bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid chromatographic method for monitoring therapeutic concentrations of L-dopa and dopamine in serum.
Authors: Riggin R M , Alcorn R L , Kissinger P T 
Published: January 2020

Abstract
We describe a new method for the simultaneous assay of 3,4-dihydroxyphenylalanine (L-dopa) and dopamine in serum. Both compounds have been determined quantitatively at concentrations as low as 10 mug/liter with a coefficient of variation of less than 4%. Peak heights were linearly related to concentration up to 10 mg/liter for each compound. Assay of human sera gave within-run and day-to-day coefficients of variation of 2.8% and 3.1% for L-dopa, and 2.9% and 3.7% for dopamine. The linear relationship between readings nA, y-axis) and concentration (mug/liter) is described by the following equations: y = (21.0 +/- 0.082)x + (0.46 +/- 0.31 SD) for L-dopa and y = (17.0 +/- 0.10)x + (0.08 +/- 0.04 SD) for dopamine. The procedure combines liquid/solid extraction, liquid chromatography, and controlled-potential electrochemistry. The simplicity, sensitivity, and accuracy of this method make it suitable for routine clinical analysis of serum samples to optimize bioavailability for individual patients. After the extraction procedure is completed, samples can be analyzed at the rate of 10/h.
Relative merits of some methods for amphetamine assay in biological fluids.
Authors: Bost R O , Sutheimer C A , Sunshine I 
Published: January 2020

Abstract
We describe principles and details that we use for amphetamine determination in blood and urine by photometric, thin-layer chromatographic, gas-chromatographic, and immunologic (EMIT and radioimmunoassay) procedures. Results, interferences, stabilities, and economic considerations are intercompared and recommendations are made.
Determination of ionized calcium in serum that has been exposed to air.
Authors: Wybenga D R , Ibbott F A , Cannon D C 
Published: January 2020

Abstract
We examined changes in ionized calcium concentration in serum after its exposure to air. Samples with total protein concentrations ranging from 50 to 90 g/liter were equilibrated with CO2 in nitrogen (5/95, by vol) or CO2 alone, to produce pH values of 7.0 to 8.0. Ionized calcium was then measured with an Orion flow-through electrode system. Curves relating pH and ionized calcium concentration had statistically identical slopes regardless of protein concentration. A factor was derived, based on pH change, for correcting values for ionized calcium in serum exposed to air, and its validity was confirmed by comparing corrected values for samples allowed to stand at ambient temperature (23 degrees C) without anaerobic precautions with values initially obtained on anaerobic aliquots of the same samples.
Automated approach to radioimmunoassays of somatotropin (human growth hormone) and insulin.
Authors: Green G , Dyce D , Gimovsky A , Lo D H 
Published: January 2020

Abstract
The adaptation of human somatotropin and insulin assays to the automated Centria radioimmunoassay system [Clin. Chem. 21, 1305 (1975)] is reported. For the somatotropin assay, reaction conditions include a borate/bovine serum albumin buffer (pH 8.4) AND 20-H Incubation at 4 degrees C. Assay results for clinical samples compared favorably (correlation coefficient = 0.930) with values obtained from a reference laboratory. The means determined for 92 patients' samples were 4.3 mug/liter (reference laboratory) and 5.1 mug/liter (Centria). Intra- and inter-run precision ranged from 3.2 to 15.9%. For the insulin assay, a phosphate/bovine serum albumin buffer (pH 7.4) is used, with a 20-h incubation at 4 degrees C. Previously analyzed insulin samples from a reference laboratory were determined by the Centria analyzer with excellent correlation (r = 0.965). Means for patients' samples were 43.0 milli (USP) units of insulin per liter (reference laboratory) and 47.5 milliunits of insulin per liter (Centria). In both assays an anionicexchange gel is used in the separation step. The criterion of parallelism, an indication of the validity of a radioimmunoassay, was satisfied in both assays. The Centria radioimmunoassay system offers the advantage of automating all the critical steps of these radioimmunoassays.
A radioimmunoassay for human serum myoglobin: method development and normal values.
Authors: Rosano T G , Kenny M A 
Published: January 2020

Abstract
We describe a radioimmunoassay that will measure both normal and above-normal concentrations of myoglobin in serum. Myoglobin isolated from human pectoralis muscle was purified by (NH4)2SO4 fractionation and Sephadex gel filtration and injected into rabbits to elicit antisera. Myoglobin was radiolabeled by an acylation with [125]-3-(4-hydroxyphenyl) propionic acid N-hydroxysuccinimide ester. With the purified myoglobin and antisera, we then developed a radioimmunoassy that involves simultaneous regent addition, a 3.5-h incubation at 37 degrees C, and separation of the antibody-bound fraction by precipitation with polyethylene glycol. Information is given on detection limit, precision, linearity, recovery, and specimen preservation. Cross-reactivity to human hemoglobin is negligible. Finally, we investigated the possible relationship between serum myoglobin concentration and muscle mass.
Creatine kinase and its isoenzymes in the serum of women during pregnancy and the peripartum period.
Authors: McNeely M D , Baerris B , Papsin F R , Lyons E , Schipper H 
Published: January 2020

Abstract
In serum obtained from 28 women before, during, and after normal labor and delivery, creatine kinase activity was seen to be distinctly elevated immediately after labor and 24 h later, but had returned to normal six weeks later. In most cases the increase was due to the MM isoenzyme and was attributed to skeletal-muscle damage associated with labor. In 15 cases, the BB isoenzyme was observed, and in three patients the MB isoenzyme. Cord blood, which contains all three isoenzymes, may be the source of the MB and BB isoenzymes. Uterine muscle contains exclusively BB isoenzyme, and therefore uterine muscle damage is a likely source of the serum BB isoenzyme. The relationship among these isoenzymes in serum after delivery must be recognized, to avoid misdiagnosing myocardial infarction at this critical time.
Adenosine deaminase activity in lymphocytes of normal persons, leukemic patients, and kidney-transplant recipients.
Authors: Yasmineh W G , Brynes R K , Lum C T , Abbasnezhad M 
Published: January 2020

Abstract
We determined the activity of adenosine deaminase in normal lymphocytes from peripheral blood, leukemic cells from patients with various hematologic malignancies, and mononuclear cells from kidney-transplant patients, by adapting the method of Hopkinson et al. [Ann. Hum. Genet. 32, 361 (1969)] to the centrifugal analyzer. Normal lymphocytes separated on Ficoll-Hypaque from peripheral blood had a mean activity of 1.42 U/10(9) cells (SD = 0.57; N = 33). Cells similarly isolated from patients with acute lymphoproliferative and myeloproliferative disease generally showed greater values, but the ranges overlapped. Cells from patients with chronic lymphocytic leukemia had activities that were within or below the normal range. Mononuclear cells isolated from the peripheral blood of 15 stable renal allograft recipients showed a mean activity of 1.90 U/10(9) cells (SD = 0.59), not significantly different from normal. In contrast, cells from five patients with biopsy-proven allograft rejection showed a mean activity of 12.84 U/10(9) cells (SD = 10.10), which was significantly different from that of the stable patients.
Electrophoretic patterns for serum glycoproteins reflect the presence of human breast cancer.
Authors: Silverman L M , Dermer G B , Tökes Z A 
Published: January 2020

Abstract
We describe a group of glycoproteins that are synthesized and released by human breast tumors maintained in organ culture and similar glycoproteins released by a human breast carcinoma cell line (BT-20). The electrophoretic mobility of these glycoproteins on cellulose acetate is consistent with increased glycoprotein-staining material present in the alpha2- to beta-globulin region of serum glycoprotein electropherograms from patients with breast cancer. Moreover, after mastectomy, this glycoprotein material in serum decreases to concentrations seen in a control population of patients with benign breast lesions. Patients with proven metastatic breast cancer have patterns reflecting their clinical status: those who respond to treatment have glycoprotein electropherograms similar to the group of patients with benign breast lesions, while those who do not have increased amounts of alpha2- beta-glycoprotein. We believe serum glycoprotein measurements in breast-cancer patients reflect the presence of glycoproteins that are released by the malignant cells and enter the circulation.
Use of protein containing magnetic microparticles in radioassays.
Authors: Ithakissios D S , Kubiatowicz D O 
Published: January 2020

Abstract
We describe a radioassay method that involves the use of magnetic protein microparticles composed of a water-insoluble protein matrix containing magnetically responsive material. We define two different types of particles according to the mechanism of action: (a) The substrate is sorbed nonspecifically by the protein matrix of the particle or by a second substance such as charcoal or ion-exchange resin incorporated within the protein matrix of the particle. These particles are useful for separating free from bound substrate. Examples of these are albumin magnetic microparticles for use in a total thyroxine radioassay and triiodothyronine uptake test, or albumin magnetic microparticles containing charcoal for use in a vitamin B12 radioassay. (b) The substrate is sorbed specifically by a binding protein incorporated within the matrix of the particles. The binding protein can include antibodies or other specific nonimmune proteins. Particles of this type are useful in solid-phase radioassays. These particles are exemplified by albumin magnetic microparticles containing sockeye salmon serum, used in a solid-phase B12 radioassay. We discuss the methods for the preparation of both types of magnetic microparticles and their use in radioassays. We describe a unique inexpensive magnetic separation rack, which provides simple, fast, and reproducible separation of the magnetic microparticles from their suspending medium during the assay.
Radioimmunoassay of lysergic acid diethylamide (LSD) in serum and urine by using antisera of different specificities.
Authors: Ratcliffe W A , Fletcher S M , Moffat A C , Ratcliffe J G , Harland W A , Levitt T E 
Published: January 2020

Abstract
We raised high-titre antisera to two LSD-bovine serum albumin conjugates, one linked via the indole nitrogen, the other via the amide side-chain. The antisera were specific for different parts of the LSD molecule, as demonstrated by cross-reactivity studies with LSD, its metabolites, ergot alkoloids, and closely related compounds. The antisera were used to develop a double-antibody radioimmunoassay with a detection limit of about 0.4 mug of LSD per liter of unextracted urine or serum. We saw no nonspecific interference by urine, serum, or from a series of commonly used drugs. There was good correlation between immunoassay values obtained with the two antisera (r = 0.91). However, the antiserum linked via the indole nitrogen gave consistently higher results for samples from persons who had taken LSD, owing to greater cross-reactivity with LSD metabolites. Radioimmunoassay by use of two such antisera is a more specific screening procedure for LSD abuse than has been available previously. In addition, antisera cross-reacting with LSD metabolites allow measurement of these compounds, for which there is no satisfactory method at the concentrations found in biological fluids in man.
Copper, zinc, magnesium, and calcium in plasma and cerebrospinal fluid of patients with neurological diseases.
Authors: Bogden J D , Troiano R A , Joselow M M 
Published: January 2020

Abstract
We investigated whether information on concentrations of some trace-mental concentrations in blood plasma or cerebrospinal fluid, or both, could be of value in diagnosis or management of various neurological diseases, and whether concentrations in plasma could serve as a means of estimating the protein or metal concentrations in cerebropsinal fluid. Samples of both from 82 patients were analyzed for copper, zinc, magnesium, and calcium by atomic absorption spectrophotometry. Protein concentrations in cerebrospinal fluid were also determined. Metal and protein concentrations in plasma and in cerebrospinal fluid were not strongly enough correlated to permit the estimation of one from the other. However, the correlation coefficients between calcium in plasma and cerebrospinal fluid (r = 0.41), magnesium and protein in cerebrospinal fluid (r = 0.40), magnesium in plasma and calcium in cerebrospinal fluid (r = 0.36), and magnesium and calcium in cerebrospinal fluid (r = 0.66) were statistically significant (P less than .01). Patients with cerebral infarctions had abnormally high copper concentrations in their plasma and cerebrospinal fluid. The ratio of plasma copper to plasma zinc was also significantly higher in cases of cerebral infarction.
Radioimmunoassay for adenosine 3', 5'-cyclic monophosphate and guanosine 3',5'-cyclic monophosphate in human blood, urine, and cerebrospinal fluid.
Authors: Goldberg M L 
Published: January 2020

Abstract
I describe a highly sensitive and very specific assay for cyclic AMP and cyclic GMP in body fluids. An adaptation of the method of Harper and Brooker [j. cyclic Nucleotide Res. 1,207 (1975)], its advantage lies in the fact that the simple acetylation of the samples--a procedure developed by these workers--greatly increases specificity and sensitivity beyond those of previous methods and permits the measurement of femtomole quantities of both cyclic nucleotides without prepurification. Because the range of the cyclic AMP assay is 20-200 fmol, and that of cyclic GMP 10-15 fmol, experiments can be performed with use of only microliters of fluid. The method requires no extraction and thus no complicated corrections are necessary for analytical recovery.
Genetic Variability of Clinical Chemical Values
Authors: Havfik Richard , Garrison Robert , Fabsitz Richard , Feinleib Manning 
Published: January 2020

Abstract
A study of cardiovascular risk factors in middle-aged twin men provided an opportunity to test for genetic variability in the SMA 12/60 (Technicon) battery of clinical chemistry tests. Classical twin methodology was used to analyze the variation of monozygotic and dizygotic twins. In addition, frequency of co-twin contact was used to control for ef¬fects of differences in shared environment. Genetic vari¬ability played a definite role in controlling four of the 11 reported tests: one-hour serum glucose, serum urea ni¬trogen, uric acid, and bilirubin. No genetic variation was found for lactate dehydrogenase, phosphorus, and alkaline phosphatase. Significantly higher means for calcium, total protein, albumin, and aspartate aminotransferase in monozygotic twins precluded any statement about heredity and environment for these tests.
New substrate for fluorometric determination of gamma-glutamyltransferase activity in serum.
Authors: MacQueen J D , Driscoll R C , Gargiulo R J 
Published: January 2020

Abstract
We describe the preparation of a new substrate, N-gamma-L-glutamyl-5-aminoisophthalic acid dimethyl ester hydro-chloride, for the fluorometric determination of gamma-glutamyltransferase activity in serum by the "front-surface" technique. Details of the resulting method are provided. The final reaction mixture contains 4 mmol of the substrate per liter of tris(hydroxymethyl)aminomethane (100 mmol/liter) and glycylglycine (75 mmol/liter) at pH 8.2 (25 degrees C).
Choice of monitoring isotope in double label radioimmunoassays with nonimmunological separation techniques.
Authors: Peeters T L , Vantrappen G R 
Published: January 2020

Abstract
We discuss the suitability of some radioactive isotopes as volume markers in radioimmunoassays, from a radiochemical point of view. For three eligible isotopes (22Na, 60Co, and 75Se) we studied the concentration of the marker in the precipitate formed in the separation phase of radioimmunoassays. For all those kinds of separations tested (charcoal, ammonium sulfate, polyethylene glycol, and ethanol), binding or coprecipitation was virtually absent or negligible with 22Na but 75Se was strongly concentrated in the precipitate. Concentration of 60Co occurred only with charcoal and ethanol precipitation. Because heavy metals tend to bind to serum proteins, we conclude that of all radioactive isotopes commercially available only 22Na should be used in radioimmunoassays with nonimmunological separation methods.
Preparation of a phospholipase C-antihuman IgG conjugate, and inhibition of its enzymatic activity by human IgG.
Authors: Wei R , Riebe S 
Published: January 2020

Abstract
We labeled IgG with phospholipase C, using 1-cyclohexyl-3-(2-morpholinoethyl)-carbodiimide. Enzymaticactivity of the resulting conjugate was inhibited when it was complexed with human IgG, but rabbit or goat IgG was not effective in suppressing the enzyme activity. Normal erythrocytes were used as substrate for the enzyme, enzymatic activity being assessed by measuring the release of hemoglobin. The substrates for phospholipase C are phospholipids, which are major components of the erythrocyte membranes. Hence, the phospholipids in the membranes are viewed as being "immobilized." Perhpas such immobilization of substrate may be a requisite to the inhibition phenomenon.
Lactate dehydrogenase isoenzymes linked to beta-lipoproteins and immunoglobulin A.
Authors: Trocha P J 
Published: January 2020

Abstract
A clinically asymptomatic individual had an abnormal electrophoretic pattern for lactate dehydrogenase, seven isoenzyme bands being present. This atypical pattern was a result of an interaction of lactate dehydrogenase with immunoglobulin A and beta-lipoprotein. Lactate dehydrogenase enzymes LD2 and LD3 were the isoenzymes responsible for the formation of the complexes.
Direct micromethod for colorimetry of serum ornithine carbamoyltransferase activity, with use of a linear standard curve.
Authors: Vassef A A 
Published: January 2020

Abstract
Determination of serum ornithine carbamoyltransferase (EC 2.1.3.3) activity can be a valuable diagnostic tool in the detection of liver diseases involving cytolytic processes. I describe a micromethod for measuring this activity in serum, in which the reaction product, citrulline, is measured colorimetrically in the incubation mixture without prior deproteinization. To eliminate the interference of serum protein precipitation, the concentration of sulfuric acid in the color reagent has been decreased, without substantial loss of sensitivity. Optimizing the conditions of citrulline determination, in which antipyrine and 2,3-butanedione monoxime are used, has resulted in a linear standard curve. The color formed by citrulline is found to be stable in room lighting and sensitive only to direct sunlight. The precision of the method is inversely correlated to serum enzyme activity, the CV varying between 4.6 and 21.1%.
Relative merits of two electrophoretic and two column-chromatographic kets for determining serum creatine kinase isoenzyme MB activity.
Authors: Hamlin C , Ackerman E 
Published: January 2020

Abstract
Prospective analysis (by use of commercially available kits) of 339 validated admission specimens from patients consecutively admitted to a cardiac monitoring unit revealed sensitivities of 68 and 63% for two electrophoretic assays (Bioware and Helena) and up to 73 and 77% for two chromatographic assays (Roche and Worthington). Specificities were 94.8, 96,6, 90.2, and 89.7% and efficiencies were 90.2, 90.7, 87.0, and 87.0, respectively. Although these results differ from early reports, they agree well with several recent studies. However, 86 (25%) of the specimens gave at least one discrepant result based on clinical evaluation of the patients, and 68 (20%) gave at least one discrepant result between methods.
Results with commercial radioassay kits compared with microbiological assay of folate in serum and whole-blood.
Authors: McGown E L , Lewis C M , Dong M H , Sauberlich H E 
Published: January 2020

Abstract
We compared results with three commercial folate radioassay kits [Bio-Rad, New England Nuclear (NEN), and RIA Products] with those by microbiological assay for more than 200 samples of human serum and whole blood. All but one kit (NEN) compared favorably with the microbiological assay for serum samples, although there were notable diagnostic discrepancies. Two kits (NEN and Bio-Rad) were tested on whole-blood samples; both yielded values significantly higher than those by microbiological assay. The frequency distributions of erythrocyte folate data differed strikingly between the two kits; the NEN method yielded a much narrower range of normal values than did either the Bio-Rad or the microbiological assay. Radioassay kits appear to be suitable diagnostic agents for serum folate, if the behavior of a particular kit is investigated thoroughly before its routine use. However, the diagnostic value of radioassays of erythrocyte folate needs to be validated.
Kinetic centrifugal analyzer and manual determination of serum urea nitrogen, with use of o-phthaldialdehyde reagent.
Authors: Levinson S S 
Published: January 2020

Abstract
o-Phthaldialdehdye reagent was used in assaying urea with a miniature centrifugal analyzer. Seventeen samples can be assayed kinetically in 2 min at a current cost of less than a penny per test. The reaction is initiated in the instrument upon simultaneous mixing of the o-phthaldialdehyde reagent containing 10 microliter of sample with dilute sulfuric acid/N-(1-naphthyl)ethylenediamine dihydrochloride reagent. The reaction is monitored kinetically at 546 nm during the initial 2 min, when the rate is nearly constant. The reaction of o-phthaldialdehyde with urea reaches equilibrium by about 7 or 8 min, but the method cannot be used for end-point analysis because of interference by the blank reaction. A 1.2 g/liter solution of o-phthaldialdehyde used in conjunction with 2 mol/liter sulfuric acid solution was found to be most suitable for centrifugal analyzers. I also describe a manual version of the procedure that gives a linear standard curve up to 1.0 g of urea nitrogen per liter.
Hyperlipoproteinemia phenotype determination by agarose gel electrophoresis updated.
Authors: Papadopoulos N M 
Published: January 2020

Abstract
Hyperlipoproteinemia phenotyping has been re-evaluated by an improved agarose gel electrophoretic test. Eight varieties of serum lipoprotein electrophoretic patterns are demonstrated, two from clinically normal normolipidemic subjects and six from patients with hyperlipoproteinemia that include the phenotypes 1, 2a, 2b, 3, 4, and 5. The sharp delineation of the lipoprotein patterns achieved by this technique facilitates the differentiation and identifcation of the lipoprotein phenotypes. Furthermore, the lipoprotein patterns can be visually evaluated, correlated with their corresponding serum lipid values, and associated with the clinical and hereditary features of the hyperlipoproteinemia phenotypes. This test system can also be used in clinical trials and epidemiological studies.
Faster determination of clottable fibrinogen in human plasma: an improved method and kinetic study.
Authors: Inada Y , Okamoto H , Kanai S , Tamaura Y 
Published: January 2020

Abstract
Clottable fibrinogen in human plasma was determined by measuring spectrophotometrically the increase in turbidity with time due to the fibrinogen-fibrin conversion with thrombin. From the maximal absorbance, Amax, at 450 nm obtained 2 min or less after thrombin as added to plasma, we estimated the fibrinogen concentration in plasma of normal subjects and patients. Analysis of the rate of the absorbance increase yielded the Km value, 1.6 X 10(-5) mol/liter, which closely agrees with the Km of 1.2 X 10(-5) mol/liter obtained by analysis of the fibrinopeptides released from fibrinogen.