bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of interference by hemoglobin in the determination of total bilirubin. II. Method of Jendrassik-Grof.
Authors: Shull B C , Lees H , Li P K 
Published: January 2020

Abstract
Oxyhemoglobin in erythrocyte hemolysates interferes with the Jendrassik-Grof assay. Destruction of azobilirubin occurs when oxyhemoglobin is oxidized to methemoglobin during diazotization or to alkaline hematin with addition of alkaline tartrate. The most probable mechanism is by oxidation with an agent such as hydrogen peroxide or a related species resulting from hemoglobin oxidation. Methemoglobin also appears to cause some destruction of azobilirubin during diazotization. Methemoglobin forms during diazotization because of reactions of oxyhemoglobin with both diazo reagent and nitrite ion. Formation of methemoglobin is, therefore, more rapid in the test than in the blank mixture and, under reaction conditions, its absorbance is less than that of oxyhemoglobin. This results in spectral interference when neutral azobilirubin is assayed. Alkaline tartrate abolishes this spectral error by causing rapid formation of alkaline hematin in both test and blank.
Biochemical individuality and the recognition of personal profiles with a computer.
Authors: Robertson E A , Van Steirteghem A C , Byrkit J E , Young D S 
Published: January 2020

Abstract
Multitest analysis of an individual's blood provides a biochemical profile that reflects his identity and pathophysiological state. During a six-week period we repeatedly profiled 10 volunteers for 22 different analytes, using continuous-flow and discrete analyzers (SMAC, KA 150 enzyme analyzer, ABA-100, AutoAnalyzers) and manual procedures. Two years later, we obtained multiple follow-up profiles. Using linear discriminant functions derived from the first five (or first 10) specimens from each subject, we were able correctly to identify 96% (or 100%) of the specimens collected during the remainder of the six-week testing period. Ninety percent of the two-year follow-up specimens were correctly identified when we used all the original profiles to calculate the discriminant functions. Deliberately mislabeled specimens were also correctly identified by discriminant analysis. Profiles of individual samples (and average profiles for each subject) were graphically displayed as computer-drawn faces and non-linear maps. Covariances between pairs of tests on repeated profiles differed significantly for different subjects. Inter-test relationships were graphically displayed by nonlinear mapping.
Screening radioimmunoassay for aldosterone in preheated plasma without extraction and chromatography.
Authors: Connolly T M , Tibor L , Gless K H , Vecsei P 
Published: January 2020

Abstract
We directly estimated plasma aldosterone radioimmunologically with use of an antiserum raised against an aldosterone-3-oxime/bovine serum albumin conjugate, the estimation being on samples with and without heating (60 degrees C), and diluted and undiluted. Values so obtained were compared with those by radioimmunoassay after extraction and chromatography. The correlation--even negative values were obtained--was poorest when the steroid was directly estimated in nonheated, undiluted plasma. Correlations were best (r = 0.918) for preheated and diluted native plasma, and the interassay CV was 9.8% (n = 57). However, there were some extraordinarily high values. After equilibrium dialysis of native and preheated (60 degrees C) plasma (15 plasma samples), the percentages of apparent free aldosterone and cortisol increased from 51.4 +/- 2.6% (SEM) to 64.3 +/- 1.6% and from 11.5 +/- 2.2% to 61.1 +/- 1%, respectively. We conclude that aldosterone-binding proteins play a role in direct radioimmunoassays of aldosterone in plasma, but by heating (with or without diluting) the plasma, direct assay can be used as a simple, fast, and inexpensive screening method.
Circulating CK-MB and CK-BB isoenzymes after prostate resection.
Authors: Kimler S C , Sandhu R S 
Published: January 2020

Abstract
We studied the effect of prostate resection on serum creatine kinase (EC 2.7.3.2) and lactate dehydrogenase (EC 1.1.1.27) isoenzymes in 22 patients. Two hours after their operations, two-thirds of these patients had increased total creatine kinase activity. The MB isoenzyme was demonstrated in sera of 66% of the patients and the BB isoenzyme in 76%. MB content varied from 1 to 7% of total creatine kinase activity, the average activity being 7.4 +/- 6 (SD) U/L. BB content varied from 1 to 29% of the total creatine kinase activity, the average activity being 8.5 +/- 5.4 U/L. No patients showed evidence of cardiac damage. In contrast to the enzyme changes associated with cardiac injury, MB isoenzyme seen after prostate resection is usually associated with the appearance of BB activity. In addition, the ratio of lactate dehydrogenase isoenzymes 1 and 2 was "inverted" in only five of the 33 patients, and appeared to corrlate with the degree of hemolysis in the postoperative sera. The prostate contains all three creatine kinase isoenzymes, BB predominating.
Lipid interference in steroid radioimmunoassay.
Authors: Rash J M , Jerkunica I , Sgoutas D S 
Published: January 2020

Abstract
To study lipid interference in steroid radioimmunoassays in which dextran-coated charcoal is used as the separating agent, we tested triolein and phosphatidylcholine as model hydrophobic and amphipathic lipids, respectively. Addition of either caused distortion of the standard curve to an extent that was inversely related to the polarity of the steroid molecule. Both lipids form a dispersion that entraps steroid molecules. When we increased the charcoal concentration, the effect of phosphatidylcholine addition was eliminated for assays of both polar and nonpolar steroids. In contrast, the effect from triacylglycerol was not corrected, particularly in assays of nonpolar steroids. We also studied mixtures of lipids mimicking the mixture of lipids extracted from plasma of normolipemic and hyperlipemic indviduals. The degree of lipemia that can be tolerated differs from assay to assay, and primarily varies directly with the polarity of the steroid being assayed.
Immobilized-enzyme rate-determination method for glucose analysis.
Authors: Sokol L , Garber C , Shults M , Updike S 
Published: January 2020

Abstract
We present a rate-determination method for analyzing glucose. A glucose enzyme electrode serves as the sensor and is made by placing a gel-immobilized layer of glucose oxidase over the tip of a Clark-type O2 electrode. The electrode membrane is made of Teflon and is derivatized by etching with a suspension of colloidal sodium metal in organic solvent. The enzyme is coupled to the membrane surface by use of paraformaldehyde. The immobilized-enzyme method is compared with a similar solution-enzyme method and with the National Glucose Reference method. The immobilized enzyme method compares favorably with the solution-enzyme method and offers the advantages of simplicity, economy of enzyme, and linearity over a greater range of concentration.
A fluorometric determination of sphingomyelinase by use of fluorescent derivatives of sphingomyelin, and its application to diagnosis of Niemann-Pick disease.
Authors: Gatt S , Dinur T , Barenholz Y 
Published: January 2020

Abstract
We synthesized fluorescent derivatives of sphingomyelin (N-acyl-sphingosylphosphocholine) and used them as substrates for several sphingomyelinases. The following five fluorescent probes, each attached to the terminal carbon atom of the fatty acyl residue, were introduced into sphingomyelin: dansyl, pyrene, carbazole, 4-chloro-7-nitrobenz-2-oxa-1,3-diazole, and anthroic acid. We compared the rates at which the fluoro- and radiolabeled sphingomyelins were hydrolyzed. They were the same with the following three spingomyelinases: (a) a purified enzyme from Staphylococcus aureus; (b) at Triton X100-treated extract of human brain (assayed at pH 7.4 in the presence of Mg2+; and (c) aqueous extracts of brain lysosomes, skin fibroblasts, and amniotic cells, assayed at pH 5.0. Homogenates of skin fibroblasts of a patient with Niemann-Pick disease had practically no activity when assayed at pH 5, with fluorosphingomyelin as substrate. When fluorosphingomyelin was mixed in various proportions with natural sphingomyelin, enzymes from each of the three sources hydrolyzed the two substrates at equal rates. The fluorosphingomyelins can be used to estimate with great sensitivity the sphingomyelinase activity in extracts of tissues or cells, in tears, and probably in hair follicles, as well as diagnose Niemann-Pick disease, either pre- or post-natally
Evaluation and clinical application of a dextran-charcoal method for measuring bound testosterone in human plasma.
Authors: Tcholakian R K , Jones G M , Sanborn B M , Rodriguez-Rigau L J , Reimondo G G 
Published: January 2020

Abstract
A method for rapidly determining bound and free testosterone in human plasma is evaluated and described, in which dextran-coated charcoal is used to separate bound and free testosterone. Intra- and inter-assay CV's were 1.9 and 3.8%, respectively. At least 50% of the "bound" testosterone was associated with species that behaved like sex steroid hormone-binding globulin on Sephadex G-25 chromatography and polyacrylamide gel electrophoresis. Bound and free testosterone concentrations were determined in normal men, normal women (during the menstrual cycle and during normal pregnancy), and in women with various degrees of hirsutism. We conclude that determining the circulating proportions of bound and free testosterone is helpful in the diagnostic evaluation of hirsutism in women, and in the investigation of normal and pathological conditions where androgen concentrations may be altered.
Evaluation of a radioenzymic kit for determination of plasma catecholamines.
Authors: Tasseron S J , Fiolet J W , Willebrands A F 
Published: January 2020

Abstract
We evaluated a commercially available reagent test-kit (Upjohn) for simultaneously determining norepinephrine, epinephrine, and dopamine in 50-microL of plasma. The three catecholamines are enzymically converted into the radioactive O-methyl derivatives and separated by thin-layer chromatography. Day-to-day precision (CV) was 11, 10, and 14% for norepinephrine, epinephrine, and dopamine, respectively. The relationship between concentration of catecholamine and radioactivity (net dpm) was linear to at least 8 ng (corresponding to 1 mumol/L in plasma). Sensitivity was approximately 2 pg for dopamine, 1 pg for each of the other two catecholamines. Under our conditions, epinephrine was not quite completely resolved from the other two fractions. Catecholamine values determined in normal humans, after 30 min supine and after normal laboratory activity, agreed well with those found by other investigators. Correlation was good between kit results and those obtained in another laboratory that used self-prepared reagents and "high-performance" liquid chromatography for the separation.
Determination of urinary placental estriol by reversed-phase liquid chromatography with fluorescence detection.
Authors: Taylor J T , Knotts J G , Schmidt G J 
Published: January 2020

Abstract
We describe a liquid-chromatographic procedure for determining urinary estriol concentrations. The urine sample, after enzymatic hydrolysis to free the conjugated estrogen, is extracted with ether, and an aliquot of the resulting extraction residue is injected into the liquid chromatograph. Sample components are separated with a reversed-phase C18 column and isocratic elution with an acetonitrile/water mobile phase. Using a far-ultraviolet excitation wavelength, we measure the natural fluorescence of the eluted estrogen with a fluorescence detector. The procedure provides excellent sensitivity for determing near-term pregnancy concentrations of urinary estriol. The selectivity of the method limits the effect of potentially interfering compounds.
The multilayered film analyzer: glucose in serum, plasma, cerebrospinal fluid, and urine; and urea nitrogen in serum and plasma.
Authors: Warren K , Kubasik N P , Brody B B , Sine H E , D'Souza J P 
Published: January 2020

Abstract
Some basic laboratory performance criteria were studied for the Eastman Kodak glucose and urea nitrogen analyzer. Serum, plasma, urine, and cerebrospinal fluid were tested. Precision, both "within-day" and "between-day," for both analytes was less than 2.2% (CV). Both analytes demonstrated linearity, with about 100% recovery of added substrates. Comparisons with continuous-flow procedures demonstrated good correlation. A variety of sera and plasmas can be used for glucose analysis; oxalate--fluoride-treated plasma is unacceptable for use in analysis for urea nitrogen. We saw no effects on glucose or urea nitrogen analysis from hemolysis, lipemia, icterus, some common drugs, ammonia, or abnormally high protein concentrations. Minimum amounts detectable were: glucose (serum) 104 mg/L; glucose (cerebrospinal fluid) 100 mg/L; and urea nitrogen (serum) 21 mg/L. Calibration procedures are discussed for protein-based and aqueous samples.
Parallel evaluation of Astra 8 and Astra 4 multichannel analyzers in two hospital laboratories.
Authors: Truchaud A , Hersant J , Glikmanas G , Fievet P , Dubois O 
Published: January 2020

Abstract
We evaluated the new Beckman multichannel analyzers Astra 8 and Astra 4. Both instruments performed the following tests: Na, K, Cl, CO2, urea, glucose, and creatinine in plasma and Na, K, Cl, and creatinine determinations in urine. We tested precision, accuracy, and linearity at the usual concentrations in plasma and urine. We compared the Astra 8 and Astra 4 with continuous-flow (SMA 6) and discrete analyzers such as IL 243, Beckman KLiNa Flame, Beckman System 1, Corning 920 M Chloride Meter, and the Corning Blood-Gas Analyzer 175. Special tests were performed on plasma-to-plasma and urine-to-plasma carryover. Both analyzers are easy to operate and suitable for both emergency and routine use.
Measurement of sodium valproate in serum by direct-insertion chemical-ionization/mass spectrometry.
Authors: Schier G M , Gan I E , Halpern B , Korth J 
Published: January 2020

Abstract
To quantitatively determine sodium valproate, we use a stable isotope-labeled internal standard and chemical-ionization/mass spectrometry, without prior chromatographic separation. The technique is rapid, simple, sensitive, and provides for the routine analysis of 100 microL of serum with good within-day and day-to-day precision. The technique also allows for the simultaneous determination of phenobarbital, mephobarbital, carbamazepine, primidone, and phenytoin.
Clinical evaluation of an immunoinhibition procedure for creatine kinase-MB.
Authors: Obzansky D , Lott J A 
Published: January 2020

Abstract
We have clinically evaluated the Dade "Cardiozyme" immunoinhibition procedure for determination of creatine kinase isoenzyme MB (CK-MG) in 71 patients who were suspected of having had an acute myocardial infarction. Electrophoresis for CK-MB was also carried out. On the basis of diagnostic sensitivity and specificity for myocardial infarction, we found the Dade procedure for CK-MB to be somewhat inferior to electrophoresis. In 11 patients for whom the time of infarction was known, we observed normal CK-MB results for two of them by both immunoinhibition and electrophoresis during the first 24 h, but subsequently could detect abnormal CK-MB results by both methods. Thus in some patients such data are not helpful for making a diagnosis in the first 24 h. The Dade procedure is easy to perform, but lacks sensitivity in the region of low CK-MB activity, requires a very stable spectrophotometer, is imprecise, and produces negative numerical results in patients without myocardial infarction.
Improved radiochemical method for measuring ferrochelatase activity.
Authors: Williams H L , Johnson D J , Haut M J , Slater S , Brennan R G , Altstatt L B 
Published: January 2020

Abstract
We describe a radiochemical method for measuring ferrochelatase activity in the in vitro incorporation of iron into mesoporphyrin-IX to form mesoheme. 59Fe is used to quantify ferrochelatase activity in rat liver. The uptake of iron is linearly related to the time allowed for it to occur, and the reaction proceeds optimally under reducing and anerobic conditions, maintained in sealed lyophilization vials under a positive pressure of nitrogen.
Use of an alumina column in estimating total iron-binding capacity.
Authors: Starr R T 
Published: January 2020

Abstract
I describe a simple, rapid technique for saturating the transferrin in serum and then removing unbound (excess) iron. This technique involves use of an easily prepared column of basic chromatographic alumina and a saturating solution of ferric chloride in citric acid. This method, when compared with the magnesium carbonate method of Ramsay (Clin. Chim. Acta 2: 221, 1957) by regression analysis and tests of precision, showed a negative bias for results by the alumina technique with respect to the magnesium carbonate method.
An improved ultrafiltration method for free thyroxine and triiodothyronine in serum.
Authors: Sophianopoulos J , Jerkunica I , Lee C N , Sgoutas D 
Published: January 2020

Abstract
We describe an ultrafiltration technique for rapidly and directly determining free triiodothyronine or free thyroxine, or both. After equilibrating serum at 37 degrees C with purified tracer of high specific activity, we placed 0.15 mL of serum in 2.8 mL of phosphate buffer (0.1 mol/L, pH 7.4) in the ultrafiltration cell and obtained successive 0.2- and 0.6-mL fractions of protein-free ultrafiltrate. Under our conditions free ligand concentration was independent of flow rate. After purifying the second fraction with protein-coated charcoal, we could determine the proportion of free triiodothyronine or free thyroxine. Samples from normal adult men and women, including women who were taking oral contraceptives or were pregnant, and from hypo- and hyperthyroid patients gave results that agreed with those obtained by equilibrium dialysis. Speed is the main advantage of the method: one technologist can complete the procedure in 2 h and, using a multi-micro-ultrafiltration system, can process many samples in one day. For laboratories where index-type reactions are performed routinely and direct free triiodothyronine or free thyroxine is determined only on selected specimens, this method is superior to dialysis. It is also very convenient for rapidly purifying tracers, to at least 97% radiochemical purity, with 94% recovery and no dilution.
Comparison of turbidimetric and light-scattering measurements of immunoglobulins by use of a centrifugal analyzer with absorbance and fluorescence/light-scattering optics.
Authors: Hills L P , Tiffany T O 
Published: January 2020

Abstract
We have developed a centrifugal analyzer with both fluorescence/light-scatter and conventional absorbance optics. The instrument is used in this investigation to study the formation of antigen-antibody complexes by light scattering and turbidimetric measurements, and to develop assays for human immunoglobulins G, A, and M. Concentrations are calculated from a nonlinear least-squares fit of calibrators, and antigen excess is automatically detected from kinetic curve characteristics. Precisions and patients’ results are presented, and assay sensitivity and reliability in the detection of antigen excess are compared. We also investigated the effects of centrifugal force on complex formation. Both nephelometry and turbidimetry can be very satisfactorily adapted to centrifugal analyzers. We present a model to describe the observed differences between the light-scatter and the turbidity data.
Determination of organic acids in biological fluids by ion chromatography: plasma lactate and pyruvate and urinary vanillylmandelic acid.
Authors: Rich W , Johnson E , Lois L , Kabra P , Stafford B , Marton L 
Published: January 2020

Abstract
We describe the general aspects of ion chromatography and how on-line counted ion-exchange techniques can be utilized to determine pyruvic and lactic acids in plasma and vanillymandelic acid in urine. Pyruvate and lactate are extracted from deproteinized plasma by use of an ion-exclusion resin. After elution from the resin, the plasma extract is chromatographed on an anion-exchange column, with 0.66 mmol/L sodium bicarbonate as the mobile phase. The effluent is detected with an electrical conductivity cell. Vanillylmandelic acid is extracted from diluted urine by use of an anion-exchange resin. After elution from resin, the urine extract is chromatographed on an ion-exclusion column, followed by electrochemical detection. We evaluated the procedures for precision, linearity, analytical recovery, intefering substances, and correlation with an established procedure. the combination of a preliminary resin extraction, an ion chromatographic separation, and a conductivity or electrochemical detector results in rapid, specific methods that can be adapted for use in the clinical laboratory. Preliminary data for other organic acids are presented.
Serum protein profiles by "high-performance" liquid chromatography with detection at multiple wavelengths.
Authors: Schlabach T D , Abbott S R 
Published: January 2020

Abstract
We have separated serum proteins in only 15 min by high-performance liquid chromatography. The identification of several peaks in the chromatographic profile was greatly aided by the use of multiple-wavelength detection. We have found a good correlation between retention times and electrophoretic mobilities. Serum samples with increased γ- or β-globulins, as determined by electrophoresis, resulted in chromatographic profiles with strongly increased peaks in the appropriate regions. This chromatographic method revealed both relative and absolute differences in individual protein concentrations among several serum samples.
Concentration of immunoreactive trypsin and activity of pancreatic isoamylase in serum compared in pancreatic diseases.
Authors: Fahrenkrug J , Magid E 
Published: January 2020

Abstract
We measured the concentration of immunoreactive trypsin and the enzymic activity of pancreatic isoamylase in sera from 103 patients with pancreatic diseases and 29 other subjects serving as a reference group. Almost all patients with pancreatic diseases had abnormal values for both enzymes. A strong positive correlation between these two variables over a 1000-fold range was observed.
Rapid, fully automated radioimmunoassay of prostatic acid phosphatase in serum.
Authors: Dass S , Bowen N L , Bagshawe K D 
Published: January 2020

Abstract
Prostatic acid phosphatase was purified from human semen and its purity established by biochemical and immunological criteria. Rabbits were injected with the purified isoenzyme to raise specific antisera. The prostatic acid phosphatase was radiolabeled with 125I by the Chloramine T method. We developed a fully automated double-antibody radiommunosassay for measuring prostatic acid phosphatase in serum from patients with carcinoma of the prostate and from several control groups. The lower detection limit of the radioimmunoassay was 2.0 microgram of prostatic acid phosphatase per litre of serum. Values for most members of the control group was &lt;2.0 microgram/L; patients with metastatic carcinoma of the prostate had values ranging from &lt;2.0 to 300 microgram/L of serum.