bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diagnostic Accuracy and Prognostic Relevance of the Measurement of Cardiac Natriuretic Peptides: A Review
Authors: Clerico Aldo , Emdin Michele 
Published: February 2004

AbstractBackground: The pathophysiologic and clinical relevance of cardiac natriuretic hormone (CNH) assays has been investigated in numerous experimental and clinical studies. Authors have sought to evaluate the diagnostic accuracy and prognostic relevance of the measurement of CNHs according to evidence-based laboratory medicine principles.Methods: In June 2003, we ran a computerized literature search on National Library of Medicine using keywords “ANP” and “BNP” and found more than 12 300 and 1200 articles, respectively. A more refined search with keywords “ANP or BNP assay” extracted ∼7000 and 800 articles, respectively. Only studies specifically designed to evaluate the diagnostic accuracy and prognostic relevance of CNH measurements were selected from this huge mass of articles to be discussed in this review.Content: Several studies suggested that CNH assays may be clinically useful for the screening and classification of patients with heart failure, as a prognostic marker in cardiovascular disease, in the follow-up of patients with heart failure, and because they may reduce the need for further cardiac investigation. However, it is difficult to compare even the best-designed studies because not only did the authors evaluate different populations, they also used different gold standards.Conclusions: CNH assays and conventional diagnostic work-ups provide complementary information for evaluation of the presence and severity of cardiac dysfunction and clinical disease. Several aspects of CNH assays are still to be elucidated, and further work is needed to carefully assess their diagnostic accuracy and prognostic value in cardiac disease.
Size Distributions of Maternal and Fetal DNA in Maternal Plasma
Authors: Chan K C Allen , Zhang Jun , Hui Angela B Y , Wong Nathalie , Lau Tze K , Leung Tse N , Lo Kwok-Wai , Huang Dolly W S , Lo Y M Dennis 
Published: February 2004

Abstract
Background: The discovery of fetal DNA in maternal plasma has opened up an approach for noninvasive prenatal diagnosis. Despite the rapid expansion in clinical applications, the molecular characteristics of plasma DNA in pregnant women remain unclear.
Methods: We investigated the size distribution of plasma DNA in 34 nonpregnant women and 31 pregnant women, using a panel of quantitative PCR assays with different amplicon sizes targeting the leptin gene. We also determined the size distribution of fetal DNA in maternal plasma by targeting the SRY gene.
Results: The median percentages of plasma DNA with size &gt;201 bp were 57% and 14% for pregnant and nonpregnant women, respectively (P &lt;0.001, Mann–Whitney test). The median percentages of fetal-derived DNA with sizes &gt;193 bp and &gt;313 bp were 20% and 0%, respectively, in maternal plasma.
Conclusion: Plasma DNA molecules are mainly short DNA fragments. The DNA fragments in the plasma of pregnant women are significantly longer than those in the plasma of nonpregnant women, and the maternal-derived DNA molecules are longer than the fetal-derived ones.
Liquid Chromatography–Tandem Mass Spectrometry Assay for Simultaneous Measurement of Estradiol and Estrone in Human Plasma
Authors: Nelson Robert E , Grebe Stefan K , O’Kane Dennis J , Singh Ravinder J 
Published: February 2004

Abstract
Background: Estradiol (E2) and estrone (E1) measurements form an integral part of the assessment of female reproductive function and have expanding roles in other fields. However, many E1 and E2 immunoassays have limited functional sensitivity, suffer from cross-reactivity, and display poor intermethod agreement. To overcome these problems, we developed a sensitive liquid chromatography–tandem mass spectrometry (LC-MS/MS) assay for the simultaneous measurement of E1 and E2.
Methods: After dansyl chloride derivatization, samples were separated by fast gradient chromatography and injected into a tandem mass spectrometer after formation of positive ions with atmospheric pressure chemical ionization. The limits of detection and quantification, recovery, linearity, precision, and reference intervals were determined, and performance was compared with several immunoassays.
Results: Total run time per sample was 5 min. The multiple-reaction monitoring ion pairs were m/z 506/171 for 3-dansyl-estradiol and m/z 504/171 for 3-dansyl-estrone. The limits of detection for E1 and E2 were 12.9 pmol/L (3.5 ng/L) and 10.3 pmol/L (2.8 ng/L), respectively. Interassay imprecision (CV) was 4–20% (n = 20). The limits of quantification (functional sensitivities) for E1 and E2 were 44.1 pmol/L (11.9 ng/L) and 23.2 pmol/L (6.3 ng/L), respectively. The assay was linear to &gt;2200 pmol/L (∼600 ng/L) for each analyte. Recoveries were 93–108% for E1 and 100–110% for E2. No cross-reactivity was observed. Method comparison with several immunoassays revealed that the latter were inaccurate and prone to interferences at low E1 and E2 concentrations.
Conclusions: LC-MS/MS allows rapid, simultaneous, sensitive, and accurate quantification of E1 and E2 in human serum.
Online Measurement of Urea Concentration in Spent Dialysate during Hemodialysis
Authors: Olesberg Jonathon T , Arnold Mark A , Flanigan Michael J 
Published: February 2004

Abstract
Background: We describe online optical measurements of urea in the effluent dialysate line during regular hemodialysis treatment of several patients. Monitoring urea removal can provide valuable information about dialysis efficiency.
Methods: Spectral measurements were performed with a Fourier-transform infrared spectrometer equipped with a flow-through cell. Spectra were recorded across the 5000–4000 cm−1 (2.0–2.5 μm) wavelength range at 1-min intervals. Savitzky–Golay filtering was used to remove baseline variations attributable to the temperature dependence of the water absorption spectrum. Urea concentrations were extracted from the filtered spectra by use of partial least-squares regression and the net analyte signal of urea.
Results: Urea concentrations predicted by partial least-squares regression matched concentrations obtained from standard chemical assays with a root mean square error of 0.30 mmol/L (0.84 mg/dL urea nitrogen) over an observed concentration range of 0–11 mmol/L. The root mean square error obtained with the net analyte signal of urea was 0.43 mmol/L with a calibration based only on a set of pure-component spectra. The error decreased to 0.23 mmol/L when a slope and offset correction were used.
Conclusions: Urea concentrations can be continuously monitored during hemodialysis by near-infrared spectroscopy. Calibrations based on the net analyte signal of urea are particularly appealing because they do not require a training step, as do statistical multivariate calibration procedures such as partial least-squares regression.
Definitive Diagnosis of Mitochondrial Neurogastrointestinal Encephalomyopathy by Biochemical Assays
Authors: Martı́ Ramon , Spinazzola Antonella , Tadesse Saba , Nishino Ichizo , Nishigaki Yutaka , Hirano Michio 
Published: February 2004

Abstract
Background: Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is caused by mutations in the gene encoding thymidine phosphorylase (TP). The clinical manifestations of MNGIE are recognizable and homogeneous, but in the early stages, the disease is often misdiagnosed. This study assesses the reliability of biochemical assays to diagnose MNGIE.
Methods: We studied 180 patients with clinical features suggestive of MNGIE, 14 asymptomatic TP mutation carriers, and 20 controls. TP enzyme activity in the buffy coat was determined by a fixed-time method, and the plasma nucleosides thymidine (dThd) and deoxyuridine (dUrd) were assessed by a gradient-elution reversed phase HPLC method. TP was sequenced through standard procedures in patients who met the clinical criteria for MNGIE.
Results:Twenty-five of the 180 patients fulfilled the clinical criteria for MNGIE and had homozygous or compound heterozygous TP mutations. All had drastically decreased TP activity [mean (SD), 10 (15) nmol thymine formed · h−1 · (mg protein)−1 vs 634 (217) nmol thymine formed · h−1 · (mg protein)−1 for the controls]. Relative to the control mean, TP activities were reduced to 35% in mutation carriers and 65% in MNGIE-like patients. All 25 MNGIE patients had detectable plasma dThd [8.6 (3.4) μmol/L] and dUrd [14.2 (4.4) μmol/L]. Controls, carriers, and MNGIE-like patients showed no detectable plasma dThd and dUrd.
Conclusions:We propose a diagnostic algorithm based on the determination of plasma dThd and dUrd, TP activity in buffy coat, or both to make a definitive diagnosis of MNGIE. Increased concentrations of dThd (&gt;3 μmol/L) and dUrd (&gt;5 μmol/L) in plasma or a decrease in buffy coat TP activity to ≤8% relative to controls is sufficient to diagnose MNGIE.
Determination of Folate Vitamers in Human Serum by Stable-Isotope-Dilution Tandem Mass Spectrometry and Comparison with Radioassay and Microbiologic Assay
Authors: Pfeiffer Christine M , Fazili Zia , McCoy Les , Zhang Ming , Gunter Elaine W 
Published: February 2004

Abstract
Background: Current clinical methods for folate give different results and cannot measure the various forms of folate. We developed an isotope-dilution tandem mass spectrometric method coupled to liquid chromatography (LC/MS/MS) as a candidate reference method for 5-methyltetrahydrofolic acid (5MeTHF), 5-formyltetrahydrofolic acid (5FoTHF), and folic acid (FA) in human serum.
Methods: We quantitatively isolated folates from 275 μL of serum with a phenyl solid-phase extraction cartridge, then detected and quantified them in stabilized serum extracts by positive-ion electrospray ionization LC/MS/MS. We used an isocratic mobile phase of acetic acid in organic solvent on a C8 analytical column. 13C-labeled folates were used as internal standards.
Results: Limits of detection in serum were 0.13 (5MeTHF), 0.05 (5FoTHF), and 0.07 (FA) nmol/L. Within- and between-run imprecision (CV) was &lt;7% for 5MeTHF and &lt;10% for 5FoTHF at concentrations &gt;0.5 nmol/L, and &lt;10% for FA at concentrations &gt;2.0 nmol/L. Total folate (TFOL) concentrations determined by competitive protein binding radioassay were ∼9% lower than results obtained with LC/MS/MS. The microbiologic assay gave ∼15% higher TFOL results with FA calibrator and no difference with 5MeTHF calibrator. The mean (SD) [range] TFOL in 42 sera was 35.5 (17.8) [6.5–75.6] nmol/L. Thirty-two samples with TFOL &lt;50 nmol/L had, on average, 93.3% 5MeTHF, 2.3% FA, and 4.4% 5FoTHF. Ten samples with TFOL &gt;50 nmol/L had, on average, 81.7% 5MeTHF, 15.7% FA, and 2.5% 5FoTHF.
Conclusions: This stable-isotope-dilution LC/MS/MS method can quantify 5MeTHF, 5FoTHF, and FA in serum. Currently used clinical assays agree with this candidate reference method.
Quantification of Free Sialic Acid in Urine by HPLC–Electrospray Tandem Mass Spectrometry: A Tool for the Diagnosis of Sialic Acid Storage Disease
Authors: Valianpour Fredoen , Abeling Nicolaas G G M , Duran Marinus , Huijmans Jan G M , Kulik Willem 
Published: February 2004

AbstractBackground: Sialic acid storage diseases (SSDs) are severe autosomal recessive neurodegenerative disorders caused by a transport defect across the lysosomal membrane, which leads to accumulation of sialic acid in tissues, fibroblasts, and urine. Defective free sialic acid transport can be established by quantification of free sialic acid in urine.Methods: Urine sample size was adjusted to the equivalent of 100 nmol of creatinine. After addition of 2-keto-3-deoxy-d-glycero-d-galactonononic acid as internal standard, samples were diluted with water to an end volume of 250 μL. We used 10 μL for HPLC–tandem mass spectrometric analysis in the negative electrospray ionization mode, monitoring transitions m/z 308.3→m/z 86.9 (sialic acid) and m/z 267.2→m/z 86.9 (internal standard). The overall method was validated and studied for ion suppression, interfering compounds, and pH effects. Samples from controls (n = 72) and SSD patients (n = 3) were analyzed.Results: The limit of detection was 3 μmol/L. Intraassay imprecision (CV; n = 10) was 6%, 3%, and 2% at 30, 130, and 1000 mmol/mol creatinine, respectively; corresponding interassay CV (n = 10) were 5%, 5%, and 2%. Recovery was 109% (100–1000 mmol/mol creatinine). The mean (SD) [range] excretion rates (mmol/mol creatinine) were 31.3 (16.6) [0.7–56.9] at 0–1 year (n = 20), 21.2 (9.8) [6.3–38.3] at 1–3 years (n = 15), 14.4 (8.2) [1.7–32.9] at 3–10 years (n = 25), and 4.6 (2.6) [0–9.8] above age 10 years (n = 12). SSD patients 1.2, 3.9, and 12 years of age had concentrations of 111.5, 54.2, and 36.1 mmol/mol creatinine, respectively.Conclusions: The HPLC-tandem MS method for free sialic acid in urine is more rapid, accurate, sensitive, selective, and robust than earlier methods and may serve as a candidate reference method for free sialic acid in diagnosis of SSD.
Genetic Effects on Baseline Values of C-Reactive Protein and Serum Amyloid A Protein: A Comparison of Monozygotic and Dizygotic Twins
Authors: MacGregor Alex J , Gallimore J Ruth , Spector Tim D , Pepys Mark B 
Published: February 2004

Abstract
Background: C-Reactive protein (CRP) and serum amyloid A protein (SAA) are exquisitely sensitive acute-phase reactants, but their baseline values are surprisingly constant in individuals in the general population. These values, especially of CRP, are associated with future atherothrombotic events, and the determinants of baseline CRP and SAA concentration are therefore of considerable interest.
Methods: CRP and SAA concentrations were measured by well-validated automated microparticle capture enzyme immunoassays, standardized on the respective WHO International Reference Standards, in serum from 146 monozygotic and 164 dizygotic healthy female UK twin pairs from the general population, with mean (range) ages of 58.0 (40–69.6) and 55.7 (40–70.3) years, respectively, who were also very closely matched for height, weight, body mass index, blood pressure, and lifestyle variables. Statistical modeling based on variance components analysis was used to estimate the genetic contribution to the observed values.
Results: As reported previously, CRP values were associated with body mass index, smoking, and hormone replacement therapy. After exclusion of the few samples with CRP concentrations &gt;10 mg/L, which indicate an ongoing acute-phase response rather than baseline values, and inclusion of adjustments for all known confounding variables, there was significantly higher correlation of CRP and SAA results among monozygotic than among dizygotic twins. The estimated hereditability (95% confidence interval) of baseline values was 52% (40–62%) for CRP and 59% (49–67%) for SAA.
Conclusion: There is a substantial genetic contribution to baseline serum concentrations of CRP and SAA.
Can we win them all? Benefits and costs of structured and flexible innovation– implementations
Authors: Drach‐Zahavy Anat , Somech Anit , Granot Michal , Spitzer Ada 
Published: February 2004

AbstractBureaucratic job structuring was compared with person–job integration in an attempt to determine which of the two approaches was a better means for innovation implementation in the workplace. The solution was hypothesized to be complex, depending on the criteria chosen for innovation effectiveness. Seventy incumbents of new linking roles in healthcare organizations were recruited. They provided data on the innovation–implementation approach applied in their case. Measures for different stakeholders' perceptions of innovation effectiveness were gathered. Three colleagues of the incumbents provided performance appraisals, reflecting internal customers' criteria for innovation effectiveness, each incumbent completed a questionnaire about burnout as a reversed proxy of innovation effectiveness, and semi‐structured observations of incumbents' activities provided an index of the fit between their role behaviors and role requirements, reflecting external customers' criteria for effectiveness. While performance appraisals were found to gain most from implementation through bureaucratic job structuring, the fit between incumbents' role behaviors and role requirements benefited most from implementation through person–job integration. Decreased burnout required maximizing the two implementation processes. These findings point to possible trade‐offs between the different criteria for innovation effectiveness, and call for combining features from the two implementation processes to produce a superior implementation approach. Copyright © 2004 John Wiley & Sons, Ltd.
A time for everything: how the timing of novel contributions influences project team outcomes
Authors: Ford Cameron , Sullivan Diane M. 
Published: February 2004

AbstractOne of the primary reasons organizations utilize project teams is to encourage members with diverse intellectual resources to produce novel associations that give rise to creative solutions. When creative sparks fly, learning, innovation and superior performance are often the result. However, in this paper we argue that creative sparks often create heat of another sort—frustration resulting from unfocused effort and diminished productivity. Utilizing Gersick's (1988) punctuated equilibrium model of project team development as a theoretical foundation, we argue that the meaning and impact of novel contributions change during a project team's life cycle. Novel contributions are beneficial to a project team early in its development when its primary goals are to learn more about a problem, search for useful information, and articulate tentative solutions. After the midpoint transition, when a team's attention shifts toward executing the proposal and satisfying external stakeholders before a looming deadline, additional attempts to introduce novel ideas are likely to disrupt performance and induce frustration. We develop a model and accompanying research propositions suggesting that the relationship between novel proposals and the value attributed to those proposals is contingent on timing with respect to a project team's midpoint transition. Copyright © 2004 John Wiley & Sons, Ltd.
Potential contribution of maximum subsurface temperature anomalies to the climate variability
Authors: Qian Weihong , Zhu Yafen , Liang Jianyin 
Published: February 2004

AbstractOn the interannual time scale, sea‐surface temperature anomalies (SSTAs) that are concerned with climate variability at global and regional scales have been widely investigated in previous studies. Through the analysis of the monthly 46‐year (1955–2000) expendable bathythermograph data, we show that subsurface temperature anomalies (STAs) can directly affect the SSTAs in the major air–sea interaction regions. Along the equatorial Pacific, four important features for STAs have been characterized. (1) The STAs and SSTAs are well correlated in the eastern equatorial Pacific (EEP) due to the fact that the thermocline anomalies have only to be mixed with the surface over a very short distance. (2) The STAs are always stronger than SSTAs at any location. (3) In the time between El Niño and La Niña, and vice versa, the STAs propagate eastward along the thermocline without mixing with SSTAs in the central Pacific. (4) An El Niño or La Niña can develop only when the maximum positive or the maximum negative STA propagates to the EEP. Inside and outside the tropical basins the STA was more centred on the thermocline than the 20°C isotherm. These features inform us that the maximum STAs (MSTAs) from each vertical STA profile can be used to indicate the anomalous wave‐propagation signal or thermocline variations in the worldwide oceans. This analysis implies that the MSTA is also a potential factor controlling climate variability and is a better indicator than SSTA, because MSTAs memorize the change in air–sea interaction signals and represent a huge deposit of energy in the upper ocean. The correlations between SSTAs and MSTAs with a coefficient of more than 0.60 are predominantly located in the EEP, the northern North Pacific, the southern subtropical Indian Ocean, and the northern North Atlantic Ocean. These correlations are discussed from case and statistical analyses.The leading pattern of SSTAs and MSTAs in the tropical Pacific, Atlantic and Indian Oceans are decomposed using empirical orthogonal functions (EOFs) and their EOF patterns might be able to explain the difference between MSTAs and SSTAs. Their periods of mode series are performed from a global wavelet spectral analysis. Copyright © 2004 Royal Meteorological Society
Sequential dynamics of inflammatory cytokine, angiogenesis inducing factor and matrix degrading enzymes during spontaneous resorption of the Herniated disc
Authors: Kato Tsuyoshi , Haro Hirotaka , Komori Hiromichi , Shinomiya Kenichi 
Published: February 2004

AbstractIntervertebral disc herniation (HD) is one of the most common orthopaedic conditions. MRI analysis of HD has revealed a spontaneous resorption mechanism related with neo‐vascularization. It appears that the interaction of activated macrophages with disc tissues leads to the generation of inflammatory cytokines. Moreover, inflammatory cytokines such as tumor necrosis factor‐α (TNF‐α) is required for the induction of angiogenesis inducing factors such as vascular endothelial growth factor (VEGF) or matrix degrading enzymes such as MMP‐3, MMP‐7 and plasmin. We hypothesized that these molecules play a crucial role during spontaneous HD resorption. In this study, we have examined the sequential expression of these molecules using a co‐culture system which is composed of the interaction of activated macrophages and disc tissues as a model of the acute response of inflammation occurred in HD. We have also considered the mechanism of activating latent MMPs during HD resorption process. Current our results indicate that upregulation of both TNF‐α mRNA and protein expressions occur first in the inflammation induced by HD. VEGF upregulation follows the increased level of TNF‐α expression. Both plasmin and MMP‐3 are upregulated at later time points. We also demonstrate that both TNF‐α and VEGF induce upregulated expression of urokinase‐type plasminogen activator (u‐PA). Our previous work has demonstrated that TNF‐α could upregulate the expression of VEGF, MMP‐3 and MMP‐7 in the co‐culture system. It has been reported that plasmin could affect to activate latent MMPs. Based on these findings, we suggest that TNF‐α acts as the initiator of inflammation following contact between macrophages and disc chondrocytes and that plasmin and u‐PA play a crucial role in activation of MMPs. We propose a spontaneous HD resorption cascade. Further understanding of the resorption process may provide future novel therapies for HD. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.