from human serum. Formation of a serum/charcoal colloid is avoided by incubating serum on a limited surface area with activated charcoal, in a lateral oscillating shaker. Particle-free serum of negligible turbidity is obtained without ultracentrifugation by ejecting the centrifugate through a cellulose ester membrane. By this technique, more than 80% of thyrotropin, triiodothyronine, thyroxine, cortisol, insulin, digoxin, folate, estriol, or an ether derivative of testosterone is removed from serum. About 70% of follitropin and somatotropin are removed, as well as half the choriogonadotropin. Serum protein remains intact throughout the adsorption process.
Determination of 5-hydroxytryptophan in plasma by high-performance liquid chromatography and fluorometric detection after phthaldialdehyde reaction.
Authors: Enbaek F , Magnussen I 
Published: January 2020

Abstract
We describe the sensitive and precise determination 5-hydroxytryptophan in plasma from patients treated with this compound. The method is based on solvent extraction of plasma, high-performance liquid chromatography and continuous fluorometric detection after reaction with phthaldialdehyde in strong acid. The combined time for chromatography and reaction is 25 min. The sensitivity of the method is adequate to quantitate 0.05 mumol of 5-hydroxytryptophan per liter, in 750 microliter of plasma. No interference by other hydroxyindole compounds was found.
Measurement of chloride in sweat by use of a selective electrode and strip-chart recorder.
Authors: Warwick W J , Hansen L G 
Published: January 2020

Abstract
We describe a method for direct potentiometric measurement of sweat chloride by use of a chloride-selective electrode, with strip-chart recording of the measurement to facilitate interpretation of the measurement. Comparison of this method and the Gibson and Cooke method [Pediatrics 23, 545 (1959)] gave a correlation coefficient of 0.86. Recording of the same test at various pressures showed that different pressures had little effect if they were kept constant.
Radioimmunoassay of creatine kinase isoenzymes in human serum: isoenzyme MM.
Authors: Van Steirteghem A C , Zweig M H , Schechter A N 
Published: January 2020

Abstract
Measurement of the mass concentration of serum enzymes by radioimmunoassay provides direct quantitation of specific isoenzymes and may be less subject to some of the limitations of traditional assay procedures for enzymes. We describe the development of a sensitive and specific radioimmunoassay for the muscle isoenzyme of creatine kinase, CM-MM, in human serum. CK-MM, purified from human skeletal muscle, was used to raise high-titer antisera and for iodination by the Chloramine T method. The radioimmunoassay required 50 microliter of sample, utilized a double-antibody separation method, and was completed in 24 h. Cross reactivity with CK-BB was virtually zero, 3--17% with CK-MB. The mass concentration of CK-MM in the serum of healthy subjects ranged from 36 to 1668 microgram/liter and correlated closely with total CK enzymatic activity. Serum concentrations of CK-MM from casually selected patients correlated less well with total CK enzymatic activity, suggesting the existence of other CK isoenzymes or the presence of inactive forms.
Archival storage of clinical laboratory data.
Authors: Soffer S , Entine S , Wolfe T , Eggert A , Friedman R 
Published: January 2020

Abstract
This paper describes a data-base system for the maintenance of cumulative clinical data. A unique aspect of this data base is its ability dynamically to alter its two-level format to create an alternative three-level hierarchical structure in order to optimize retrieval efficiency. The relative advantages of these two types of data-base structures are discussed and examples of their use in clinical resrarch are presented.
Adenylate kinase inhibition by adenosine 5'-monophosphate and fluoride in the determination of creatine kinase activity.
Authors: Meiattini F , Giannini G , Tarli P 
Published: January 2020

Abstract
The current methods for the determination of creatine kinase (EC 2.7.3.2) activity are derived from Oliver's method, in which AMP is used to decrease interference by adenylate kinase (EC 2.7.4.3). Recently, Szasz et al. and Rosano et al. described methods in which diadenosine pentaphosphate and fluoride, respectively, are used to reduce this interference. However, diadenosine pentaphosphate does not sufficiently inhibit such activity of hepatic origin, while fluoride alone can only inhibit it at concentrations at which the fluoride tends to precipitate as MgF2. Finally, Szasz et al., the Committee on Enzymes of the Scandinavian Society for Clinical Chemistry and Clinical Physiology, and the German Society for Clinical Chemistry have proposed methods in which both AMP and diadenosine pentaphosphate are used to inhibit adenylate kinase. We have found that by using low concentrations of AMP and fluoride together, we can greatly diminish this interference without significant loss of creatine kinase activity and with no precipitation of MgF2.
Improved method for fractionating gamma-glutamyltransferase by electrophoresis on cellulose acetate.
Authors: Burlina A 
Published: January 2020

Abstract
I describe a method of fractionating gamma-glutamyltransferase on cellulose acetate. The tracing is obtained in parallel with that of serum protein, and the gamma-glutamyltransferase bands are characterized by correspondence with the major protein fractions. The overall pattern of the isoenzyme activity in normal sera is one of activity in the alpha1- and alpha2-globulin regions. In hepatic diseases four bands are usually present, but some more specific observations are possible, e.g., the presence of an intense beta-globulin band in occlusive icterus, intra- or extrahepatic, and a marked alpha2-globulin band in alcoholism. The potentialities of this technique as a diagnostic and prognostic aid together with its simplicity prompt me to recommend its use in the clinical laboratory.
Use of Values for Calcium and Protein Serum, and of a Derived Index Obtained from a Probability Population Sample
Authors: Kelly Anthea , Munan Louis , PetitClerc Claude , Ho Kok Ping , Billon Bernard 
Published: January 2020

Abstract
Volume 22
p 1726: In the footnote to Table 3, the last half of the sentence should read " for SI units, the index becomes (80 calcium - 120)/protein."
Volume 23
p 1779: In column two of "corrections," the word "malate" should be substituted for "maleate."
p 2127: In column two, last line, change "chinic" to "chenodeoxycholic." On the next page, change the last part of the sub-legend to Figure 7 to read "(5) ursodeoxycholic acid, (6) cholic acid."
p 2205: col. two, line 32. For "mg/g body weight" read "mg/kg body weight."
p 2288: In the last sentence of the abstract, change ".... 0.3 to 7.8 mole..." to "... 0.3 to 7.8 mmol...."
p 2289: Table 1, footnote a should read: "Millimoles of 4NP injected/270 x 10-3 moles of 4NPP. This is calculated as if the 4NP were present in 270 nmol of 4NPP...."
p 2290: In Table 2, in column A "7.76d" should read "7.76c"
p 2356: The reader may incorrectly infer that the "Gamma-Coat Kit" (CA 535, 536; 555, 556) is intended for the analysis of dried blood samples on paper in screening for congenital hypothyroidism in infants. Actually, that kit is intended for serum thyroxine assay. A modified kit dedicated to dried blood-sample screening for hypothyroidism is currently under development and will be introduced shortly as CA-538, 558.
Further, in Tables and text, the "3.5-mm" disks referred to should read "3.18 mm" (⅛''). This is of significance, because the error in diameter produces a 20% error in the apparent blood volume or thyroxine content per disk in the Tables.
Inadvertent omissions from the list of invited reviewers (p 2360) and our annual index are, respectively:
Jocelyn M. Hicks and Royden Rand
and
"Direct Spectrophotometric Determination of α-Amylase Activity in Saliva, with p-Nitrophenyl α-Maltoside as Substrate," by Baiba K. Gillard, Henry C. Markman, and Stephen A. Feig. (p 2279)
A radioimmunoassay for nortriptyline (and other tricyclic antidepressants) in plasma.
Authors: Maguire K P , Burrows G D , Norman T R , Scoggins B A 
Published: January 2020

Abstract
The radioimmunoassay for nortriptyline described here can detect as little 1 microgram/liter of plasma. Within-day precision and day-to-day precision (CV) were +/- 6 and +/- 11%, respectively, over the concentration range 100-200 microgram/liter. The major metabolite hydroxy-nortriptyline, does not cross react with the antiserum. Results so obtained correlate closely with results by a double-isotope derivative dilution technique. The major advantages of this technique over currently available methods are its sensitivity, convenience (many samples can be processed in one day), simplicity, and cost. Further, prior extraction of plasma samples is not required. Cross-reactivity studies have been carried out with all other available tricyclic antidepressants. The antiserum has the ability to bind these drugs, thus radioimmunoassay for all the tricyclic antidepressant drugs can be set up because concurrent use of more than one of these drugs is rare.
Measurement of sodium in albumin solutions with ion-selective electrodes.
Authors: Mohan M S , Bates R G , Hiller J M , Brand M J 
Published: January 2020

Abstract
We have investigated the variations in the potentials of sodium-selective glass-membrane electrodes in various concentrations of albumin. These protein solutions serve as a simple model for measurements of electrolytes in whole blood, plasma, or serum with such an electrode. The results indicate that albumin-sodium binding and variations in liquid-junction potentials are of negligible importance. Mostly, the effect of albumin on the sodium glass-electrode potential is attributable to variations in the activity of sodium, determined by the water content of the solutions. We have calculated apparent fractional protein volumes in albumin solutions from measurements of sodium glass-electrode potential and find they compare well with the classical McLean-Hastings formulation. Our results indicate the need to correct experimentally determined potentiometric electrolyte concentrations for protein volumes.
Enzymatic determination of blood ethanol, with amperometric measurement of rate of oxygen depletion.
Authors: Cheng F S , Christian G D 
Published: January 2020

Abstract
A rapid electrochemical measurement of blood ethanol is proposed. Alcohol is oxidized by NAD+ in the presence of alcohol dehydrogenase; and the NADH produced is aerobically oxidized by horseradish peroxidase. The rate of depletion of buffer-carried oxygen, which is directly proportional to the alcohol concentration in the sample, is amperometrically monitored with a membrane oxygen-sensing electrode. Only a 5-microliter sample of whole blood is required, with no deproteinization, incubation, extraction, or dilution. Results, obtained in less than 1 min, correlate well with those obtained by gas-chromatographic and spectrophotometric methods.
Detection and elimination of contaminations interfering with the determination of zinc in plasma.
Authors: Reimold E W , Besch D J 
Published: January 2020

Abstract
We undertook detailed examination of the practices and procedures involved in the analysis of serum for zinc by atomic absorption spectrophotometry, to identify possible sources of zinc contamination. Some degree of contamination was found in almost all steps of the procedure. These findings are presented and alternative materials and procedures are described that significantly decrease or eliminate contamination from extraneous zinc. The plasma of 76 normal adults was analyzed by the revised procedure, and a lower mean value was obtained than has been previously reported.
Determination of cadmium in urine by graphite-furnace atomic absorption spectroscopy.
Authors: Vesterberg O , Wrangskogh K 
Published: January 2020

Abstract
A simple procedure for graphite-furnace atomic absorption analysis of cadmium in urine, based on the use of a temperature-controlled heating unit, is described. The temperature of the carbon rod is measured by resistance and controlled by electronic feedback. We studied the influence of various heating times and temperatures of ashing and atomization, as well as suitable diluents. Urine samples were diluted with an equal volume of 0.3 mol/liter HNO3, and 1 to 5 microliter of the mixture was analyzed, with background correction. Signals were evaluated electronically, giving values for integrated peaks as well as for peak heights. The detection limit was 1.2 nmol/liter. The method appears to be accurate and reproducible. The CV averaged 8% for concentrations in the range 20 to 100 nmol/liter. Correlations with a chelation-extraction method was 0.994.
Two immunofluorescent methods compared with a radial immunodiffusion method for measurement of serum immunoglobulins.
Authors: Blanchard G C , Gardner R 
Published: January 2020

Abstract
We found high correlations when the values for immunoglobulins G, A, and M, obtained from the analysis of a group of 50 or more human sera by a measured-time radial immunodiffusion method, were compared to values found by two new commercial immunofluorescent methods. The Fiax and the Immuno-Fluor systems make use of fluorescently labeled antibodies and solid-phase immunoadsorbents and offer simple, precise, and objective methods for immunoglobulin quantitation. The Fiax procedure is less time consuming than is the Immuno-Fluor and gives IgG and IgA concentrations that are in close agreement with those found by radial immunodiffusion and IgM values that are significantly lower than the radial immunodiffusion values. The IgG results determined by the Immuno-Fluor method compare well with the radial immunodiffusion results, uhile the IgA values are significantly higher and IgM values significantly lower than those obtained by radial immunodiffusion.
Posture and the composition of plasma.
Authors: Dixon M , Paterson C R 
Published: January 2020

Abstract
For a group of normal medical students, we examined the effect of posture on the concentration of a number of constituents in plasma. On standing, there is a significant increase in plasma total protein, albumin, calcium, alkaline phosphatase, bilirubin, and cholesterol--all proteins or substances bound to protein. Although it is possible to make an allowance for postural variations in plasma calcium, no correction is possible for changes in protein concentrations and care is needed whenever the precise values are important, as in the follow-up of patients with the nephrotic syndrome.
A preliminary evaluation of tissue polypeptide antigen in serum or urine (or both) of patients with cancer or benign neoplasms.
Authors: Menendez-Botet C J , Oettgen H F , Pinsky C M , Schwartz M K 
Published: January 2020

Abstract
We evaluated assays of Tissue Polypeptide Antigen in serum and urine, as an index to the presence of cancer. In the assay, serum, which is first absorbed with human albumin-labeled sheep erythrocytes, or untreated urine (diluted with an equal volume of TPA-free serum) is incubated with antibody specific to Tissue Polypeptide Antigen and then reacted with sheep erythrocytes labeled with Tissue Polypeptide Antigen. We found an increased concentration of Tissue Polypeptide Antigen in the serum of 378 of 513 (74%) and in the urine of 49 of 77 (64%) patients with cancer, as compared with 40/112 (36%) and 7/29 (24%), respectively, for individuals with benign neoplasms. Normal individuals were defined as those with less than 0.09 unit of the antigen per milliliter of specimen. Concentrations exceeding this were found in 2/67 (3%) sera and 6/56 (11%) urines from supposedly normal persons. Tissue Polypeptide Antigen was found in above-normal concentrations in patients with cancer, regardless of neoplasm type and extension, with a higher proportion of abnormal values in patients with distal metastases.
Enzyme-coupled measurement of ethanol in whole blood and plasma with a centrifugal analyzer.
Authors: Jung G , Férard G 
Published: January 2020

Abstract
We describe an automated enzymic method for ethanol determination with a centrifugal analyzer (the GEMSAEC) by measuring the rate of the reaction catalyzed by alcohol dehydrogenase and coupled to aldehyde dehydrogenase. The detection limits, reproducibility, and accuracy of the method have been evaluated. It can be applied to whole blood or plasma, with or without previous deproteinization. Our results, compared with those by an automated alcohol dehydrogenase method in the presence of semicarbazide, show an improved linearity, sensitivity, and rapidity of determination.
Biochemical changes in a porcine model of acute pancreatitis.
Authors: Marenberg S P , Lott J A , Pflug B K , Kibbey W E , Carey L C 
Published: January 2020

Abstract
Pancreatitis was induced in 11 miniature pigs by infusing a bile salt-trypsin solution into the pancreatic duct. Seven animals served as sham-operated controls. Serum ionized calcium, total calcium, albumin, total protein, inorganic phosphorus, urea nitrogen, magnesium, insulin, glucagon, and hematocrit were determined every six to 12 h over a period of one week in both test and control animals. We observed significant decreases in ionized and total calcium, modest decreases in albumin, and significant increases in the inorganic phosphorus, urea nitrogen, and hematocrit in the pancreatitic pigs. The latter two findings were consistent with early acute hypovolemia. Glucagon and insulin appeared to play no role in the hypocalcemia. Glucagon concentrations increased to the same degree in both test and control animals, probably as a result of the stress of being handled and operated on. The highest concentrations of inorganic phosphorus and the lowest concentrations of both ionized and total calcium were seen 18 h after the induction of pancreatitis in the test animals. These findings suggest that parathyrin (parathormone) was not being secreted in adequate amounts, or that the target organs were unresponsive to parathyrin.
Isolation of gamma-glutamyltransferase from human liver, and comparison with the enzyme from human kidney.
Authors: Shaw L M , London J W , Petersen L E 
Published: January 2020

Abstract
We isolated gamma-glutamyltransferase [(gamma-glutamyl)-peptide:amino acid gamma-glutamyltransferase, EC 2.3.2.2] from human liver and compared some of its properties with the same enzyme prepared from human kidney. The enzymes from these two sources are very similar with respect to initial velocity kinetic constants, pH optima of the transpeptidation and autotransfer reactions, heat stability, competitive inhibition by glutathione of the colorimetric assay in which gamma-glutamyl-4-nitroanilide is substrate, stability of catalytic activity to trypsinization, and relative rates of transfer of the gamma-glutamyl moiety from gamma-glutamyl-4-nitroanilide and L-[glycine-2-3/]glutathione to some amino acids and small peptides. The kidney enzyme is inhibited more by the gamma-glutamyl acceptor substrate, glycylglycine, as reflected in a sevenfold lower value for the inhibition constant KiA. Major differences were observed in the lectin-binding properties of liver gamma-glutamyltransferase compared to the kidney enzyme. Lectin-binding property differences are retained for the trypsinized form of the liver and kidney enzymes, although the degree of precipitation was less for certain lectins as compared to the untreated enzyme. Lectin-binding properties were reversed by carbohydrates specific for each lectin. We adapted the histochemical staining technique of Rutenberg et al. [J. Histochem. Cytochem. 17, 517 (1969)] to the detection of gamma-glutamyltransferase activity in acrylamide gels; diffusion artifacts are minimized and the color produced is stable for several days. Untreated and trypsinized forms of the liver enzyme both migrated faster in acrylamide gels (as single bands) than did the corresponding forms of the kidney enzyme.
Rapid determination of light halogenated hydrocarbons in urine.
Authors: Youssefi M , Faust S D , Zenchelsky S T 
Published: January 2020

Abstract
We describe a rapid method for determining light halogenated hydrocarbons (LHH) in urine by electron capture gas-liquid chromatography. The hydrocarbons are extracted from urine into pentane. A 2-microliter injection of the pentane extract provides a detection limit of less than 1 microgram/liter.