bluuebunny/crossref_metadata_2025_split huggingface dataset:
New techniques and tools for clinical chemistry.
Authors: Hieftje G M 
Published: January 2020

Abstract
In this paper are described and evaluated several new tools of potential use in clinical chemistry. The first, intended to minimize required sample volumes, is a device with which a total sample volume of 1 microL can be dispensed in the form of 1000 identical aliquots. Any number of such nanoliter aliquots can be taken if larger samples are needed. The second new tool is one for detecting anions or cations separated by ion chromatography. Unlike conventional conductometric detectors used in ion chromatography, the new system offers potential sensitivities in the sub-microgram per liter range and useful operating ranges up to 100 mg/L. The third tool is a scheme for background correction in atomic absorption spectrometry; the new technique requires no special auxiliary sources or double-beam optics. Finally, fluorescence time-decay curves and fluorescence lifetimes are shown to be able to overcome the effects of diffusional quenching and scattering resulting from turbidity of solutions in clinical fluorometry.
A rapid method for repurifying partly degraded radiolabeled steroids.
Authors: Jawad M J , Wilson E A , Vernon M W 
Published: January 2020

Abstract
This rapid method for repurifying radiolabeled steroids from degraded products is based upon differential partitioning of intact and degraded molecules between aqueous-phase solution and anhydrous diethyl ether. Results compare favorably with those by liquid-chromatographic methods.
Kinetics of enzymatic O-methylation: its value in assays for catecholamines in plasma.
Authors: Mason L , Weinkove C 
Published: January 2020

Abstract
The kinetics of enzymatic O-methylation of catecholamines were studied under conditions like those used in the radioenzymatic assay of plasma catecholamines. Inappropriate Michaelis-Menten kinetics and linear approximations of exponential equations were not used. Mathematical analysis indicated the importance of the ratio of methyl donor (S-adenosylmethionine) to substrate (catecholamine) concentration. If the reaction is incomplete, only a large ratio will allow linear approximations between product formed and initial catecholamine concentration. The use of high-concentration internal standards to correct for plasma interference may give erroneous results by reducing this ratio. Accuracy will be improved by ensuring (a) that S-adenosylmethionine is always greatly in excess of catecholamine, (b) that concentrations of added standards are of the same order as for endogenous catecholamine, and (c) that a high activity of enzyme is used, to allow the reaction to reach completion even in the presence of some inhibition.
Myoglobin concentration, creatine kinase activity, and creatine kinase B subunit concentrations in serum during thyroid disease.
Authors: Docherty I , Harrop J S , Hine K R , Hopton M R , Matthews H L , Taylor C J 
Published: January 2020

Abstract
Changes in values for myoglobin, total creatine kinase (EC 2.7.3.2), and creatine kinase B-subunit in the serum of patients with thyroid disease are compared with values for these during the 24-h after myocardial infarction. Concentrations of all three of these muscle-derived proteins were significantly higher than normal in patients with primary hypothyroidism, and declined with treatment. Values for total creatine kinase activity were below-normal in hyperthyroid patients, but increased after treatment. Values for total creatine kinase and, to a lesser extent, myoglobin in hypothyroidism extend into the range of values observed after myocardial infarction. The mechanism of the changes in these analytes in hypothyroidism may be related to increased leakage from skeletal-muscle cells or diminished clearance from the circulation, or both.
Transient creatine kinase-BB activity in serum or plasma after cardiac or respiratory arrest.
Authors: Massey T H , Goe M R 
Published: January 2020

Abstract
We studied the transient appearance of creatine kinase (EC 2.7.3.2) isoenzyme BB, as measured by electrophoresis, in serum or plasma from 19 patients who had just experienced cardiac or respiratory arrest. Creatine kinase BB activity was greatest 0.5 to 3 h after the arrest, with values (measured at 30 degrees C) ranging from 3 to 27 U/L (mean, 7.8 U/L) in 18 patients who were successfully resuscitated. Elimination time for the isoenzyme ranged from 8 to 48 h (mean, 20 h). Elimination t1/2 varied from 4.6 to 16 h for 13 patients from whom adequate serial blood specimens were obtained. We could find no correlation between peak BB activity and eventual case outcome. We attribute this to the near impossibility of drawing a blood specimen exactly when the isoenzyme activity peaks, the instability of creatine kinase BB activity at 37 degrees C, and the fact that nine of these patients died after second or multiple arrests.
Simultaneous measurement of ethosuximide, primidone, phenobarbital, phenytoin, carbamazepine, and their bioactive metabolites by liquid chromatography.
Authors: Ou C N , Rognerud C L 
Published: January 2020

Abstract
A simple, isocratic liquid-chromatographic method was developed for simultaneously measuring ethosuximide, primidone, phenobarbital, phenytoin, carbamazepine, and their bioactive metabolites within 10 min. The chromatographic system involves a Waters' Radial-NOVA PAK C18 reversed-phase column and acetone/methanol/acetonitrile/10 mmol/L phosphate buffer (10/21/8/61 by vol, pH adjusted to 7.95 with NaOH) as mobile phase. The antiepileptic drugs are extracted from 50 microL of serum by mixing with 50 microL of acetonitrile containing 10 mg of tolybarb per liter as internal standard. After centrifugation, 20 microL of the supernate is injected onto the column and eluted with mobile phase at the rate of 2.8 mL/min at ambient temperature. The column effluent is monitored at 200 nm. The method can detect the five antiepileptic drugs in concentrations as low as 0.5 mg/L. Analytical recovery ranges from 98 to 102%. Within-run CV ranged from 2.9 to 5.8% and between-run CV from 4.7 to 7.1%. The method can also be used to measure N-desmethyl-methsuximide, chloramphenicol, and pentobarbital.
Creatine kinase isoenzymes in human cerebrospinal fluid and brain.
Authors: Chandler W L , Clayson K J , Longstreth W T , Fine J S 
Published: January 2020

Abstract
Extracts of normal brains obtained at autopsy and cerebrospinal fluid (CSF) from patients with global brain ischemia were analyzed for creatine kinase (CK; EC 2.7.3.2) isoenzymes. We used both qualitative and quantitative assays (electrophoresis and immunoinhibition). Brain extracts contained CK-BB isoenzyme and mitochondrial CK. In 54 CSF samples free of blood contamination and with total activities ranging from 7 to 2010 U/L (mean 202 U/L), virtually all of the CK activity was due to CK-BB, and none to CK-MM or CK-MB. We conclude that brain contains CK-BB and mitochondrial CK, but lacks CK-MM and CK-MB. After cardiac arrest, CK-BB is released into the CSF. Any CK-MM in the CSF is probably from blood contamination, in which case immunoinhibition with anti-CK-M antibodies accurately quantifies CK-BB.
Tissue proteins in breast cancer, as studied by use of two-dimensional electrophoresis.
Authors: Stastny J , Prasad R , Fosslien E 
Published: January 2020

Abstract
Proteins from 25 specimens of malignant breast tissue were separated by "high-resolution" two-dimensional gel electrophoresis. The number of polypeptide spots detectable in individual gels varied from 259 to 471 (mean 347; SD 68) per milligram of wet tissue. Many polypeptide spots were not consistently present in all malignant tissues. Ten different in vivo polypeptides, observed neither in five non-malignant breast tissues nor in human milk, were present in more than 22 of the 25 cases of breast tumor tissues examined. Five of these polypeptides appeared to be identical to five in vitro polypeptides found in separations from cultured human ductal carcinoma cells. Further studies are required to verify the specificity of these tumor-associated proteins before they can be considered for breast tumor-specific in vitro diagnostic testing or targeting in selective in vivo anti-cancer therapy.
Metabolic relationship between urea and guanidino compounds as studied by automated fluorimetry of guanidino compounds in urine.
Authors: Natelson S 
Published: January 2020

Abstract
In this automated system for assaying guanidino compounds, the compounds are resolved on an ion-exchange (Dowex 50) column, then reacted with phenanthrenequinone in alkaline solution. This mixture is then acidified and the resulting fluorescence is measured (lambda ex, 305 nm; lambda em, 395 nm). I applied the system to the analysis of urine from control rats and rats given L-canavanine, L-canavaninosuccinic acid, L-guanidinosuccinic acid, L-arginine, or urea, intraperitoneally. The recorder tracings are compared with those obtained for urine from healthy and uremic humans. After urea administration some guanidinosuccinate is excreted, along with substantial quantities of another substance that elutes just before guanidinosuccinate and so may be mistaken for it. Urine from uremic humans also shows this unidentified peak, but not urine from untreated rats or healthy humans. L-Canavanine gives rise, mainly, to guanidine and homoserine, apparently by reduction. Similarly, canavaninosuccinate is reduced to homoserine and guanidinosuccinate. Arginine gives rise to small quantities of guanidinosuccinate. Guanidinosuccinate is excreted mainly unchanged. When the guanidinosuccinate concentration is increased, excretion of guanidinoacetic acid is suppressed.
Rapid assessment of the distribution of apolipoproteins C-II and C-III subspecies in triglyceride-rich lipoproteins by isoelectric focusing.
Authors: Bugugnani M J , Koffigan M , Kora I , Ouvry D , Clavey V , Fruchart J C 
Published: January 2020

Abstract
We describe an isoelectric-focusing method for rapidly separating and quantifying apolipoprotein (apo) C-II and C-III subspecies of triglyceride-rich lipoproteins. Concentrated very-low-density lipoproteins (VLDL) or delipidated apo VLDL are focused on dry acrylamide plates, after their rehydration with ampholytes and urea. Apo C-II and apo C-III in VLDL are resolved into four major bands--C-II (pI 5.01), C-III0 (pI 5.10), C-III1 (pl 4.92), and C-III2 (pI 4.84)--at the same pI values as for purified apo C. This precise technique can be used without delipidating VLDL. The relative percentage of C apoproteins found in VLDL from plasma of normal subjects agreed with previously published data. The ratio of apo C-II to apo C-III decreased in patients with chronic renal failure or with coronary artery disease.
Development of an agarose gel electrophoresis technique for determining alpha-amylase isoenzymes.
Authors: Royse V L , Jensen D M 
Published: January 2020

Abstract
Evaluation of alpha-amylase isoenzymes as a clinical diagnostic aid by previous methodologies has been either too insensitive or too cumbersome for routine clinical laboratory use. With use of an agarose gel electrophoresis system (Worthington Diagnostic Systems, Inc.) serum amylase activity can easily be resolved into at least nine isoenzymes, the resolution being comparable with that of isoelectric focusing. Samples can be analyzed in less than one working day, with use of conventional reagents.
Limits of detection and quantification, as applied to an assay for digoxin.
Authors: Kalman S M , Clark D R , Moses L E 
Published: January 2020

Abstract
The low-range sensitivity of a drug assay in routine use is an important aspect of that assay's clinical usefulness. We define three concepts for determining low range sensitivity: LC, the detection threshold; LD, the lower limit of "virtually ensured" detection; and LQ, the limit of quantitative determination. To illustrate these concepts, we apply them to a radioimmunoassay for digoxin, and show that for standards ranging from 0.3 to 5.0 micrograms/L, the LQ is 0.35 micrograms/L (+/- 10%).
Inhibitor binding assay for angiotensin-converting enzyme.
Authors: Fyhrquist F , Tikkanen I , Grönhagen-Riska C , Hortling L , Hichens M 
Published: January 2020

Abstract
We describe a new principle for the determination of enzymes, here applied to angiotensin-converting enzyme (ACE, EC 3.4.15.1) in human serum. The enzyme inhibitor binding assay is based on specific binding of labeled inhibitor to the active center of the enzyme. Serum (10-15 microL) is incubated with 125I-labeled ACE inhibitor (" 351A ," a p- hydroxybenzamidine derivative of N-(1-carboxy-3-phenylpropyl)-L-lysyl-L-proline) at pH 7.0 at 37 degrees C for 2 h in a non-equilibrated system. Inhibitor bound to ACE is separated by adsorption to coated charcoal, the radioactivity remaining in the supernate is counted, and the ACE value is calculated from a standard curve. Sensitivity for ACE in serum is 200 U/L, corresponding to 5.0 ng of ACE purified from human lung. The coefficient of variation was 3.9% within assay, and 6.4% between assays for normal ACE activities. Correlation with a comparison spectrophotometric method (Am J Med 59: 363-372, 1975) for ACE assay was excellent (r = 0.98) in 59 samples from healthy subjects and from patients with various diseases including active sarcoidosis. The novel assay principle presented here is simple and specific, and can be extended to use with various biological fluids and tissues, and to other enzymes as well.
Radioenzymatic Assay for Direct Measurement of Plasma Pyridoxal 5'-Phosphate
Authors: Camp Vernon M , Faraj Bahjat A , Chipponi Jacques 
Published: January 2020

Abstract
Vol. 29
p 642: In column two, sixth line from the bottom, change "25 000" to "54 000." Insert an addition (italicized here) to the next to last line in that column so that it reads".. ., then dialyzed overnight against the same buffer at 4 °C, then divided..."
p 843: In line six under Results and Discussion, change "mg" to "µg"
p 1537: In revision of this paper a paragraph of introduction was inadvertently omitted (which cites refs. 1-5), as were the first two paragraphs under Materials and Methods, which should read as follows:
Human placentas were obtained from the obstetrical department within 12 h of delivery. Fresh human abdominal muscle was obtained within 12 h of autopsy. All tissues were stored at 4 °C and processed, as described below, within 6 h.
Placenta and abdominal muscle were stripped free of membranes and blood vessels, cut into small pieces, and extensively washed at 4 °C with cold saline (NaCl, 9 g/L). Muscle CK-MM and placental CK-BB were purified according to the method of Armstrong et al. (6), with the following modifications: we used dithioerythritol (Sigma Chemical Co., St. Louis, MO 63178), 15 mmol/L, instead of 2-mercaptoethanol, omitted the final (NH4)2SO4 precipitation and final Sephadex G-100 fractionation, and used DE-52 (Whatman Ltd., Maidstone, Kent, U.K.) instead of DEAE-cellulose (Cellex-D; Bio-Rad Laboratories, Richmond, CA 94804).
p 2026: First paragraph, lines nine and 16: delete "500" (the Dextran used in the cited reference was a 50 000-dalton preparation, not the 500 000-Da Pharmacia preparation).
p 2029: In line 10 of the first full paragraph in column two, change "1.171" to "0.117."
p 2125: First two columns and Table 1: All lipase results expressed as kU/L should be divided by 3600.
Vol. 30
p 170: The next-to-last paragraph was inadvertently omitted in layout and should read as follows:
If the sample was first incubated at 37 °C until the serum became clear (i.e., until the cryoprecipitate dissolved) and the enzyme activity immediately determined at 30 °C (Figure 2, curves 1 and 2), normal activity was observed.
Increased prostate-type acid phosphatase activity in serum and typical bone lesions simulating the presence of prostatic carcinoma.
Authors: Peters O , Gorus F , De Boeck M , Dehou M F , Van Camp B 
Published: January 2020

Abstract
In a man with myelomonocytic leukemia, the association of increased prostatic acid phosphatase activity in serum and the presence of typical bone lesions on roentgenography suggested the existence of disseminated prostatic carcinoma. During the clinical observation period, however, prostatic involvement could not be proved. Moreover, bone pain and prostatic-type acid phosphatase activity in serum closely paralleled monocyte counts and the degree of hepatosplenomegaly and leukemic skin lesions. Finally, meticulous postmortem examination of the prostate showed no prostatic carcinoma. This clinical picture appears to be entirely explicable in terms of leukemic organ infiltration and the proliferation of monocytes, which are known to contain acid phosphatase isoenzymes like those in the prostate.
Evaluation of the Amniostat-FLM assay for assessment of fetal lung maturity.
Authors: Lockitch G , Wittmann B K , Mura S M , Hawkley L C 
Published: January 2020

Abstract
Results of the "Amniostat-FLM" assay, a rapid semiquantitative test for phosphatidylglycerol, were compared with determinations of the lecithin/sphingomyelin (L/S) ratio, with phosphatidylglycerol measured by two-dimensional thin-layer chromatography, and with results of the "shake test" for 94 specimens of amniotic fluid. Correlation between results with the Amniostat and the other tests was excellent. All four tests are very accurate when predicting lung maturity. The predictive value of a negative test, i.e., that hyaline membrane disease would not occur, was between 92 and 100%. However, the accuracy of predicted lung immaturity is poor. For all four tests, predictions of lung immaturity were incorrect in more than 50% of the cases. Of the 49 infants born within 72 h of testing, none developed hyaline membrane disease when phosphatidylglycerol was detectable by either method or when the shake test indicated fetal lung maturity, but three infants with L/S ratio greater than 2/1 did develop the disease. The Amniostat provides a rapid screening method for detecting phosphatidylglycerol in amniotic fluid, which could well replace the thin-layer chromatographic method for measuring phosphatidylglycerol in the panel of diagnostic tests for fetal lung maturity.
n-Electrode three-dimensional liquid chromatography with electrochemical detection for determination of neurotransmitters.
Authors: Matson W R , Langlais P , Volicer L , Gamache P H , Bird E , Mark K A 
Published: January 2020

Abstract
Coulometric electrodes in series have been used with liquid chromatography with electrochemical detection to increase selectivity and resolution for the direct analysis of tissue neurotransmitters. Use of three coulometric sensors for electrochemical modification, selectivity, and peak identification has been expanded into "gate" cells of three or four coulometric electrodes that allow elimination of all electrochemically irreversible substances, and "array" cells of up to 15 coulometric electrodes for separation of co-eluting compounds by their current/voltage characteristics. On-column sensitivity of the sensor arrays is 0.4 to 4 pg. Gate cell selectivity favors electrochemically reversible compounds over irreversible ones, e.g., 3-methoxy-4-hydroxyphenylglycol vs ascorbate, by a factor of up to 10(4). Resolution across the multi-electrode array cells allows separation of co-eluting compounds with half-wave potentials differing by as little as 30 to 40 mV. Cells with three to 15 electrodes have been used to measure monoamines and metabolites in brain; monoamines directly in serum filtrate; and the state of oxidation of 5-hydroxytryptamine and 5-hydroxytryptophan in cerebrospinal fluid of patients with Alzheimer's disease.
Delta bilirubin in serum of pediatric patients: correlations with age and disease.
Authors: Brett E M , Hicks J M , Powers D M , Rand R N 
Published: January 2020

Abstract
At least four bilirubin fractions can be separated and identified by liquid chromatography, the least understood being the "delta" fraction (B delta), which apparently is covalently bound to albumin. To learn more about the incidence and significance of B delta, we assayed serum from 539 infants and children, both by the chromatographic method and the routine colorimetric Jendrassik-Grof method. The proportion of B delta appeared to correlate with both age and disease course. For infants younger than 28 days B delta generally was less than 2% of total bilirubin; for hyperbilirubinemic older infants and children the median B delta value was 35%. High B delta (greater than 50% of total bilirubin) in newborns was associated with intra- and extra-hepatic cholestasis, biliary cirrhosis, biliary atresia, and hepatitis. Among older infants and children, a proportion of low B delta (less than 10%) was found in hemolytic anemias, sepsis, shock, and other non-hepatic jaundice. In several cases, when low B delta was accompanied by increased conjugated bilirubin, the prognosis was very poor. Delayed clearance of B delta from the circulation together with its reactivity in direct diazo methods may interfere with interpretation of values for conjugated bilirubin as measured by classical methods.
How Brazilian congressmen connect: homophily and cohesion in voting and donation networks
Authors: Bursztyn Victor S , Nunes Marcelo G , Figueiredo Daniel R 
Published: January 2020

Abstract
Two fundamental activities in the career of a congressman are raising campaign funds and voting on bills. Characterizing the interplay between these two activities is crucial for democracy as it provides explicit feedback to voters on potential conflicts of interest. In this work, we investigate the Brazilian Congress to shed light on the relationships between the donations received by congressmen elected in 2014 and their voting behaviours during 2015 and 2016. By consolidating publicly available data from the House of Representatives and the Superior Electoral Court (TSE), we construct a dataset containing elected congressmen, campaign donors and donations, and legal bills and votes. This leads to the donation network (edges represent co-donation) and voting network (edges represent co-voting) in which nodes are congressmen. We examine homophily and cohesion of congressmen in these two networks with respect to their political parties and electoral regions. Our results indicate that regions exhibit stronger homophily than political parties in the donation network, while this trend is opposite for the voting network. In this sense, we find that partisan cohesion is strong and diverse in the voting network, while regional cohesion is consistently negligible. These findings are an indication of Brazil’s fragmented and weak federalist system where partisan interests override regional interests.
Proposed treatment algorithm for cardiac device-related subclavian vein stenosis: a case series
Authors: Lu Wei-Da , Chen Ju-Yi 
Published: January 2020

Abstract

Background
Subclavian vein obstruction may occur in patients with pacemaker leads, which may make the implantation of new pacemaker leads difficult.

Case summary
We report two cases in which upgrading to cardiac resynchronization therapy pacemaker was challenging due to total central vein occlusion. In the first case, a 78-year-old woman with permanent pacemaker implantation, 5 years ago, was successfully treated by balloon venoplasty. In the second case, balloon venoplasty was unsuccessful in a 46-year-old woman who has received twice single-chamber implantable cardioverter-defibrillator, 12 years and 5 years ago, due to vessel crowding, so a contralateral side puncture, along with a tunnel technique, was performed to solve this problem.

Discussion
Cardiac implantable electronic device-related subclavian vein stenosis can present a challenge to common cardiac resynchronization therapy device upgrades in the absence of appropriate techniques.