bluuebunny/crossref_metadata_2025 huggingface dataset:
Complex biochemical syndrome of hypocalcemia and hypoparathyroidism during cytotoxic treatment of an infant with leukemia.
Authors: Wandrup J , Kancir C
Published: January 2020

Patients with cancer are especially vulnerable to the development of hyper- and hypocalcemia. These disorders may be the basic clinical manifestation of cancer or may result from vigorous cancer treatment. During cytotoxic treatment of a child with leukemia we describe the longitudinal course of ionized calcium in a complex syndrome of hypocalcemia and hypoparathyroidism. The results suggest that the development of severe hypocalcemia can be explained on the basis of hypoparathyroidism in relation to hyperphosphatemia, hypomagnesemia, and acute renal failure. The low ionized calcium was unsuccessfully treated with several doses of calcium levulinate but successfully treated with 1 alpha-hydroxycholecalciferol.
Erythrocyte aldehyde dehydrogenase: assay of a potential biochemical marker of alcohol abuse.
Authors: Towell J F , Barboriak J J , Townsend W F , Kalbfleisch J H , Wang R I
Published: January 2020

Erythrocyte aldehyde dehydrogenase (ALDH; EC 1.2.1.3) may be a new biochemical indicator of alcohol abuse. An improved assay for it is described and characterized. We found that expression of erythrocyte ALDH activity in terms of hemoglobin was valid, and preferable to expression in terms of erythrocyte volume. A normal reference interval was determined from results for 375 healthy subjects (236 men, 139 women). We compared these data with results for 109 men admitted to our alcohol detoxification program. The mean erythrocyte ALDH of the alcohol abusers was 30% lower than our mean value for men (p less than 0.001). Values did not change between the time the patient presented for admission and greater than 48 h later (when blood-ethanol concentration was zero). Other variables that affect erythrocyte ALDH activities--changes in pH, temperature, other assay conditions, and drug treatments such as disulfiram and nitrate anti-anginals--are discussed.
Direct solid-phase chemiluminescence immunoassay for salivary progesterone.
Authors: De Boever J , Kohen F , Vandekerckhove D
Published: January 2020

A simple, direct chemiluminescence immunoassay for progesterone in mixed, unstimulated saliva is described. We use purified polyclonal anti-progesterone antibodies covalently coupled to polyacrylamide beads and progesterone-11 alpha-hemisuccinyl-aminobutylethyl isoluminol as the chemiluminescent ligand marker. Bound and free ligand are separated by simple centrifugation. The detection limit of the assay is 1.5 pg per tube (38 pmol/L). Intra- and interassay coefficients of variation for low, medium, and high progesterone concentrations are 7.9, 6.8, 8.8% and 9.3, 6.9, 8.5%, respectively. Analytical recovery of added progesterone is 99.6%. Mean +/- SD progesterone concentrations (pmol/L) in saliva are 178 +/- 46 in the follicular phase, 313 +/- 90 in the periovulatory phase, and 658 +/- 166 in the luteal phase of the menstrual cycle. Correlation between progesterone concentrations in serum (assayed by RIA after extraction) and in saliva is good (r = 0.88, p less than 0.001, n = 96). The assay is simple, fast (4 h, including 1.5 h of incubation time), and reliable.
Importance of simultaneous determination of coproporphyrin and hemoglobin in contaminated amniotic fluid.
Authors: Francoual J , Lindenbaum A , Benattar C , Dehan M , Cohen H , Leluc R
Published: January 2020

To detect the presence of meconium and blood, we determined coproporphyrin and hemoglobin in 78 amniotic fluid samples, classified according to their visual aspect as clear (n = 45) or meconium-stained (n = 33). Among the 33 samples visually judged as meconial, a comparison of the results of their biochemical analysis with the mean values for clear amniotic fluids showed that only five of the 33 were contaminated solely with meconium. Seven others were exclusively bloody, and 19 were meconial and bloody. In two, the contaminant was neither meconium nor blood. Evidently, when the fluid is brownish, simple visual examination does not suffice for distinguishing meconium from old blood or other pigments. We propose a simple, rapid, and reliable method for simultaneously measuring contamination with meconium or blood.
Intra- and interindividual biological variation of five analytes used in assessing thyroid function: implications for necessary standards of performance and the interpretation of results.
Authors: Browning M C , Ford R P , Callaghan S J , Fraser C G
Published: January 2020

Intra- and interindividual components of biological variation have been determined for total thyroxin (TT4), free thyroxin (FT4), total triiodothyronine (TT3), free triiodothyronine (FT3), and thyrotropin (TSH). Calculated analytical goals (CV, %) for the precision required for optimal patient care are: TT4 less than or equal to 2.5, FT4 less than or equal to 4.7, TT3 less than or equal to 5.2, FT3 less than or equal to 3.9, and TSH less than or equal to 8.1. The marked degree of individuality demonstrated for all hormones indicates that, if conventional population-based reference ranges are used uncritically, major changes in hormone concentration may not be correctly identified for some patients because observed values continue to lie within the reference range. At analyte concentrations approximating the mean values found in this study, and for analytical performance meeting the appropriate analytical goal, the differences required for consecutive results to be significantly different (p less than or equal to 0.5) have been calculated as: TT4, 14.7 nmol/L; FT4, 5.7 pmol/L; TT3, 0.6 nmol/L; FT3, 1.3 pmol/L, and TSH, 0.7 milli-int. unit/L.
Immunoassays for low concentrations of albumin in urine.
Authors: Silver A , Dawnay A , Landon J , Cattell W R
Published: January 2020

We have developed and validated simple, rapid immunoassays to measure concentrations of albumin in urine ranging from 5 to 200 mg/L. We use antiserum to human albumin, raised in sheep, and we separate the antibody-bound and free fractions of albumin by using a second antiserum, produced in donkeys, against the Fc fragment of sheep IgG. These two antisera can be mixed and added to assay tubes as a single reagent without inhibiting antigen binding. Samples or standards are incubated for at least 30 min with fluorescein-labeled albumin and the premixed antiserum reagent. After brief centrifugation, the supernate is discarded and the precipitate containing the bound fraction is dissolved and its fluorescence measured. Alternatively, 125I-labeled albumin can be used as tracer with all other reagents unchanged; in this case one simply counts the radioactivity of the bound fraction. A reference interval of less than 0.2-2.8 mg/mmol of creatinine was obtained for untimed, daytime, midstream urine specimens from 80 healthy subjects.
Evaluation of the Hybritech Photon Analyzer and of an improved procedure for choriogonadotropin in serum.
Authors: Alexander R L , Mueller D S , Lipe A L , Minton J S , Szmurlo R E
Published: January 2020

We evaluated the Hybritech Photon Analyzer for its applicability to enzyme immunoassays. This instrument measures absorbances only at 405, 450, and 490 nm. Photometric linearity was good at all three wavelengths. However, the true absorbance range at these wavelengths was 0-1.6 A instead of 0-2.0 A as specified by the manufacturer. We also evaluated the Hybritech "Tandem-E" method for quantifying choriogonadotropin (hCG) in serum. A modification of the recommended procedure improved the precision of the assay. The detection limit of the modified procedure, 1 int. unit/L, permits reliable assays of hCG at concentrations near the upper limit of normal (3 int. units/L). Results by both procedures varied linearly with hCG concentrations up to 250 int. units/L. The Photon Analyzer eliminates the need for manual calculations. Quantitative results agree within +/- 1% with those measured in the "Stasar III" spectrophotometer.
Liquid-chromatographic analysis for cyclosporine with use of a microbore column and small sample volume.
Authors: Annesley T , Matz K , Balogh L , Clayton L , Giacherio D
Published: January 2020

This liquid-chromatographic assay requires 0.2 to 0.5 mL of whole blood, avoids the use of diethyl ether, and consumes only 10 to 20% of the solvents used in prior methods. Sample preparation involves an acidic extraction with methyl-t-butyl ether, performed in a 13 X 100 mm disposable glass tube, then a short second extraction of the organic phase with sodium hydroxide. After evaporation of the methyl-t-butyl ether, chromatography is performed on an "Astec" 2.0-mm (i.d.) octyl column. We compared results by this procedure with those by use of earlier larger-scale extractions and their respective 4.6-mm (i.d.) columns; analytical recoveries of cyclosporins A and D were comparable with previous findings and results for patients' specimens were equivalent, but the microbore columns provided greatly increased resolution and sensitivity.
Liquid-chromatographic method for estimating urinary sugars: applicability to studies of intestinal permeability.
Authors: Delahunty T , Hollander D
Published: January 2020

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Liquid-chromatographic determination of beta 2-microglobulin, alpha 1-acid glycoprotein, and albumin in urine.
Authors: Turpeinen U , Koivunen E , Stenman U H
Published: January 2020

We report a reversed-phase "high-performance" liquid-chromatographic assay for beta 2-microglobulin, alpha 1-acid glycoprotein, and albumin in urine. The urine samples are chromatographed on a 15 X 3.2 mm C18-column with a solvent gradient between two mixtures: 1 mL of trifluoroacetic acid per liter of water and 1 mL of trifluoroacetic acid per liter of acetonitrile. The proteins are detected at 218 nm. The useful lower limit of sensitivity for quantification is 0.1 micrograms of each protein in 100-microliters injected samples, corresponding to 1 mg of protein per liter of urine. The linear measuring range extends from 0.1 to 100 micrograms of protein for each peak. Mean analytical recoveries ranged from 92 to 100%. The mean within-assay CV was 7.5%, the between-assay CV 15%. Comparison of results with those obtained by immunoturbidimetry and radioimmunoassay shows acceptable correlation. Reproducible and rapid with low operational cost, this method is suitable for use in routine screening and quantification of urinary proteins.
Use of immunoglobulin heavy- and light-chain measurements compared with existing techniques as a means of typing monoclonal immunoglobulins.
Authors: Whicher J T , Wallage M , Fifield R
Published: January 2020

Using automated measurements of kappa and lambda light chains and IgG, IgA, and IgM, we assessed the utility of the kappa/lambda ratio and the heavy chain/light chain ratio in characterizing monoclonal immunoglobulins previously identified by sensitive electrophoresis on agarose gel and typed by immunofixation or immunoelectrophoresis. We examined 348 selected samples, of which 165 contained monoclonal components, finding that 93.4% were detected and 89% correctly typed by this approach. Eight samples were shown to contain monoclonal light chains that were not visible as bands on electrophoresis but demonstrated abnormalities of the kappa/lambda or heavy chain/light chain ratio.
Enzyme immunoassay of angiotensin I and renin.
Authors: Scharpé S , Verkerk R , Sasmito E , Theeuws M
Published: January 2020

We developed a sensitive and specific heterogeneous enzyme immunoassay for measuring angiotensin I (AI) or renin (EC 3.4.99.19) activities. Linking AI under carefully controlled conditions by means of N-succinimidyl-3-(2-pyridyldithio)propionate to highly purified beta-D-galactosidase (EC 3.2.1.23) produced a well-defined conjugate in high yield. The procedure is simple and consists of three steps: (a) incubate 0.5 mL of plasma with 100 microL of inhibitor solution for 1 h to generate renin activity; (b) incubate this with labeled AI for 1 h at 37 degrees C; and (c) do a double-antibody precipitation. Bound beta-D-galactosidase activity is determined, with O-nitrophenyl-beta-D-galactoside as substrate, by measuring the liberated O-nitrophenol at 410-420 nm. The analytical range of the assay extends from 62.5 to 4000 ng/L, and renin activities so measured in plasma correlate well with those measured by an established radioimmunoassay (n = 35, r = 0.97, intercept -0.6, and slope 1.44).
Alkaline phosphatase isoenzymes in the plasma of preterm and term infants: serial measurements and clinical correlations.
Authors: Crofton P M , Hume R
Published: January 2020

Serial measurements of the bone and fetal intestinal isoenzymes of alkaline phosphatase (EC 3.1.3.1) in the plasma of 43 term and 43 preterm infants, from birth to six weeks later, indicate that the bone isoenzyme gradually increases over this period in both preterm and term infants fed with unsupplemented commercial formulas. Preterm babies given formula supplemented with calcium (with or without additional phosphate) had significantly lower bone isoenzyme activities for most of the study period. The concentrations of fetal intestinal isoenzyme increased, under the stimulation of milk feeding, from generally undetectable at birth to a peak during the first two weeks postpartum, and then declined. This increase was highly significantly negatively correlated with gestational age, the preterm infants having a much higher and more prolonged increase in this isoenzyme than did term infants. Unlike the adult isoenzyme, fetal intestinal alkaline phosphatase in plasma showed no relationship with blood group status.
Direct quantification of coproporphyrins and uroporphyrins in urine by derivative synchronous fluorescence spectroscopy.
Authors: Valcárcel M , Gómez Hens A , Rubio S , Petidier A
Published: January 2020

The second-derivative synchronous fluorescence spectroscopic technique is applied to the simultaneous and direct assay of coproporphyrins and uroporphyrins in human urine. This technique resolves the overlapping conventional spectra, obviating the need for pre-analysis sample separation techniques, and measurements can be made in a single scan. The amplitudes of the derivative peaks are linearly related to uroporphyrin (0.4 to 300 micrograms/L) and coproporphyrin (0.4 to 250 micrograms/L) concentrations. The detection limit for both porphyrins is 0.1 microgram/L. Analytical recoveries range between 98 and 101%. Within- and between-assay CVs are reported. Results for 24-h urine specimens correlated well with those obtained by an extraction-ion-exchange chromatography combined method. The proposed method is inexpensive and requires no sophisticated detection equipment.
Identification and analysis of nine metabolites of cyclosporine in whole blood by liquid chromatography. 2: Comparison of patients' results.
Authors: Lensmeyer G L , Wiebe D A , Carlson I H
Published: January 2020

We used a "high-performance" liquid-chromatographic assay [for parent cyclosporine (CsA) and nine metabolites] and a radioimmunoassay to detail the diversity of results among whole-blood samples from patients with transplanted organs. Heterogeneous populations of metabolites in samples collected just before the next dose of CsA were detected by HPLC, with CsA, M17, M1, or M8 predominating; M21, M203-218, MUNDF1, and M18 were detected in lesser amounts. Results by HPLC vs RIA for CsA or for individual metabolites vs CsA (or RIA) were diverse, with correlation coefficients (r) ranging from 0.058 to 0.933. RIA vs HPLC(sum of CsA + metabolites) gave the best comparison (slope = 0.931, y-intercept 14 micrograms/L, r = 0.933); but the scatter of data about the regression line remained significant (Sy/x = 132 micrograms/L). Most important, RIA/HPLC(CsA) vs HPLC(sum of metabolites) was remarkably poor (r = 0.222). A 12-h pharmacokinetic curve (for drug concentrations in a heart-transplant patient) displayed dissimilar times for peak concentrations of CsA and metabolites; each differed in the proportion (48% to 81% of peak concentration) eliminated from blood over the 12 h. These studies exemplify the utility of a more-inclusive, specific assay to monitor the diverse disposition of cyclosporines in patients and to demonstrate the errors associated with use of the RIA/HPLC ratio technique to predict metabolite concentrations.
Immunonephelometry of apolipoprotein B with a centrifugal analyzer.
Authors: Hanson N Q , LeGeault T S , Freier E F
Published: January 2020

We developed an automated immunonephelometric assay for the measurement of apolipoprotein B (apo B) with a light-scattering microcentrifugal analyzer. Pretreating specimens with a dilute solution of Tween 20 or triglyceride lipase decreased the nephelometric response of apo B. Polyethylene glycol is included in the reaction mixture, and the reaction is complete within 4 min. The method is precise (CV = 6.5%, mean = 0.68 g/L) and the standard curve is linear to an apo B concentration of 2.8 g/L. Lipemia does not interfere with the method if grossly lipemic specimens are centrifuged to remove chylomicrons.
An assessment of the use of fixed limits to characterize intralaboratory performance by proficiency testing.
Authors: Ehrmeyer S S , Laessig R H
Published: January 2020

Currently, proficiency-testing (PT) programs are expanding the use of fixed limits to evaluate interlaboratory performance. These limits are an attempt to relate total allowable intralaboratory analytical error and performance in a PT program. Fixed limits are a means of counteracting the effects of overly stringent performance requirements derived from the interlaboratory group mean and standard deviations (SD) achieved by today's very precise analytical systems. Our previously described computer model of a PT program is used to delineate the quantitative relationship between the magnitude of intralaboratory coefficient of variation (CV) and bias that is compatible with fixed interlaboratory limits of 5, 10, 15, and 20% relative error. However, fixed limits alone do not fully characterize intralaboratory performance. The efficiency, or the percentage of times a laboratory's PT results are required to fall within the fixed limit, also must be considered when criteria for PT performance are being set. For example, a 10% fixed limit and a 80% efficiency will allow laboratories having CV-bias combinations from 8%-0%, 7%-4%, etc., to pass PT. The use of a 95% efficiency will allow CV-bias combinations from 4.8%-0%, 3.5%-4%, etc., to pass PT. We give a figure that depicts all possible combinations for four fixed limits and six efficiencies.
Participation of peptide moieties in adhesive behavior of antigenic mannans of Candida albicans to the plastic microtiter plate in enzyme-linked immunosorbent assay.
Authors: Tojo M , Shibata N , Mikami T , Suzuki M , Suzuki S
Published: January 2020

We report our studies of the mechanism of the adhesion of mannans of Candida albicans NIH A-207 and C. albicans NIH B-792 strains to the surface of a polystyrene microtiter plate being utilized for enzyme-linked immunosorbent assay (EIA) of antigens of this pathogenic yeast species. This binding was manifested predominantly by the peptide moieties of the mannans forming hydrophobic bonds with the plastic molecule. Eliminating the peptide of each mannan by treating it with a hot aqueous alkaline solution of NaBH4 also eliminated color development in the EIA.
Effect of daylight on the reaction of thiols with Ellman's reagent, 5,5'-dithiobis(2-nitrobenzoic acid).
Authors: Walmsley T A , Abernethy M H , Fitzgerald H P
Published: January 2020

The reaction of 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB, Ellman's reagent) with thiols is sensitive to daylight, in particular to ultraviolet radiation at wavelengths around 325 nm. Exposure to light at the absorbance maximum of the yellow product (the thionitrobenzoate ion) at 410 nm had no effect on the reaction. The light-sensitive species is apparently the DTNB, because a spectral-irradiation experiment showed that the wavelength of light that produced the maximum rate of absorbance change coincided with the peak absorbance of DTNB, and it was well separated from the thionitrobenzoate absorbance peak. Ascorbate is ineffective as a stabilizer and can produce an apparent increase in the rate of DTNB destruction. In a practical example we found the light interference to be severe when hydrolysis of propionylthiocholine by plasma cholinesterase (EC 3.1.1.8) was measured after a 20-min incubation. The apparent cholinesterase activity in clear glass or plastic tubes exposed to diffuse daylight could be decreased to 25% of the value obtained for samples in light-excluded tubes. We recommend the reaction be carried out in artificial room light, with total elimination of daylight, because window glass does not sufficiently attenuate 325-nm wavelength irradiation.
Assessment of magnesium status.
Authors: Elin R J
Published: January 2020

The adult human body contains approximately 24 g (1 mol) of magnesium--about half in bone and half in soft tissues. Only about 0.3% of the total body magnesium is present in serum, yet the majority of analytical data obtained is from this body fluid. Assessing the magnesium status of an individual is difficult, there being at present no simple, rapid, and accurate test to determine intracellular magnesium, but determination of total and free magnesium in tissues and physiological tests provide some information. Changes in magnesium status have been linked to cardiac arrhythmias, coronary heart disease, hypertension, and premenstrual syndrome. A better understanding of magnesium transport and of factors controlling magnesium metabolism is needed to elucidate the role of magnesium in disease processes.
Time-resolved immunofluorometric assay for the ovarian carcinoma-associated antigenic determinant CA 125 in serum.
Authors: Boerman O C , Thomas C M , Segers M F , Kenemans P , Lövgren T , Zurawski V R , Haisma H J , Poels L G
Published: January 2020

A time-resolved immunofluorometric assay (IFMA) is described for quantifying the ovarian carcinoma-associated antigenic determinant CA 125 in human serum. Monoclonal antibody to CA 125 is immobilized onto a microtiter well, and the same antibody labeled with a europium chelate is used as a tracer. After the immunoreaction the bound portion of the labeled antibody is quantified by dissociating the Eu3+ in a fluorescence-enhancement solution and measuring its fluorescence with a time-resolved fluorometer. The detection limit of the IFMA is 1.5 arb. units/mL, being about the same as that of a commercially available immunoradiometric assay (IRMA) for CA 125 (1.4 arb. units/mL). The analytical range of the IFMA extends to 2000 arb. units/mL, whereas the range of the IRMA is 500 arb. units/mL. For 29 serum samples from ovarian-cancer patients measured simultaneously in the IFMA and IRMA, orthogonal regression analysis gave the equation CA 125 (IFMA) = 0.9937 CA 125 (IRMA) - 1.211 arb. units/mL (Syx = 6.8681, r = 0.9932). Apparently, the IFMA for CA 125 is a convenient alternative to the IRMA for CA 125 because of short counting times, the use of nonradioactive, stable reagents, and the much-extended measuring range. Additionally, the microtiter format should lend itself to more fully automated procedures in laboratories doing many such analyses.
Chemical characterization of urinary glycopeptides.
Authors: Matsue H , Takagaki K , Honda K , Nakagawa Y , Gejyo F , Arakawa M , Endo M
Published: January 2020

We prepared human urinary glycopeptides from the supernatant liquid remaining after precipitation of the nondialyzable fraction with cetylpyridinium chloride. Using cation exchange and affinity chromatographies and gel filtration, we obtained 28 glycopeptide subfractions. By compositional analyses of sugar and amino acid, and by reducing-terminal analyses after reduction with NaBH4, we determined the size of the carbohydrate moiety and the types of carbohydrate-peptide linkage involved. We isolated several glycopeptides not previously described: six with sialic acid, two with fucose, two with glucose, and one with N-acetylgalactosamine. The sialic acid glycopeptides had a short carbohydrate chain of the O-glycoside type. The fucose-containing glycopeptides were fucosyllactosaminoglycans. The glucose glycopeptides were polymers linked to a small peptide moiety. The N-acetylgalactosamine-rich glycopeptide was found in an N-glycoside-type fraction, with N-acetylgalactosamine at the nonreducing terminal.