bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct enzyme immunometric measurement of plasma big endothelin-1 concentrations and correlation with indicators of left ventricular function
Authors: Haug Cornelia , Koenig Wolfgang , Hoeher Martin , Kochs Matthias , Hombach Vinzenz , Gruenert Adolf , Osterhues Hans 
Published: January 2020

Abstract
Recent studies have suggested that the plasma concentrations of endothelin-1, a potent vasoconstrictive peptide, are increased in patients with congestive heart failure. This study aimed to evaluate a new direct ELISA for big endothelin-1 (the precursor of endothelin-1), in comparison with a big endothelin-1 ELISA using plasma sample extraction, and to investigate whether plasma big endothelin-1 concentrations correlate with indicators of left ventricular function. The direct ELISA yielded significantly (P &lt;0.001) lower results than the assay with extracted samples (0.9 ± 0.5 pmol/L vs 2.7 ± 1.9 pmol/L; n = 90); however, the results of the two assays were closely correlated (r = 0.86, P &lt;0.001). Plasma big endothelin-1 concentrations exhibited a significant (P &lt;0.001) negative correlation (r = −0.46, r = −0.40) with the left ventricular ejection fraction and a significant positive correlation (r = 0.40, P &lt;0.001; r = 0.36, P &lt;0.01) with the left ventricular end-diastolic pressure and the left ventricular end-diastolic (r = 0.42, r = 0.38, P &lt;0.001) and end-systolic (r = 0.52, r = 0.47, P &lt;0.001) volume indices. Plasma big endothelin-1 concentrations were notably greater in patients with New York Heart Association (NYHA) class II–IV symptoms than in patients without cardiac disease or in patients categorized to NYHA class I. These data suggest that plasma big endothelin-1 concentrations, measured by a direct ELISA, correlate with hemodynamic indicators and symptoms of left ventricular dysfunction.
Rapid, convenient radioimmunoassay of estrone sulfate
Authors: Ranadive Girish N , Mistry Jehangir S , Damodaran Kalyani , Khosravi M Javad , Diamandi Anastasia , Gimpel Terry , Castracane V Daniel , Patel S , Stanczyk Frank Z 
Published: January 2020

Abstract
We developed a specific, simple, and rapid RIA for the direct quantification of estrone sulfate (E1S) and established its performance characteristics. The assay has a dynamic range of 0.05–90 μg/L with a detection limit of 0.009 μg/L. Intraassay CVs were 9.2%, 4.5%, and 4.6% at 0.35, 9.0, and 60 μg/L, respectively. Interassay CVs were 8.8%, 5.1%, and 5.5% at 0.076, 0.5, and 12 μg/L, respectively. Linearity of dilution studies showed values of 80–105% of expected, and recovery of E1S added to serum samples ranged from 82% to 102%. Cross-reactivities with structurally related estrogens were &lt;5%. When compared with a conventional assay (involving hydrolysis of E1S and indirect measurement of estrone), the present RIA showed excellent correlation (r = 0.99, slope = 1.54, Sy‖x = 2.14, n = 71). Mean E1S concentrations measured with this RIA for normal men (n = 20) and women in follicular (n = 20) and luteal (n = 25) phases of their menstrual cycle were 0.96, 0.96, and 1.74 μg/L, respectively. Mean E1S concentrations for oral contraceptive users (n = 20) and postmenopausal women without hormone replacement therapy (n = 21) or on hormone replacement therapy (n = 22) were 0.74, 0.13, and 2.56 μg/L, respectively. Serum concentrations of E1S in pregnant women in their first (n = 14), second (n = 17), and third (n = 15) trimesters were 20, 66, and 105 μg/L, respectively. Availability of this simple RIA should provide a useful tool for the assessment of estrogen status in women.
Increased concentrations of serum pentosidine in rheumatoid arthritis
Authors: Rodríguez-García Javier , Requena Jesús R , Rodríguez-Segade Santiago 
Published: January 2020

AbstractAdvanced glycosylation end products (AGEs) are thought to play an important role in the development of diabetic complications. Oxidative reactions are essential for the formation of some AGEs, termed glycoxidation products. Increased concentrations of pentosidine, one of such products, are found in tissue and serum in diabetes mellitus and in end-stage renal disease, suggesting that hyperglycemia and impaired renal function are important factors in AGE accumulation. We hypothesized that increased concentrations of pentosidine would also be found in pathological conditions associated with increased oxidative stress. We measured pentosidine in sera of patients with rheumatoid arthritis (RA), systemic lupus erythematosus, and diabetes. Increased serum pentosidine was found in RA (108.4 ± 146.5 nmol/L, P &lt;0.002) and in diabetes (69.6 ± 42.4 nmol/L, P &lt;0.001) as compared with healthy subjects (48.3 ± 12.0 nmol/L). These results prove that AGEs may accumulate in the absence of hyperglycemia or impaired kidney function.
Determination of glycated albumin by enzyme-linked boronate immunoassay (ELBIA)
Authors: Ikeda Kazuyoshi , Sakamoto Yuichiro , Kawasaki Yukie , Miyake Takehiro , Tanaka Kimikazu , Urata Takeyoshi , Katayama Yoshiaki , Ueda Shoichi , Horiuchi Seikoh 
Published: January 2020

AbstractA new affinity method for quantification of glycated albumin by an enzyme-linked boronate-immunoassay (ELBIA) has been established, based on the interaction between boronic acids and the cis-diols of glycated human serum albumin (HSA) trapped by anti-HSA antibody. To evaluate the ELBIA, we first examined the accuracy of the conventional boronate affinity chromatographic (BAC) method. In the BAC method, 8.1–18.9% of nonglycated albumin calibrator nonspecifically bound to the boronate affinity column, values that were regarded as the column blank. In the modified BAC method, therefore, we subtracted the column blank value from the measured glycated albumin value to obtain the true value. Because glycated albumin values measured by ELBIA were exactly the same as reported by the modified BAC method, we suggest that the ELBIA results reflect the real status of albumin glycation. We have also developed a fully automated ELBIA system, allowing multiple, rapid, and precise measurements of glycated albumin.
Rapid detection of a recombinant hotspot associated with Charcot–Marie–Tooth disease type 1A duplication by a PCR-based DNA test
Authors: Chang Jan-Gowth , Jong Yuh-Jyh , Wang Wen-Pin , Wang Jyh-Chwan , Hu Chaur-Jong , Lo Man-Chi , Chang Chih-Peng 
Published: January 2020

Abstract
A 1.5-Mb duplication on chromosome 17p11.2-p12 (CMT1A duplication) caused by a misalignment of the CMT1A repeat sequences (CMT1A-REPs) is associated with Charcot–Marie–Tooth disease type 1A (CMT1A). A hotspot of crossover breakpoints located in a 3.2-kb region of the CMT1A-REPs accounts for three-quarters of the rearrangements in CMT1A patients. We developed a PCR-based diagnostic method to detect a recombination hotspot associated with the CMT1A duplication. Thirty-one CMT1A Chinese patients from different families and 50 healthy people over 65 years of age were studied. Twenty-seven of the 31 cases demonstrated the 3.2-kb hotspot crossover, of which there were two subgroups. The type 1 crossover breakpoint was located at the distal CMT1A-REP around the PmeI site, and accounted for 24 of the 27 cases with a 3.2-kb hotspot crossover in CMT1A duplication patients. The type 2 crossover breakpoint was located at the distal CMT1A-REP around the base 3625 region, accounting for 3 of the 27 cases. The results correlated very well with the results of Southern transfer analysis. This study has a potentially important role in the diagnosis of CMT1A disease.
Assessment of simple colorimetric procedures to determine smoking status of diabetic subjects
Authors: Smith Robert F , Mather Hugh M , Ellard Gordon A 
Published: January 2020

Abstract
The performance of a simple colorimetric assay for urinary nicotine metabolites to assess smoking status in diabetic subjects (n = 251) was investigated. Several variations of the colorimetric assay and a qualitative extraction procedure were evaluated in comparison with a cotinine immunoassay as the “gold standard.” Among these, the best overall performance was achieved with the qualitative test (sensitivity 95%; specificity 100%). The quantitative measurement of total nicotine metabolites performed less well (sensitivity 92%; specificity 97%) but could be improved by incorporating a blank extraction (sensitivity 98%; specificity 98%). Allowance for diuresis appeared to offer no advantage over the other methods. These results support previous findings regarding the use of these colorimetric procedures in nondiabetic subjects and, contrary to other recent observations, their performance was not impaired in diabetic patients.
Radioimmunoassay of bound and free melatonin in plasma
Authors: Di Wei-Li , Kadva Aban , Djahanbakhch Ovrang , Silman Robert 
Published: January 2020

Abstract
We describe a nonextraction procedure, and two extraction procedures, for RIA of melatonin in human plasma. All procedures showed a diurnal rhythm of melatonin in human subjects, with interindividual differences greater than interprocedure differences. However, further investigations demonstrated considerable variability of recovery in the nonextraction procedure, suggesting a variability of binding proteins between samples. Combining recovery and dialysis experiments in the extraction procedures, we demonstrated that chloroform was unable to extract albumin-bound melatonin from a human serum albumin solution but, paradoxically, was able to extract bound and free melatonin from a plasma sample. The methanol extraction procedure extracted free and bound melatonin from all sources. These results indicate that albumin binding can substantially affect the RIA procedures. We conclude that assays should be validated against free and bound melatonin and that the two forms should be independently investigated when assessing bioactivity.
Enzyme conversion immunoassay for determining total homocysteine in plasma or serum
Authors: Frantzen Frank , Faaren Arne Ludvig , Alfheim Ingrid , Nordhei Arne Kristian 
Published: January 2020

Abstract
A rapid and precise immunoassay for quantification of total homocysteine in blood samples is presented. The method avoids the use of radioisotopes and chromatographic separations and relies on enzymatic conversion of homocysteine to S-adenosyl-l-homocysteine, followed by quantification of S-adenosyl-l-homocysteine by an enzyme-linked immunoassay in microtiter format. The within- and between-assay imprecision is &lt;6% and 8%, respectively, and results by the method show good correlation with those by HPLC. Including controls and calibrators in duplicates, 82 samples can be analyzed within 2.5 h. The procedure can be fully automated.
Assessment of sequence-based p53 gene analysis in human breast cancer: messenger RNA in comparison with genomic DNA targets
Authors: Williams Cecilia , Norberg Torbjörn , Ahmadian Afshin , Pontén Fredrik , Bergh Jonas , Inganäs Mats , Lundeberg Joakim , Uhlén Mathias 
Published: January 2020

Abstract
The high prevalence of p53 mutations in human cancers and the suggestion from several groups that the presence or absence of p53 mutations might have both prognostic and therapeutic consequences point to the importance of optimal methods for p53 determination. Several strategies exploring this have been described, based either on mRNA or genomic DNA as a template. However, no comparative study on the reliability of the two templates has been performed. The principal aim of this study was to study the concordance of RNA- and DNA-based direct sequencing methods in detecting p53 mutations in breast tumors. In 100 tumors, 22 mutations were detected by both methods. Furthermore, one stop mutation, two splice-site mutations, and one intron alteration were found only by genomic sequencing. In addition, the comparative study suggests that cells with missense mutations have increased steady-state concentrations of p53-specific mRNA, in contrast to cells with a gene encoding a truncated protein.
Semiautomated microtiter plate assay for monitoring peptidylprolyl cis/trans isomerase activity in normal and pathological human sera
Authors: Küllertz Gerhard , Lüthe Sabine , Fischer Gunter 
Published: January 2020

AbstractAn UV/VIS spectrophotometric assay technique was developed that was able to routinely monitor peptidylprolyl cis/trans isomerase (PPIase) activity of biological fluids in 96-well microtiter plates. The assay, based on monitoring the cis-to-trans isomerization of succinyl-Phe-cisPro-Phe-4-nitroanilide as substrate in a chymotrypsin-coupled reaction, yields a throughput of 96 samples per 30 min. The assay’s capacity was exemplified by dealing with the PPIase activity in several normal and pathological human sera. Reference values of 151 healthy subjects (83 females, 69 males, 17 to 60 years old) were found to possess significant sex-specific differences. PPIase activity factor K of the sera was significantly greater in males (5th, 50th, 95th percentiles: 17, 36, 55 K) than females (14, 30, 48 K). PPIase activities of sera from healthy donors (n = 151) were significantly higher (Mann–Whitney rank-sum test P &lt;0.0001) than those of patients (n = 47). PPIase activity in serum samples stored at 4 °C was stable for at least 20 h.
Prenatal and postnatal diagnoses of thalassemias and hemoglobinopathies by HPLC
Authors: Fucharoen Suthat , Winichagoon Pranee , Wisedpanichkij Raewadee , Sae-Ngow Busara , Sriphanich Rungrat , Oncoung Warangkana , Muangsapaya Wanna , Chowthaworn Jew , Kanokpongsakdi Sujin , Bunyaratvej Ahnond , Piankijagum Anong , Dewaele Chris 
Published: January 2020

AbstractThe conventional approach to qualitative and quantitative analyses of hemoglobin (Hb) molecules for the diagnoses of hemoglobinopathies requires a combination of tests. We used an automated HPLC (VARIANT™) system to study α-thalassemia and β-thalassemia syndromes in Thailand. The beta-thalassemia short program is applicable to the diagnosis of α-thalassemia and β-thalassemia disorders, including Hb H, EA Bart’s disease, and EF Bart’s disease, in adults, newborns, and fetuses. The system cannot quantify accurately certain Hb molecules, such as Hb H and Hb Bart’s. The alpha-thalassemia short program was therefore developed and used to quantify Hb Bart’s to detect α-thalassemia genotypes in cord blood. This automated HPLC system is an alternative approach to the diagnosis of complicated thalassemia syndromes in Thailand and Southeast Asia.
A non-(1–84) circulating parathyroid hormone (PTH) fragment interferes significantly with intact PTH commercial assay measurements in uremic samples
Authors: Lepage Raymond , Roy Louise , Brossard Jean-Hugues , Rousseau Louise , Dorais Claude , Lazure Claude , D’Amour Pierre 
Published: January 2020

AbstractWe have previously shown that the Nichols assay for intact parathyroid hormone (I-PTH) reacts with a non-(1–84) molecular form of PTH. This form behaves as a carboxy-terminal fragment and accumulates in renal failure, accounting for 40–60% of the measured immunoreactivity. We wanted to see whether this was a common event with other commercial two-site I-PTH assays. We thus compared the ability of three commercial kits [Nichols (NL), Incstar (IT), and Diagnostic System Laboratories (DSL)] to measure I-PTH in 112 renal failure patients and to detect hPTH(1–84) and non-(1–84)PTH on HPLC profiles of serum pools from uremic patients with I-PTH concentrations of 10–100 pmol/L. The behavior of synthetic hPTH(7–84), a fragment possibly related to non-(1–84)PTH was also compared with hPTH(1–84) in the three assays. The I-PTH concentrations measured with the three assays in the 112 uremic samples were highly related (r2 ≥ 0.89, P &lt;0.0001), and the values measured with NL were, on average, 23% higher than IT. Values measured with DSL were 23% and 56% higher than IT for values less than and more than 40 pmol/L, respectively. The three assays detected two HPLC peaks on four different profiles corresponding to hPTH(1–84) and non-(1–84)PTH. This last peak represented 36 ± 8.4% of the immunoreactivity with NL, 24 ± 5.5% with IT, and 25 ± 2.8% with DSL (NL vs IT or DSL: P &lt;0.05). These differences were confirmed by a 50% lower immunoreactivity to hPTH(7–84) compared with hPTH(1–84) for IT and DSL but not for NL. These results suggest that most of the two-site I-PTH assays would cross-react with non-(1–84)PTH material, thus explaining about one-half of the 2–2.5 × higher I-PTH concentrations reported in uremic patients without bone involvement than in subjects without uremia.
Intrinsic and routine quality of serum total potassium measurement as investigated by split-sample measurement with an ion chromatography candidate reference method
Authors: Thienpont Linda M , Van Nuwenborg Jean E , Stöckl Dietmar 
Published: January 2020

Abstract
We evaluated the intrinsic quality of eight routine test systems for the measurement of serum total potassium (K+), as well as the routine quality of four of these systems, using a group of 60 single-donation serum samples that had been certified with an ion chromatography reference method. The intrinsic quality of the tests was evaluated by analysis of the sera in the manufacturers’ application laboratories under strict internal quality control. The routine quality was evaluated by analysis of the same sera in five (per system) routine laboratories under daily working conditions. The results of the study were interpreted in light of the most stringent specifications derived from the biological variation of K+, which require limits of 6.3% for total error and 1.6% for systematic error. The study revealed that the intrinsic quality of all systems was excellent. None of the test systems yielded a substantial number of results outside the 6.3% total error limit, and only one test system exceeded the 1.6% systematic error limit. The majority of the routine laboratories reproduced the manufacturers’ intrinsic quality. In particular, most laboratories satisfied the 6.3% total error limit. However, several laboratories exceeded the 1.6% systematic error limit. Generally, there was a considerable difference in quality between the participating laboratories. This showed that the major problems for serum K+ analysis (for samples with no unusual matrices and with concentrations within the reference interval) are at the routine laboratory.
Standards of laboratory practice: antiepileptic drug monitoring
Authors: Warner Ann , Privitera Michael , Bates David 
Published: January 2020

Abstract
Discussion and development of standards for appropriate monitoring led to the following key recommendations for ordering, sampling, and analyzing antiepileptic drugs: Monitoring should usually be done on trough specimens after steady-state has been reached and always with an appropriate medical indication; non-steady-state concentrations may be indicated in selected situations. Monitoring of free phenytoin and free valproic acid is indicated in specific situations and should be done in serum. The metabolite of primidone, phenobarbital, should be measured concurrently with parent drug, but the active metabolite of carbamazepine does not need to be monitored unless the patient is exhibiting an unusual toxic response that cannot be otherwise explained. Assays used for antiepileptic drug monitoring should display a long-term CV of &lt;10% and preferably &lt;5%. Subtherapeutic and supratherapeutic drug concentrations should be investigated on a regular basis as part of a quality assurance process.
Rapid capillary zone electrophoresis in isoelectric histidine buffer: high resolution of the poly-T tract allelic variants in intron 8 of the CFTR gene
Authors: Gelfi Cecilia , Perego Marilena , Righetti Pier Giorgio , Cainarca Silvia , Firpo Stefania , Ferrari Maurizio , Cremonesi Laura 
Published: January 2020

Abstract
The poly-T tract in intron 8 of the cystic fibrosis conductance transmembrane regulator (CFTR) gene exists in three variants, 5T, 7T, and 9T. The 7T and 9T variants generate a predominantly normal transcript, whereas the 5T variant engenders an anomalous product. The analysis of the poly-T tract is assuming increasing relevance, both to assess the implication of the CFTR gene in congenital bilateral absence of the vas deferens and to evaluate genotype-phenotype correlation in cystic fibrosis. Mapping of the poly-T tract has been performed by cumbersome and time-consuming methodologies. Capillary zone electrophoresis, combined with laser-induced fluorescence detection, was introduced for a rapid separation of the poly-T tract amplified products. As separation buffer, we adopted 200 mmol/L histidine (pH = pI = 7.6), and the capillary was filled with 10% polyacrylamide, allowing separations in less than 10 min. Capillary zone electrophoresis results were in perfect agreement with dot-blot analysis.
Ultrarapid drug metabolism: PCR-based detection of CYP2D6 gene duplication
Authors: Steijns Linda S W , Van Der Weide Jan 
Published: January 2020

AbstractThe enzyme debrisoquine 4-hydroxylase (CYP2D6), which metabolizes many widely used drugs, is highly polymorphic. The activity of the enzyme ranges between subjects from ultrafast to a complete absence. Therefore, metabolic capacity varies, producing intersubject differences in therapeutic efficacy and side effects at standard recommended doses. Up to 7% of Caucasians may demonstrate ultrarapid drug metabolism (UM) because of inherited alleles with multiplicate functional CYP2D6 genes, causing an increased amount of enzyme to be expressed. Identification of UM subjects is of potential clinical importance for adjustment of doses in drug therapy, as well as to avoid misidentification of noncompliance. In our study, we tested recently designed PCR assays for the detection of the UM genotype. We found a 3.5% prevalence of UMs carrying duplicate active CYP2D6 genes in a population consisting of 202 psychiatric patients.
Biological variations and genetic reference values for apolipoprotein E serum concentrations: results from the STANISLAS cohort study
Authors: Vincent-Viry Monique , Schiele Françoise , Gueguen René , Bohnet Karin , Visvikis Sophie , Siest Gérard 
Published: January 2020

AbstractSerum apolipoprotein (apo) E concentrations were determined by immunoturbidimetry in 4284 subjects from 4 to 71 years of age and belonging to 1003 nuclear families recruited for the STANISLAS cohort study between January 1994 and August 1995. Values for apo E ranged from 16 to 169 mg/L, with a geometric mean ± SD values of 46.6 ± 13.8 mg/L in the overall sample. The interindividual variability varied from 24.6% to 32.0% among family members. Females exhibited higher apo E values than males until the age of 17–26 years. Conversely, after the age of 26 years, serum apo E concentrations were higher in men than in women. Biological factors affecting serum apo E concentrations were described in fathers, mothers, sons, and daughters and explained up to 32.0% of the apo E variability in daughters and 19.0% in fathers. The main biological factors affecting apo E concentrations were the following: apo E polymorphism, waist-to-hip ratio, oral contraceptive intake, puberty, body mass index, age, and gender. Given the importance of apo E polymorphism in the regulation of apo E concentrations, we recommend the use of genetic-based reference values for the clinical interpretation of serum apo E concentrations.