bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estrogen Negatively Regulates Epidermal Growth Factor (EGF)-Mediated Signal Transducer and Activator of Transcription 5 Signaling in Human EGF Family Receptor-Overexpressing Breast Cancer Cells
Authors: Boerner Julie L. , Gibson Matthew A. , Fox Emily M. , Posner Erika D. , Parsons Sarah J. , Silva Corinne M. , Shupnik Margaret A. 
Published: June 2005

Abstract
Breast cancer cell growth may be stimulated by 17β-estradiol (E2) or growth factors like epidermal growth factor (EGF). However, tumors typically depend on only one of these pathways and may overexpress either estrogen receptor (ER) or EGF receptor (EGFR) and related family members. Tumors overexpressing EGFR are more aggressive than those expressing ER. Intracellular mediators of these growth-stimulatory pathways are not completely defined, but one potential common mediator of EGF and E2 signaling is the transcription factor signal transducer and activator of transcription 5 (STAT5). To investigate the role of STAT5 in potential crosstalk between E2 and EGF, MDA-MB231 and SKBr3 breast cancer cells, which are ER-negative and overexpress human EGF family receptors, were used. Introduction of ERα and treatment with E2 decreased EGF-induced tyrosine phosphorylation of STAT5b, basal and EGF-induced STAT5-mediated transcription, and EGF-stimulated DNA synthesis in these cells. Suppressive effects of E2-ΕRα were specific for STAT5, as EGF stimulation of MAPK was unaffected. Deletion/mutation analysis of ERα demonstrated that the DNA-binding domain was insufficient, and that the ligand-binding domain was required for these responses. ERα transcriptional activity was not necessary for suppression of STAT5 activity. Overexpression of c-Src did not prevent suppression of STAT5 activity by E2 and ERα. However, ERα did prevent basal increases in STAT5 activity with overexpressed c-Src. In the context of human EGF receptor family overexpression, E2-ER opposes EGF signaling by regulating STAT5 activity. STAT5 may be a crucial point of signaling for both E2 and growth factors in breast cancer cells, allowing targeted therapy for many types of breast tumors.
Inhaled Iloprost in Pulmonary Arterial Hypertension
Authors: Baker Stacey E , Hockman Rebecca Haynes 
Published: June 2005

OBJECTIVE To review the pharmacology, pharmacodynamics, and clinical trials evaluating inhaled iloprost in pulmonary arterial hypertension (PAH). DATA SOURCES A MEDLINE search (1996–February 2005) was performed using the key words pulmonary hypertension, iloprost, and epoprostenol. Information regarding Food and Drug Administration approval was obtained via the Internet. STUDY SELECTION AND DATA EXTRACTION All clinical trials using inhaled iloprost in PAH published in English were identified. Additionally, references from the identified articles were reviewed. DATA SYNTHESIS A stable analog of prostacyclin, inhaled iloprost is thought to promote benefit in PAH through vasodilation, antiproliferative effects, and inhibition of platelet aggregation. In a placebo-controlled trial of 203 patients, inhaled iloprost significantly improved the combined endpoint of change in New York Heart Association functional class and 10% improvement in 6-minute walk distance (p = 0.007). Small, short-term clinical trials demonstrated hemodynamic benefits for inhaled iloprost alone and in combination with other pulmonary vasodilating agents. The aerosolized delivery route and low incidence of adverse events are positive attributes for inhaled iloprost, while the frequency of administration and lack of comparative data limit its role in PAH. CONCLUSIONS Currently, inhaled iloprost offers potential benefit for patients with contraindications to bosentan, preference for non-parenteral products, ineligibility for parenteral therapy, or as adjunctive therapy with other pulmonary vasodilators. Larger, long-term clinical trials are needed to solidify the role for inhaled iloprost in the management of PAH.
Calibration Curves for Real-Time PCR
Authors: Lai K Kay-Yin , Cook Linda , Krantz Elizabeth M , Corey Lawrence , Jerome Keith R 
Published: June 2005

Abstract
Background: Despite the increasing use of real-time PCR in the diagnosis and management of viral infections, there are no published studies adequately addressing the optimum number of calibrators, the number of replicates of each calibrator, and the frequency with which calibration needs to be repeated. This study was designed to address these issues.
Methods: Cycle threshold data (ABI 7700) was collected from &gt;50 consecutive real-time PCR runs for hepatitis B and Epstein–Barr viruses. Our routine calibration curve made from serial 10-fold dilutions run in duplicate was compared with alternative options, including duplicate 100-fold dilutions, inclusion of a low-copy calibrator, and omission of the duplicate determination. Control data were used to examine the use of an average calibration curve made from multiple runs.
Results: Use of duplicate serial 10-fold dilutions led to the least imprecision, duplicate 100-fold dilutions had slightly higher imprecision, and calibration curves obtained with singlet measurements showed the greatest imprecision. For patient data, the duplicate 100-fold dilution calibration curve produced results that best matched those from the routine calibration curve. Use of singlet dilutions or inclusion of a low-copy calibrator produced poorer agreement. Variability in controls was lower with a daily calibration curve than with an average calibration curve.
Conclusions: Duplicate 100-fold dilution calibration curves produced equivalent results and the same imprecision as curves with more calibrators, and thus are a valid alternative. Laboratories should carefully evaluate the variability resulting from the use of average calibration curves before adopting this approach.
Evaluation of the Quantitative Analytical Methods Real-Time PCR for HER-2 Gene Quantification and ELISA of Serum HER-2 Protein and Comparison with Fluorescence in Situ Hybridization and Immunohistochemistry for Determining HER-2 Status in Breast Cancer Patients
Authors: Tse Chantal , Brault Didier , Gligorov Joseph , Antoine Martine , Neumann Rainer , Lotz Jean-Pierre , Capeau Jacqueline 
Published: June 2005

Abstract
Background: HER-2 status is generally determined by immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH). Both methods are only semiquantitative, require a tumor sample, and can be difficult to reproduce. We compared these methods with 2 quantitative approaches, one measuring HER-2 gene copy number in tissue by real-time quantitative PCR (qPCR), and the other measuring shed HER-2 protein in serum by ELISA in patients with metastatic disease.
Methods: We analyzed 52 cases of metastatic breast cancer for which both serum collected at the diagnosis of metastasis and stored primary breast tumor specimens were available. The within- and between-run imprecision of real-time qPCR and ELISA were evaluated according to Clinical and Laboratory Standards Institute (formerly known as NCCLS) recommendations. Concordance among the 4 methods was assessed by calculating the κ statistic and its 95% confidence interval (95% CI).
Results: The CVs for within- and between-run imprecision were both &lt;10% with qPCR and ELISA. There was good agreement of results between qPCR and IHC (κ = 0.81; 95% CI, 0.64–0.99), qPCR and FISH (κ = 0.77; 95% CI, 0.58–0.96), ELISA and IHC (κ = 0.65; 95% CI, 0.41–0.89); and ELISA and FISH (κ = 0.69; 95% CI, 0.46–0.92).
Conclusions: Measurements of HER-2 gene expression by qPCR and of serum HER-2 protein by ELISA are highly reproducible approaches for determining HER-2 status in metastatic breast cancer. In addition, ELISA eliminates the need for biopsy.
Iron Stores, Blood Donation, and Insulin Sensitivity and Secretion
Authors: Fernández-Real José Manuel , López-Bermejo Abel , Ricart Wifredo 
Published: June 2005

Abstract
Background: Epidemiologists have observed that blood donation is associated with decreased risk of type 2 diabetes and cardiovascular disease.
Methods: We investigated the relationship between iron stores and insulin sensitivity, after controlling for known confounding factors, and compared insulin sensitivity between blood donors and individuals who had never donated blood (nondonors). In 181 men, insulin sensitivity and insulin secretion were evaluated through frequently sampled intravenous glucose tolerance tests with minimal model analysis. Men who donated blood between 6 months and 5 years before inclusion (n = 21) were carefully matched with nondonors (n = 66) for age, body mass index, waist-to-hip ratio, and cardiovascular risk profile, including blood lipids, blood pressure, and smoking status.
Results: Frequent blood donors (2–10 donations) had increased insulin sensitivity [3.42 (1.03) vs 2.45 (1.2) × 10−4 · min−1 · mIU/L; P = 0.04], decreased insulin secretion [186 (82) vs 401.7 (254) mIU/L · min; P &lt;0.0001], and significantly lower iron stores [serum ferritin, 101.5 (74) vs 162 (100) μg/L; P = 0.017] than nondonors, but the 2 groups had similar blood hematocrits and blood hemoglobin concentrations.
Conclusions: Blood donation is simultaneously associated with increased insulin sensitivity and decreased iron stores. Stored iron seems to impact negatively on insulin action even in healthy people, and not just in classic pathologic conditions associated with iron overload (hemochromatosis and hemosiderosis). According to these observations, it is imperative that a definition of excessive iron stores in healthy people be formulated.
Multiplexed Analysis of Biomarkers Related to Obesity and the Metabolic Syndrome in Human Plasma, Using the Luminex-100 System
Authors: Liu Mine Y , Xydakis Antonios M , Hoogeveen Ron C , Jones Peter H , Smith E O’Brian , Nelson Kathleen W , Ballantyne Christie M 
Published: June 2005

Abstract
Background: The complex pathology of disease has sparked the development of novel protein expression profiling techniques that require validation in clinical settings. This study focuses on multiplexed analyses of adipocytokines and biomarkers linked to the metabolic syndrome, diabetes, and cardiovascular disease.
Methods: Multiplexed immunoassays using fluorescent microspheres and the Luminex-100 system were performed on plasma from 80 obese patients (40 with the metabolic syndrome) before and after 6–8 weeks of diet-induced weight loss. Leptin, insulin, C-peptide, monocyte chemoattractant protein-1 (MCP-1), eotaxin, interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and IL-6 concentrations measured with multiplex panels from 3 different manufacturers were compared with results from commercial ELISAs. Detection limits and between- and within-run imprecision were determined for each analyte. Bland–Altman analysis was used to determine agreement between multiplexed immunoassays and ELISAs.
Results: Correlation between the Luminex multiplexed assays and ELISAs was good for leptin (Linco), insulin (Linco), MCP-1 (Biosource and Upstate), and eotaxin (Biosource) with correlation coefficients of 0.711–0.895; fair for eotaxin (Upstate) and C-peptide (Linco) with correlation coefficients of 0.496–0.582; and poor for TNF-α, IL-8, and IL-6 (Linco, Biosource, Upstate, and R&D) with correlation coefficients of −0.107 to 0.318. Within- and between-run imprecision values for the multiplex method were generally &lt;15%. Relative changes in plasma leptin and insulin concentrations after diet-induced weight loss were similar whether assessed by multiplex assay or ELISA.
Conclusion: Although this technology appears useful in clinical research studies, low assay sensitivity and poor correlations with conventional ELISA methods for some analytes with very low plasma concentrations should be considered when using the Luminex platform in clinical studies.
Postanalytical External Quality Assessment of Blood Glucose and Hemoglobin A1c: An International Survey
Authors: Skeie Svein , Perich Carmen , Ricos Carmen , Araczki Agnes , Horvath Andrea R , Oosterhuis Wytze P , Bubner Tanya , Nordin Gunnar , Delport Rhena , Thue Geir , Sandberg Sverre 
Published: June 2005

Abstract
Background: Diabetes mellitus (DM) is diagnosed and monitored worldwide by blood glucose (BG) and glycohemoglobin A1c (HbA1c) testing, respectively. Methods for quality assessment of clinician interpretations of changes in these laboratory results have been developed. This study uses survey responses from general practitioners (GPs) in different countries to investigate possible differences in interpretation of results, as well as the feasibility of performing international postanalytical external quality assessment surveys (P-EQAS).
Methods: GPs recruited from 7 countries received questionnaires requesting interpretation of changes in a potentially diagnostic capillary BG result and an HbA1c value obtained during monitoring of a patient with type 2 DM. GPs were asked to estimate clinically significant differences between 2 consecutive laboratory results [critical difference (CD)/reference change value] for both BG and HbA1c. The CDs reported by GPs were used to calculate the analytical variation (CVa), which was taken as the quality specification for analytical imprecision. Participants received national benchmarking feedback reports after the survey.
Results: The study included responses from 2538 GPs. CDs in BG results showed the same pattern and were comparable among countries. Calculated median CVa values would be possible to attain at 80% confidence but not at the conventional 95% confidence. For HbA1c, the same pattern was shown across countries, but with lower changes considered true when HbA1c increased than when it decreased. Despite the consistent pattern, variations among GPs were considerable in all countries.
Conclusions: Assessments of CDs for BG and HbA1c were similar internationally, and quality specifications for these analytes based on clinicians’ opinions are therefore interchangeable among countries. International P-EQAS may contribute to a more rational use of laboratory services and clinical guidelines.
High-Throughput Purification of Viral RNA Based on Novel Aqueous Chemistry for Nucleic Acid Isolation
Authors: Hourfar Michael K , Michelsen Uwe , Schmidt Michael , Berger Annemarie , Seifried Erhard , Roth W Kurt 
Published: June 2005

Abstract
Background: Extraction protocols using magnetic solid phases offer a high potential for automation. However, commercially available magnetic-bead–based assays either lack the sensitivity required for viral diagnostics or are disproportionately expensive.
Methods: We developed an aqueous chemistry for extraction of viral nucleic acids from plasma samples by use of common magnetic silica beads. Nucleic acids were bound to the beads at acidic conditions in the presence of a kosmotropic salt and were eluted at a slightly alkaline pH. The method was implemented on a standard pipetting workstation for fully automated extraction of up to 48 samples of 240 μL plasma in 1 batch.
Results: The detection limit of the method was comparable to the spin-column–based QIAamp Viral RNA Mini Kit, which relies on chaotropic salts and binding to a silica membrane, as the comparison method. The 95% detection limit was 23.1 IU per PCR for HIV-1 and 10.7 IU per PCR for hepatitis C virus (HCV). Suitability for clinical routine testing was confirmed in a total of 178 HIV-1- or HCV-positive plasma samples. The method linearity (R2) was &gt;0.99 for the viruses evaluated.
Conclusions: Use of reagents without organic solvents allows simple and cost-effective automation of this method on common pipetting robots with low risk of contamination. Performance characteristics of the novel extraction method make it suitable for use in diagnosis of infectious diseases and viral load determinations.
Multianalyte Quantification of Vitamin B6 and B2 Species in the Nanomolar Range in Human Plasma by Liquid Chromatography–Tandem Mass Spectrometry
Authors: Midttun Øivind , Hustad Steinar , Solheim Einar , Schneede Jørn , Ueland Per M 
Published: June 2005

AbstractBackground: Homocysteine, a risk factor of cardiovascular disease, cognitive disorders, and pregnancy complications, exists at a point of metabolic convergence of several B vitamins, including vitamins B6 and B2 (riboflavin). Measurement of the various forms of these vitamins may be useful for the study of hyperhomocysteinemia as well as for the assessment of vitamin status.Methods: Plasma (60 μL) was deproteinized by mixing with an equal volume of 50 g/L trichloroacetic acid that contained d2-pyridoxal 5′-phosphate, d3-pyridoxal, and d8-riboflavin as internal standards. Pyridoxal (PL), pyridoxal 5′-phosphate (PLP), pyridoxine (PN), pyridoxine 5′-phosphate, pyridoxamine (PM), pyridoxamine 5′-phosphate, 4-pyridoxic acid (PA), riboflavin, flavin mononucleotide (FMN), and FAD were separated on a C8 reversed-phase column, which was developed with an acetonitrile gradient in a buffer containing acetic acid and heptafluorobutyric acid. The analytes were detected by tandem mass spectrometry in the positive-ion mode.Results: The chromatographic run lasted 8 min. Within- and between-day CVs were 3%–20% and 6%–22%, respectively, and recoveries were 78%–163%. Limits of detection (signal-to-noise ratio = 5) were in the range 0.1–4.0 nmol/L, and the response was linear over several orders of magnitude. In samples from 94 healthy persons, we obtained median concentrations (nmol/L) of 35.4 for PLP, 16.9 for PL, 22.4 for PA, 10.3 for riboflavin, 7.5 for FMN, and 63.1 for FAD. PN and PM were also detected in some cardiovascular patients taking B6 supplements.Conclusions: This method based on liquid chromatography–tandem mass spectrometry measures all known plasma forms of vitamins B6 and B2, which span a wide range of polarity. The assay is characterized by simple sample processing with no derivatization, low sample volume requirement, and a short run time.
The Nonpeptide Calcitonin Gene-Related Peptide Receptor Antagonist BIBN4096BS Lowers the Activity of Neurons with Meningeal Input in the Rat Spinal Trigeminal Nucleus
Authors: Fischer Michael Jochen Marco , Koulchitsky Stanislav , Messlinger Karl 
Published: June 2005

Calcitonin gene-related peptide (CGRP) has been suggested to play a major role in the pathogenesis of migraines and other primary headaches. CGRP may be involved in the control of neuronal activity in the spinal trigeminal nucleus (STN), which integrates nociceptive afferent inputs from trigeminal tissues, including intracranial afferents. The activity of STN neurons is thought to reflect the activity of central trigeminal nociceptive pathways causing facial pain and headaches in humans.In a rat model of meningeal nociception, single neuronal activity in the STN was recorded. All units had receptive fields located in the exposed parietal dura mater. Heat and cold stimuli were repetitively applied to the dura in a fixed pattern of ramps and steps. The nonpeptide CGRP receptor antagonist BIBN4096BS was topically applied onto the exposed dura or infused intravenously.BIBN4096BS (300 μg/kg, i.v.) reduced spontaneous activity by ∼30%, the additional dose of 900 μg/kg intravenously by ∼50% of the initial activity, whereas saline had no effect. The activity evoked by heat ramps was also reduced after BIBN4096BS (900 μg/kg, i.v.) by ∼50%. Topical administration of BIBN4096BS (1 mm) did not significantly change the spontaneous neuronal activity within 15 min.We conclude that the endogenous release of CGRP significantly contributes to the maintenance of spontaneous activity in STN neurons. Blockade of CGRP receptors, possibly at central and peripheral sites, may therefore be an effective way to decrease nociceptive transmission. This may offer a new therapeutic strategy for the treatment of facial pain and primary headaches.
F2‐Isoprostanes as Markers of Oxidant Stress: An Overview
Authors: Musiek Erik S. , Morrow Jason D. 
Published: June 2005

AbstractThe isoprostanes are a unique series of prostaglandin‐like compounds formed in vivo via a non‐enzymatic mechanism involving the free radical–initiated peroxidation of arachidonic acid. This unit summarizes selected aspects regarding current knowledge of these compounds and their value as markers of oxidative injury. Novel aspects related to the biochemistry of isoprostane formation are discussed and methods by which these compounds can be analyzed and quantified are summarized. A considerable portion of this unit examines the utility of F2‐isoprostanes as markers of oxidant injury in vitro and in vivo. Numerous studies carried out over the past decade have shown that these compounds are extremely accurate measures of lipid peroxidation in animals and humans and have illuminated the role of oxidant injury in a number of human diseases.
Experimental analysis of viscoelastic properties in carbon black‐filled natural rubber compounds
Authors: Sajjayanukul Tibhawan , Saeoui Pongdhorn , Sirisinha Chakrit 
Published: June 2005

AbstractProcessability and viscoelastic properties of natural rubber (NR) compounds filled with different carbon black loadings and types were investigated with the use of a steady shear rheometer, namely, the Mooney viscometer, and an oscillatory rheometer, namely, the Rubber Process Analyser (RPA2000). It was found that the type and amount of carbon black strongly influence the viscoelastic properties of rubber compounds. Both the dilution effect and filler transient network are responsible for the viscoelastic properties, depending on the vulcanization state. In the case of uncured compounds, the damping factor of the uncured NR decreases with increasing black loading. This is attributed to the reduction of mobilized rubber content in the compound (or the dilution effect). However, in the case of the cured NR vulcanizates, the filler transient network is the dominant factor governing the damping factor of the vulcanizate. With increasing black loading, the damping factor of the vulcanizate clearly increases. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2197–2203, 2005
Pb2+ binding by polyaspartyl polymers and their application to Pb2+ removal from glycyrrhizin
Authors: Sun Bo , Mi Zhen‐Tao , Ouyang Jie , An Gang , Song Xiao‐Kai 
Published: June 2005

AbstractPolyaspartate is an excellent Pb2+‐binding agent in comparison with some polyaspartamide derivatives with different side chains, in that it possesses a higher Pb2+ uptake and a lower Pb2+ equilibrium concentration. Equilibrium sorption data for Pb2+ on polyaspartate can be well fitted with the Freundlich and Langmuir models. Experimental results show that a crosslinked polyaspartate hydrogel is superior to poly(acrylic acid)‐based resins and polystyrene‐based chelating resins. IR spectra and X‐ray photoelectron spectra reveal that the polyaspartate hydrogel binds Pb2+ by both an ion‐exchange mechanism and a chelating mechanism. The polyaspartate hydrogel is also an effective agent for the removal of Pb2+ from glycyrrhizin. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2215–2220, 2005