bluuebunny/crossref_metadata_2025_split huggingface dataset:
A systems approach to fluorescent immunoassay: general principles and representative applications.
Authors: Curry R E , Heitzman H , Riege D H , Sweet R V , Simonsen M G 
Published: January 2020

Abstract
We have developed an automated system for the immunoassay of subnanogram quantities of clinically interesting compounds by molecular fluorescence. The system includes all the necessary reagents and an automated fluorometer. The microprocessor-based instrument consists of a measurement and data-processing module and an automated sampling unit. With use of 10 pmol/L amounts of fluorescent dyes such as fluorescein, measurements with precision and accuracy of 1--3% are attained. In a competitive-binding fluorescence immunoassay, antigen labeled with a fluorescent dye competes with antigen in the sample or standard for a limited amount of antibody immobilized on a polyacrylamide bead 2--5 micrometers in diameter. After separating antibody-bound from free tracer, we measure the amount of fluorescence bound to the beads. In representative example assays, correlation of fluorescence immunoassay (y) with a reference radioimmunoassay (x) of thyroxine was y = 1.01x + 13 nmol/L, r = 0.98. Correlation of fluorescence immunoassay (y) with a reference radioimmunoassay (x) of triiodothyronine was y = 0.99x + 0.004 nmol/L, r = 0.96.
Improved method for detecting hemagglutination by centrifugal analysis.
Authors: Wenz B , Feng C S , Karmen A 
Published: January 2020

Abstract
Centrifugal analysis can be used to detect hepatitis B surface antigen, antibody to rubella virus, and fibrin-related antigen. The procedure is performed with the same reagents used in conventional hemagglutination studies. Positive and negative reactions are distinguished by the rates of erythrocyte clearance in the centrifugal field (delta A/delta time); positive cells move more rapidly than negative cells, and this difference varies directly with the concentration of detectable antigen or antibody. This phenomenon is thought to be a result of the greater adhesion of negative cells to the cuvette's surface. Sensitivity and specificity are greater in the centrifugal analysis technique than in the more conventional hemagglutination tests. False-positive reactions are eliminated and the quantitative data are accurate and reproducible.
Instrumentation and techniques for analysis of hydrogen peroxide and peroxide-producing reactions involving earthworm (Diplocardia longa) bioluminescence.
Authors: Wampler J E , Mulkerrin M G , Rich E S 
Published: January 2020

Abstract
Earthworm bioluminescence (species Diplocardia longa) is a sensitive tool for determination of peroxide titers in biological systems, with linearity of the standard curve for hydrogen peroxide extending from 10 nmol/L in the assay to greater than 1 mmol/L, and with sensitivity to 2 pmol of peroxide per assay. This assay's insensitivity to extraneous protein, turbidity, and solutes that are not redox active makes it particularly useful for automated or crude sample analysis and for analysis of oxidases and their substrates in coupled reactions. Examples of this latter application we discuss are analyses of glucose and putrescine oxidases and their substrates. In each case linear standard curves are obtained, covering several decades of concentration. The coupled reactions also allow in situ detection of oxidases in electrophoresis gels. We also describe a small, portable photometer system and an on-line computer-controlled instrument system that has facilitated development of these assays and will also allow automatic scanning of bioluminescence in gels. The data-collection and decision-making algorithms of this system are simple and easily adaptable for use in an inexpensive computer-based photometer system.
Aminoglycoside antibiotic measurement by bioluminescence, with use of plasmid-coded enzymes.
Authors: Daigneault R , Larouche A , Thibault G 
Published: January 2020

Abstract
We describe a bioluminescent assay for gentamicin in serum that is applicable to the measurement of other aminoglycosides as well. The assay is based on the measurement of residual ATP with the luciferase reaction after incubation of the antibiotic with a plasmid-coded enzyme. Two aminoglycoside-inactivating enzymes were used: an adenylytransferase and an acetyltransferase coupled to S-acetyl coenzymeA synthetase. We investigated the latter system further because of the good stability of the acetyltransferase, its recovery in high yield from bacteria, and its more favorable ATP/gentamicin mass ratio. Serum ATPases were inactivated at 60 degrees C for 20 min. The operating range of the assay was 0-15 mg of gentamicin per liter. The precision (CV) was 10.1% at a concentration of 2 mg/L and 1.1% at 10 mg/L. The method correlated well with a radio-enzymatic assay for mock unknown sera (r = 0.981). The results were available within 2 h.
A new screening system for nonsteroidal anti-inflammatory drugs based upon inhibition of chemiluminescence produced from human cells (granulocytes).
Authors: Van Dyke K , Van Dyke C , Udeinya J , Brister C , Wilson M 
Published: January 2020

Abstract
A new screening system for nonsteroidal anti-inflammatory drugs that involves use of human phagocytic cells has been developed in which chemiluminescence measurement is used. Luminol-dependent chemiluminescence is measured after the addition of opsonized (coated with antibodies and complement) zymosan particles to human granulocytic leukocytes in the presence or absence of drugs. Of all the compounds tested, indomethacin was the most potent in blocking chemiluminescence, with measurable inhibitory activity at 5 mumol/L. The order of inhibitory potency at 0.1 mmol/L and in the presence of Ca2+ and Mg2+ was indomethacin greater than sodium salicylate greater than fenoprofen Ca greater than tolmetin greater than naproxen greater than ibuprofen. It is likely that the active compound itself must be added to the system because aspirin did not inhibit chemiluminescence, whereas its metabolite, sodium salicylate, was markedly inhibitory. Dexamethasone and methylprednisolone also did not inhibit chemiluminescence. The drugs that inhibit chemiluminescence are also known inhibitors of prostaglandin synthase (cyclooxygenase portion).
Immunoradiometric serum ferritin concentration compared with stainable bone-marrow iron as indices to iron stores.
Authors: Forman D T , Vye M V 
Published: January 2020

Abstract
Immunoradiometric analysis has made it possible to measure ferritin reliably in serum. The determination is a sensitive means of assessing body iron because concentrations of ferritin closely parallel the body's reticuloendothelial iron stores. The information provided is similar to that obtained from bone-marrow aspirates or biopsies stained for iron with Prussian Blue. Comparative studies indicate good correlation between iron content in the marrow and serum ferritin, except possibly in patients with leukemia and metastatic tumors to the bone marrow. The clinical value of the assay in relation to other indicators of iron status (i.e., hemoglobin, erythrocyte indices, serum iron and iron-binding capacity, and erythrocyte protoporphyrin) is in its specificity and sensitivity for assaying physiological iron stores.
Computer-assisted analysis of two-dimensional electrophoreses of human lymphoid cells.
Authors: Lester E P , Lemkin P , Lipkin L , Cooper H L 
Published: January 2020

Abstract
Two-dimensional electrophoresis in polyacrylamide gel provides a highly reproducible display of biosynthetically pulse-labeled cellular polypeptides, whose relative rates of synthesis can be judged from the relative spot densities they produce in fluorographic images of the electrophoreses. When experimental and control cell populations synthesize protein at differing rates, either the sample load per gel or the duration of exposure of gel to film may be adjusted to produce comparable experimental and control images with no alteration in the rank order of relative spot density. However, variation in the duration of pulse-labeling may significantly alter relative spot density. Film density saturation and nonlinear response to radiation may also alter relative spot density for polypeptides with very large or very small amounts of radioactivity. Stimulation of human peripheral blood lymphocytes with phytohemagglutinin alters the relative synthesis rates of certain polypeptides visualized on the gels. These can be quantitated by using an automated series of computer algorithms to analyze the images. Data from this analysis confirm statistically significant alterations in the relative densities produced by certain polypeptides. Various human lymphoblastoid cell lines may also be distinguished from each other by this technique.
Diagnosis of viral infections by multicomponent mass spectrometric analysis.
Authors: Abbott R , Anbar M , Faden H , McReynolds J , Rieth W , Scanlon M , Verkh L , Wolff B 
Published: January 2020

Abstract
Metabolic profiles of urine extracts of humans with viral infections, as well as of media of virus-infected human tissue cultures, have been analyzed by non-fragmenting mass spectrometry and compared with corresponding controls. The spectra were then subjected to several alternative computerized statistical procedures to detect diagnostic biochemical profiles. Controlled longitudinal studies on fully informed, consenting volunteers who received sandfly fever virus demonstrate the onset of a characteristic metabolic pattern that precedes the onset of symptoms and subsides when the patients overcome the infection. Longitudinal studies of human tissue cultures infected with poliomyelitis virus demonstrate characteristic metabolic patterns within a few hours after infection. Non-fragmenting mass spectrometry may thus provide the clinical laboratory with a sensitive, reliable test for viral infections significantly faster than attainable by current techniques.
Continuous-flow zone electrophoresis: experimental demonstration and discussion of potential clinical and research applications.
Authors: Fosslien E , Anderson D N , Nastir A 
Published: January 2020

Abstract
We report continuous-flow sample application and continuous electrophoretic separation on a moving cellulose acetate tape. This very simple automated electrophoretic system requires minimum electronic control circuitry. Samples and calibrators are pumped by a peristaltic pump from sample containers onto a continuously moving cellulose acetate tape. Applied samples are interspaced with rinse solution (buffer) and small air segments for sample integrity. Electrophoretic separation, staining, and destaining are all continuous functions performed on the continuously moving tape. The system appears suitable for separation of proteins. Continuous-flow application could be combined with discrete sample application onto the same tape for continuous counter-immunoelectrophoresis; moreover, counter-electrophoresis of two continuously applied proteins, with one applied in a gradient, could potentially produce a system for automated gradient counter-immunoelectrophoresis. It should also be possible to design a simple system for automated immunofixation electrophoresis.
Combined liquid chromatograph/mass spectrometer for involatile biological samples.
Authors: Blakley C R , Carmody J C , Vestal M L 
Published: January 2020

Abstract
A new liquid chromatograph/mass spectrometer has been developed in our laboratory for application to analysis of biological molecules of extremely low volatility. Oxyhydrogen flames rapidly vaporize the total liquid-chromatographic effluent, and molecular and particle beam techniques are used to efficiently transfer the sample to the ionization source of the mass spectrometer. This new instrument is comparable in cost and complexity to a combined gas chromatograph/mass spectrometer, but extends the capabilities of combined chromatography/mass spectrometry to a broad range of compounds not previously accessible. We are currently testing biologically significant samples with this instrument, using reversed-phase liquid-chromatographic separation and both positive and negative ion chemical-ionization mass spectrometry. Results have been obtained from mixtures of nucleic acid components—bases, nucleosides, and nucleotides—and from amino acids, peptides, saccharides, fatty acids, vitamins, and antibiotics. In all cases investigated to date, ions indicative of molecular mass are obtained in at least one of the operating modes available. Detection limits are typically in the 1-10 ng range for full mass scans (about 80-600 amu); sub-nanogram quantities are usually detectable with single-ion monitoring.
Specific detection of primary amines in the effluent of a gas-chromatographic column by on-line measurement of fluorescence.
Authors: Chow F , Karmen A 
Published: January 2020

Abstract
Compounds with primary amino groups react with o-phthalaldehyde in solution to yield highly fluorescent products. This reaction is now in wide use for detecting amino acids and amines in liquid-chromatography effluents. We report here a method for using o-phthalaldehyde to detect primary amines in the effluent of a gas-liquid-chromatographic column. The effluent gas, nominally 20 mL/min, is delivered to a scrubber consisting of a small-bore, simulated capillary chromatographic column that is simultaneously supplied with 1 mL/min of the reagent solution. The liquid effluent of the scrubber, separated from the gas, is drawn through the flow cell of a fluorometer. Short-chain amines and ammonia were quantitatively scrubbed. The response of the fluorometer was directly proportional to the number of nanomoles injected into the column. Less than a nanomole of amine was detectable. Comparison of results with those from a hydrogen flame-ionization detector showed minimal additional peak broadening or compromise of resolution. These results demonstrate the feasibility of using highly specific, as well as sensitive, liquid-chromatographic detection methods for gas-liquid chromatography.
Liquid chromatography with amperometric reaction detection involving electrogenerated reagents: applications with in-situ generated bromine.
Authors: King W P , Kissinger P T 
Published: January 2020

Abstract
We describe the use of electrogenerated reactants for continuous on-line reaction detection with thin-layer hydrodynamic amperometry. The reagent is introduced into the liquid-chromatographic column effluent at a constant rate by using controlled-current electrochemistry. After the effluent passes through a short reaction coil, the reagent concentration is monitored at the detector. Reaction of eluted compounds with bromine is signalled by changes in the current detected. The direct electrochemical control of the reagent concentration allows changes to be made, even during the course of obtaining a chromatogram. Depending on the specific reagent or reaction, the reagent is supplied either by addition of a second stream or by direct generation in the mobile phase. The latter configuration provides sufficient baseline stability to permit detection of the uptake of as little as 10 pmol of reagent bromine. The technique has been used to detect nanograms of underivatized fatty acids, prostaglandins, and phenols after separation by reversed-phase liquid chromatography.
Electrophoretic, kinetic, and immunoinhibition properties of gamma-glutamyltransferase from various tissues compared.
Authors: Shaw L M , Petersen-Archer L , London J W , Marsh E 
Published: January 2020

Abstract
gamma-Glutamyltransferase (EC 2.3.2.2) from human liver, kidney, pancreas, and duodenum migrated in acrylamide gels (65 g/L) as a single band with the following decreasing order of electrophoretic mobility: liver &gt; pancreas &gt; kidney &gt; duodenum. The initial velocity kinetic constants of pancreatic and duodenal gamma-glutamyltransferase and of the enzyme in human serum were determined and compared with those we previously established for the enzyme from human kidney, liver, and serum. The greatest differences were in the glycylglycine competitive-inhibition constants: kidney gamma-glutamyltransferase was the most strongly inhibited and pancreatic enzyme the second most strongly inhibited by high concentrations of glycylglycine, with the liver and duodenal isoenzymes only slightly inhibited and the enzyme in serum not inhibited over the concentration range (0-150 mmol/L) of glycylglycine used. Differences between the other kinetic constants of these isoenzymes were much smaller. Human liver gamma-glutamyltransferase was obtained in a highly purified form by a six-step procedure that included papain digestion of the original homogenate. Rabbit antisera raised against this preparation inhibited liver, kidney, and pancreatic gamma-glutamyltransferase activity equally well (78, 76, and 78% inhibition, respectively), but inhibited the hog-kidney enzyme only slightly (1%). We conclude that the polypeptide portions of the isoenzyme molecules are structurally similar but that the carbohydrate moieties differ significantly in structure and topography.
Rapid radioimmunoassay for prostate-specific acid phosphatase in human serum.
Authors: Vihko P , Kostama A , Jänne O , Sajanti E , Vihko R 
Published: January 2020

Abstract
We describe a rapid radioimmunoassay for human prostatic acid phosphatase (EC 3.1.3.2) in serum, with use of monospecific antisera raised in rabbits against the primary highly purified acid phosphatase (pl 4.9) from human prostates, and with a second antibody-polyethylene glycol porecipitation. This radioimmunoassay is sensitive and can be performed within 5 h. Concentrations of the immunoreactive acid phosphatase in sera of healthy men (n = 394) ranged from 0.3 to 3.6 microgram/L (mean 1.94, SD 0.66 microgram/L). Concentrations of the enzyme in sera of men with benign prostatic hyperplasia (n = 56) or with carcinoma of nonprostatic origin (n = 24) were identical with those of the reference group. Serum concentrations of immunoreactive prostatic acid phosphatase of patients with occult, non-metastatic, and metastatic prostatic carcinoma varied from 1.7 to 9.3 (n = 9), 4.2 to 59.4 (n = 12), and 20 to 198 (n = 10) microgram/L, respectively. The amount of immunoassayable prostatic acid phosphatase was unchanged for at least five days in serum stored at 4 degrees C.
Gas chromatographic-mass spectrometric identification of isosaccharino-1,4-lactone in human serum and urine.
Authors: Niwa T , Maeda K , Ohki T , Saito A , Sakakibara J , Kobayashi K 
Published: January 2020

Abstract
We have identified alpha-isosaccharino-1,4-lactone and beta-isosaccharino-1,4-lactone in the ethyl acetate extract of an ultrafiltrate of blood and of normal human urine, using high-resolution gas chromatography-mass spectrometry. The ultrafiltrate of blood was obtained from three patients on hemodialysis, one with psoriasis vulgaris, one with uremia, and one with amyotrophic lateral sclerosis. The concentration of beta-isosaccharino-1,4-lactone in the ultrafiltrate was two- to threefold that of alpha-isosaccharino-1,4-lactone. Mass fragmentography showed that isosaccharino-1,4-lactone is normally present in human serum in a concentration of 1.7 (SD 1.5) mg/L. In physiological fluid, isosaccharino-1,4-lactone apparently is present in its hydrated form, isosaccharinate.
Modified aca method for determination of iron chelated by deferoxamine and other chelators.
Authors: Steinmetz W L , Glick M R , Oei T O 
Published: January 2020

Abstract
Iron in serum and urine specimens containing deferoxamine (a chelator used in treating acute iron intoxication) can be measured by the DuPont aca discrete-analyzer method for iron if 0.5 mL of a 100 mL/L solution of thioglycolic acid (mercaptoacetic acid) is added to the IRN-1 and IRN-2 test packs before their use. This reagent releases the unreactive chelated iron, allowing reliable colorimetry. Because about 50% of hemoglobin iron is measured by the modified method, hemolysed samples should not be used (or results should be corrected for hemoglobin iron). The modification allows emergency determination to total serum iron and assessment of urinary iron during chelation therapy, as well as measurement of plasma iron in samples treated with sodium citrate or oxalate plus fluoride (the unmodified aca iron method gives falsely low iron values in the presence of these chelators). About 60% of iron present as the dextran complex (Imferon) is measured by the modified aca method, as compared with &lt;5% by the unmodified aca technique.
Advantage of Florisil over charcoal separation in a mechanized testosterone radioimmunoassay.
Authors: Harman S M , Tsitouras P D , Kowatch M A , Kowarski A A 
Published: January 2020

Abstract
We have facilitated radiommunoassay of testosterone by mechanizing every pipetting step and separating bound from free hormone by shaking assay tubes with activated magnesium silicate (Florisil) in a multi-tube Vortex mixer. Compared with dextran-charcoal separation, Florisil separation has the advantage that testosterone is only negligibly adsorbed except during active shaking, so that the interval for adding adsorbent does not produce discrepancies in bound hormone estimates between first and last assay tubes in a series. Our method gave CVs of 5% (within assay) and 6% (between assay) for samples containing 4.0 mug of testosterone per liter, considerably better than those obtained with charcoal (respectively 12 and 15%). The assay also had low blank values and demonstrated excellent accuracy.
Improved ultrafiltration method for determining unbound cortisol in plasma.
Authors: Jerkunica I , Sophianopoulos J , Sgoutas D 
Published: January 2020

Abstract
We describe a modified ultrafiltration method for measuring unbound cortisol in diluted or undiluted plasma or serum. After equilibration at 37 degrees C with purified [3H]cortisol, plasma or serum with or without buffer was placed in the ultrafiltration cell and two successive 0.2-mL fractions of protein-free ultrafiltrate were obtained. Under our conditions, free ligand concentration was independent of flow rate. The second fraction (the first is discarded) was used for determining the proportion of unbound cortisol. The assay is rapid (less than 2 h), practical (no more than 1.5 mL of plasma or serum is necessary), and reproducible (CV: 4.5% within assay and 5.2% in different assays). Samples from normal men and women (blood taken at 0800 and 1600 hours), from pregnant women, and from patients with Cushing's disease and adrenal insufficiency gave results that agreed with those obtained by equilibrium dialysis.
Assay for trimethoprim in serum and urine by means of ion-pair chromatography.
Authors: Watson I D , Shenkin A , McIntosh S J , Cohen H N 
Published: January 2020

Abstract
We describe a rapid, precise, and reliable procedure for assay of trimethoprim in serum and urine by ion-pair chromatography. Trimethoprim concentrations in urine are determined by an externally standardized, direct-injection procedure; assay in serum involves a simple preliminary extraction and internal standardization. The assays are suitable for pharmacokinetic studies and have been applied to determination of trimethoprim concentrations in serum and urine during therapy with Co-trimoxazole, a sulfonamide/trimethoprim preparation.