bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of a rapid non-radioisotopic nucleic acid analysis system to the detection of sexually transmitted disease-causing organisms and their associated antimicrobial resistances.
Authors: Urdea M S , Kolberg J , Clyne J , Running J A , Besemer D , Warner B , Sanchez-Pescador R 
Published: January 2020

Abstract
We devised a versatile method for detecting nucleic acids in crude lysates of biological samples. A controlled network of nucleic acid hybrids composed of the target fragment, several oligonucleotide probes, branched DNA amplifiers, and labeled oligonucleotides is produced on a solid phase to ultimately incorporate 60 to 300 molecules of alkaline phosphatase, which are detected with a chemiluminescent substrate. The visible light output can be recorded on a luminometer or on instant black-and-white film. Assays have been developed for the detection of Chlamydia trachomatis, Neisseria gonorrhoeae, and for genes conferring penicillin and tetracycline resistance. Conducted much like ELISAS, the assays are performed in about 4 h (for 96 samples) in microliter dishes. The molecular detection limit of approximately 50,000 molecules of double-stranded DNA has permitted us to detect 1 to 10 x 10(3) of C. trachomatis and N. gonorrhoeae with specific probe sequences. Both plasmid and genomic target sequences can be detected by the same procedure. All of the assay components, except for a set of unmodified oligonucleotide probes, are universally applicable for all targets.
Investigation of protoporphyrin IX standard materials used in acid-extraction methods, and a proposed correction for the millimolar absorptivity of protoporphyrin IX.
Authors: Gunter E W , Turner W E , Huff D L 
Published: January 2020

Abstract
Erythrocyte protoporphyrin (EP) has been used for more than 30 years as an indicator of lead intoxication, iron deficiency, and porphyrias. Recently, numerous analytical problems associated with various EP methods have been reported, including a lack of consensus among investigators regarding the best calibration material or analytical procedure. We investigated commercially available protoporphyrin IX (PPIX) standard materials and measured the millimolar absorptivity (m epsilon) of these materials, focusing on variables affecting the determination of their absorptivities. Among the five forms of PPIX available, PPIX dimethyl ester, when hydrolyzed to PPIX free acid, gave the most consistent and reproducible results. This work confirmed our earlier observations, made on more than 600 separate occasions during 12 years, that the m epsilon of PPIX free acid in 1.5 mol/L HCl at the Soret maximum is 297 +/- 1.3 L.mmol-1.cm-1, 19% higher than the arbitrary value of 241 L.mmol-1.cm-1 generally accepted by most investigators but based on unpublished data. We propose that the m epsilon of 297 L.mmol-1.cm-1 for PPIX be adopted and that PPIX dimethyl ester be used for the calibration of acid-extraction methods. A detailed protocol for the preparation and verification of PPIX from the dimethyl ester is available upon request.
Estimation of true values in radioimmunoassays.
Authors: Riesco O F , Hajri-Mezghani S , Cekan S Z 
Published: January 2020

Abstract
We tested the accuracy of radioimmunoassays for two hormones, progesterone and estradiol, in relation to the use of two different antisera in each assay and to the degree of purification from plasma before the assay was done. Each analyte was assayed either in a diethyl ether extract, in a zone eluted from a Sephadex LH-20 chromatographic column, or in fractions of a chromatographic zone (from Sephadex LH-20 or Celite) that passed a test of "radiochemical purity." Statistically indistinguishable results were obtained in the assay of radiochemically pure fractions of both analytes, irrespective of the antiserum used. In addition, one of the antisera from each hormone gave equivalent results in the radioimmunoassay of ether extracts, even with no preceding chromatography. We demonstrated in this way that results obtained with use of highly specific antisera may, after a single chromatography, but even without any chromatographic purification, be as nearly accurate and as closely reflect the true value as those obtained in the assay of radiochemically pure hormones, an assay that has a character of a reference method (as defined by the IFCC).
Simple, sensitive assay of polyamines by high-performance liquid chromatography with electrochemical detection after post-column reaction with immobilized polyamine oxidase.
Authors: Maruta K , Teradaira R , Watanabe N , Nagatsu T , Asano M , Yamamoto K , Matsumoto T , Shionoya Y , Fujita K 
Published: January 2020

Abstract
This simple, rapid liquid-chromatographic assay of urinary polyamines (putrescine, spermidine, spermine, and cadaverine) involves electrochemical detection with a post-column immobilized enzyme, polyamine oxidase (EC 1.4.3.6) from soybean seedlings. Polyamines are separated by isocratic ion-pairing reversed-phase chromatography, then enzymatically converted, with release of hydrogen peroxide, via the post-column reactor with immobilized polyamine oxidase; the hydrogen peroxide is detected by electrochemical oxidation on a platinum electrode. The detection limits for injected putrescine, spermidine, and spermine were 0.3, 0.5, 0.6, and 4 pmol, respectively, with linear ranges of two to three orders of magnitude. Reproducibility was also good, with CV values less than 7%. The efficiency of the immobilized enzyme column was not decreased after analysis of 300 urine samples. Putrescine and spermidine excretion in urine from patients with blood cancers and solid cancers was significantly increased.
A 125I-radioimmunoassay for measuring androstenedione in serum and in blood-spot samples from neonates.
Authors: Thomson S , Wallace A M , Cook B 
Published: January 2020

Abstract
We developed a radioimmunoassay with a gamma-emitting radioligand to measure androstenedione in human serum and in dried blood-spot samples from newborns. Antisera were raised in rabbits against androstenedione linked to bovine serum albumin at positions 3, 6, or 11 on the steroid nucleus. Radioligands were prepared by linking [125I]iodohistamine at positions 3, 6, or 11. Linkages were through either carboxymethyloxime or hemisuccinate bridges. All label and antibody combinations were examined, and the most sensitive and specific combination (antiserum raised against androstenedione-3-carboxymethyloxime-bovine serum albumin with an androstenedione-carboxymethyloxime-[125I]iodohistamine label) was selected for full evaluation. We report the performance of these selected reagents in an immunoassay for androstenedione in both serum and dried blood-spot samples from neonates. We measured concentrations of androstenedione in serum under normal and pathological conditions such as congenital adrenal hyperplasia and polycystic ovarian disease. Diurnal variation in normal men was observed. Androstenedione was measured in blood spots from neonates born at term or prematurely, with respiratory distress syndrome, or with congenital adrenal hyperplasia.
Accuracy and precision of analyses for total cholesterol as measured with the Reflotron cholesterol method.
Authors: Bachorik P S , Bradford R H , Cole T , Frantz I , Gotto A M , Roberts K , Warnick G R , Williams O D 
Published: January 2020

Abstract
We compared plasma cholesterol measurements made with the Boehringer Mannheim Reflotron reflectance photometric analyzer in 1298 capillary blood samples with measurements made in venous blood samples collected at the same time and analyzed in four standardized Lipid Research Clinics laboratories. The Reflotron measurements averaged 0.8% to 7.8% lower than the laboratory values. Correlations (r) between the two sets of measurements ranged from 0.92 to 0.96. In some samples, however, the Reflotron values differed from the laboratory values by greater than or equal to 12%; the cholesterol concentrations in these samples tended to be higher than in those for which better agreement was observed. The smaller negative biases were observed when test strips were used that were calibrated with reference to the Centers for Disease Control Reference Method for cholesterol. The agreement between sequential Reflotron values averaged less than or equal to 4.3%. There was an average difference of less than or equal to 1.0% between Reflotron measurements made in each of two sequential capillary blood samples taken from a single finger puncture.
Murine monoclonal antibody adsorbed onto vinylidene fluoride floccules used to eliminate antibody interference in "sandwich"-type immunoassays.
Authors: Newman E S , Moskie L A , Duggal R N , Goldenberg D M , Hansen H J 
Published: January 2020

Abstract
We have previously reported that human anti-mouse IgG antibody (HAMA) can cause false-positive and false-negative results in "sandwich"-type monoclonal antibody (MAb) assays. To eliminate HAMA interference in "sandwich"-type MAb assays, we investigated the use of MAb on solid-phase, vinylidene fluoride floccules, which we have previously used as a solid-phase second antibody for RIA. The simple procedure effectively removes greater than 95% of HAMA from the most positive serum we have obtained from patients hyperimmunized to murine MAb, and it allows for accurate quantification of carcinoembryonic antigen. The solid-phase complex, added to blood, effectively removes HAMA and (or) "HAMA-type" heterophilic antibody from the sera or plasma.
Characterization of sulfasalazine's interference in the measurement of conjugated bilirubin by the Ektachem slide method.
Authors: Franquemont D W , Sutphen J L , Herold D A , Bruns D E 
Published: January 2020

Abstract
We describe the cases of four patients who were taking sulfasalazine for inflammatory bowel disease, whose conjugated bilirubin concentrations in serum exceeded their corresponding total bilirubin concentrations as measured with a multilayer film analyzer, the Ektachem 400. Sulfasalazine added to pooled human serum at therapeutic concentrations increased the apparent conjugated bilirubin, as measured with the Ektachem, in a linear and dose-related fashion. Measured unconjugated bilirubin was simultaneously decreased to values less than -3 mg/L. The same interference occurred on the Ektachem 700, but an algorithm prevented the instrument from reporting the results. The major metabolites of sulfasalazine in blood did not interfere with analysis for those fractions of bilirubin. Sulfasalazine's strong absorbance at 400 nm explains its interference with determination of conjugated bilirubin in this instrument.
Estimation of reference intervals for total protein in cerebrospinal fluid.
Authors: Lott J A , Warren P 
Published: January 2020

Abstract
Protein in cerebrospinal fluid (CSF) was measured by a modified biuret procedure and in two automated instruments, the Du Pont aca and the Kodak Ektachem. The latter's dry-slide reagent was also evaluated for precision, linearity, and effect of potential interferents. In vitro, ampicillin and vancomycin increase the apparent value for CSF protein as measured with the Ektachem slides. We excluded patients with disorders of the central nervous system, and we estimated the central 95% percentile reference intervals for CSF protein for each of the three methods. We found no age or gender dependence of values. By the biuret procedure, the reference interval is 140 to 620 mg/L.
Enzyme-linked immunosorbent assay for free thyroxin in human serum.
Authors: Chui S H , Wan K C , Lam C W , Lewis W H 
Published: January 2020

Abstract
We describe a simple enzyme-linked immunosorbent assay (ELISA) in which microtiter plates are used for determining the free thyroxin concentration (FT4) in serum. Only commercially available chemicals and reagents are needed, including the antiserum. The working range is 1 to 60 ng/L. Turnaround time is about 4 h. Within-run coefficients of variation (CV) for FT4 concentrations of 9.0, 19.0, and 35.0 ng/L were less than 5%; between-run CVs were 10% to 11%. Results by a radioimmunoassay method for 150 sera correlated well (r = 0.922).
Normal biochemical and hematological values in New Zealand white rabbits.
Authors: Hewitt C D , Innes D J , Savory J , Wills M R 
Published: January 2020

Abstract
Animal model systems are used extensively for experimental in vivo studies. When biochemical and hematological measurements are made, reference intervals for the animal species must be determined. Here, the subjects for our study were young adult male New Zealand White rabbits. Blood was sampled from 110 normal healthy rabbits. Biochemical and hematological blood variables were measured by methods available in our routine service laboratory, and we report the ranges.
An interlaboratory study of blood-gas analysis: dependence of pO2 and pCO2 results on atmospheric pressure.
Authors: Burnett R W , Itano M 
Published: January 2020

Abstract
Blood-gas data from a large interlaboratory survey were analyzed to determine whether pO2 and pCO2 results are affected by the atmospheric pressure at the measuring location. A small but statistically significant dependence was found, averaging about 2.3% per 100 mmHg (1.7% per 10 kPa) for pO2 and 1.0% per 100 mmHg (0.75% per 10 kPa) for pCO2.
Cost-effective assays for use in monitoring carbamazepine, phenobarbital, and phenytoin in serum.
Authors: Moore F M , Simpson D 
Published: January 2020

Abstract
Using Syva "EMIT" reagents and the Cobas Bio centrifugal analyzer, we have developed cost-effective assays for therapeutic drug monitoring of carbamazepine, phenobarbital, and phenytoin. With these optimized methods one can assay up to 2470 samples with a single 100-test EMIT kit with good precision and accuracy. Between-batch CVs, based on results of repeat analysis of routine patients' samples, were 4.6%, 7.0%, and 5.3%, respectively. Results correlated well with those by methods previously used [gas chromatography and fluorescence polarization (Abbott TDx)], but there was a negative bias (-10.9%) of our method for phenobarbital results in patients' samples, as compared with those obtained with the TDx.
Amiodarone and the thyroid.
Authors: Kennedy R L , Griffiths H , Gray T A 
Published: January 2020

Abstract
An antiarrhythmic drug, amiodarone, contains 37% iodine by weight and is structurally similar to the thyroid hormones. The drug inhibits hepatic 5'-deiodinase, resulting in increases in serum thyroxin and "reverse" triiodothyronine, whereas the concentration of triiodothyronine in serum is decreased. There is a significant incidence of either hypothyroidism or hyperthyroidism in patients who are being treated with the drug. This is largely the effect of iodine released from the drug during chronic therapy, but in susceptible individuals amiodarone may unmask autoimmune thyroid disease. Some effects of the drug suggest that it may interfere with the action of thyroid hormones at the cellular level, inducing a state of localized hypothyroidism.
Quantification of strontium in plasma and urine with flameless atomic absorption spectrometry.
Authors: Leeuwenkamp O R , van der Vijgh W J , Hüsken B C , Lips P , Netelenbos J C 
Published: January 2020

Abstract
This analytical method for determination of Sr in plasma and urine involves flameless atomic absorption spectrophotometry (FAAS). Drying, charring, and atomization were optimized with respect to temperature, temperature ramp, and duration for Sr in dilute HNO3 and Sr in plasma diluted 20-fold with dilute HNO3. Calibration curves (r greater than 0.995) were linear in the concentration range 5-250 micrograms/L for Sr in various media, with intercepts negligibly small except for the calibration curves in 1:1-diluted plasma and undiluted urine. The estimated detection limits for Sr in 20-fold-diluted plasma and 50-fold-diluted urine were 2 and 3 micrograms/L, respectively. Endogenous Sr in plasma and urine was estimated at 16 (SD 8) micrograms/L and 158 (SD 26) micrograms/L (n = 6), respectively. Intra- and interassay CVs were 9.1% and 5.3% for 20-fold-diluted plasma at a Sr concentration of 25 micrograms/L, and 6.9% and 4.8% at a concentration of 250 micrograms/L. The respective CVs were 8.2% and 1.2% for 50-fold-diluted urine at the low concentration, and 4.0% and 4.6% at the high concentration. In a pharmacokinetic pilot study of 2.5 mmol of Sr orally administered to a healthy volunteer, the peak plasma concentration of Sr, 4.4 mg/L, decayed bi-exponentially [t1/2, alpha = 24 h, t1/2, beta = 77 h]; the estimated first-order absorption rate constant was 0.005 min-1; and the observed decay (day 0-6) of the urinary Sr/creatinine ratio closely paralleled the plasma decay [t1/2 = 70 h].
Purification and characterization of intact lactoferrin found in the urine of human milk-fed preterm infants.
Authors: Hutchens T W , Henry J F , Yip T T 
Published: January 2020

Abstract
Little is known about the metabolic fate of ingested lactoferrin in human-milk-fed term or preterm infants. Enzyme-linked immunosorbent assays and sodium dodecyl sulfate/polyacrylamide gradient gel electrophoresis (SDS-PAGGE) with immunoblots have demonstrated that the urinary excretion of lactoferrin by preterm infants fed exclusively human milk exceeded that by formula-fed infants. The origin and molecular integrity of the excreted lactoferrin, however, are unclear. We have developed extraction and separation procedures involving a stationary phase of immobilized single-stranded DNA (ssDNA) that allows the efficient (greater than 80%) and rapid isolation of pure, intact lactoferrin from infants' urine. We purified lactoferrin to apparent homogeneity from infants' urine in one step, using the immobilized ssDNA with mobile phases containing up to 6 mol of urea per liter. The purified lactoferrin was evaluated by SDS-PAGGE; silver-staining revealed one protein band at 78 kDa; immunoblots confirmed the presence of intact lactoferrin. High-performance affinity chromatography with use of immobilized metal ion (Cu2+) suggested the presence of intact, iron-saturated lactoferrin. Subsequent chromatography on high-performance reversed-phase (C18) columns independently verified sample identity and purity.
Highly sensitive assays of autoantibodies to thyroglobulin and to thyroid peroxidase.
Authors: Beever K , Bradbury J , Phillips D , McLachlan S M , Pegg C , Goral A , Overbeck W , Feifel G , Smith B R 
Published: January 2020

Abstract
These highly sensitive assays are based on the interaction between thyroid autoantibodies and 125I-labeled autoantigens. Serum samples are incubated with labeled thyroid peroxidase (TPO) or thyroglobulin (Tg) to allow the formation of antibody-labeled antigen complexes. The complexes are then precipitated by addition of solid-phase Protein A. In the presence of high concentrations of TPO antibody or Tg antibody, more than 50% of the respective labeled antigen was precipitated, whereas only 1-2% was precipitated in the absence of autoantibody. Interassay CVs were 3.2% and 5.7%, respectively, for the anti-TPO and anti-Tg assays. There was no cross-reactivity between Tg antibody and TPO antibody. Results correlated highly significantly with results from other assay systems based on antigen-coated cells or plastic supports, but the assays described here were considerably more sensitive. Scatchard analysis of the assay data provided information on the affinity and serum concentration of TPO autoantibodies (ka approximately 10(9) L/mol and concentrations up to 1 g/L) and Tg autoantibodies (ka approximately 4 x 10(10) L/mol and concentrations up to 1 g/L). Overall, these assays provide a sensitive, precise, and convenient system for measuring and investigating the properties of thyroid autoantibodies.
Microassay for screening newborns for galactosemia with use of a fluorometric microplate reader.
Authors: Yamaguchi A , Fukushi M , Mizushima Y , Shimizu Y , Takasugi N , Arashima S , Ohyanagi K 
Published: January 2020

Abstract
We describe a microassay for measuring galactose (Gal) and galactose 1-phosphate (Gal-1-P) in dried blood spots. After a coupled enzyme reaction involving galactose dehydrogenase (GADH, EC 1.1.1.48) and alkaline phosphatase (AP, EC 3.1.3.1) in a microplate well, NADH fluorescence is measured by a highly sensitive fluorometric microplate reader, capable of rapid measurement of fluorescence (2 min per 96 samples). Within- and between-run CVs for measurements of Gal at 90 mg/L with Gal-1-P at 130 mg/L were both less than 5% (n = 8), and analytical recoveries for Gal at 90 mg/L and Gal-1-P at 130 mg/L were 98% and 92%, respectively. Five hundred dried blood-spot samples can be assayed within 2 h, with full calculation of results by an on-line microcomputer. This rapid and reliable assay system is very useful for the routine screening of newborns for galactosemia.
IgA-CK-BB complex with CK-MB electrophoretic mobility can lead to erroneous diagnosis of acute myocardial infarction.
Authors: Venta R , Geijo S A , Sánchez A C , Bao C G , Bartolome L A , Casares G , Lopez-Otin C , Alvarez F V 
Published: January 2020

Abstract
This patient, on admission, presented with a tentative diagnosis of myocardial infarction: the electrocardiogram showed a nonspecific ST-segment and T-wave abnormalities, and total creatine kinase (CK; EC 2.7.3.2) activity was slightly increased (238 U/L). However, a high electrophoretic value for CK-MB (50% of total CK activity) and the electrophoretic pattern of lactate dehydrogenase (EC 1.1.1.27) isoenzymes ruled out myocardial infarction. The isoenzyme migrating as CK-MB was found later to contain no immunologically normal CK-M subunits, and it was bound to IgA. A mixture of the patient's serum and a human serum control containing all CK isoenzymes showed altered electrophoretic mobility only for CK-BB, indicating that the patient's serum contained antibodies to the B unit of CK. Elution from a Sephadex G-200 column showed that the peak at which most of the anodic CK was eluted corresponded to a molecular mass of approximately 200 kDa. Evidently this atypical isoenzyme was an IgA-CK-BB complex. Because this macro CK type 1 can mimic CK-MB, it may therefore be a source of confusion.
Diabetes mellitus and survival of esophageal cancer patients after esophagectomy: a systematic review and meta-analysis
Authors: Zheng Xi , Ma Xingsheng , Deng Han-Yu , Zha Panpan , Zhou Jie , Wang Ru-Lan , Jiang Rui 
Published: January 2020

SUMMARYDiabetes mellitus (DM) is one of the most common comorbidities in esophageal cancer patients who undergo esophagectomy. It is well established that DM has an unfavorable impact on short-term outcomes of patients with surgically treated esophageal cancer; however, whether DM has any impact on long-term survival of these patients remains unclear. We performed the first meta-analysis to investigate the impact of DM on survival of surgically treated esophageal cancer patients. We searched the following databases systematically to retrieve relevant studies on January 2, 2019: PubMed, Embase, and Web of Science. The main outcome data consisting of 3- and 5-year overall survival (OS) rates and hazard ratios (HRs) of OS were extracted to compare survival between patients with and without DM. We finally included for meta-analysis a total of eight cohort studies involving 5,044 esophageal cancer patients who underwent esophagectomy. We found no significant difference between 3-year (risk ratio [RR] = 0.94, 95% CI: 0.73–1.21; P = 0.65) and 5-year (RR = 0.92, 95% CI: 0.80–1.08; P = 0.31) OS rates between patients with and without DM after esophagectomy. Moreover, DM was not found to be an independent predictor of OS for these patients (HR = 1.10, 95% CI: 0.65–1.84; P = 0.72). Our study suggests that DM appears to have no significant impact on long-term survival of esophageal cancer patients who undergo esophagectomy. To improve the prognosis of these patients, it may be more important to control glycemic level in patients with DM who undergo esophagectomy. However, further high-quality studies with appropriate adjustment for confounding factors are needed to verify this conclusion.