bluuebunny/crossref_metadata_2025_split huggingface dataset:
Suitability of control materials. General principles and methods of investigation.
Authors: Bretaudiere J P , Dumont G , Rej R , Bailly M 
Published: January 2020

Abstract
We propose methods for characterizing the behavior of quality-control specimens. Candidate quality-control specimens and authentic patients' specimens were analyzed by various methods. Patients' specimens were chosen to be fully representative of those encountered, including subsets from persons who were healthy, had defined disease states, were in therapy, or whose specimens were lipemic, icteric, etc. The analytical methods chosen include those most commonly used as well as reference analytical methods. Procedures for characterizing the behavior of patients' specimens and candidate quality-control specimens are proposed and their applicability is demonstrated. The linear ratio method is a univariate graphical approach in which differences in accuracy among methods for any specimen or group of specimens are each displayed on a linear scale. Correspondence analysis is a descriptive multivariate statistical technique that allows both the specimens and the analytical methods to be characterized. The statistical techniques, in our application, allow the behavior of quality-control specimens to be assessed with respect to authentic patients' specimens without influencing the assessment process. Correspondence analysis provides a graphic representation by projecting both the specimens and the analytical methods on factorial planes. The appropriateness of te behavior of a quality-control specimen may be inferred from its position relative to those of authentic patients' specimens. These statistical techniques also provide some information regarding the specificity of analytical methods.
Automation of plasma antithrombin III assays.
Authors: Holmes E W , Fareed J , Bermes E W 
Published: January 2020

Abstract
We have developed automated assays for antithrombin III for use with the Gilford 3500 and the Multistat Microcentrifugal Analyzer. The assays are two-stage kinetic-rate methods and involve use of human thrombin and the chromogenic peptide substrate S-2238. The reagents are prepared in-house from commercially available components. Both automated methods have good precision and results correlate well with both an established chromogenic substrate assay and an immunological assay. The automated assays offer the advantages of speed, sensitivity, high throughput, and low reagent consumption and are useful for both routine work and high-volume testing in clinical studies and screening programs.
Separation of serum high-density lipoprotein for cholesterol determination: ultracentrifugation vs precipitation with sodium phosphotungstate and magnesium chloride.
Authors: Seigler L , Wu W T 
Published: January 2020

Abstract
We compared two methods for separation of serum high-density lipoprotein: selective precipitation with sodium phosphotungstate and magnesium chloride, and ultracentrifugation in sodium chloride solution (relative density 1.063). When the cholesterol content (determined enzymically with a centrifugal analyzer) of fractions obtained by each method was compared (ultracentrifugation = x), the correlation coefficient was 0.97; y = 1.01x - 11.2 mg/L; p less than 0.05; n = 54. The within-day and between-day coefficients of variation for this method were 1.1 and 4.0%, respectively. Reference intervals for high-density lipoprotein cholesterol in subpopulations categorized by age and sex were based on data obtained from volunteer blood donors.
Bile acid assays as an index of cholestasis.
Authors: Woodman D D , Maile P A 
Published: January 2020

Abstract
Four bile acid profiles, bilirubin, alkaline phosphatase, alanine aminotransferase, glutamate dehydrogenase, and isocitrate dehydrogenase were measured in rats in which normal bile flow had been disturbed either by administration of alpha-naphthylisothiocyanate or by surgical ligation of the bile duct. The most sensitive index to the early onset of cholestasis was an increase in total cholate. This increase was measurable before morphological changes could clearly be identified.
Liquid-chromatographic analysis for common tricyclic antidepressant drugs and their metabolites in serum or plasma with the technicon "FAST-LC" system.
Authors: Bannister S J , van der Wal S , Dolan J W , Snyder L R 
Published: January 2020

Abstract
We describe a single procedure for assay of seven tricyclic antidepressant drugs and metabolites in serum or plasma: protriptyline, nortriptyline, amitriptyline, desmethyldoxepin, doxepin, desipramine, and imipramine. With the Technicon "FAST-LC" system, samples are aspirated directly into the unit and pretreated via double extraction; the concentration of each drug is then determined by "high-performance" liquid chromatography. Final chromatograms are monitored at 205 nm, at analysis rates of 7.5 samples/h. Concentration and absorbance are linearly related for each drug from 0 to 1400 micrograms/L. Day-to-day CVs averaged 5 to 6% for each drug, and there is good correlation of FAST-LC values with those obtained by gas-chromatographic methods. Total sample volume is 750 microliters.
Comparison of concentrations of some trace, bulk, and toxic metals in the hair of normal and dyslexic children.
Authors: Capel I D , Pinnock M H , Dorrell H M , Williams D C , Grant E C 
Published: January 2020

Abstract
Hair from dyslexic children, analyzed by flameless atomic absorption spectrometry, showed significantly higher concentrations of magnesium and copper than did hair from control subjects. The hair from dyslexic children also contained significantly higher concentrations of aluminum and cadmium than that from control children; the cadmium concentration exceeded the normal acceptable range. There were no significant differences in the case of lead, calcium, selenium, or mercury. Our results indicate that excessive cadmium burden could be implicated in this form of learning disorder.
Kinetic immunoturbidimetry of human choriomammotropin in serum.
Authors: Price C P , Spencer K 
Published: January 2020

Abstract
The sensitivity of kinetic immunoturbidimetry as a method for the measurement of specific proteins has been shown previously to be equivalent to 1 mg of analyte per liter. We confirm this in the method for human choriomammotropin described here. A relatively large sample volume is required, which results in other components of serum influencing the immunoprecipitin reaction. The technique is shown to be precise, and results compare well with those by a commonly available radioimmunoassay. The method performs well, as judged from results obtained for assayed quality control materials and in an external quality assurance program. The method is rapid (instrument assay time 120 s per sample), automated, and economical for routine use.
Enzyme immunoassay for specific determination of the synthetic estrogen, ethynyl estradiol, in plasma.
Authors: Turkes A , Dyas J , Read G F , Riad-Fahmy D 
Published: January 2020

Abstract
In this enzyme immunoassay for ethynyl estradiol, a conjugate of the 3-(O-carboxymethyl)ether with horseradish peroxidase is used as the label and a conjugate of the 6-(O-carboxymethyl)oxime with bovine serum albumin as the immunogen. A solid-phase antibody procedure is used in separating antibody-bound and free steroid. The lower limit of sensitivity of the assay is 2 pg per assay tube. Interference by synthetic progestagens was minimized by extracting the sample with an anti-estrogen serum before assay. Results obtained with a comparison radioimmunoassay and this procedure agreed well (r greater than 0.98).
Steroid radioimmunoassay--effect of shortened incubation time on specificity.
Authors: Vining R F , Compton P , McGinley R 
Published: January 2020

Abstract
Use of a briefer incubation interval in several steroid radioimmunoassays markedly increases cross reactions with some closely related steroids. The dissociation rates of the various steroid/antibody complexes play a critical role in determining the specificity of the antiserum, and the maximum specificity of an antiserum will be exploited only if it is incubated to equilibrium. The commonly used method for estimating the time required to reach equilibrium--i.e., the time required for the %(B0/T) value to "plateau"--grossly underestimates the true interval required, and we suggest that the minimum incubation period for steroid radioimmunoassay should be based on a knowledge of both the dissociation and the association rate.
Optimization of a mechanized amidolytic factor-X assay; influence of reaction conditions and reagents.
Authors: van Wijk E M , Kahlé L H , Wiebosch M , ten Cate J W 
Published: January 2020

Abstract
We describe the effect of pH and NaCl concentration on the activation of factor X in plasma by Russell's viper venom and on the amidolytic activity of the activated enzyme towards factor Xa-sensitive chromogenic substrates. An increasing NaCl concentration results in a decrease in the activation rate of factor X by Russell's viper venom, whereas in this step no pH effect is observed. Increasing NaCl concentrations decrease the Km and Vmax for both the factor Xa-sensitive chromogenic substrates, S 2222 and S 2337. Km values were lowest between pH 7.8 and 8.6; Vmax increased with increasing pH. Comparison of NaCl and KCl in the activation step as well as in the amidolytic step shows that the observed effect is specific for Na+, not just an effect of ionic strength. No difference was detected between activation by the crude venom or its purified factor X-activating enzyme. Also, values with the substrates S 2222 or S 2337 were the same in the mechanized amidolytic factor X assay.
Fluorescence polarization immunoassay. I. Monitoring aminoglycoside antibiotics in serum and plasma.
Authors: Jolley M E , Stroupe S D , Wang C H , Panas H N , Keegan C L , Schmidt R L , Schwenzer K S 
Published: January 2020

Abstract
Fluorescence polarization immunoassays of the aminoglycoside antibiotics gentamicin, tobramycin, and amikacin in plasma and serum are described and shown to be clinically useful. The aminoglycoside tracers were prepared by reacting the parent compounds with 5-[(4,6-dichlorotriazin-2-yl)-amino] fluorescein. Antisera specific for the compounds were raised in rabbits by conventional procedures. Tracer, sample, and diluted antiserum are combined and, after a 15-min incubation at ambient temperature, the polarization of the fluorescence of the tracer is determined in a specially designed fluorometer. The assays are designed to give accurate trough (i.e., minimum during therapy) values and to be free of matrix effects. Severely icteric samples may interfere, but this can be overcome by blank subtraction. The performance of the assays with clinical specimens compared favorably with that of some commercially available assays.
Differential assay for urinary catecholamines by use of liquid chromatography with fluorescence detection.
Authors: Jackman G P 
Published: January 2020

Abstract
I describe a relatively simple and rapid procedure for quantitative analysis for unconjugated urinary norepinephrine, epinephrine, and dopamine. Catecholamines are isolated from urine on a carboxylic acid ion-exchange resin (Bio-Rex 70) and eluted with 0.8 mol/L boric acid. The eluates are assayed for the individual catecholamines by "high-performance" liquid chromatography with an octadecylsilane reversed-phase column and 10 mmol/L perchloric acid-acetonitrile (99/1) as the mobile phase. The catecholamines are detected by measuring their intrinsic fluorescence on excitation at 200 nm. The method is highly reproducible, the coefficient of variation for normal concentrations in urine being 4.4% for norepinephrine, 8.8% for epinephrine, and 4.8% for dopamine. Moreover, it appears to be practically free of interference by drugs or endogenous compounds in urine. The range of catecholamine concentrations found in 143 hypertensive patients agrees well with previous studies.
Radioimmunoassay for serum and urinary lysozyme.
Authors: Thomas M J , Russo A , Craswell P , Ward M , Steinhardt I 
Published: January 2020

Abstract
We describe a radioimmunoassay for lysozyme (EC 3.2.1.17, mucopeptide N-acetylmuramohydrolase) in plasma and urine. It involves use of an antibody, raised in rabbits, to lysozyme from urine from a patient with monocytic leukemia. This antiserum, diluted 4000-fold, is incubated with radiolabeled lysozyme for 2 h and antibody-bound lysozyme is separated from free lysozyme with dextran-coated charcoal. Validation of the assay included precision and parallelism studies with serum and urine samples from patients with monocytic leukemia and analgesic nephropathy. Results of the radioimmunoassay and those obtained with a Micrococcus lysodeikticus lytic assay correlated well (r = 0.94). Sensitivity of the assay was 3.5 micrograms/L for both serum and urine. The main advantages of the assay are its good precision and reproducibility and its high sensitivity.
Thin-layer chromatography, with fluorescence detection, of benzodiazepines and tricyclic antidepressants in serum from emergency-room patients.
Authors: Meola J M , Rosano T G , Swift T 
Published: January 2020

Abstract
We describe a rapid, sensitive procedure for detecting benzodiazepines and tricyclic antidepressants in serum. After the compounds are adsorbed on charcoal and eluted with an organic solvent mixture, the drugs are thin-layer chromatographed and detected by their fluorescence. Because it is so fast and easy (turn-around time of about 1 h), the method can be used for emergency toxicology screening. An analysis requires 1.0 mL of serum, and the limit of detection for each of the drugs is about 0.75 mg/L. The procedure is sensitive enough to allow the use of serum instead of urine for the detection of these drugs, because serum has certain advantages over urine as the sample and better reflects the state of the patient's toxicity.
Labile glycosylated hemoglobin contributes to hemoglobin A1 as measured by liquid chromatography or electrophoresis.
Authors: Nathan D M 
Published: January 2020

Abstract
The utility of glycosylated hemoglobin (HbA1) measurement as an index of chronic control in diabetes can be adversely affected by interference from a labile glycosylated fraction that changes rapidly with acute changes in blood glucose concentration. I used a "high-pressure" liquid-chromatographic assay and a newly developed electrophoretic assay to quantitate the contribution of this labile fraction. If erythrocytes are incubated at 22 degrees C in isotonic saline for 12 h before hemolysis, the labile fraction is eliminated. Its contribution is similar as measured by both assays: 2-3.5% of total HbA1 in normal cells and 7-9.5% in diabetic cells. A 3-h incubation of erythrocytes with glucose produces acute changes in apparent HbA1 concentrations by both assays, but such changes can be eliminated by the incubation in saline. Although current methods are time consuming, the labile glycosylated hemoglobin must be removed when the sample is prepared for HbA1 measurement by liquid chromatography and electrophoresis if results are not to be factitiously high.
Urinary metanephrines as measured by liquid chromatography with an on-line post-column reaction detector.
Authors: Flood J G , McComb R B 
Published: January 2020

Abstract
In this method for measuring metanephrine and normetanephrine in urine, they are freed from their conjugates by hydrolysis in acid, neutralized, and isolated on a cation-exchange resin. Both metanephrines are co-eluted with ammoniacal methanol and the eluate is concentrated 10-fold with respect to the original urine volume by evaporation and reconstitution. The recovered metanephrines ae separated by reversed-phase (C18) "high-pressure" liquid chromatography with use of a mobile phase consisting of 10 mmol/L trichloroacetate, pH 2.7, containing 30 mL of acetonitrile per liter. The metanephrines are detected at 365 nm after being converted to vanillin in a post-column reaction with alkaline periodate. Total metanephrine values for most patients were appreciably lower than values obtained by the comparison procedure, that of Pisano (Clin. Chim. Acta 5: 406, 1970); however, results obtained by the two methods for two patients with pheochromocytomas agreed well.
Three commercial immunoradiometric "kit" assays for serum ferritin evaluated.
Authors: Dunn C D , Boden D J 
Published: January 2020

Abstract
We evaluated three commercially available immunoradiometric assays for serum ferritin, with particular emphasis on the statistical validity of the results. The data show that it was unusual (a) for dose/response relationships of the standards to be linear over the whole concentration range suggested by the manufacturers and (b) for dose/response relationships of test sera to parallel those of the standards. These findings cast doubt on the ability of any of the assays reliably to discriminate small differences in ferritin concentrations. Nevertheless, all three methods gave reproducible results, but this reflects technical expertise rather than accuracy of the results per se. The method based on liver ferritin as tracer detected less of the iron-binding protein than those based on spleen ferritin, despite significant cross reactivity of the two antibodies.
Feasibility of measuring free and total bilirubin electrochemically in serum.
Authors: Koch T R , Akingbe O O 
Published: January 2020

Abstract
Bilirubin undergoes irreversible reduction at the hanging-mercury-drop electrode in tris(hydroxymethyl)methylamine buffer (0.1 mol/L, pH 8.5). Peak current is linearly related to concentration in the range 0-1 mg/L. The half-wave potential of -1.32 V vs the saturated calomel electrode is little affected by pH, whereas peak current increases with pH to pH 9.5, then decreases rapidly. Exposing the test solution to light causes the peak current to decline at a rate proportional to concentration. Albumin-bound bilirubin is electrochemically inactive, so free bilirubin can be measured in the presence of bilirubin-saturated albumin. Serum total bilirubin can be measured after much of the protein is precipitated by adding methanol. Results for serum bilirubin as measured electrochemically (y) in 20 methanolic filtrates of serum compared well with the Jendrassik-Grof Method (x) in preliminary studies: y = 0.981x -0.311; r = 0.9716. We discuss the possible mechanism of the reduction process and potential clinical applications. Polarographic measurement of bilirubin and bilirubin-binding capacity is feasible and may be advantageous as compared with existing techniques.
Charcoal hemoperfusion for treatment of carbamazepine poisoning.
Authors: Chan K M , Aguanno J J , Jansen R , Dietzler D N 
Published: January 2020

Abstract
We report a case of carbamazepine (Tegretol) poisoning that was treated with charcoal hemoperfusion. When admitted, the patient was comatose and required ventilatory support. Hemoperfusion with coated activated charcoal successfully decreased her serum carbamazepine concentration from 60 mg/L to 36 mg/L within 2 h, with subsequent clinical improvement. Approximately 39 h would have been required to obtain this decrease via the patient's inherent elimination rate. Activated charcoal hemoperfusion may be useful as an adjunctive therapy for patients in advanced comatose states with associated respiratory depression and potentially fatal outcome.
Proteins of human semen. I. Two-dimensional mapping of human seminal fluid.
Authors: Edwards J J , Tollaksen S L , Anderson N G 
Published: January 2020

Abstract
The proteins in human seminal plasma were mapped by high-resolution two-dimensional electrophoresis (ISO-DALT and BASO-DALT systems). When analyzed under dissociating conditions, samples from normal fertile males revealed a pattern of over 200 proteins, ranging in mass from 10 000 to 100 000 daltons. Comparison of the mapped proteins from these males and those who had undergone vasectomy allowed us to identify one series of glycoproteins as missing from the semen from vasectomized individuals. Glycoproteins isolated by affinity chromatography with use of concanavalin A were also mapped. Some of the protein spots were identified either by co-electrophoresis with purified proteins or by the electrophoretic transfer of proteins to nitrocellulose sheets and subsequent detection by immunological procedures. The proteins identified include a number of serum proteins as well as prostatic acid phosphatase and creatine kinase. Proteolytic events shown to occur during the liquefaction of semen that occurs early after collection indicate the importance of carefully controlled collection and preparation methods for clinical evaluation of seminal plasma. Ethylenediaminetetraacetic acid and phenylmethylsulfonyl fluoride inhibit this proteolysis.
Liquid-chromatographic determination of cyclosporin A in blood and plasma.
Authors: Sawchuk R J , Cartier L L 
Published: January 2020

Abstract
We describe a liquid-chromatographic assay for cyclosporin A in blood and plasma. The method is sensitive enough to allow quantitation of the drug at concentrations observed clinically, is isocratic, required no derivatization, and takes only 10 min of analysis time.
Protein clearances and selectivity determinations in childhood nephrosis: a reappraisal.
Authors: Ellis D , Buffone G J 
Published: January 2020

Abstract
To critically evaluate the clinical utility of determining specific proteins in patients with extensive proteinuria, we used immunonephelometric methods to measure albumin, transferrin, IgG, and alpha 2-macroglobulin in serum and in 24-h urine specimens from 37 children with idiopathic nephrotic syndrome. Renal biopsy demonstrated minimal change disease (I) in 15, focal glomerulosclerosis (II) in 15, and membranoproliferative glomerulonephritis (III) in seven patients. A three-group nonparametric rank test and three-group discriminant function analysis of the protein excretion and clearances of the four proteins we measured revealed significant differences in the excretion of IgG and the clearance of alpha 2-macroglobulin among the three groups of patients (p less than 0.05). Only patients with III had low serum complement C3 concentrations. Patients with I or II were best discriminated by differences in the excretion of transferrin and IgG, the clearance of alpha 2-macroglobulin, and the selectivity index (the clearance ratio of IgG/transferrin). These data indicate that measurement of specific urinary proteins and selectivity determinations may be helpful in predicting the type of histopathology and the prognosis of nephrotic children who have normal complement concentrations.
Sedimentation of lung-derived phospholipid during low-speed centrifugation of amniotic fluid.
Authors: Duck-Chong C G , Brown L M , Hensley W J 
Published: January 2020

Abstract
In most methods proposed for the assessment of fetal lung maturity, amniotic fluid is subjected to a preliminary low-speed centrifugation in an attempt to separate whole cells and cell debris from lung-derived surfactant phospholipid (lamellar body phospholipid). However, because lamellar body phospholipid is present in amniotic fluid in a membranous or particulate form, it is also partly sedimented by this procedure. The sedimentation of total phospholipid and lamellar body phospholipid by low-speed centrifugation has been quantitated for 49 samples of amniotic fluid from pregnancies of 30--41 weeks gestation. Isopycnic density-gradient centrifugation in a small air-driven ultracentrifuge was used to isolate lamellar body fractions from whole and centrifuged amniotic fluid. Centrifugation for 5 min at 1000 x g removed 0--70% of total phospholipid or lamellar body phospholipid, the mean values being 34 or 29%, respectively. There was an appreciable increase in lamellar body phospholipid relative to total phospholipid as a result of centrifugation in only 51% of the samples. In general, the effects of centrifugation were not related to gestational age of the fetus or the state of maturity of its lungs.