bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiparameter appraoch to the "fingerprinting" of fluorescent Pseudomonads.
Authors: Shelly D C , Warner I M , Quarles J M 
Published: January 2020

Abstract
A recent study has shown that an emission-excitation matrix could be used to provide a unique fingerprint for the selective identification and characterization of certain species of Pseudomonas. This paper describes the results of a systematic study of the variables that contribute to the uniqueness of the fingerprint. Additional insight concerning the nature of the fluorescent pigments of these species is gained by analysis with a high-performance liquid chromatograph/video fluorometer combination. While providing information about the analytical variables contributing to the analysis, this combination also added the variable of chromatographic retention time for unambiguous fingerprinting.
Microcolumn liquid chromatography: a tool of potential significance in biomedical research.
Authors: Novotny M 
Published: January 2020

Abstract
Recent progress in the area of microcolumn HPLC is reviewed with an emphasis on biomedically important directions. The potential of high efficiency separations, additional advantages of solvent economy, and the development of new detection and ancillary techniques of high-performance liquid chromatography are also discussed.
Enzymic determination of free fatty acids in serum.
Authors: Okabe H , Uji Y , Nagashima K , Noma A 
Published: January 2020

Abstract
We describe the enzymic determination of free fatty acids in serum with use of acyl-CoA synthetase (EC l.2.1.3), acyl-CoA oxidase (no EC no. assigned) and peroxidase (EC 1.11.1.7). The free fatty acids are activated by acyl-CoA synthetase in the presence of ATP and coenzyme A. The acyl-CoA formed is oxidized by acyl-CoA oxidase to enoyl-CoA with simultaneous production of hydrogen peroxide, which is oxidatively coupled with 4-amino-antipyrine and 2,4-dibromphenol in the presence of peroxidase to yield a product that absorbs maximally at 505 nm. Standard curves prepared with various kinds of fatty acids are linear to at least 2.0 mmol/L and are practically congruent. Ascorbic acid or bilirubin interferes slightly. Results by the present method correlate well with those by the colorimetric method involving 2-(2-thiozolylazo)-p-cresol (r = 0.98). Replicate analyses of standard solution and of two kinds of control sera demonstrated the following between-assay precision: mean absorbance 0.224 (SD 0.002), CV 0.85%; mean concentration, 326 (SD 7.3) and 1076 (SD 22.7) mumol/L, CV 2.24 and 2.11%, respectively.
Antigen--antibody reaction investiaged with use of a chemically modified electrode.
Authors: Yamamoto N , Nagasawa Y , Shuto S , Tsubomura H , Sawai M , Okumura H 
Published: January 2020

Abstract
The antigen-antibody reaction of human choriogenadotropin has been potentiometrically investigated by use of a cyanogen bromide-treated electrode coated with the corresponding anti-serum. The potential of the modified electrode shifts in the positive direction upon contact with a solution of choriogonadotropin. The rate of the reaction at the interface between the electrode and the solution is estimated from the potentiometric measurement to be of the order of 10(4) mol-1 s-1 in diethyl barbiturate buffer, depending to some extent on the rotation speed of the stirrer. The change in potential is almost proportional to choriogonadotropin concentration. It is also pH dependent, the maximum response being at pH 8.7. The technique, applied to samples of human urine, has shown a specific response to choriogonadotropin.
Improved analysis for urinary polyamines by use of high-voltage electrophoresis on paper.
Authors: Fujita K , Nagatsu T , Shinpo K , Maruta K , Teradaira R , Nakamura M 
Published: January 2020

Abstract
This method for assay of polyamines (putrescine, spermidine, and spermine) in large numbers of urine samples is based on preliminary analyte isolation by use of a Dowex 50W column, separation by high-voltage paper electrophoresis, reaction with ninhydrin to detect the separated amines, and subsequent direct assay with a dual-wave-length thin-layer chromatography scanner by the zigzag scanning method. By optimizing the conditions for the Dowex 50W column and high-voltage paper electrophoresis, putrescine, cadaverine, spermidine, and spermine were completely separated. The major technical improvements are room-temperature collection of urine with toluene, shorter hydrolysis time, complete separation of putrescine from cadaverine and histamine, and elimination of interference with spermine measurement. Polyamine concentrations as measured by this method agreed with those obtained by use of an amino acid analyzer. Reference intervals by this method were similar to those reported by Russell (Clin. Chem. 23: 22, 1977) with an automated amino acid analyzer. Putrescine, spermidine, and spermine excretion in urine from patients with blood cancers and solid cancers was significantly increased; information on concentrations of putrescine and spermidine were especially useful for following the clinical efficacy of cancer treatments.
Radioimmunoassay of progesterone in unextracted serum.
Authors: Haynes S P , Corcoran J M , Eastman C J , Doy F A 
Published: January 2020

Abstract
We describe a rapid, precise radiommunoassay for progesterone in 25 muL of unextracted serum. Progesterone is released from its binding protein by adding an optimal amount of cortisol, which binds to the same protein (cortisol binding globulin) as progesterone. The amount of cortisol required does not cross react with the specific progesterone antibody used. This approach considerably shortens assay time and removes a tedious and imprecise stage in the conventional assay of serum progesterone. Results correlated well (r = 0.97) with a method involving organic solvent extraction of progesterone from serum. During the two years we have used this method in a busy diagnostic endocrine laboratory, the between-assay precision (CV) for low-, medium-, and high-concentration quality control sera was 12, 7, and 9%, respectively. Data from participation in an independent external quality-control program verified the adequacies of the method.
Kinetic properties of gamma-glutamyltransferase from human liver.
Authors: PetitClerc C , Shiele F , Bagrel D , Mahassen A , Siest G 
Published: January 2020

Abstract
We studied the kinetic properties of purified "heavy" form of human liver gamma-glutamyltransferase (EC 2.3.2.2) in the presence and absence of the acceptor substrate glycylglycine under Vmax conditions and as a function of pH. gamma-Glutamyl carboxynitroanilide was used as the donor substrate. Our data suggest that hydrolysis of donor substrate is the major pathway in the absence of acceptor. Autotransfer, if it occurs, is not important. Hydrolysis and transfer reactions have different pH profiles both for Vmax and Km. The pH dependency of Vmax and Km for both the hydrolase and the transferase reactions most probably reflects a change in the rate-limiting step: deacylation of the enzyme at acidic pH and acylation at alkaline pH. Negative cooperativity, observed for both donor and acceptor substrates near neutral pH, is interpreted in terms of more than one active site per dimer for each substrate.
Fluorometry of ethylene glycol in serum.
Authors: Meola J M , Rosano T G , Swift T A 
Published: January 2020

Abstract
We describe an assay for ethylene glycol in serum, which is based on the Hantzsch condensation reaction. Ethylene glycol is dehydrogenated by sodium periodate to form two molecules of formaldehyde, which is then combined with ammonium ion and acetylacetone to form a fluorescent diacetyllutidine derivative. The detection limit of this method is 50 mg/L. The procedure is sensitive, requires only 100 micro L of serum, and the standard curve is linear over a working range of 50 to 250 mg/L. Average analytical recovery ranged from 99 to 102% and within-run precision studies showed CVs of &lt; 5%. Reagents are easily prepared and available.
Dilution as a source of error: implications for preparation and calibration of laboratory standards and for quality control of radioimmunoassays.
Authors: Gaines Das R E 
Published: January 2020

Abstract
Although dilution of materials is generally accepted to involve some error, workers often assume that this error may be discounted. However, comparing solutions of two identical materials diluted in the same way shows that dilution errors can cause a considerable departure from the expected identity. I describe this effect and its dependence on the errors at various stages of the dilution process.
Effect of detergent on kinetic Jaffé-method assay of creatinine.
Authors: Bergman A , Ohman G 
Published: January 2020

Abstract
Using isotope dilution-mass spectrometry as reference method, we show that the kinetic Jaffé method for determination of serum creatinine sometimes produces results that are much too high. Such falsely increased values were obtained in about 10% of the sera collected for routine determination of creatinine, and were most common when certain types of collecting tubes were used. The interferences could be overcome by use of detergent in the reaction mixture.
Determination of 8-methoxypsoralen in suction-blister fluid and serum by liquid chromatography.
Authors: Herfst M J , Edelbroek P M , de Wolff F A 
Published: January 2020

Abstract
A method is described for determination of 8-methoxypsoralen to 0.2 mL of suction-blister fluid or 1 mL of serum from psoriatic patients being treated with this drug. The drug is extracted from the biological matrix at pH 9.0 with a mixture of dichloromethane and light petroleum ether. 5-Methoxypsoralen is used as internal standard. Separation and quantitation are performed on a “high-performance” liquid chromatograph with use of an RP 18 reversed-phase column and detection at 245 nm. Accuracy and precision are good. Some benzodiazepines and their metabolites interfere. The lowest detectable concentration is 10 microgram/L, which means that the method is sufficiently sensitive to measure the drug concentrations in serum and suction-blister fluid for pharmacokinetic studies in patients being treated with a therapeutic dosage.
Heparin--magnesium chloride--albumin method for enzymic measurement of cholesterol in high-density lipoprotein.
Authors: Tallet F , Raichvarg D , Canal J 
Published: January 2020

Abstract
We describe a new method for measuring high-density-lipoprotein cholesterol in sera, with use of heparin, MgCl2, and albumin to precipitate very-low- and low-density lipoproteins, Lipoprotein electrophoresis and immunochemical methods show that high-density lipoprotein is completely and specifically isolated in the supernate, the cholesterol concentration of which is estimated by the enzymic method of Allain et al. (Clin. Chem. 20, 470, 1974). The precision of the method is excellent (CV = 1%) and the response is linear. Values so obtained correlate well with those obtained with the heparin-Mn2+ (r = 0.98) or the phosphotungstate-Mg2+ (r = 0.98) procedures. The technique is appropriate for routine clinical laboratory use.
Gas-chromatographic method of analysis for urinary organic acids. I. Retention indices of 155 metabolically important compounds.
Authors: Tanaka K , Hine D G , West-Dull A , Lynn T B 
Published: January 2020

Abstract
Gas-chromatographic retention indices are given, in terms of methylene units, for 155 metabolically important compounds (mostly organic acids) as trimethylsilyl derivatives on 10% OV-1 and 10% OV-17 columns. Comprehensive references on metabolic diseases that can be diagnosed by detection of these metabolites are cross-indexed to facilitate the use of the methylene-unit list. With the data presented here, it is now possible to diagnose more than 25 well-defined organic acidurias by use of gas chromatography alone.
Age-, sex-, and race-related differences in myoglobin concentrations in the serum of healthy persons.
Authors: Chen I W , David R , Maxon H R , Sperling M , Stein E A 
Published: January 2020

Abstract
A radioimmunoassay was used to study the relation of race, sex, and age to serum myoglobin concentrations in ostensibly healthy individuals: 75 white men, 76 white women, 75 black men, and 66 black women, ranging in age from 20 to 85 years. Mean serum myoglobin values were significantly higher in men than in women in both races (35 vs 31 microgram/L for whites and 44 vs 29 microgram/L for blacks). Black men had higher values than white men, but no corresponding difference was observed in the female population. Except for the group of black men, which consistently had the highest values for serum myoglobin, values were always higher for the older groups (greater than or equal to 50 years) than the younger, irrespective of race or sex. Serum myoglobin and age were significantly and directly correlated only among white men (r = 0.3408 p &lt; 0.01, n = 75). If results were expressed as a myoglobin/creatinine ratio, the distinctions by race, sex, and age were partly eliminated. Reference intervals for serum myoglobin, expressed both ways, are given for different race, sex, and age groups.
A 57Co-soap assay for plasma total non-esterified fatty acids compared with a gas-liquid chromatographic method.
Authors: Turnell D C , Price C P , France M M 
Published: January 2020

Abstract
We describe a relatively rapid radiochemical assay for determining plasma non-esterified fatty acids, by use of a Dole-type (J. Clin. Invest. 35: 150, 1956) extraction and formation of 57Co soaps. Results correlated well (r = 0.957) with those by gas-liquid chromatography. The between-batch CV for 1.12 mmol of non-esterified fatty acids per liter was 7%; the sensitivity is estimated to be 22 mumol/L.
Measurement of urinary constituents with the Astra-8 Multichannel Analyzer.
Authors: Blumenfeld T A , Griffith B 
Published: January 2020

Abstract
The Beckman Astra-8 is a computerized, discrete-microsample, multiple-test clinical chemistry analyzer. We have examined its capability to measure urine Na+, K+, Cl-, urea nitrogen, glucose, and creatinine and found that (a) the Astra measurements are linear, accurate, and precise in concentration ranges of urine analytes; (b) urine analyte concentrations measured with the Astra correlate well with those by comparison micromethods (p &lt; 0.001); and (c) the Astra has no significant carryover from adjacent urine samples or from adjacent urine and serum samples.
Creatine kinase isoenzyme patterns in neoplasms of peripheral nerve.
Authors: Balaton J , Hoag G N , Franks C R , Smith C R , DeCoteau W E 
Published: January 2020

Abstract
Normal peripheral nerve and neoplastic lesions of peripheral nerve varied in their creatine kinase (CK; EC 2.7.3.2) isoenzyme pattern, as assessed both with electrophoresis and with column chromatography. All three isoenzymes were seen in normal peripheral nerve, but the peripheral nerve tumors, neurofibroma and neurilemmoma, demonstrated predominantly CK-1 isoenzyme activity, with a trace amount of CK-3. No CK-2 activity was demonstrated in these tumors. In contrast, malignant schwannoma tissue contained all three isoenzymes, but in a different proportion than in normal peripheral nerve.
Pattern of urinary proteins and peptides in patients with rheumatoid arthritis investigated with the Iso-Dalt technique.
Authors: Clark P M , Kricka L J , Whitehead T P 
Published: January 2020

Abstract
Characteristic differences in the pattern of urinary proteins and peptides have been found in patients with rheumatoid arthritis, compared with patterns from healthy controls. These differences have been demonstrated with a two-dimensional gel electrophoretic technique (Iso-Dalt) involving isoelectric focusing in the first dimension, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the second dimension. Using simple photographic techniques, one can obtain a composite pattern of the individual protein-stained gels for each group. Comparison of the composite patterns from the rheumatoid arthritis group and the control group revealed several proteins in the urine of the rheumatoid arthritis patients not found in the control group. Two groupings of these proteins were identified: acidic, high-Mr proteins and more basic, low-Mr proteins.
Improved electrothermal determination of aluminum in serum by atomic absorption spectroscopy.
Authors: Alderman F R , Gitelman H J 
Published: January 2020

Abstract
We describe an improved method for determination of aluminum in serum by atomic absorption spectrophotometry with a graphite furnace. Interferences have been controlled and total combustion of the samples achieved by the use of new diluent in a molybdenum-treated graphite tube. The detection limit of this method is 2 microgram/L.
3-hydroxydecanedioic acid and related homologues: urinary metabolites in ketoacidosis.
Authors: Greter J , Lindstedt S , Seeman H , Steen G 
Published: January 2020

Abstract
Urine from patients with ketoacidosis was found to contain a number of aliphatic 3-hydroxy dicarboxylic acids. The acids were purified by silicic acid chromatography and their structures determined by gas chromatography-mass spectrometry of different derivatives. The major compound was 3-hydroxydecanedioic acid. Minor compounds were 3-hydroxyoctanedioic acid, 3-hydroxyoctenedioic acid, 3-hydroxydecenedioic acid, 3-hydroxydodecanedioic acid, 3-hydroxydodecenedioic acid, 3-hydroxytetradecenedioic acid, and 3-hydroxytetradecadienedioic acid. The excretion of 3-hydroxydecanedioic acid correlated positively with the excretion of hexanedioic acid, another metabolite constantly found in ketoacidosis (Pettersen et al., Clin. Chim. Acta 38: 17-24, 1972). We suggest that the 3-hydroxy dicarboxylic acids are formed from fatty acids by a combination of omega-oxidation and incomplete beta-oxidation.
Gas-chromatographic determination of amantadine in human urine.
Authors: Stumph M J , Noall M W , Knight V 
Published: January 2020

Abstract
We describe a gas--liquid-chromatographic method for determining the concentration of amantadine hydrochloride in urine with beta-phenylethylamine as internal standard. The urine sample is made alkaline and extracted with 0.5 mL of chloroform. After centrifugation the aqueous layer is aspirated, and an aliquot of the organic layer is injected directly into the gas chromatograph. Concentration and instrument response are linearly related between 2 and 125 mg/L. The limit of detection was 0.5 mg/L. Mean analytical recovery was calculated to be 97%.
Comparison of radial immunodiffusion and laser nephelometry for quantitating some serum proteins.
Authors: Alexander R L 
Published: January 2020

Abstract
After quantitating immunoglobulins G, A, and M and complement C3c and C4 in serum by using a laser nephelometer coupled with a data processor, I compared these results with values obtained by an early-readout radial immunodiffusion method. Day-to-day precision was better for nephelometry than for radial immunodiffusion for all proteins analyzed. The average coefficient of variation was 6.0% for nephelometry and 9.9% for radial immunodiffusion. Comparison of these methods gave ranked correlation coefficients of 0.945, 0.981, 0.932, 0.803, and 0.792 for IgG, IgA, IgM, C3c, and C4, respectively. Nephelometry gave significantly higher values than radial immunodiffusion for IgG, IgA, IgM, and C3c, and significantly lower values for C4 (p less than 0.001). Part of this bias was found to be due to the equation programmed in the data processor for calculating the standard curves. Within 95% limits, nephelometry gave higher normal ranges than radial immunodiffusion for IgG, IgA, and IgM. Other possible factors that can produce this bias are discussed.
Room temperature radioassay for B12 with oyster toadfish (Opsanus tau) serum as binder.
Authors: Ithakissios D S , Kubiatowicz D O , Wicks J H 
Published: January 2020

Abstract
We describe a vitamin B12 radioassay with oyster toadfish (Opsanus tau) serum in which endogenous serum B12 is released from its protein complexes at room temperature with NaOH at pH 13.6. The radioassay is reproducible (CV 4.9% within assay, 8.4% between assays) and sensitive (10 ng/L) and requires minimum manipulations. Assay accuracy is unaffected by serum protein.
Amniotic fluid phospholipids measured by continuous-development thin-layer chromatography.
Authors: Kolins M D , Epstein E , Civin W H , Weiner S 
Published: January 2020

Abstract
We describe a one-dimensional thin-layer chromatographic system for separation of amniotic fluid phosphatidylcholine, sphingomyelin, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, and phosphatidylethanolamine in amniotic fluid. We utilize short-bed continuous development and "high performance" thin-layer chromatography. Phospholipids are detected with an antimony molybdate staining reagent and quantitated by transmittance densitometry. This system is more sensitive to changes in lecithin/sphingomyelin ratios than are planimetric evaluations.
Kinetic serum creatinine assays I. The role of various factors in determining specificity.
Authors: Bowers L D 
Published: January 2020

Abstract
We studied the specificity of kinetic methods of analysis, with emphasis on creatinine determination. The error contributed by an interferent that reacts with the analytical reagent and absorbs at the wavelength of analysis is shown to be related to the ratio of the equilibrium absorbances of the analyte and interferent, the ratio of the rate constants, the extent of the analytical reaction, and the duration of the measurement. To assess the potential diminution of the interference with kinetic methods, we determined the rate constants of several alpha-keto acids in the Jaffé reaction. Evaluation of the advantages of various measuring techniques with respect to specificity showed the main factors to be the extent of the analytical reaction and the relative value of the rate constants. Total specificity for creatine appears to be unattainable with currently used kinetic techniques.
Kinetic serum creatinine assays. II. A critical evaluation and review.
Authors: Bowers L D , Wong E T 
Published: January 2020

Abstract
We have evaluated the Technicon AutoAnalyzer method, the Beckman Creatinine Analyzer II, DuPont aca, Electro-Nucleonics GEMSAEC, and Instrumentation Laboratory Model 916 kinetic methods for determination of serum creatinine. These methods, which involve the Jaffé reaction, all showed a statistically significant proportional error relative to an ion-exchange pretreatment method for creatinine in 92 serum samples; the GEMSAEC method also showed a bias. The positive interference of several acid metabolites was quantitated in each of the methods. The evidence indicates that bilirubin, although associated with a negative creatinine interference, is not the sole interferent. We determined the magnitude of this interference and studied several methods for minimizing it.
125I-labeled gonadoliberin and high specific activity and immunoreactivity: method of iodination and rapid separation.
Authors: Sarda A K , Barnes M A , Nair R M 
Published: January 2020

Abstract
We describe optimum conditions for iodinating gonadoliberin with use of relatively large proportions of Na 125I. Products of the iodination are separated on an anion-exchange resin (Amberlite IRA-400). The 125I-labeled gonadoliberin thus obtained has a high specific activity (1400 to 1590 Ci/g); because of the conditions of iodination, we believe that the predominant species of the labeled decapeptide is the mono-iodinated one. Our separation and purification of the labeled substance on ion-exchange resin is rapid, economical, and less cumbersome than the use of a Biogel P-2 column. There is no adsorption of the labeled hormone onto the resin, as evidenced by analytical recovery studies with tritium-labeled gonadoliberin. Paper-strip chromatoelectrophoresis showed no free Na 125I or radiolabeled damaged peptide fragments after purification on the resin. When antiserum was used at a concentration 32-fold that used in the regular assay procedure, only 4% of the radioactivity remained in the free form, indicating the high immunoreactivity of the labeled hormone.