bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multilayer film elements for clinical analysis: general concepts.
Authors: Curme H G , Columbus R L , Dappen G M , Eder T W , Fellows W D , Figueras J , Glover C P , Goffe C A , Hill D E , Lawton W H , Muka E J , Pinney J E , Rand R N , Sanford K J , Wu T W 
Published: January 2020

Abstract
Dry, thin films containing all necessary reagents for clinical analysis by colorimetry have been designed. Reagents in a matrix of hydrophilic polymer are coated on top of a transparent plastic base. A white isotropically porous polymer spreading layer, 80% void volume, is coated over the reagent layer(s). In the analysis, a drop (typically 10 microliter) of undiluted serum or other fluid is touched to the spreading layer. The fluid spreads rapidly and uniformly through the pore structure, filling a void volume corresponding to the drop volume. Water and low-molecular-weight components diffuse from the spreading layer into the reagent layer(s), initiating the reaction sequence. The spreading layer acts also as a white optical diffuser for reflection densitometry. Optical reflection density is linearized through use of the function developed by Williams and Clapper [J. Opt. Soc. Am. 43, 595 (1953)] to convert reflection to transmission density. A wide variety of chemical assays are compatible with this format. As an example, for the glucose film we found coefficients of variation of 1.5% in predicting glucose concentrations in control sera during 20 days. Results for glucose concentrations in several hundred patients' sera by the present method were very cose to those obtained with the Center for Disease Control's hexokinase reference method.
Development and evaluation of a glucose analyzer for a glucose controlled insulin infusion system ((Biostator).
Authors: Fogt E J , Dodd L M , Jenning E M , Clemens A H 
Published: January 2020

Abstract
The Glucose-Controlled Insulin Infusion System (Biostator) is a modular, computerized, feedback control system for dynamic control of blood glucose concentrations in diabetics. This on-line glucose analyzer for use with whole blood utilizes a novel enzyme (glucose oxidase)-membrane configuration and an electrochemical cell to measure the H202 generated. The analyzer exhibits both short- and long-range stability, and instrument response and analyte concentration are linearly related over the full range of clinical interest. The response is fast, accurate, and precise, and permits determination of blood glucose within 2 min from the moment the blood leaves the patient. Correlation studies were completed to show the agreement between the Biostator Glucose Analyzer and the FDA's recommended hexokinase/glucose-6-phosphate dehydrogenase procedure on whole blood (e.g., average per cent recovered for 11 concentrations between 250 and 900 mg/liter was: hexokinase, 95.6%, Biostator Analyzer, 95.9%; bias and SDd, respectively, at low, normal, and high glucose values were: 12 and 41 mg/liter at the 500 mg/liter level; 4 and 52 mg/liter at the 1000 mg/liter level, and 4 and 128 mg/liter at the 4000 mg/liter level). No appreciable interference is observed with above-normal concentrations of bilirubin, uric acid, creatinine, sodium salicylate, or dextran. Platelet adhesion, which tends to decrease the useful life of the membrane, has been significantly decreased.
Quantitative cytochemistry: the basis of sensitive bioassays, for comparison of bio-and immuno-reactive hormone values.
Authors: Bitensky L , Chayen J 
Published: January 2020

Abstract
Cytochemistry now extends biochemistry down to the single-cell level. Special procedures have been developed for cutting sections of uniform thickness with no measurable or detectable artifact. The cytochemical bioassays use chromogenic reactions with the immediate precipitation of the resulting chromophore so that biochemical activity can be related to the individual cells constituting a tissue. This activity, in individual cells, is measured by scanning and integrating microdensitometry which also increases the sensitivity of cytochemical measurement over that of conventional biochemistry. A hormone, or indeed any biologically active substance, acting on its target cell, causes a change in the chemical activity of that cell that mediates the physiological effect of the hormone. By cytochemical methods one can assess such changes in the target cells even if these constitute only a small part of the target-organ; thus such methods are ideally suited to measuring chemical changes of this sort induced by the hormone. Such cytochemical bioassay of polypeptide hormones, done as "within-animal" assays, are about 1000-f0ld more sensitive than the equivalent radioimmunoassays and are as precise. Thus they have two advantages: (a) bioreactive hormone is measured rather than a composite of antigenic determinants characteristic of part of the hormone molecule and (b) their increased sensitivity allows discrimination between low normal and subnormal concentrations of the circulating hormone.
Radioimmunoassay of methaqualone in human urine compared with chromatographic methods.
Authors: Mulé S J , Kogan M , Jukofsky D 
Published: January 2020

Abstract
The 125I-radioimmunoassay for methaqualone in human urine was evaluated by a comparison with newly modified gas-liquid chromatographic and thin-layer chromatographic methods. The statistically significant sensitivity value for the radioimmunoassay was at 2 microgram of methaqualone per liter of urine. The coefficient of variation was 2.88 +/- 0.39% interassay and 2.71 +/- 0.16% intraassay. There was cross-reactivity only with metabolites of methaqualone, 4'-hydroxymethaqualone being twice as sensitively measured as methaqualone. There was complete agreement between results by radioimmunoassay and by gas-liquid chromatography in 96.7% of the samples analyzed. Only 1.2% of the radioimmunoassay values were false positives, and 2.1% false negatives (phi = 0.8917, P less than 0.001). Comparisons between the thin-layer chromatographic data and the gas-liquid chromatographic or radioimmunoassay data showed less agreement because of the 50- to 200-fold higher sensitivity of the latter two techniques. Gas-liquid chromatography therefore appears to represent the best reference method for the evaluation of the radioimmunoassay, which appears to be a very sensitive and reliable technique for detecting methaqualone and its metabolites in human urine.
Bilirubin-protein interactions monitored by difference spectroscopy.
Authors: Ash K O , Holmer M , Johnson C S 
Published: January 2020

Abstract
Difference spectroscopy is used to monitor bilirubin-protein interactions, to assess the residual binding capacity of proteins for bilirubin. A change in the difference spectra monitored at 482 nm is directly proportional to bound bilirubin up to a molar ratio of bilirubin to albumin of approximately 1; increasing bilirubin beyond the 1:1 molar ratio does not further change the difference spectra. After excess free bilirubin is added, the change in the difference spectrum is proportional to the residual binding capacity of the serum for bilirubin. The risk of kernicterus among neonates may be assessed by monitoring the residual bilirubin binding capacity of serum. This report summarizes our research effort leading to an assay method which requires only 40 microliter of serum and can be completed in less than 10 min.
Simultaneous determination of serum cholesterol in high- and low-density lipoproteins with use of heparin, Ca2+, and an anion-exchange resin.
Authors: Noma A , Nezu-Nakayama K , Kita M , Okabe H 
Published: January 2020

Abstract
Cholesterol concentrations in serum high-density and low-density lipoproteins are simultaneously determined simply, specifically, and rapidly by use of the precipitation method with heparin, Ca2+, and an anion-exchange resin. The isolation of lipoproteins is reproducible, selective, and complete, as judged by electrophoresis on polyacrylamide gel and by immunoelectrophoresis, with use of samples with very-low-density lipoprotein triglyceride concentrations of less than 3.5 g/liter. The precision of the present method is as good (CV, 2.8-3.1%) as that for the method used by the U.S. Lipid Research Clinics (CV 2.0-3.2%). The present method and the heparin-Mn2+ method of the Clinics gave results that agreed reasonably well (for low-density-lipoprotein cholesterol r = 0.935, P less than 0.001; for high-density-lipoprotein cholesterol r = 0.837, P less than 0.001). we also describe the relations between high- or low-density lipoprotein cholesterol and total cholesterol, and between cholesterol concentrations in these two lipoprotein classes.
Selective purification of tartrate-inhibitable acid phosphatases: rapid and efficient purification (to homogeneity) of human and canine prostatic acid phosphatases.
Authors: Van Etten R L , Saini M S 
Published: January 2020

Abstract
We describe the synthesis of a long-chain monoamide derivative of L(+)-tartaric acid and its attachment to Sepharose 4B. Procedures are then described for use of this material in purifying human prostatic and (for the first time) canine prostatic acid phosphatases to constant specific activity and electrophoretic homogeneity. Depending on sample size, such purification is possible in one step, and is clearly faster and more efficient than are previously described methods. These materials and procedures have significant potential in studies of the comparative biochemistry and clinical chemistry of tartrateinhibitable acid phosphatases.
Enzyme-coupled ultraviolet determination of alpha-amylase activity with the GEMSAEC centrifugal analyzer.
Authors: Porter W H , Roberts R E 
Published: January 2020

Abstract
We evaluated the Harleco alpha-glucosidase/hexokinase/glucose-6-phosphate dehydrogenase-coupled alpha-amylase method, bu use of the GEMSAEC centrifugal analyzer. Performance evaluation included kinetic studies of substrate and maltose hydrolysis as well as effects of endogenous glucose and fructose. The reagent was found to give a linear response with alpha-amylase activity to greater than 1200 U/liter. Within-run precision resulted in coefficients of variation (CV) of 0.9 to 3.2% over the range studied. Day-to-day precision corresponded to CV's of 2.4 to 4.4% over the same range of alpha-amylase procedure was found to be good (r = 0.997) for patients' sera examined.
Detection of hemophilia A carriers by use of frozen plasma samples.
Authors: Yang H C , Hardin J , Vaudreuil C 
Published: January 2020

Abstract
The efficacy of using promptly frozen plasma samples in the diagnosis of the carrier state for hemophilia A was evaluated by simultaneous measurement of factor VIII acitivity and antigen in 20 normal women and 20 obligate carriers. Factor VIII antigen was measured by two methods, electroimmunoassay and immunoradiometric assay. When the factor VIII activity and antigen data were evaluated by regression analysis, 94% of the carriers were correctly identified at the 95% confidence level.
Gas-chromatographic determination of mephenytoin and desmethylmephenytoin, after off-column alkylation.
Authors: Raisys V A , Zebelman A M , MacMillan S F 
Published: January 2020

Abstract
We describe a gas-liquid chromatographic method for determining mephenytoin and its active metabolite, desmethylmephenytoin, in human serum. 5-Methyl-5-phenylhydantoin is used as the internal standard. The method involves extraction of the drugs by adsorption onto charcoal and off-column derivatization to their pentyl derivatives. Peak height and concentration are linearly related and the day-to-day CV for therapeutic concentration is about 2 to 6%. No interferences by endogenous compounds or drugs commonly used for seizure control have been encountered.
New technique for solid-phase immunoassay: application to hepatitis B surface antigen.
Authors: Park H 
Published: January 2020

Abstract
I describe a new technique for improving the sensitivity of the solid-phase "sandwich" assay, by using the through-passage receptacle in a novel flow-communication device. The technique allows a large volume of serum to flow through the antibody-coated receptacle repeatedly during the incubation and is thus termed the "flow-through large-volume incubation" method. Binding of 125I-labeled hepatitis B surface antigen to its corresponding antibody on a solid-phase by this method was more rapid and persistent than binding by the conventional method. When the method was applied to the first incubation of the sandwich assay, the test for the antigen was rendered four-, eight-, and 32-fold as sensitive as an accepted third-generation test for the antigen, by incubating 5-mL volumes of serum at (a) room temperature for 18 h, (b) 45 degrees C for 8 h, or (c) room temperature for seven days, respectively.
Iodinated digoxin derivatives with improved reactivity and stability, for use in radioimmunoassay.
Authors: Weiler E W , Zenk M H 
Published: January 2020

Abstract
We report the synthesis and properties of a new digoxin derivative, prepared by reacting cyanogen bromide-activated digoxin with tyramine. The derivative is extremely stable, and its monoiodinated form can be isolated in 85--90% purity by a single thin-layer chromatographic step. [125I]Tyramine-digoxin is immunologically stable for at least four months (immunoreactivities, 90% or greater throughout), with a shelf life of about six months. Nonspecific binding of less than 10% was observed for several batches during this time.
Determination of serum aminotransferases: activation by pyridoxal-5'-phosphate in relation to substrate concentration.
Authors: Hafkenscheid J C , Dijt C C 
Published: January 2020

Abstract
To investigate the activation of aspartate- and alanine aminotransferases by pyridoxal-5'-phosphate, we determined the enzymatic activity in serum in two different ways: (a) Preincubation of the serum alone or the serum with pyridoxal-5'-phosphate and starting the reaction by the addition of the serum sample or the serum sample + coenzyme, respectively. (b) Preincubation of the serum or the serum with pyridoxal-5'-phosphate in the reaction medium and starting the reaction by adding 2-oxoglutarate. There are only small differences in activities of both aminotransferases determined according to these two different methods. The stimulation by pyridoxal-5'-phosphate is also of the same order, when both methods are compared. Further, these enzymatic activities were measured with use of various concentrations of substrates. From our experiments we conclude that the degree of stimulation of the apoenzyme of the two enzymes is independent of which way the enzymatic reaction is carried out or the substrate concentration, except that aspartate aminotransferase activity is more stimulated by the coenzyme at higher 2-oxoglutarate concentrations.
Immunoradiometric assay of endotoxin in serum.
Authors: Leibowitz A I , Vladutiu A O , Nolan J P 
Published: January 2020

Abstract
We describe an immunoradiometric assay for the specific detection and quantitation of endotoxin from Escherichia coli 026, with use of 125I-labeled antibody. The sensitivty of this assay is 1 microgram/L.E. coli 026 endotoxin was detected in serum of rats for as long as 24 h after intraperitoneal injection of 0.1 mg of endotoxin per 100 g body weight. The assay is specific for the O-polysaccharide portion of this endotoxin, as confirmed by results after protein digestion and oxidation of the endotoxin, as well as by failure to detect endotoxin in serum after similar injections of E. coli 0127 and Salmonella typhosa 0901 endotoxins.
Hydrolysis of glutathione by human liver gamma-glutamyltransferase.
Authors: Shaw L M , Newman D A 
Published: January 2020

Abstract
We studied the catalytic hydrolysis of glutathione by human liver gamma-glutamyltransferase [(gamma-glutamyl)-peptide:amino acid gamma-glutamyltransferase, EC 2.3.2.2]. Glutamate production from glutathione was maximal at pH 7.4 (37 degrees C). Kinetically, the liver enzyme is similar to human kidney gamma-glutamyltransferase: their respective Km values with glutathione as substrate are similar (0.096 x 10(-3) mol/L and 0.097 x 10(-3) mol/L, respectively). S-Methylglutathione was hydrolyzed at a slightly higher rate than glutatione by liver gamma-glutamyltransferase. From these findings and other established properties of liver and kidney gamma-glutamyltransferase we propose that human liver is an important site of glutathione catabolism and that gamma-glutamyltransferase in liver catalyzes the first step of the catabolism of glutathione and glutathione conjugates in this organ.
A model program for education and training of clinical chemists.
Authors: Trawick W G 
Published: January 2020

Abstract
Some general guidelines can help in the assessment of clinical chemistry training and training programs. A clinical chemist must be, first of all, a good chemist, but to this must be added other knowledge and skills. A program that begins with a bachelor's degree in chemistry equivalent to the American Chemical Society's standards is proposed for the clinical chemistry technologist. The model provides more flexibility as the education proceeds toward the doctoral and postdoctoral levels and as the opportunities and responsibilities become increasingly more diverse. An essential portion of the training at all levels is experience in a clinical laboratory. It is strongly recommended that this be started early and be continued throughout the program. Certification by an independent agency (National Registry in Clinical Chemistry or American Board of Clinical Chemistry) is strongly recommended as a final step in all plans.
Hemoglobinuria and hematuria: accuracy and precision of laboratory diagnosis.
Authors: Bee D E , James G P , Paul K L 
Published: January 2020

Abstract
Five methods of assessing blood in urine were studied and compared: sedimentation count, hemacytometry, "Clini-lab" reagent strip and "N-Multistix" and "ChemStrip-8" dipsticks. The minimum sensitivity of two commercially available urine dip-stick procedures for blood was established. The study includes method association, assay variation among and within technologists, accuracy, precision, and sensitivity. Our results demonstrate generally poor association between results by the dip-stick procedures and the hemacytometer or sedimentation count. Results by the last two procedures also showed very poor association with each other.
Serum cortisol and 11 deoxycortisol by liquid chromatography: clinical studies and comparison with radioimmunoassay.
Authors: Canalis E , Caldarella A M , Reardon G E 
Published: January 2020

Abstract
We describe a liquid-chromatographic procedure for separating and measuring cortisol and 11-deoxycortisol in serum. We quantitated these steroids in patients who were undergoing various tests of pituitary and (or) adrenal function and compared the results with those obtained by two radioimmunoassays done in two different laboratories. Results of 48 tests done in 37 functionally normal humans are presented. Cortisol values for sera collected in the morning as determined by liquid chromatography were (mean +/- SD) 134 +/- 54 micrograms/L. Serum cortisol concentrations increased from 136 +/- 65 to 321 +/- 80 micrograms/L 60 min after injecting synthetic corticotropin and increased from 107 +/- 46 to 242 +/- 31 micrograms/L after insulin-induced hypoglycemia. Serum cortisol decreased from 142 +/- 49 to 26 +/- 20 micrograms/L after oral administration of metyrapone, while 11-deoxycortisol increased from less than 10 to 210 +/- 53 micrograms/L. Serum cortisol measured less than 10 micrograms/L the morning after oral ingestion of dexamethasone. Results of the dynamic tests of adrenal function correlated well with previously reported studies. However, the cortisol values obtained by our technique were generally lower than those obtained by radioimmunoassay, possibly owing to lack of specificity of the latter methods used here for comparison. In contrast, values for 11-deoxycortisol were the same by both methods. The present studies confirm the usefulness of liquid chromatography for measuring these two steroids in serum during tests of pituitary and adrenal function. Future refinements of the technique should continue to increase its clinical applications.
Improved radioimmunoassay for 11-deoxycortisol (compound S) in plasma.
Authors: Demers L M , Ebright L , Derck D D 
Published: January 2020

Abstract
We describe a radioimmunoassay for 11-deoxycortisol (Compound S) that involves preliminary chromatography on Sephadex LH-20, to isolate 11-deoxycortisol from crossreacting structurally related steroids. Pools with means of 3.4, 12.9, and 69.9 micrograms/L gave intra-assay coefficients of variation of 9.7, 9.6, and 11.4%, respectively; pools with means of 4.6, 27, and 95 micrograms/L gave inter-assay CV's of 10.1, 9.7, and 6.2%, respectively. A normal range (mean +/- 2SD) of 0.5 to 12.0 micrograms/L was obtained. This procedure is useful for the specific determination of 11-deoxycortisol, commonly determined in blood as part of the metyrapone test for assessing pituitary corticotropin reserve.
Determination of 4-O-methylated catecholamine metabolites in urine by mass fragmentography.
Authors: Muskiet F A , Fremouw-Ottevangers D C , Nagel G T , Wolthers B G 
Published: January 2020

Abstract
We describe the determination of the 4-O-methylated catecholamine metabolites 4-methoxy-3-hydroxyphenylacetic acid (iso-HVA), 4-methoxy-3-hydroxyphenylmandelic acid (iso-VMA) and 4-methoxy-3-hydroxyphenylethylene glycol (iso-MOPEG) in urine with use of mass fragmentography and deuterated internal standards. Normal values, expressed in terms of creatinine, are given as a function of age. Urinary excretion values during neuroblastoma, pheochromocytoma, and parkinsonism treated with L-DOPA, and during the intravenous administration of dopamine are discussed. For normal persons, the mean percentages (+/- SD) of 4-O-methylated metabolites relative to their 3-O-methylated analogs were 6.29 +/- 2.79% (iso-HVA/HVA), 0.70 +/- 0.57% (iso-VMA/VMA), and 0.77 +/- 0.53% (iso-MOPEG/MOPEG). We observed no significant changes in these parameters for the patients studied and conclude that the determination of 4-O-methylated catecholamine metabolites for these patients does not add information to the results obtained from their quantitatively more important 3-O-methylated analogs.
Spurious hyperbilirubinemia in uremic patients on propranolol therapy.
Authors: Stone W J , McKinney T D , Warnock L G 
Published: January 2020

Abstract
Chronic, low-grade, unexplained increases of total serum bilirubin concentration were observed in 16 of 132 (12%) chronic dialysis patients. Cessation of antihypertensive medication in four patients resulted in disappearance of hyperbilirubinemia. Propranolol was the only antihypertensive drug common to all 16 patients. Daily dosage varied among the patients, but the mean dose was 308 mg (+/- 51 SEM). Serial determinations of sera from individual patients given different doses and from the group as a whole demonstrated a linear relationship between propranolol dose and apparent total serum bilirubin concentration with continuous-flow analysis. When serum specimens from uremic patients receiving propranolol were treated with diazotized fulfanilic acid and examined spectrophotometrically, an absorbance peak distinct from but overlapping that of bilirubin was consistently demonstrated. The material producing the peak disappeared when the drug was stopped, did not dialyze, and was not reproduced by the in vitro addition of propranolol to uremic serum. We postulate that a metabolite(s) of propranolol is retained in uremic serum and interferes with the bilirubin determination.