bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interference by hemolysis with various methods for total calcium and its correction by trichloroacetic acid precipitation.
Authors: Chan K M , Arriaga C , Landt M , Smith C H , Ng R H 
Published: January 2020

Abstract
We evaluated the influence of hemolysis on total serum calcium as determined with the Du Pont aca, SMA 12/60, Ektachem 400, Corning 940 EGTA titrator, and the Beckman Astra 8, comparing results with those obtained by atomic absorption spectroscopy. We find that hemoglobin does not influence calcium measurements with the SMA 12/60, Ektachem 400, or Beckman Astra 8. The presence of hemoglobin exceeding 2 to 3 g/L caused falsely high results with the aca and falsely low results with the Corning 940 titrator. Similar interferences may be observed with other titrating or colorimetric procedures that involve direct reaction of the sample with o-cresolphthalein complexone or calcein. Upon removal of the hemoglobin by precipitation with trichloroacetic acid, the values obtained with the aca and the Corning 940 EGTA titrator were similar to those measured by atomic absorption. With nonhemolyzed serum samples the acid treatment had little or no effect on the aca procedure but resulted in a positive bias of approximately 10% with the EGTA procedure. Thus we recommend this trichloroacetic acid procedure for measuring calcium in hemolyzed samples with the aca and, with certain reservations, with the EGTA titrator.
An inter- and intralaboratory quality-control survey of radioimmunoassay of insulin, thyroxin, thyrotropin, cortisol, digoxin, gastrin, beta 2-microglobulin, and IgE in Japan with commercially available kits.
Authors: Shishiba Y , Irie M , Yamada H , Kinoshita F 
Published: January 2020

Abstract
We report results of a quality-control survey of radioimmunoassay (RIA) of eight analytes, participated in by 249 laboratories of various types throughout Japan. For the purpose of the external control survey, lyophilized specimens containing two different concentrations of each analyte were sent to the participating laboratories, which supplied both their assay values and their raw data for the standard curves and for the samples. The individual data for the standard curve were analyzed by the RIA data-processing program described by Faden and Rodbard. The precision profile obtained for the individual assay was used as the estimate of the quality of each assay. Although there was a wide scatter in assay values, the quality of the assay by the individual laboratories was not the major contributor to this scattering, because the values they reported for the assays and precision profiles of the standard curves were almost identical with those obtained from the kit manufacturers. When the reported assay values were analyzed according to the brand of kits, by analysis of variance, the treatment mean square due to difference in the make of the kits significantly exceeded the error mean square due to "within-kit" variation in the assay of insulin, thyroxin, thyrotropin, cortisol, gastrin, and digoxin. The CVs for "between-kit," "within-kit," "between-assay" and "within-assay" variations (the latter two aspects were studied in a representative laboratory, for convenience of comparison) were about 20, 15, 13, and 7%, respectively. Because the observed within-kit variation is of almost the same magnitude as that expected from the combination of within-assay and between-assay variation, the skill of the users probably was equal and the accuracy and precision of the kits probably had the greatest impact on assay variation. This survey also emphasizes the criteria for commercially available RIA kits.
Free triiodothyronine and free thyroxin in sera of pregnant women and subjects with congenitally increased or decreased thyroxin-binding globulin.
Authors: Franklyn J A , Sheppard M C , Ramsden D B , Hoffenberg R 
Published: January 2020

Abstract
Concentrations of free thyroxin (T4) and free triiodothyronine (T3) were measured in sera from pregnant women, in subjects with congenitally increased or decreased thyroxin-binding globulin (TBG), and in euthyroid controls. Measured free hormone concentrations were compared with calculated values for free hormone derived from concentrations of total T4, total T3, and binding proteins. Measured and calculated concentrations of free T4 and free T3 were below normal in the pregnant subjects but were normal in subjects with congenital increases of TBG. The low concentrations of free hormone in pregnancy are at variance with the euthyroid status of these subjects. Measured free T4 was normal, but concentrations of free T3 were less in the euthyroid congenitally low-TBG group.
Development of a screening system for cystic fibrosis.
Authors: Coury A J , Fogt E J , Norenberg M S , Untereker D F 
Published: January 2020

Abstract
We have developed a simple method for detecting high concentrations of chloride in sweat from ambulatory subjects, a measurement useful in the detection of cystic fibrosis. The method is based on the standard approach of stimulating sweat generation through iontophoresis of pilocarpine nitrate into the skin, followed by collection and analysis of the sweat for chloride concentration. The sweat-stimulating reagents are contained in polymeric gel pads, which are used in conjunction with a small battery-powered stimulator. The chloride analysis is subsequently done on the stimulated site by use of a thin test patch that picks up a fixed amount of sweat and changes color if the chloride concentration is higher than a predetermined value. The successful completion of a test is indicated by a fill tab, which changes color when the appropriate amount of sweat has been picked up by the chloride test patch.
Homogeneous immunoassay based on chemiluminescence energy transfer.
Authors: Patel A , Campbell A K 
Published: January 2020

Abstract
The chemiluminescent compound aminobutylethyl-isoluminol (ABEI) and its isothiocyanate derivative have been coupled to a range of haptens (progesterone, cyclic AMP, cyclic GMP) and protein antigens (IgG, C9). All the derivatives were chemiluminescent, immunologically active, and stable for more than six months. When the ABEI-labeled antigens bind to their respective fluorescein-labeled antibodies, there is a shift in the ratio of chemiluminescence at 460 nm (blue) to that at 525 nm (green). This nonradiative energy transfer was used to establish homogeneous immunoassays, which require no separation step. These assays were at least as sensitive as the conventional radioimmunoassays and could accurately measure substances in serum (i.e., for IgG, results correlated by r = 0.96 relative to those by 125I assay) and tissue extracts (cyclic AMP, r = 0.91 relative to 3H assay), and also were used to evaluate the kinetics of antibody-antigen binding. Chemiluminescence energy transfer provides a new method for quantifying ligand-ligand interactions in the 10(-15) to 10(-18) mol range without first separating bound and free ligand. This provides a unique opportunity to investigate chemical events in single cells and intact cells.
Trace metal analysis by laser-enhanced ionization in flames.
Authors: Travis J C , Turk G C , DeVoe J R 
Published: January 2020

Abstract
We review atomic flame spectrometry of metals based on the selective laser-enhancement of the rate of atomic ionization. A discussion of basic principles, prior literature, and instrumentation is followed by an overview of analytical figures of merit for the technique, and a look at its present status and areas for future development.
Stabilities of some constituents of marmoset (Callithrix jacchus) plasma under various conditions of storage.
Authors: Davy C W , Jackson M R , Walker J M 
Published: January 2020

Abstract
The stability of various marmoset (Callithrix jacchus) plasma constituents was investigated after storage at room temperature, 4 degrees C, and -20 degrees C. The method of sequential analysis ensured that the between-run bias of the methods of analysis used was drastically reduced, and the definitions of stability were linked to the imprecision of these methods. Optimal conditions for storage for as long as 48 h depended on the analyte being measured. Room temperature was optimal for cholinesterase and acetylcholinesterase; 4 degrees C for protein, albumin, alanine aminotransferase, isocitrate dehydrogenase, sorbitol dehydrogenase, lactate dehydrogenase, and glutamate dehydrogenase; and -20 degrees C for glutathione reductase and alkaline phosphatase. For aspartate amino-transferase and gamma-glutamyltransferase, either 4 degrees C or -20 degrees C would be suitable. Reasons are advanced for some conflicting reports in the published work, and we emphasize the need to investigate each analyte and species separately.
A screening method for biotinidase deficiency in newborns.
Authors: Heard G S , Secor McVoy J R , Wolf B 
Published: January 2020

Abstract
We describe a method for neonatal screening for biotinidase (EC 3.5.1.12) deficiency. Biotinidase activity is assessed colorimetrically from dried samples of whole blood spotted on the same filter papers as used in the neonatal screening for phenylketonuria. After the reaction, samples from normal infants are characteristically purple, whereas those from affected individuals are straw-colored. To confirm the deficiency, the enzyme is quantitatively assayed in additional blood spots or serum. A pilot study has been initiated with samples obtained by the Commonwealth of Virginia for phenylketonuria testing.
Clinical usefulness of estriol assay for predicting "light-for-dates" infants.
Authors: Evans J J , Wilkinson A R , Aickin D R 
Published: January 2020

Abstract
A method was developed for determining clinical usefulness of a test for predicting "light-for-dates" infants before birth. The method was applied in a prospective study of assay of maternal estriol at 35-36 weeks of gestation as a means of identifying such infants. With the tenth centile for estriol values as the cutoff, low estriol values identified less than a third of all light-for-dates infants, and less than a third of pregnancies with low estriol values were associated with births of light-for-dates infants. Our reanalysis of data from three other published studies, using the same method of assessment, gave similar results. When laboratory tests are expected to provide clinically relevant information, we urge that data should be appropriately collected, analyzed, and reported, so clinical usefulness can be evaluated.
Influence of substrate concentration on the activation of transketolase, aspartate aminotransferase, and glutathione reductase by coenzymes.
Authors: Hafkenscheid J C , van Dijk C M 
Published: January 2020

Abstract
We investigated the mechanism by which the three most commonly measured enzymes in erythrocytes are activated by their respective coenzymes by determining the catalytic activity concentrations of transketolase (EC 2.2.1.1), aspartate aminotransferase (EC 2.6.1.1), and glutathione reductase (EC 1.6.4.2) in relation to various substrate concentrations. We conclude that the underlying mechanisms by which the enzymes are activated are not the same.
Results of a nationwide survey of analyses for creatine kinase and creatine kinase isoenzymes.
Authors: Boone D J , Duncan P H , MacNeil M L , Smith B F , Houston B , Hearn T L 
Published: January 2020

Abstract
More than 300 laboratories participated in an interlaboratory survey of creatine kinase (CK, EC 2.7.3.2) determinations in which they analyzed seven lyophilized samples for total CK and CK isoenzymes and furnished information about their methodology. The samples were not necessarily intended to mimic typical patients' specimens but rather to determine the analytical ability of the laboratories to distinguish isoenzyme fraction CK-MB from CK-BB and to detect small but abnormal amounts of CK-BB. For total CK measurement, most laboratories used an NADP+ reduction method monitored at 340 nm (89%), and reported results in units per liter (U/L) (99%) at either 30 degrees C (34%) or 37 degrees C (60%). Despite the variety of analytical conditions, most laboratories (89%) correctly reported results within their normal range for all samples. The 287 laboratories that reported isoenzyme distributions in the samples used either cellulose acetate (37%) or agarose (44%) electrophoresis, ion-exchange chromatography (9%), or immunoinhibition (7%). Results from laboratories that used nonspecific CK-MB immunoinhibition techniques were biased when a significant amount of CK-BB isoenzyme was present.
On the interpretation of serial laboratory measurements in acute myocardial infarction.
Authors: Albert A , Harris E K , Chapelle J P , Heusghem C , Kulbertus H E 
Published: January 2020

Abstract
Serial laboratory determinations are now routinely performed on patients admitted to intensive-care units. Adequate interpretation of such cumulative information for clinical decision-making purposes is a challenging problem. We describe a statistical method for predicting--sequentially as the data become available--the patient's outcome, death or survival. Thus, the method goes beyond previously reported techniques that base such prediction on only a single multivariate observation. The method has been applied to daily measurements of serum urea and lactate dehydrogenase, performed during one week on patients hospitalized in the coronary-care unit with acute myocardial infarction. Two baseline variables were also included in the dynamic risk index so derived: the age of the patient and the number of previous myocardial infarctions recorded on admission. We also discuss the problems of selecting the most-predictive laboratory tests and of determining for each test the amount of past data needed to achieve satisfactory prediction. We distinguish between global evaluation of the dynamic risk index obtained (in terms of specificity and sensitivity) and individual interpretation (in terms of posterior/prior probability ratio) of a given risk score for a particular patient. The approach described may contribute to more effective use of results of repeated laboratory tests on critically ill patients.
Quantification of alprazolam in serum or plasma by liquid chromatography.
Authors: McCormick S R , Nielsen J , Jatlow P 
Published: January 2020

Abstract
A reversed-phase "high-performance" liquid-chromatographic assay for the quantification of alprazolam in serum or plasma is described. Serum or plasma is extracted with toluene/isoamyl alcohol (99/1 by vol), evaporated, and reconstituted in the mobile phase. The latter is washed with hexane, then subjected to reversed-phase liquid chromatography and ultraviolet detection at 202 nm. Either U-31485, an alprazolam analog, or lorazepam, a 3-hydroxybenzodiazepine, is satisfactory as internal standards. Major alprazolam metabolites and various other commonly used drugs do not interfere. The useful lower limit of sensitivity for quantification is 2.5 micrograms/L. Peak height and alprazolam concentration are linearly related from 2.5 to 100 micrograms/L. For 10 and 20 micrograms/L concentrations, within-run CVs were 1.4% and 0.9% and the between-runs CVs 4.8% and 3.2%. Steady-state serum concentrations ranged from 25 to 55 micrograms/L in patients taking 1.5 to 6.0 mg per day, orally. Preliminary data suggest the method is also suitable for analysis of the structurally similar triazolobenzodiazepine, triazolam.
Isolation and characterization of cancer-associated galactosyltransferase isoenzyme.
Authors: Ram B P , Munjal D D 
Published: January 2020

Abstract
We isolated galactosyltransferase (EC 2.4.1.22) from pleural effusions of a lung cancer patient and a patient with cirrhosis by precipitation with ammonium sulfate, followed by gel filtration on Sepharose 6B, and affinity chromatography on columns of alpha-lactalbumin-agarose and protein A-Sepharose. By this procedure the enzyme from both sources was purified 40 000-fold with approximate yields of 37% and 60%, respectively, and did not contain immunoglobulin. Electrophoresis on polyacrylamide gel of the enzyme from the cancer patient (slower moving) and from the non-cancer patient (faster moving) gave one sharp band for each. Their respective relative molecular masses, 74 131 and 107 151, were estimated by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and gel filtration, respectively. The isoenzymes were active between pH 5 and 8, most active at 7, and showed no activity below pH 4 or above pH 9. Activity was greatest at temperatures between 37 and 40 degrees C. At 30 degrees C or 50 degrees C the activity was more than halved, and was lost completely above 60 degrees C. The isoenzymes had an absolute requirement for Mn2+. Omitting the surfactant Triton X-100 from the buffer resulted in considerable loss in activity of both isoenzymes. Glucose can be used as an acceptor for these isoenzymes if alpha-lactalbumin is present in the assay mixture. These isoenzymes had different Km values for UDP-galactose, N-acetylglucosamine, and Mn2+.
Serum copper concentration significantly less in abnormal pregnancies.
Authors: Buamah P K , Russell M , Milford-Ward A , Taylor P , Roberts D F 
Published: January 2020

Abstract
We estimated copper concentration in maternal serum during 244 normal and 15 abnormal pregnancies. Values were lower in the abnormal pregnancies than in the normal ones, and did not vary with gestational age between 15 to 18 weeks in normal pregnancies.
Automated continuous-flow radioimmunoassay for salivary estriol.
Authors: Truran P L , Read G F 
Published: January 2020

Abstract
We have automated a radioimmunoassay for salivary estriol by using the "Southmead" continuous-flow system. The assay, based on a well-validated manual assay, involves a Sepharose-coupled antiserum and an 125I-radioligand. The antibody-bound and free radioligand fractions are separated by on-line filtration. Performance of the automated assay has been reliable during six months of regular use, and compares favorably with that of the manual assay. Drift (0.5 nmol/L per 100 samples) and sample carryover (3%) are acceptable, and the throughput rate is 55 samples per hour. The system is suitable for the assay of the large numbers of samples generated by daily saliva specimen collection in the third trimester of pregnancy.
Aberrant creatine kinase and lactate dehydrogenase response in a myocardial infarct patient.
Authors: Smalley D L , Womack B , Handorf C , Acchiardo S 
Published: January 2020

Abstract
A 65-year-old woman failed to develop increased creatine kinase or lactate dehydrogenase activity after a myocardial infarction. She had no measurable creatine kinase MB isoenzyme and no detectable patterns of normal LD isoenzyme activity. These determinations five months after the infarction showed normal values for total activity and isoenzyme patterns.
Biclonal IgA and IgM gammopathy in lymphocytic lymphoma.
Authors: Weinstein S , Jain A , Bhagavan N V , Scottolini A G 
Published: January 2020

Abstract
We report the case of a 76-year-old white man with a diffuse, well-differentiated lymphocytic lymphoma at the base of his tongue. Although serum electrophoresis, immunoelectrophoresis, and immunofixation showed he had a biclonal IgA kappa and IgM kappa gammopathy, biopsy of the tumor showed a positive immunoperoxidase response only for IgM kappa. The biclonal pattern persisted after chemotherapy, despite shrinkage of the tumor mass. The association of IgA and IgM appears to be the least frequent combination of separate biclonal immunoglobulins, the clinical course of such patients being more often that of lymphoma or macroglobulinemia than of myeloma. However, the symptomatology can be highly variable, as our case uniquely demonstrates.
Operational research and cost containment: a general mathematical model of a workstation.
Authors: Winkel P 
Published: January 2020

Abstract
To facilitate planning and management, I have derived a mathematical model describing the dynamics of a workstation that receives a mixture of routine and emergency specimens. The model parameters include the maximal specimen-processing rate (to be defined by personnel representatives) and the longest delay allowed for emergency specimens at the workstation. Based on the model, a computer-simulation technique has been developed to maximize the length of time (planned pauses) during which the workstation could be closed without causing undue delay of routine and emergency specimen results. The application of this technique is illustrated with real data, in which more than 50% of the specimens were emergency specimens. Three pauses, constituting 35% of working hours, could be introduced with a negligible impact on the turnaround time of emergency specimens (mean increase = 8 min). The model may also be used to derive, as a function of time of day, the largest extra workload that may be presented to a workstation without creating overwork. The workload could be increased by 45%, provided that all additional specimens arrived before noon.
Determination of free thyroxin in serum by ultrafiltration: validation of a method and preliminary results.
Authors: Shannon N , Woolf P D 
Published: January 2020

Abstract
We describe the determination of concentrations of free thyroxin in serum by ultrafiltration based on the Amicon micropartition system. The assay is straightforward and requires about 4 h for 25 samples. Our results demonstrate a correlation coefficient of 0.81 compared with equilibrium dialysis, and of 0.88 compared with radioimmunoassay. For sera from 49 normal, 25 hyperthyroid, 24 hypothyroid, 50 euthyroid sick, and 13 pregnant subjects, the means (and SD) were respectively: 19.3 (4.9), 40.1 (13.6), 5.0 (2.9), 25.9 (10.5), and 16.1 (3.2) ng/L. The interassay CV was 9.9% and the intra-assay CV 7.2%. We conclude that this procedure is useful in the diagnosis of thyroid disease and offers advantages of simplicity, rapidity, and economy.
Automated calmagite compleximetric measurement of magnesium in serum, with sequential addition of EDTA to eliminate endogenous interference.
Authors: Liedtke R J , Kroon G 
Published: January 2020

Abstract
We describe an automated method for magnesium assay, for use with the Cobas-Bio centrifugal analyzer. Magnesium is reacted with calmagite, a dye, and the absorbance of the magnesium-dye complex at 520 nm is measured. EDTA is then added to break up the complex and the absorbance at 520 nm is re-measured to correct for sample color and turbidity. Including ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) and triethanolamine in the dye reagent eliminates interference by calcium and iron. Within-run CVs were less than 2.0% for concentrations of magnesium ranging from 18 to 40 mg/L, and less than 4% for a magnesium concentration of 9.4 mg/L. Day-to-day precision data, determined over five months were: mean = 21.0 mg/L, CV = 2.7%; mean = 43.0 mg/L, CV = 3.2% (n = 550 for both). Comparison of the Cobas-Bio method (y) with an atomic absorption spectrometric method (x) gave the following results: y = 0.968x + 0.448, r = 0.986, Sy/x = 0.34 mg/L, mean x = 19.8 mg/L, mean y = 19.6 mg/L, n = 44. Hemoglobin, bilirubin, and turbidity do not interfere. The standard curve is linear up to a magnesium concentration of 97 mg/L.
Combined immunochemical and electrophoretic determinations of proteins in paired serum and cerebrospinal fluid samples.
Authors: Papadopoulos N M , Costello R , Kay A D , Cutler N R , Rapoport S I 
Published: January 2020

Abstract
Albumin and immunoglobulin G were simultaneously determined in paired serum and cerebrospinal fluid samples from healthy volunteers. The albumin quotient and the IgG index were calculated to establish normal values. High-resolution electrophoresis was also performed with the same samples and the electrophoretic patterns were correlated with the numerical values to improve the reliability of the test results. Representative examples from abnormal conditions are also shown, to illustrate the increased accuracy and useful applications of this combined analysis in the diagnosis of neurological conditions.