bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multilayer film analysis: evaluation of ion-selective electrolyte slides.
Authors: Costello P , Kubasik N P , Brody B B , Sine H E , Bertsch J A , D'Souza J P 
Published: January 2020

Abstract
We evaluated the Kodak Ektachem multilayer ion-selective electrolyte slides. For various types and concentrations of control material the precision (CV) within- and between-day ranged from 0.5 to 1.3% (1.7-2.1%) for sodium, 1.2 to 2.2% (2.7-2.9%) for potassium, 2.9 to 4.6% (5.9-6.7%) for carbon dioxide, and 0.7 to 1.6% (1.3-1.4%) for chloride. For all these analytes, analytical recovery was about 100%, except in the supra-physiological ranges, for which carbon dioxide recovery was about 110-120%. Either serum or heparin-treated plasma can be used, interchangeably, for analysis; use of serum treated with lithium iodoacetate is unacceptable. Comparisons with results by continuous-flow procedures demonstrated good correlation for sodium, potassium, and chloride; carbon dioxide comparisons indicate an Ektachem calibrator change may be required. Abnormally low protein concentrations or lipemia had no observed effects on results for electrolytes. Abnormally high protein concentrations affect sodium results slightly (approximately 5 mmol/L).
Modified handling of internal catecholamine standards in radioenzymic assays.
Authors: Ellis J P , Burns J W 
Published: January 2020

Abstract
A departure from a radioenzymic procedure widely used for plasma catecholamine assay is reported, in which we use "mean net standards" instead of individual internal standards. Interlaboratory/intermethod analyses validated use of the modified principle and demonstrated its preferential use over the conventional principle. Also demonstrated is use of the modified procedure for calculating catecholamine concentrations of several plasma samples collected from an exercising man and an acceleration-stressed swine. Benefits already derived from use of the procedure include: (a) quantification of certain plasma samples that could not be satisfactorily quantified by conventional options, (b) an apparent gain in analytical precision in virtually all other analyses, and (c) costs of analysis reduced by about 25%.
Screening for neonatal Duchenne muscular dystrophy by bioluminescence measurement of creatine kinase in a blood sample spotted on paper.
Authors: Dellamonica C , Collombel C , Cotte J , Addis P 
Published: January 2020

Abstract
Neonatal screening for Duchenne-type muscular dystrophy is greatly simplified by use of a new bioluminescence procedure for creatine kinase. The blood of newborn myopathic children consistently showed increased activity. The improved method permits the analysis from a dried sample of whole blood spotted on filter paper; it shows high correlation with existing procedures and is highly specific and precise. The use of the improved method in a screening program involving 158 000 newborns is reviewed. We find a prevalence of 1/5929 living eighth-day boys.
Preparation of soluble apolipoproteins A-I, B, and C-II by a chromatofocusing column method, and evaluation of their concentrations in serum in pulmonary disease.
Authors: Jauhiainen M , Laitinen M , Marniemi J , Liippo K , Penttilä I , Hietanen E 
Published: January 2020

Abstract
A chromatofocusing column method for isolating ApoB is described. LDL is first isolated by sequential ultracentrifugation and delipidated with n-butanol/diisopropyl ether. Chromatofocusing of ApoLDL yielded a large ApoB peak at pI 5.0-5.3. ApoA-I and ApoC-II were prepared analogously, with HDL and VLDL as the source of apoprotein. Antisera were raised in rabbits, and electroimmunoassay techniques were used for determination. ApoB was water-soluble after chromatofocusing. Intra-assay precision (CV) was 4.7% for ApoA-I, 7.8% for ApoB in the "rocket" electrophoresis. Interassay precision (CV) was 6% for ApoA-I and 8% for ApoB. Apolipoprotein concentrations were measured in subjects who had undergone lung resection and patients with obstructive pulmonary disease. After lung resection, the concentration of ApoA-I in serum was significantly decreased (p less than 0.001) and that of ApoB significantly increased (p less than 0.001) as compared with controls. The ApoA-I/ApoB ratio was significantly lower in the lung-resection group. ApoA-I and ApoB concentrations were unchanged in chronic obstructive pulmonary disease. ApoC-II concentrations in each group were similar to those for control subjects. Of the lipids, values for total cholesterol were above normal after lung resection (p less than 0.002), as were those for triglycerides (p less than 0.02).
Creatine kinase activity and isoenzyme pattern in various normal tissues and neoplasms.
Authors: Tsung S H 
Published: January 2020

Abstract
I measured total creatine kinase (CK; EC 2.7.3.2) activity and isoenzyme pattern in normal and neoplastic tissues. CK activity was detected in all of them examined. In various tumors it was greater than, less than, or the same as that in normal tissue, no clear correlation being seen between total activity and growth rate or degree of differentiation. In several cases, there was a greater proportion of the CK-MM isoenzyme, and 15 of 53 cases showed an atypical CK-MM band. The atypical CK-MM band, also reported by others, might be an insensitive and nonspecific tumor marker. The CK-BB isoenzyme, ubiquitous in neoplastic tissues, might accordingly be a nonspecific marker. Total CK activity was very low in most tumor tissues. Presumably a bulky tumor or an advanced stage of malignancy is a requisite to release of routinely detectable CK-BB into the circulation.
Isoelectric focusing in agarose: classification of genetic variants of alpha 1-antitrypsin.
Authors: Buffone G J , Stennis B J , Schimbor C M 
Published: January 2020

Abstract
Polyacrylamide has been the matrix of choice for isoelectric focusing owing to the virtual absence of electroendosmosis in this medium. Certain inherent limitations associated with polyacrylamide have prompted some investigators to use low-electroendosmosis agarose for isoelectric focusing, but with limited success thus far. We have developed a method for isoelectric focusing in agarose for the classification of alpha 1-antitrypsin variants. Sera are applied directly to agarose gels containing a pH 4-5 ampholyte mixture, focused for less than 1 h, and directly immunofixed. Resolution of major bands is equivalent to polyacrylamide, and Pi M subtypes can be distinguished without the use of a separator. This application demonstrates the high resolution of isoelectric focusing in agarose, a more practical and convenient matrix than polyacrylamide.
Direct determination of cadmium in urine with use of a stabilized temperature platform furnace and Zeeman background correction.
Authors: Pruszkowska E , Carnrick G R , Slavin W 
Published: January 2020

Abstract
In this determination of Cd in urine, simple aqueous standards were used to which NaCl and the matrix modifier were added. The urine was diluted fivefold with water. The mean analytical recovery of added Cd for urine samples was 101%, with individual variations of less than 4%. We used the stabilized temperature platform furnace, Zeeman background correction, pyrolytically coated graphite tubes, and (NH4)2HPO4 plus HNO3 as a matrix modifier. The sensitivity of the method provided a characteristic amount of 0.35 pg of Cd per 0.0044 A X s, obtained with integrated absorbance readings. The absolute Cd detection limit in urine was 0.15 pg, corresponding to 0.04 microgram/L of urine. Lower relative detection limits for Cd in urine can be attained if the analytical situation demands it.
Effect of variations in room temperature on measured values of blood gas quality-control materials.
Authors: Ong S T , David D , Snow M , Hansen J E 
Published: January 2020

Abstract
We compared four commercial quality-control materials equilibrated in sealed ampoules at 21 or 26 degrees C in three models of blood gas machines and found po2 differences of about 13.3 Pa (10 mmHg) for an aqueous mixture with hemoglobin; about 6.7 Pa (5 mmHg) for two aqueous buffers without hemoglobin, and none for a fluorocarbon-containing emulsion. Differences for pco2 and pH were small but statistically significant. Variability within machines for pco2, po2, and pH was small but differences among machines were large, especially for po2. These results emphasize that aqueous solutions and hemoglobin-containing mixtures used for proficiency testing and quality control should be equilibrated at the temperature recommended by the manufacturer, opened, and sampled promptly.
Development and analytical performance of a functional assay for fibrinogen on the Du Pont aca analyzer.
Authors: Siefring G E , Riabov D K , Wehrly J A 
Published: January 2020

Abstract
A method for determination of functional fibrinogen has been developed for the Du Pont aca discrete clinical analyzer. This fully automated assay is based on the rate of fibrin turbidity formation when thrombin is added to the test sample. The rate of this reaction is enhanced by added calcium chloride and dextran. The assay range is from 0.50 to 8.00 g/L. Within-run reproducibility studies at the medical decision level of 1.0 g/L showed a CV of 2.5%. There was no interference by heparin up to 10 USP units per milliliter of plasma.
Simultaneous determination of haloperidol and its reduced metabolite in serum and plasma by isocratic liquid chromatography with electrochemical detection.
Authors: Korpi E R , Phelps B H , Granger H , Chang W H , Linnoila M , Meek J L , Wyatt R J 
Published: January 2020

Abstract
We describe a liquid-chromatographic method for simultaneous quantification of haloperidol and its reduced metabolite in plasma and serum. Haloperidol and reduced haloperidol are concentrated from blood samples by liquid/liquid extraction into a hexane/isoamyl alcohol mixture, with chlorohaloperidol as the internal standard. For chromatographic separation we used a reversed-phase cyano-bonded column and a mobile phase of pH 6.8 phosphate buffer/acetonitrile (55/45 by vol). Haloperidol and its reduced metabolite are detected electrochemically at +0.90 V potential between the working and reference electrodes. As little as 0.5 ng per injection is detectable. Within- and between-day CVs for determinations of haloperidol and reduced haloperidol ranged from 4 to 7% each at a concentration of 10 micrograms/L. Haloperidol concentrations measured by this method correlated well with those by gas-chromatography with nitrogen-sensitive detector and by radioimmunoassay. The present method can be used to study the effects of haloperidol on the central nervous system. It is simple enough for use in clinical laboratories that are monitoring haloperidol concentrations in the blood of psychiatric patients.
Immunonephelometric determination of retinol-binding protein in serum and urine.
Authors: Parviainen M T , Ylitalo P 
Published: January 2020

Abstract
An immunonephelometric method developed for measurement of retinol-binding protein (RBP) in serum and urine can detect it in concentrations of about 30 micrograms/L, which is in the lower limit of its normal concentration in urine (range 0-0.56 mg/L; mean +/- SD 0.19 +/- 0.15; n = 44). Urinary RBP was increased (range 0.93-29.5 mg/L) in all of 25 urine specimens from 13 subjects being treated with aminoglycoside (tobramycin). Urinary excretion of RBP was correlated (r = 0.83) with the excretion of beta 2-microglobulin. The within-assay and day-to-day precision (CV) was determined over the detection range of 0.03-8 mg/L. Within these limits the corresponding CVs varied from 4 to 27% and from 8 to 30%, respectively. The method had fairly good precision within the optimal measuring range of approximately 0.4 to 4.5 mg/L for both urine and 20-fold diluted serum samples. For various RBP concentrations our analytical recovery was 89-114% of added RBP. Results by this method correlated well (r = 0.96, n = 24) with those by a radial immunodiffusion method.
Liquid-chromatographic determination of cephalosporins and chloramphenicol in serum.
Authors: Danzer L A 
Published: January 2020

Abstract
A "high-performance" liquid-chromatographic technique involving a radial compression module is used for measuring chloramphenicol and five cephalosporin antibiotics: cefotaxime, cefoxitin, cephapirin, and cefamandol. Serum proteins are precipitated with acetonitrile solution containing 4'-nitroacetanilide as the internal standard. The drugs are eluted with a mobile phase of methanol/acetate buffer (30/70 by vol), pH 5.5. Absorbance of the cephalosporins is monitored at 254 nm. Standard curves are linear to at least 100 mg/L. The absorbance of chloramphenicol is monitored at 254 nm and 280 nm, and its standard curve is linear to at least 50 mg/L. The elution times for various other drugs were also determined, to check for potential interferents.
Urinary 4-hydroxy-3-methoxymandelic (vanillylmandelic) acid, 4-hydroxy-3-methoxyphenylacetic (homovanillic) acid, and 5-hydroxy-3-indoleacetic acid determined by liquid chromatography with electrochemical detection.
Authors: Fujita K , Maruta K , Ito S , Nagatsu T 
Published: January 2020

Abstract
We describe a simple liquid-chromatographic assay of urinary 4-hydroxy-3-methoxymandelic (vanillylmandelic) acid, 4-hydroxy-3-methoxyphenylacetic (homovanillic) acid, and 5-hydroxy-3-indoleacetic acid with electrochemical detection, with direct injection of the sample. The first two analytes are measured simultaneously; 5-hydroxy-3-indoleacetic acid is measured separately. Chromatographic conditions for assay of the three were: column temperature, 65 and 60 degrees C; mobile phase, potassium phosphate buffer (0.2 mol/L, pH 3.0) for 6 min, then potassium phosphate buffer plus acetonitrile (9/1 by vol) for 20 min; flow rate, 0.7 mL/min; oxidation potential, 600 and 450 mV vs an Ag/AgCl reference electrode; and sensitivity, 40 and 160 nA at full scale. Values so obtained agreed well with those obtained for samples that were first solvent-extracted.
Rapid acetylcholinesterase screening test for neural tube defect.
Authors: Hay D L , Ibrahim G F , Horacek I 
Published: January 2020

Abstract
A 5-min optimized automated assay for measuring acetylcholinesterase (AChE) and total cholinesterase (ChE) in amniotic fluids is described in which a centrifugal analyzer is used. Total ChE was measured by using acetylthiocholine iodide and monitoring the color developed after 5,5'-dithiobis(2-nitrobenzoic acid) is added. We evaluated four direct and indirect procedures for measuring AChE in which thiocholine is generated. These methods involve either the specific enzyme inhibitors ethopropazine and BW284C51 or the specific substrates S-butyrylthiocholine and acetyl-beta-methylthiocholine. We found the last method distinguishes normal pregnancies most efficiently from those with neural tube defect. Filtering samples through 0.22-micron membrane filters before analysis decreased the incidence of false positives. Significantly increased AChE concentrations were noted in all abnormal pregnancies (n = 45) and in 4.8% of normal pregnancies (n = 310). The rapid AChE assay involving acetyl-beta-methylthiocholine, when applied alongside a rapid alpha-fetoprotein assay, increases the efficiency of screening programs for pregnancies with neural tube defect to 99.4%. It also identifies samples with negative results for alpha-fetoprotein that require further examination by the sensitive gel-electrophoretic test for AChE.
Reference intervals for amylase isoenzymes in serum and plasma of infants and children.
Authors: Gillard B K , Simbala J A , Goodglick L 
Published: January 2020

Abstract
Measurement of pancreatic (P) and salivary-like (S) amylase isoenzyme activity in serum of adults is useful as an indirect indicator of pancreatic and salivary gland exocrine dysfunction. To extend the use of this assay to the pediatric population, we measured amylase isoenzymes in 546 serum and plasma samples and defined normal reference intervals for the P and S isoenzymes as a function of age in newborns, infants, and children. The mean activity of P isoenzyme in newborns is 3% of that of adults, begins to increase at seven to eight months, and reaches adult values by five years. The mean activity of S isoenzyme in serum is 32% of the adult mean at birth, begins to increase by three to four months, and reaches adult values by 19 months; children five to 12 years old have slightly higher values than adults. These changes with age underscore the importance of the use of age-matched reference intervals when serum amylase isoenzyme activities are measured as diagnostic indicators.
Technical considerations in the use of "high-performance" liquid chromatography in therapeutic drug monitoring.
Authors: Giese R W 
Published: January 2020

Abstract
I review the methodology of "high-performance" liquid chromatography as applied to therapeutic drug monitoring. Aside from direct injection of sample, sample cleanup involves miscible and immiscible organic solvent extractions, solid-phase extraction, and size separations. Column considerations are bonded phases, column dimensions, particle size, guard columns, stability, pH range, and reproducibility. In a section on mobile phase, the reversed-phase mode is discussed along with temperature and degassing. Absorbance and fluorescence detectors are used most commonly. The parameters "capacity factor," "efficiency," and "asymmetry value" are helpful for interpreting chromatograms, as are the aspects of peak tailing, peak quantitation, "complex solutes," and "crowded chromatograms." Finally, automation, competing methodology, and prospects are discussed.
Specific micro-radioimmunoassay for prednisolone in serum.
Authors: Olivesi A , Smith D S , White G W , Pourfarzaneh M 
Published: January 2020

Abstract
Use of an 125I radioimmunoassay involving antiserum coupled to magnetizable cellulose, after prednisolone-21-phosphate interference is removed by dichloromethane extraction at pH 7.4 and endogenous glucocorticoid interference is removed by selective chemical derivatization with Girard's Reagent T [(carboxymethyl)trimethylammonium chloride hydrazide], allows determination of prednisolone in 10 microL of serum. Results correlate well with those of an established liquid-chromatographic method for separating prednisolone from its metabolites.
Transcutaneous and capillary pCO2 and pO2 measurements in healthy adults.
Authors: Wimberley P D , Pedersen K G , Thode J , Fogh-Andersen N , Sørensen A M , Siggaard-Andersen O 
Published: January 2020

Abstract
Transcutaneous carbon dioxide and oxygen tensions (tc-pCO2 and tc-pO2) were measured in seven healthy adult volunteers during hyperventilation in atmospheric air and during CO2 inhalation. Three skin sensors were applied to each subject: an O2 electrode, a CO2 electrode, and a combined O2-CO2 electrode, each heated to 44 degrees C. We observed close correlation between tc-pCO2 and capillary-pCO2, the relation being close to that calculated from the anaerobic temperature coefficient of pCO2 in blood. For O2, on the other hand, the relationship between transcutaneous and capillary values appeared more complex. Electrode drift during in-vivo monitoring was greater for pCO2 (up to 12%) than for pO2 (up to 7%), but generally we observed no differences in drift between the combined and the single electrodes. We conclude that tc-pCO2 measured with a single or a combined electrode reliably predicts capillary-pCO2 in healthy adults and that changes are rapidly observed. Our conclusions regarding tc-pO2 values are less definite because of uncertain interpretation of the capillary-pO2 values.
Transcutaneous carbon dioxide for short-term monitoring of neonates.
Authors: Kost G J , Chow J L , Kenny M A 
Published: January 2020

Abstract
We studied transcutaneous pCO2 monitoring in 70 neonates, most of them premature with respiratory distress syndrome. Measurements were at 44 degrees C. Calibration drift was large in some instances. Least squares linear regression analyses of transcutaneous pCO2 (y) vs arterial pCO2 (x) in kilopascals showed, for all observations (n = 516), for one observation randomly selected from each patient (n = 70), and for the first observation from each patient (n = 70): y = -0.28 + 1.80x, y = 0.01 + 1.74x, and y = 0.73 + 1.63x, respectively. Regression lines for individual patients with 14 or more observations each were not coincident (F = 2.80, p less than 0.002). Transcutaneous pCO2 monitoring was most useful clinically as a means of following short-term trends in arterial pCO2 continuously during extubation and afterward when avoiding re-intubation. In view of the potential for error associated with drift, we recommend that intervals between calibrations be limited to about 3 h.
Simultaneous liquid-chromatographic determination of hypoxanthine, xanthine, urate, and creatinine in cerebrospinal fluid, with direct injection.
Authors: Niklasson F 
Published: January 2020

Abstract
In this method for simultaneously determining hypoxanthine, xanthine, urate, and creatinine in cerebrospinal fluid, centrifuged sample is directly injected on a reversed-phase liquid-chromatographic column. On elution with potassium phosphate buffer the compounds are quantified by their absorbance at 260 nm. Random error (CV) was between 1.2 and 3.4% and analytical recoveries were 99-104% at physiological concentrations.
Use of a solid-state multihead gamma counter in a second-generation system for solid-phase immunoassay.
Authors: Parsons G H , Rogers C H , Polsky-Cynkin R , Wood A M , Miles L E , Rogers A H 
Published: January 2020

Abstract
Simultaneous advances in detector technology and solid-phase separation systems, as well as the availability of powerful desktop computers, have made possible the development of "second-generation" solid-phase immunoassays. These retain the advantages of classical solid phase while significantly accelerating reaction kinetics. Hapten assays--such as for digoxin, thyroxin, and triiodothyronine uptake--in batches of 48 are processed in about 20 min from reagent introduction until hard-copy printout, with minimal operator involvement. The system also functions as a 48-detector gamma counter, capable of counting and reducing data for any 125I-based RIA that can be run in a 12 X 75 mm test tube. System control, data management, and computer screen displays of kinetic data are provided by an unmodified Hewlett Packard HP-87XM computer. User-friendly disc-based software facilitates the creation and storage of counting and data reduction protocols for as many as 30 RIAs from various manufacturers as well as up to 30 of our own assays.
Applications of fast protein liquid chromatography TM in the separation of plasma proteins in urine and cerebrospinal fluid.
Authors: Cooper E H , Turner R , Johns E A , Lindblom H , Britton V J 
Published: January 2020

Abstract
Fast Protein Liquid Chromatography TM (FPLC), in which an anion-exchange column is used, provides rapid separation and reproducible profiling of the plasma proteins in urine and cerebrospinal fluid (CSF). Chromatographic separation of the proteins takes 1 h for urine specimens and 45 min for CSF. The elution sequence from the anion-exchange column is similar to the electrophoretic mobility. Individual proteins have the same retention times independently of which type of specimen is used. The elution characteristics of 21 plasma proteins have been identified. We illustrated some applications of this system, including the profiling of tubular protein-uria, the isolation of Bence Jones proteins from urine, and the investigation of hemoglobin-derived products in the CSF.