bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid-chromatographic method for estimating urinary sugars: applicability to studies of intestinal permeability.
Authors: Delahunty T , Hollander D 
Published: January 2020

Abstract
Sugars of exogenous origin excreted in the urine can be rapidly quantified by "high-pressure" liquid chromatography. A simple extraction with an ion-exchange resin is used to prepare the sample for analysis. Aliquots (20 microL) are chromatographed on a cation-exchange column at 85 degrees C, with water as the mobile phase. Sugars are detected with a refractive index detector. Lactulose, rhamnose, and mannitol all give discrete peaks and a linear response up to 5 g/L, with analytical recoveries from urine of 80, 62, and 80%, respectively. Precision is good, the CVs for lactulose, rhamnose, and mannitol being 2.9, 4.0, and 5.6%, respectively. The only endogenous compound consistently present in the chromatograms is urea, which does not interfere. However, glucosuria, if present, could interfere with the lactulose estimation. This method may be a simple, labor-saving means of quantifying urinary sugars in the clinical laboratory.
Aqueous and serum-based materials compared for use as simulated calibrators for three ionized calcium analyzers.
Authors: Toffaletti J , Bird C , Berg C , Abrams B 
Published: January 2020

Abstract
To determine if bias between different ionized calcium analyzers could be decreased, we analyzed 10 control fluids during a study in which ionized calcium was measured in more than 150 serum and whole-blood samples. After calibrating three ionized calcium analyzers (Radiometer ICA 1, Nova 8, and AVL 980) with the manufacturers' respective calibrators, we used the between-instrument differences of the control fluids to simulate recalibration of the analyzers during each analytical run. A filtered human serum pool containing ionized calcium at 1 mmol/L concentration, with CO2 removed and having no added buffer, was the only material that consistently decreased between-analyzer bias of both serum and whole blood. Another human serum pool containing about 1.3 mmol of ionized calcium and about 10 mmol of bicarbonate per liter was even better at minimizing analyzer biases for serum samples, but was not as effective for whole-blood samples. Some additives used to buffer pH apparently adversely affected both the accuracy and precision of some, but not other, calcium ion electrodes. We conclude that if a reference material is developed for calibration of ionized calcium analyzers, it should be tested on several analyzers for use with both serum and whole blood, and it should be at least as effective as a human serum material, such as that used here.
Polyethylene glycol can be validly omitted from chromogenic peptide substrate assay for antithrombin III.
Authors: Kolde H J 
Published: January 2020

Abstract
To investigate whether the characteristics of a commercial test kit for antithrombin III (Berichrom Antithrombin III) could be influenced by surfactants such as Tween-80 or polyethylene glycol (PEG), we performed some experiments with the original kit reagents and with the reagents dissolved in surfactants. Neither the reliability of the calibration curve nor the data for precision and assay kinetics were amended by the addition of either PEG to the (human) thrombin reagent or Tween-80 to the chromogenic substrate. In the same test system, assays with some other chromogenic substrates and with bovine thrombin showed comparable behavior. Evidently, if one follows the working scheme proposed for this kit, the use of surfactants is not warranted.
Five methods for determining urinary calcium compared.
Authors: Gowans E M , Fraser C G 
Published: January 2020

Abstract
We compared frequently used methods for calcium in urine with respect to linearity, analytical recovery, within- and between-batch imprecision, bias, and practicability. We assayed serum, lyophilized urine, native urine, and an aqueous reference solution of calcium carbonate. We found that atomic absorption spectrometry and the Corning 940 Analyzer have the widest ranges of linearity; the methylthymol blue method has the poorest analytical recovery. All methods--the aforementioned three plus the Du Pont aca and Technicon RA-1000 methods--had acceptable precision, although random errors were found with the methylthymol blue method, and, except for one type of commercial lyophilized urine assayed by the Technicon method, there were no matrix problems or difficulties with bias. We cannot recommend the methylthymol blue method, but evidently urinary calcium assays can be adequately done with many currently available methods. Intralaboratory attention to methodology should give improved performance in assessment programs.
Creatine kinase isoenzymes in extracts of various human skeletal muscles.
Authors: Tsung J S , Tsung S S 
Published: January 2020

Abstract
We have attempted to "map" creatine kinase (CK; EC 2.7.3.2) anatomically by assaying biopsy specimens of skeletal muscles taken from different locations from 109 surgical patients. Substantial activities of CK-MM were present in every specimen; CK-MB was observed in about 44% of these, at approximately 1 to 6% of the total CK activity.
Development of a simple device for processing whole-blood samples into measured aliquots of plasma.
Authors: Burtis C A , Johnson W F , Walker W A 
Published: January 2020

Abstract
A capillary processor and aliquoter has been designed and fabricated that is capable of accepting aliquots of whole blood and automatically processing them into discrete aliquots of plasma. The device consists of two disks, each of which contains 16 individual capillaries and a processing rotor. One disk accepts larger capillaries that hold approximately 100 microL of whole blood each. The second disk accepts 2.54-cm-long precision capillaries of various internal diameters, which provide exact sample volumes from 1 to 10 microL. The processing rotor contains 16 individual compartments and chambers to accept both disks. Applying centrifugal force transfers the aliquots of whole blood into their respective compartments, where they are separated into cellular and plasma fractions. As the rotor speed is slowly decreased, an aliquot of plasma is withdrawn by capillary action into each measuring capillary. The disk containing the 16 measured aliquots of plasma is then removed and placed into a modified rotor for conventional centrifugal analysis. This device can entrain and deliver microliter volumes of liquids with precision and accuracy (1-2%) near that of mechanical pipettes. Assays of the separated plasma aliquots also have acceptable precision (e.g., CVs approximately 3% for measurements of serum enzymes).
Application of pattern-recognition techniques in wavelength selection for instrumentally read reagent strips.
Authors: Chu A Y , Lopatin W 
Published: January 2020

Abstract
Pattern recognition techniques--discriminant analysis and principal component analysis--are utilized in selecting the wavelengths for monitoring, by reflectance spectroscopy, color-generating reactions involving uric acid and cholesterol in serum. The data base we used was accumulated by a rapid-scanning reflectance spectrophotometer that measured reflectance at 16 wavelengths every 5 s after the reaction was initiated. The data were then analyzed in multidimensional space mainframe computer with commercial statistical software packages. The most appropriate wavelengths were those that yielded the largest generalized distance between analyte concentration by discriminant analysis and the largest weighting coefficient by principal component analysis. For uric acid, taking the ratio of reflectance measured at two wavelengths instead of at a single wavelength much better separates the clinically significant concentrations. For cholesterol, the initiated. The data were then analyzed in multidimensional space hemoglobin, can be clearly demonstrated y the "pattern" generated with principal component analysis. generalized distance between analyte generalized distance between analyte concentration by discriminant
A radioimmunoassay for the antimalarial drug chloroquine.
Authors: Freier C , Alberici G , Turk P , Baud F , Bohuon C 
Published: January 2020

Abstract
We describe a 3H-based RIA for the antimalarial drug chloroquine (CLQ), the most commonly used antimalarial drug. In the assay a monoclonal antibody is used that is directed against 4-amino-7-chloroquinoline conjugated to keyhole limpet hemocyanin by the glutaraldehyde method. Besides CLQ, this antibody also recognizes with good affinity the 4-aminoquinoline homologs, hydroxychloroquine and amodiaquine. No extraction step or sample preparation is required, and the method can detect as little as 10 micrograms/L, the lower concentration in plasma of humans who are taking CLQ as a preventive measure. The between-assay CV is less than or equal to 10%, the within-assay CV less than or equal to 3%. Results correlate with those by liquid chromatography (r2 = 0.96). The speed and simplicity of the RIA method make it useful in evaluating the CLQ concentrations in acutely toxic patients.
Urine discoloration after acetaminophen overdose.
Authors: Clark P M , Clark J D , Wheatley T 
Published: January 2020

Abstract
Three patients with acetaminophen overdose were observed to have dark-brown urine at an early stage of their illness. Subsequently, acute anuric renal failure and hepatic dysfunction developed in all three. p-Aminophenol was identified by chromatographic and colorimetric methods in the urine of each case and is thought to be responsible for the discoloration.
Ultramicromethod for measuring the activity of terminal deoxynucleotidyl transferase.
Authors: Léotard B , Marchand-Arvier M , Vigneron C 
Published: January 2020

Abstract
We describe an ultramicromethod for measurement of terminal deoxynucleotidyl transferase activity. The materials used are as proposed by Hösli (Clin Chem 1977;23:1476-84) for antenatal diagnosis. The technique is based on the methods of Beutler and Kuhl (Am J Clin Pathol 1978;70:733-7) and Yasmineh et al. (Clin Chem 1980; 26:891-5). The procedure makes it possible to reduce the blood sample to 2 mL at the most and to reduce the cost of the measurement very considerably. The technique gives results similar to those given by the conventional techniques.
Faster assay of H2 in breath by dedicated instruments compared with conventional gas chromatography.
Authors: Gaffney P T , Buttenshaw R L , Thomas M J , Read R S , Ward M 
Published: January 2020

Abstract
Recently available instruments dedicated to the clinical assay of hydrogen in breath were tested and the results compared with those from a conventional thermal conductivity gas chromatograph. We found the Quintron Model 12 Microlyzer and the GMI Exhaled Hydrogen Monitor to give much faster and more sensitive results than the Gow-Mac 550 conventional gas chromatograph, and their readout is digital rather than graphical. Linearity of response, accuracy, and precision were similar for all those instruments. Maintenance requirements and performance characteristics of the three instruments are compared in detail and practical advice is given on daily operation.
Detection and confirmation of cocaine use by chromatographic analysis for methylecgonine in urine.
Authors: Clark D R , Hajar T M 
Published: January 2020

Abstract
Methylecgonine is a common metabolite of cocaine in man. We prepared methylecgonine and developed thin-layer chromatographic and gas-chromatographic methods for its detection in urine. Seventy urine specimens from our drug screening laboratory were tested by our method and by EMIT. Both methods were positive for 26 urines, and both were negative for 42 urines. The other two urines were shown to contain cocaine by GC/MS, and no detectable metabolites. We thus demonstrated that detection of methylecgonine and cocaine is as sensitive a test for cocaine use as EMIT.
Laboratory evaluation of the Koné "Progress" discrete analyzer.
Authors: Cynober L , Morgant G , Morelet L , Giboudeau J 
Published: January 2020

Abstract
The Koné "Progress," a discrete analyzer for use in clinical chemistry, was evaluated. The apparatus exhibited a high degree of precision and linearity, and no carryover. Results correlated well with those obtained with our routine equipment [Olli C + D (Koné), G-300 (Greiner), and Corona (Clinicon)].
The theophylline method of the Abbott "Vision" analyzer evaluated.
Authors: Chan K M , Koenig J , Walton K G , Francoeur T A , Lau B W , Ladenson J H 
Published: January 2020

Abstract
We evaluated the analytical performance of the Abbott "Vision" analyzer for theophylline measurement. The within-day precision (CV) was 1.8% and 3.1% at theophylline concentrations of 15.2 and 25.2 mg/L, respectively; between-day precision was 3.5% and 4.8% at 14.9 and 24.4 mg/L, respectively. Bilirubin (143 mg/L) and triglyceride (7.4 g/L) did not interfere, but hemoglobin caused lower values for apparent theophylline, the magnitude of the decrease being proportional to the hemoglobin concentration. At the cutoff concentration of 1 g/L programmed into the instrument by the manufacturer, hemoglobin reduced the theophylline value by less than 10%. Results by the Vision method (y) compared well with those by the "TDX" procedure (x): r = 0.98, y = 0.978x - 0.270 mg/L. The Vision method gave comparable theophylline values for serum, plasma, and whole-blood samples. We also validated analytically and clinically that capillary blood samples collected by finger stick can be used interchangeably with blood samples collected by venipuncture for monitoring theophylline therapy.
Quantification of desferrioxamine in blood plasma by inductively coupled plasma atomic emission spectrometry.
Authors: Bourdon S , Houzé P , Bourdon R 
Published: January 2020

Abstract
A sensitive method, inductively coupled plasma atomic emission spectroscopy, is used to measure desferrioxamine in blood plasma. The desferrioxamine is transformed into its iron chelate, ferrioxamine, which is extracted into benzyl alcohol, then re-extracted into HCl (0.5 mol/L), which is used as the sample for the spectroscopy. For a 0.5-mL plasma sample, the detection limit (1 microgram/mL) suffices for following the concentration of desferrioxamine in plasma after its subcutaneous or intramuscular injection (40 mg per kg of body weight). Neither blood pigments nor trace metals interfere.
Variables affecting resolution of lung phospholipids in one-dimensional thin-layer chromatography.
Authors: Krahn J 
Published: January 2020

Abstract
Resolution of the confusion in the literature about the separation of lung phospholipids in thin-layer chromatographic systems has awaited a systematic study of the variables that potentially affect this separation. In this study I show that: incorporation of ammonium sulfate into silica gel "GHL" has a dramatic effect on separation of lung phospholipids; this effect is equally dramatic but different in activated and nonactivated gels; when it picks up moisture, ammonium sulfate-activated gel very rapidly loses its ability to resolve lecithin from phosphatidylinositol; in gel containing ammonium sulfate, small amounts of phosphatidylethanolamine are hydrolyzed to lyso-phosphatidylethanolamine.
Laboratory assessment of a commercial kit for measuring fructosamine in serum.
Authors: Jury D R , Dunn P J 
Published: January 2020

Abstract
We have evaluated the laboratory performance and clinical usefulness of the Roche fructosamine kit. As used with an Abbott ABA 100 bichromatic analyzer, the kit response varied linearly with fructosamine concentration to 5.0 mmol/L (deoxymorpholinofructose equivalents). Interbatch precision was 4.1% and 3.6% for respective fructosamine concentrations of 3.2 and 5.0 mmol/L; intrabatch precision was 3.2% and 3.0% (fructosamine = 3.0 and 4.0 mmol/L). In 55 nondiabetic subjects all fructosamine values were less than 3.0 mmol/L, 95% were less than 2.7 mmol/L. For both fructosamine and glycated hemoglobin (Hb A1c) the 95th percentile of the reference range corresponded to approximately the 10th percentile of values observed in 108 diabetic subjects. In the latter subjects fructosamine concentrations correlated somewhat (r = 0.6504) with the Hb A1c value and for eight diabetic subjects indicated a similar degree of diabetic control over a 10-week period. From assessments of sensitivity and specificity for predicting abnormal glucose tolerance in 145 subjects, we conclude that this assay of serum fructosamine reflects diabetic control about as well as Hb A1c estimation, but neither can replace the glucose tolerance test for the diagnosis of diabetes.
Automated and manual quantitative assays of choriogonadotropin in serum compared.
Authors: Beinlich C J , Carpenter R H 
Published: January 2020

Abstract
We found the analytical performance of a rapid, automated assay of human choriogonadotropin (hCG) in serum, the Stratus hCG Fluorometric Enzyme Immunoassay, superior to a widely used manual assay for hCG (Hybritech Tandem-E hCG). The two assays were comparable in sensitivity; recovery; cross reactivity with lutropin, follitropin, and thyrotropin; and freedom from interference from hemoglobin and bilirubin. Patient-correlation studies indicated good quantitative agreement [Stratus hCG = (1.08 X Tandem hCG) - 4.3 int. units/L]. However, intra- and interassay precision was substantially better with the Stratus hCG assay, and this may allow earlier confirmation of pregnancy.
Total or free thyroxin as a primary test of thyroid function.
Authors: Penney M D , O'Sullivan D J 
Published: January 2020

Abstract
We compared measurement of free thyroxin (fT4) and total thyroxin (tT4) in serum as a primary screening test of thyroid function, based solely on biochemical diagnostic classification. The normal 95% reference intervals for fT4 and tT4 were equated by probit transformation, which allowed us directly to compare the efficiency of the biochemical classification. fT4 showed a small but distinct advantage over tT4 in the diagnosis of hyperthyroidism, but narrowing the reference interval proportionally for fT4 and tT4 to improve the sensitivity of the screening test resulted in the loss of this advantage. No clear advantage of fT4 over tT4 for the initial diagnosis of hypothyroidism was found at any reference interval.
Comparison of the urinary glycoconjugates excreted by patients with type I and type II fucosidosis.
Authors: Kin N M 
Published: January 2020

Abstract
Glycoconjugates were isolated, by repeated chromatography on Biogel P-4, from urine of two patients with different phenotypes of fucosidosis, type I (acute) and type II (chronic). Studies of the isolated compounds with thin-layer chromatography, chromatography on Biogel P-4, gas-liquid chromatography, and 1H- and 13C-nuclear magnetic resonance spectroscopy showed differences in the excretion patterns of fucosyl glycoconjugates in the urine of these patients. The amount of the diglycosylasparagine, fuc alpha 1-6glcNAc-Asn, excreted was significantly lower for the type I than for the type II patient. On the other hand, the reducing hexasaccharide gal beta 1-4(fuc alpha 1-3)glcNAc beta 1-2man alpha 1-3/6man beta 1-4glcNAc was present in much greater quantities in urine from the type I patient. The differences in the excretion patterns of these glycoconjugates may be attributed to different substrate specificities for the residual alpha-L-fucosidases in the two forms of the disease. I propose that such differences may be exploited for the early laboratory diagnosis of the type II form of the disease, particularly by thin-layer chromatography.
Modification of intra-erythrocytic homeostasis in uremic patients, as studied with 31P nuclear magnetic resonance.
Authors: Monti J P , Gallice P , Baas M , Murisasco A , Crevat A 
Published: January 2020

Abstract
Intra-erythrocytic pH, ATP concentrations, and 2,3-diphosphoglycerate relaxation times were studied in living erythrocytes by "high-resolution" 31P NMR spectroscopy to assess homeostasis within the cells. In uremic patients, intra-erythrocytic pH is significantly decreased before hemodialysis, but is corrected equally well by hemodialysis against either acetate or bicarbonate. This acidic pHi may be correlated with the increased concentration of ATP in erythrocytes in uremia, which is partly corrected by these two types of hemodialysis. Similarly, the significant decrease of spin-spin relaxation times in uremic patients is corrected by hemodialysis.
Autoantibody against diiodinated tyrosine-gastrin in a patient with Graves' disease.
Authors: Noguchi M , Adachi H , Aoki E , Iida Y , Kasagi K , Endo K , Konishi J , Torizuka K 
Published: January 2020

Abstract
We describe autoantibodies against iodinated gastrin in a patient with Graves' disease. Values for serum gastrin differed in this case, depending on which of two different radioimmunoassay (RIA) kits was used. RIA with the dextran-coated charcoal method for separation of free tracer gastrin gave a value less than 9.5 pmol/L, whereas the value by a RIA kit by the double-antibody method was 318 pmol/L. The patient's serum contained a binding protein for 125I-labeled gastrin, as detected by Sephadex G-200 column chromatography. The IgG fraction was responsible for the ability of serum to bind 125I-labeled gastrin. Interestingly, of the two possible forms of iodinated gastrins, monoiodinated (MIT) and diiodinated (DIT) tyrosine-125I-labeled gastrin, only the latter bound to patient's IgG. Furthermore, DIT-gastrin, but not gastrin or MIT-gastrin, inhibited the binding of DIT-125I-labeled gastrin. The patient's serum evidently contains autoantibodies against DIT-gastrin that interfere with RIA of gastrin.
Stability of model immune complexes during zone electrophoresis and isoelectric focusing in agarose gels.
Authors: Vertosick F T , Kelly R H 
Published: January 2020

Abstract
We evaluated the stability of model immune complexes, consisting of radioiodinated follitropin (125I-FSH), bound either to a mouse monoclonal antibody to FSH or to sheep polyvalent anti-FSH antiserum, during zone electrophoresis and isoelectric focusing in agarose gels. The complexes were relatively stable during zone electrophoresis at conventional voltages (less than 40 V/cm), about 80% of the initially bound antigen migrating in the gamma region. Highter voltages resulted in a linear increase in the antigen stripped from the gamma region. By contrast, isoelectric focusing very effectively dissociated the acidic 125I-FSH from the basic sheep immunoglobulins, even if the complexes were subjected to electromotive forces alone, i.e., by loading them onto the neutral region of the gel. The monoclonal complexes were not dissociated by high voltage alone. The monoclonal complexes could be completely dissociated by loading them at the anode, where gel acidification enhances complex dissociation. These observations can form the basis of a simple technique for isolating and dissociating human immune complexes before Western immunoblot analysis. Furthermore, the ease and rapidity with which bound and free antigen can be separated during zone electrophoresis in agarose suggests that this technique may have some application in clinical immunoassays.