bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prognostic Use of Circulating Plasma Nucleic Acid Concentrations in Patients with Acute Stroke
Authors: Rainer Timothy H , Wong Lawrence K S , Lam Wynnie , Yuen Eddie , Lam Nicole Y L , Metreweli Constantine , Lo Y M Dennis 
Published: February 2004

Abstract
Background: At present there is no simple, accurate blood test that may be used to determine the severity of stroke or to predict mortality and morbidity in stroke patients presenting to emergency departments.
Methods: Patients with stroke-like symptoms who presented to an emergency department of a university hospital in Hong Kong were recruited for the study. DNA extracted from patients’ plasma was analyzed for the β-globin gene with a fluorescent-based PCR test. The primary outcome measures were in-hospital and 6-month mortality and morbidity using the post-stroke modified Rankin Score.
Results: Among the 88 consecutive patients recruited to the study, 70 (80%) had ischemic stroke, 11 (13%) had intracerebral hemorrhage, and 7 (8%) had transient ischemic attacks. Median plasma DNA concentrations taken within 3 h of symptom onset were higher in patients who died compared with those who survived at discharge (6205 vs 1334 kilogenome-equivalents/L; P = 0.03). Among patients with NIH Stroke Scale scores &gt;8, median plasma DNA concentrations were higher in patients who died compared with those who survived to 6 months (2273 vs 968 kilogenome-equivalents/L; P = 0.002). Plasma DNA concentrations correlated with the volume of cerebral hematoma (r = 0.66; P = 0.03). Plasma DNA concentrations &gt;1400 kilogenome-equivalents/L had a sensitivity of 100% and a specificity of 74.4% for predicting hospital mortality after stroke, and the area under the ROC curve was 0.89 (95% confidence interval, 0.80–0.94). The adjusted odds ratio for plasma DNA concentrations predicting 6-month mortality was 1.6 (1.1–2.4; P = 0.03) and for predicting 6-month post-Rankin Score &gt;2 was 1.8 (1.0–3.3; P = 0.05).
Conclusion: Plasma DNA concentrations correlate with stroke severity and may be used to predict mortality and morbidity in the emergency room.
The D-Dimer Test for Deep Venous Thrombosis: Gold Standards and Bias in Negative Predictive Value
Authors: Philbrick John T , Heim Steven 
Published: February 2004

Abstract
Background: Because venous ultrasound (US) fails to fully image the calf veins, there is the potential for US gold standard studies to classify patients with calf deep venous thrombosis (DVT) in the nondiseased category, causing bias in test index calculations. A false increase in negative predictive value (NPV) is especially likely because calf DVT false-negative tests will be counted in the numerator along with the true-negative tests in NPV calculations. We verified the presence and magnitude of this bias for the d-dimer test.
Methods: We abstracted data on overall (calf and thigh) and thigh-only test sensitivity, specificity, and NPV from the six English language studies published between March 1995 and October 2001 that compared d-dimer to a gold standard (GS) capable of imaging both thigh and calf veins and that also stratified results by thigh and calf location. Thigh specificity and NPV were calculated classifying calf DVT patients as free of disease.
Results: The six studies included 81–214 participants and provided 26 comparisons of 16 different d-dimer assays to the GS. Thigh sensitivity was higher than overall sensitivity in 22 of 26 comparisons (range, −0.3 to 8.6); thigh specificity was lower than overall specificity in all comparisons (range, −0.7 to −7.8); and thigh NPV was higher than overall NPV in 22 of 26 comparisons and unchanged in 4 comparisons (range, 0.0–9.2). NPV was &gt;95% in 20 of the thigh results but &gt;95% in only 8 of the overall results.
Conclusions: Different GS can produce clinically significant differences in test indices. Care must be taken in interpreting DVT studies that evaluate d-dimer as a rule-out test and that use US as a GS, because missed calf DVT can falsely increase the NPV.
Cleaved Protein S (PS), Total PS, Free PS, and Activated Protein C Cofactor Activity as Risk Factors for Venous Thromboembolism
Authors: Borgel Delphine , Reny Jean-Luc , Fischelis David , Gandrille Sophie , Emmerich Joseph , Fiessinger Jean-Noël , Aiach Martine 
Published: February 2004

AbstractBackground: Although hereditary protein S (PS) deficiency is clearly associated with venous thromboembolism (VTE), the importance of low PS concentrations as a risk factor for VTE in other patients is still a matter of debate. To clarify this issue, we designed a case-control study to evaluate the role of different molecular forms of plasma PS.Methods: We quantified plasma cleaved, total, and free PS and activated protein C (APC) cofactor activity in 87 VTE patients and 174 controls matched for age, sex, and hormonal treatment. Free PS was measured by ELISA or by enzyme-linked ligand sorbent assay (ELSA). Cleaved and total PS were measured by ELISA.Results: In controls, the mean (SD) concentration of circulating cleaved PS was 39 (14) nmol/L, corresponding to 10% (3.5%) of total PS. Concentrations of cleaved PS and total PS were not significantly different in patients with VTE compared with controls. However, in our population, low free PS measured by ELISA or ELSA, as well as APC cofactor activity values were significantly associated with VTE with odds ratios (95% confidence intervals) of 2.9 (1.3–6.3), 2.5 (1.1–5.6), and 2.9 (1.3–6.4), respectively, in multivariate analyses.Conclusion: Phenotypic low PS detected by APC cofactor activity assay or by an assay specific for free PS should be considered a risk factor for VTE.
Evaluation of Human Serum Albumin Cobalt Binding Assay for the Assessment of Myocardial Ischemia and Myocardial Infarction
Authors: Bhagavan Nadhipuram V , Lai Ernest M , Rios Patricia A , Yang Jinsheng , Ortega-Lopez Anna M , Shinoda Hiroko , Honda Stacey A A , Rios Carlos N , Sugiyama Cheryl E , Ha Chung-Eun 
Published: February 2004

AbstractBackground: Clinical diagnoses were correlated with results of a Co(II)–albumin binding assay in 167 patients treated at an emergency department of a health maintenance organization.Methods: Patients were evaluated as being nonischemic or potentially ischemic through standard coronary disease indicators [creatine kinase (CK), CK-MB, cardiac troponin I, and electrocardiographic findings] and were tested by a Co(II)–albumin binding assay. Samples were tested anonymously, and the study was double-blinded. The sensitivity and specificity of this assay for the detection of ischemia were evaluated by ROC curve analysis. Known Co(II) binding sites on albumin were analyzed by N-terminal amino acid sequencing.Results: The mean absorbance units (ABSU) ± 2 SD for non-myocardial ischemic and myocardial ischemic individuals measured at 470 nm were 0.43 ± 0.10 and 0.63 ± 0.25, respectively (P &lt;0.0001). The area under the ROC curve was 0.95 [95% confidence interval (CI), 0.92–0.99], and at a cutoff value of 0.50 ABSU, sensitivity and specificity were 88% (78–94%) and 94% (86–98%), respectively, suggesting a high distinction between the two groups. When we compared non-acute myocardial infarction (AMI) and AMI ischemic individuals, the area under the ROC curve was 0.66 (95% CI, 0.53–0.79) and was considered a poor discriminator between these two groups. N-Terminal amino acid sequencing data for purified albumin showed normal amino acid residues for six of seven high-ABSU (≥0.70) individuals and one nonischemic individual tested. However, only one individual with a high ABSU (0.80) had two missing amino acid residues (DA) from the N-terminal region. Clinical diagnosis for this patient did not reveal an ischemic event.Conclusions: The Co(II)–albumin binding test may serve as a useful diagnostic tool in emergency facilities for the assessment of myocardial ischemia. High and low ABSU were associated with myocardial ischemic individuals and non-myocardial ischemic individuals, respectively. However, the Co(II)–albumin binding was a poor discriminator between ischemic individuals with and without MI.
Catecholamine-Synthesizing Enzymes in Carcinoid Tumors and Pheochromocytomas
Authors: Meijer Wim G , Copray Sjef C V M , Hollema Harry , Kema Ido P , Zwart Nynke , Mantingh-Otter Ietje , Links Thera P , Willemse Pax H B , de Vries Elisabeth G E 
Published: February 2004

Abstract
Background: Serotonin is the principal endocrine product of carcinoid tumors, but simultaneously increased production of catecholamines has been described in these tumors. As it is not clear whether these tumors contain specific enzymes for catecholamine synthesis, we aimed to detect catecholamine-synthesizing enzymes [tyrosine hydroxylase (TH), dopamine-β-hydroxylase (DBH), and phenylethanolamine-N-methyltransferase (PNMT)] in midgut carcinoid tumors and pheochromocytoma and to correlate enzyme expression to serotonin production as well as catecholamines and metabolites excreted in urine.
Methods: Paraffin-embedded tumor specimens from 21 midgut carcinoid patients and 20 pheochromocytoma patients (10 sporadic and 10 MEN type IIa-related tumors) were stained for TH, DBH, and PNMT, using a three-step biotin-avidin-peroxidase method.
Results: TH was demonstrated in 9 (43%) of 21 carcinoids and in all (100%) of 20 pheochromocytomas, DBH in 8 (38%) carcinoids and in 15 (75%) pheochromocytomas, and PNMT in 7 (33%) carcinoids and in 13 (65%) pheochromocytomas. Increased urinary excretion of catecholamines and metabolites was observed in 10 (48%) carcinoid patients and in all pheochromocytoma patients. No clinically relevant association between enzyme expression and urinary excretion of catecholamines and metabolites was found.
Conclusions: Catecholamine-synthesizing enzymes are present in many carcinoid tumors. This finding possibly indicates the existence of a catecholamine-synthesizing pathway in carcinoids similar to that found in pheochromocytoma.
New ELISA System for Myeloid-related Protein Complex (MRP8/14) and Its Clinical Significance as a Sensitive Marker for Inflammatory Responses Associated with Transplant Rejection
Authors: Ikemoto Masaki , Tanaka Tomoko , Takai Yuri , Murayama Hiroshi , Tanaka Koichi , Fujita Masatoshi 
Published: February 2004

AbstractBackground: C-reactive protein (CRP), a useful marker for inflammatory diseases, is not always sensitive to inflammatory reaction in the liver or other tissues. The aim of this study was to develop a sensitive and specific method for detecting inflammatory responses associated with transplant rejection.Methods: We developed a new, highly sensitive ELISA system for the measurement of serum human myeloid-related protein complex (MRP8/14), using monoclonal antibodies against MRP8/14, and applied it to specimens obtained from patients undergoing small intestine or liver transplantation.Results: This assay could detect MRP8/14 concentrations as low as 2 μg/L. Within-run CVs were 3.7–6.1% and between-day CVs were 5.6–8.7% for MRP8/14 concentrations of 117-3300 μg/L. Mean recovery was 104% (range, 80–128%). We observed a marked increase in serum MRP8/14 postoperatively in most recipients of transplants, followed by an increase in CRP 1–7 days after the increase in the complex. The increase in serum MRP8/14 occurred simultaneously with permeation of lymphocytes into the transplanted tissues as a result of rejection of the graft tissues.Conclusions: Accurate measurement of serum MRP8/14 provides a useful clinical diagnostic method tool for detecting inflammation associated with rejection of transplanted tissues.
Standardization of Two Immunoassays for Human Glandular Kallikrein 2
Authors: Haese Alexander , Vaisanen Ville , Finlay Judith A , Pettersson Kim , Rittenhouse Harry G , Partin Alan W , Bruzek Debra J , Sokoll Lori J , Lilja Hans , Chan Daniel W 
Published: February 2004

AbstractBackground: Measurement of human kallikrein 2 (hK2) has improved early detection and staging of prostate cancer. However, reported concentrations of hK2 among currently used assays have not been standardized in any way. We compared two hK2 assays and five different recombinant hK2 variants (rhK2) and suggest a common calibrator as an important step and putative reference substance in hK2 assay standardization.Methods: We measured 146 sera by two hK2 assays, using assay-specific calibrators to assess the difference between the two assays. Serial dilutions of five rhK2 preparations were measured repeatedly, with one preparation assigned as calibrator and the others as unknowns to define which variant provided the closest match between the two assays. This rhK2 variant was used to recalibrate both assays. We measured hK2 concentrations in the same 146 patients to evaluate the change in the difference.Results: Use of assay-specific calibrators for comparison of the two assays yielded a Deming regression equation of: y = 0.789 (95% confidence interval, 0.674–0.922)x + 0.014 (0.004–0.025) μg/L; R2 = 0.667. Analysis of five rhK2 variants revealed that the enterokinase (ek)-rhK2 form provided the best match between both assays. Using the ek-rhK2 as a common calibrator, we observed a change in the slope of the regression curve to: y = 1.106 (0.872–1.340)x + 0.006 (−0.002 to 0.016) μg/L; R2 = 0.648, suggesting an increase in the mean estimate of agreement between the two assays.Conclusion: Calibration with a common calibrator substantially increased agreement between the assays. The ek-rhK2 variant provided the best performance of all tested rhK2 variants and should undergo mass spectrometry and amino acid analysis for exact mass determination and value assignment to evaluate its potential as a reference material for immunoassays for hK2.
Quantitative Urine Particle Analysis: Integrative Approach for the Optimal Combination of Automation with UF-100 and Microscopic Review with KOVA Cell Chamber
Authors: Ottiger Cornelia , Huber Andreas R 
Published: February 2004

AbstractBackground: Automated systems have enabled the counting of particles in urine to be standardized. Their superiority over traditional sediment analysis has been well documented, but they have not gained wide acceptance. The reasons for this are that sediment analysis has been performed and interpreted for decades. Additionally, pathologic casts and other unknown particles still must be confirmed under the microscope. Furthermore, comparison between the methods has revealed outliers and thus decreased confidence in automation.Methods: We used the standardized KOVA cell chamber system to count particles and compared the results with UF-100 flow cytometry as an alternative to traditional sediment analysis.Results: We compared 252 randomly selected urine samples and obtained a review rate of 33%. Microscopic verification was necessary because of the presence of casts, yeast, sperm, dysmorphic erythrocytes, and some misclassified erythrocytes or leukocytes that were detected by incongruent dipstick results and abnormal scattergrams. We obtained correlation coefficients of 0.966 for erythrocytes and 0.935 for leukocytes. Criteria for an algorithm to identify samples that needed microscopic review were derived from comparisons between the number of particles from UF-100, dipstick results, cell chamber counting, and sediment analysis.Conclusions: Automated cell counting combined with microscopic counting with a standardized cell chamber system is useful. An objective algorithm for review criteria can be developed via systematic comparison of UF-100 flow cytometry and microscopy. Only urine samples that meet these criteria need to be confirmed microscopically.
Identification of Rat Targets of Anti-Soluble Liver Antigen Autoantibodies by Serologic Proteome Analysis
Authors: Ballot Eric , Bruneel Arnaud , Labas Valérie , Johanet Catherine 
Published: February 2004

AbstractBackground: Anti-soluble liver antigen (SLA) autoantibodies are specific for autoimmune hepatitis type 1 and are the only immunologic marker found in 15–20% of hepatitis cases previously considered cryptogenic. Anti-SLA antibodies react with the 100 000g supernatant from rat liver homogenate, but the molecular targets remain controversial.Methods: We characterized anti-SLA targets by one- and two-dimensional immunoblotting analysis. The recognized proteins were identified by peptide mass fingerprint analysis after matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry.Results: Three proteins of 35 kDa and pI 6.0, 50 kDa and pI between 6.0 and 6.5, and 58 kDa and pI between 6.5 and 7.0 were stained more intensely by anti-SLA positive-sera than by control sera. After in-gel tryptic digestion, MALDI-TOF analysis of the generated peptides enabled the clear identification of N-hydroxyarylamine sulfotransferase, isoforms of α-enolase, and isoforms of catalase.Conclusions: Possible antigens for anti-SLA antibodies include a sulfotransferase, α-enolase(s), and catalase(s). Two-dimensional electrophoresis combined with mass spectrometry offers a versatile tool to identify molecular targets of autoantibodies and thus to improve diagnostic tools and the understanding of the immune process.
Distribution of Fasting Plasma Insulin, Free Fatty Acids, and Glucose Concentrations and of Homeostasis Model Assessment of Insulin Resistance in a Representative Sample of Quebec Children and Adolescents
Authors: Allard Pierre , Delvin Edgard E , Paradis Gilles , Hanley James A , O’Loughlin Jennifer , Lavallée Claudette , Levy Emile , Lambert Marie 
Published: February 2004

AbstractBackground: Plasma fasting insulin and the homeostasis model assessment of insulin resistance (HOMA-IR) are markers of IR, which, at least in part, mediates the relation of obesity to increased cardiovascular risk. Increased free fatty acids (FFAs) may be involved in the pathogenesis of IR. Our objectives were to describe the distributions of fasting plasma insulin, glucose, and FFAs and HOMA-IR in youth and to assess the relationship between FFAs and markers of IR.Methods: Fasting plasma insulin, glucose, and FFAs were measured in a representative sample of Quebec youth comprising 2244 individuals 9, 13, and 16 years of age.Results: In all age and sex groups, glucose exhibited remarkably tight distributions (median CV, 7.1%) in contrast to insulin, HOMA-IR, and FFAs (median CVs, 52%, 54% and 45%, respectively). For every percentile examined, 9-year-olds had lower insulin concentrations and HOMA-IR values than 13- and 16-year-olds. We observed strong correlations between insulin concentrations and HOMA-IR values, as well as close similarity in their rankings of individuals. The mean concentrations of glucose were higher in our population than in other Caucasian pediatric populations. No positive correlations were detected between FFAs and markers of IR.Conclusions: We report some of the first data on the distributions of fasting plasma insulin, HOMA-IR, and FFAs from a representative sample of youth. HOMA-IR does not appear more informative than fasting insulin as a marker of IR. Our findings on higher mean glucose concentrations in this population require confirmation in other representative samples of youth to assess whether the North American distribution of glucose concentrations is shifting positively.
False-Positive Acetaminophen Results in a Hyperbilirubinemic Patient
Authors: Bertholf Roger L , Johannsen Laura M , Bazooband Alireza , Mansouri Vafa 
Published: February 2004

Abstract
Background: Acetaminophen was falsely detected in the plasma of a severely jaundiced patient, and a methodologic interference from bilirubin was suspected.
Methods: Acetaminophen was measured by an enzymatic method (GDS Diagnostics). The putative bilirubin interference was investigated in 12 hyperbilirubinemic specimens and in bilirubin linearity calibrators. The analytical method was modified to correct for background absorbance at a second wavelength. Hyperbilirubinemic specimens were fortified with acetaminophen to assess the effect of the interference on acetaminophen measurements.
Results: Acetaminophen was detected in 12 specimens from hyperbilirubinemic patients without a history of recent acetaminophen exposure. Dilution of hyperbilirubinemic specimens produced a nonproportional decrease in apparent acetaminophen concentrations, and no acetaminophen was detected when bilirubin was &lt;50 mg/L. Background correction at a second wavelength failed to compensate for the interference. Although erroneous acetaminophen concentrations were detected in all specimens with high bilirubin, acetaminophen measurements in fortified specimens were accurate.
Conclusion: The data are consistent with bilirubin interference in the enzymatic and/or chromogenic reactions involved in the acetaminophen method.
Quantitative Analysis of Circulating Mitochondrial DNA in Plasma
Authors: Chiu Rossa W K , Chan Lisa Y S , Lam Nicole Y L , Tsui Nancy B Y , Ng Enders K O , Rainer Timothy H , Lo Y M Dennis 
Published: February 2004

AbstractBackground: Recent studies have demonstrated the existence of circulating mitochondrial DNA in plasma and serum, but the concentrations and physical characteristics of circulating mitochondrial DNA are unknown. The aim of this study was to develop an assay to quantify mitochondrial DNA in the plasma of healthy individuals.Methods: We adopted a real-time quantitative PCR approach and evaluated the specificity of the assay for detecting mitochondrial DNA with a cell line (ρ0) devoid of mitochondria. The concentrations and physical characteristics of circulating mitochondrial DNA were investigated by experiments conducted in three modules. In module 1, we evaluated the concentrations of mitochondrial DNA in plasma aliquots derived from four blood-processing protocols. In module 2, we investigated the existence of both particle-associated and free forms of mitochondrial DNA in plasma by subjecting plasma to filtration and ultracentrifugation. In module 3, we used filters with different pore sizes to investigate the size characteristics of the particle-associated fraction of circulating mitochondrial DNA.Results: The mitochondrial DNA-specific, real-time quantitative PCR had a dynamic range of five orders of magnitude and a sensitivity that enabled detection of one copy of mitochondrial DNA in plasma. In module 1, we found significant differences in the amounts of circulating mitochondrial DNA among plasma aliquots processed by different methods. Data from module 2 revealed that a significant fraction of mitochondrial DNA in plasma was filterable or pelletable by ultracentrifugation. Module 3 demonstrated that filters with different pore sizes removed mitochondrial DNA from plasma to different degrees.Conclusions: Both particle-associated and free mitochondrial DNA are present in plasma, and their respective concentrations are affected by the process used to harvest plasma from whole blood. These results may have implications in the design of future studies on circulating mitochondrial DNA measured in different disease conditions.