The Helicobacter pylori breath test: a surrogate marker for peptic ulcer disease in dyspeptic patients.
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Biomarkers↗
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Results for “Biomarker testing”
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Can a state-of-the-art D-dimer test be used to determine the need for CT imaging in patients suspected of having pulmonary embolism?
RATIONALE AND OBJECTIVES: The purpose of this study was to determine whether a simple rapid blood test can obviate computed tomography (CT) in a sizable percentage of patients suspected of having pulmonary embolism, based on the hypothesis that negative D-dimer results could eliminate any further search for pulmonary embolism. MATERIALS AND METHODS: At the authors' institution, 2,121 sequential patients underwent a whole-blood antibody agglutination test for cross-linked fibrin degradation products (D-dimer). Of these patients, 844 had positive test results and were not further considered. A retrospective review included reports of all multisection combined CT venographic and pulmonary angiographic studies obtained within 48 hours of the D-dimer assay for the 1,277 patients with negative D-dimer results; 229 (18%) of these 1,277 patients underwent combined CT venography and pulmonary angiography, usually within 24 hours. RESULTS: Retrospective review of the imaging examinations that were discrepant with the D-dimer results revealed only three false-negative D-dimer results. Of the 229 patients in whom combined CT venography and pulmonary angiography was performed for suspected pulmonary embolism, 226 (98.7%) had no evidence of acute pulmonary embolism or deep venous thrombosis. The negative predictive value of a negative D-dimer result was therefore 98.7% (confidence interval, 96.2%-99.7%). CONCLUSION: The D-dimer assay is a simple rapid blood test that is sensitive to the presence of acute thrombosis. Very few patients with negative results have acute deep venous thrombosis or pulmonary embolism, with combined CT venography and pulmonary angiography used as the reference standard.
Acute Disease↗
Tuberculous peritonitis: a non-invasive test.
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Adenosine Deaminase↗
Diagnostic tests for meningitis--a dilemma.
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Biomarkers↗
[Complex assessment of nicotine dependence using questionnaires and measurement of carbon oxide concentration in exhaled air].
AIM: To study nicotine dependence (ND) basing on special questionnaires and measurement of CO concentrations in the exhaled air. MATERIAL AND METHODS: 350 smokers (318 males and 32 females) aged 20-57 years (mean age 37.1 +/- 7.3 years) were studied. ND was assessed by Fagerstrom test (FT), motivation to smoke and to quit tests, smoking history and exhaled CO measurement. In addition, respiratory complaints and ventilation parameters such as peak expiratory flow (PEF) and forced expiratory volume per 1 sec (FEV1) were measured. RESULTS: Mean daily cigarette number was 14.2 +/- 7.3; smoking duration 16.3 +/- 7.8 years and smokers index 170.9 +/- 87.8. Smoking women differed from smoking men in ND, PEF% and FEV1% decline as well as CO level. Exhaled CO was 21.1 +/- 9.5 ppm, on the average, corresponding to moderate dependence. ND and daily cigarette number produced a direct impact on the exhaled CO level. FT findings directly correlated with the number of daily cigarettes and CO level (mean 3.2 +/- 2.3). Among motivation to smoke factors was the demand to release tension. CONCLUSION: ND varies considerably among smokers by severity. Smoking men and women differ considerably by ND. Along with dependence tests, exhaled CO measurement provides objective verification of ND.
Adult↗
Prenatal organophosphate ester exposure and epigenetic changes at birth: a characterization of the methylome in the ECHO cohort.
BACKGROUND: Prenatal exposure to organophosphate esters (OPEs) affects multiple child health domains. Alterations to the DNA methylome are a plausible mechanism through which these changes occur. This study characterized DNA methylation signatures at birth associated with prenatal OPE biomarkers. METHODS: We included 736 mother-infant pairs from 7 sites in the Environmental influences on Child Health Outcomes (ECHO) Cohort. Five OPE biomarkers were quantified in maternal urine samples collected during the second and third trimesters and modeled as log2-transformed continuous variables. Using covariate-adjusted linear regression, we tested associations between OPE biomarkers and locus-specific, regional, and global cord blood DNA methylation changes measured by Illumina 450 K and EPIC arrays, and gestational epigenetic age measured by the Knight gestational age epigenetic clock generated with measures from the 27 K, 450 K, and EPIC arrays. When feasible, we examined relationships by sex. FINDINGS: Global hypomethylation at multiple regions was associated with BDCPP concentrations (p = 0.003 to 0.02, coef = -0.002). Differentially methylated regions annotated to PCDHGB1 and SLC43A2 were associated with BDCPP and DPHP concentrations, respectively (FDR q < 0.05). In sex-specific analyses, global hypomethylation was associated with prenatal BDCPP (p = 0.006 to 0.03, coef = -0.0003 to -0.0002) and DBUP_DIBP (p = 0.01, coef = -0.0007 to -0.0006) concentrations in females; and global hypermethylation was associated with DBUP_DIBP concentrations in males (p < 0.05, coef = 0.0004). BCETP concentrations were significantly associated with decelerated epigenetic aging at birth in females (p < 0.05, coef = -0.05). INTERPRETATION: Prenatal exposure to OPEs impacts child methylation at birth, suggesting a potential mechanism for the association between prenatal OPE exposure and child health outcomes.
Humans↗
Classification of osteoarthritis biomarkers: a proposed approach.
OBJECTIVE: Osteoarthritis (OA) biomarkers are needed by researchers and clinicians to assist in disease diagnosis and assessment of disease severity, risk of onset, and progression. As effective agents for OA are developed and tested in clinical studies, biomarkers that reliably mirror or predict the progression or amelioration of OA will also be needed. METHODS: The NIH-funded OA Biomarkers Network is a multidisciplinary group interested in the development and validation of OA biomarkers. This review summarizes our efforts to characterize and classify OA biomarkers. RESULTS: We propose the "BIPED" biomarker classification (which stands for Burden of Disease, Investigative, Prognostic, Efficacy of Intervention and Diagnostic), and offer suggestions on optimal study design and analytic methods for use in OA investigations. CONCLUSION: The BIPED classification provides specific biomarker definitions with the goal of improving our ability to develop and analyze OA biomarkers, and to communicate these advances within a common framework.
Arthrography↗
Potential diagnostic aids for abnormal fatty acid metabolism in a range of neurodevelopmental disorders.
Disorders of neurodevelopment include attention deficit hyperactivity disorder, dyspraxia, dyslexia and autism. There is considerable co-morbidity of these disorders and their identification often presents difficulties to those making a diagnosis. This is especially difficult when a multidisciplinary approach is not adopted. All of these disorders have been reported as associated with fatty acid abnormalities ranging from genetic abnormalities in the enzymes involved in phospholipid metabolism to symptoms reportedly improved following dietary supplementation with long chain fatty acids. If definitive disorders of lipid metabolism could be defined then the diagnosis and subsequent management of neurodevelopmental disorders might be transformed. In the identification of those disorders of development which involve lipid metabolism, there are now several tests, measures of lipid metabolism, which could be useful.
Apraxias↗
ROC methodology within a monitoring framework.
Receiver operating characteristic (ROC) methodology is widely used to evaluate and compare diagnostic tests. Generally, each diagnostic test is applied once to each subject in a population and the results, reported on a continuous scale, are used to construct the ROC curve. We extend the standard method to accommodate a framework in which the diagnostic test is repeated over time to monitor for occurrence of an event. Unlike the usual situation in which event status is static, the problem we address involves event status that is not constant over the monitoring period. Subjects generally are classified as non-events, or controls, until they experience events that convert them to cases. Viewing the data as incomplete discrete failure time data with time-varying covariates, potentially useful diagnostic markers can be related appropriately in time with the true condition and varying amounts of information per individual can be taken into account. The ROC curve provides an assessment of the performance of the test in combination with the schedule of testing. Within this framework, a computational simplification is introduced to calculate variances and covariances for the areas under the ROC curves. Periodic monitoring for reperfusion following thrombolytic treatment for acute myocardial infarction provides a detailed example, whereby the lengths of the testing interval combined with different diagnostic markers are compared.
Angioplasty, Balloon, Coronary↗
Identification of 9-O acetyl sialoglycoconjugates (9-OAcSGs) as biomarkers in childhood acute lymphoblastic leukemia using a lectin, AchatininH, as a probe.
Neoplastic transformation causes changes in cell surface architecture, most notably, aberrant sialylation. Exploiting the restricted specificity of a 9-O acetyl sialic acid (9-OAcSA) binding lectin, AchatininH (ATN(H)), we have identified two 9-O acetyl sialoglyconjugates (9-OAcSGs) on lymphoblasts of 87 children suffering from acute lymphoblastic leukemia (ALL). The preferential binding of ATN(H) to lymphoblasts induces their 11-fold increased agglutination (81 +/- 7.8%) compared to peripheral blood mononuclear cells (PBMC) of normal donors (8 +/- 4.3%) which corroborates with flow cytometry studies. Agglutination of MOLT-4 (87 +/- 4.8%), a lymphoblastoid cell line and MDCK (91.25 +/- 0.01%), a cell line expressing surface 9-OAcSA, confirms the preferential binding of ATN(H) to lymphoblasts through their surface 9-OAcSGs. Furthermore, fluorometric quantitation reveals a 4.6-fold increase in % of 9-OAcSA on lymphoblasts of ALL patients (42.1 +/- 4.1%) compared to normal donors (9.2 +/- 3.4%). Western blotting confirms that ATN(H) recognizes two membrane sialoglycoconjugates, of MW 120 kDa and 90 kDa, both having 9-OAcSA alpha2 --> 6 GalNAc terminal sugar moiety as their lectinogenic epitope. We propose that these 9-OAcSGs may serve as biomarkers for detection and monitoring of lymphoblasts in ALL and accordingly merit therapeutic considerations.
Agglutination Tests↗
Ammonia vapour in the mouth as a diagnostic marker for Helicobacter pylori infection: preliminary 'proof of principle' pharmacological investigations.
Most current non-invasive tests for Helicobacter pylori depend on the conversion of labelled (13C or 14C) urea to labelled carbon dioxide (13CO2 or 14CO2) and ammonium (NH4+) by the enzyme urease, with the labelled CO2 detected in exhaled air. Despite suggestions going back over a number of years, the alternative possibility of using NH4+ (in the form of gaseous ammonia [NH3]) as the test parameter has received little or no attention. However, this approach is now being explored using a chemiresistive sensor detecting sub-parts per million concentrations of NH3. An in vitro 'glass stomach' (containing various volumes of hydrochloric acid [HCl] and ammonium chloride [NH4Cl]) was used to evaluate the means of increasing 'gastric' pH to that of the NH4+-->NH3 transition that occurs significantly at pH 9.24. This 'stomach' also was used to study mechanisms by which NH3 may be expelled in a pulse (as a surrogate belch), either by the in situ production of CO2 or through an exogenous source. On the basis of the protocols developed, H. pylori-negative subjects were tested before and after ingestion of 10 mg NH4Cl (as a surrogate for bacteria-produced NH4,), and H. pylori-positive subjects were tested without taking urea or NH4Cl. 'Intragastric' pH in the in vitro 'glass stomach' could be increased above pH 9.24 by adding a mixture of 15-30 mL magnesium hydroxide mixture (or the proprietary equivalent) and 50 mL water, and the resulting NH3 expelled by adding 100 mL CO2-saturated cold water (sparkling water). In vivo, NH3 levels in the oral cavity of H. pylori-negative subjects were increased after ingestion of 10 mg NH4Cl; however, levels in the oral cavity of a small number of H. pylori-positive subjects were two- to threefold higher after magnesium hydroxide and sparkling water. On the basis of in vitro studies, an in vivo protocol was developed to increase gastric pH above that required for the NH4+-->NH3 transition, and a mechanism established to release the NH3 into the oral cavity. Preliminary in vivo data confirm the chemiresistive sensor is sufficiently sensitive to NH3 to distinguish H. pylori-negative subjects who have taken 10 mg NH4Cl from those who have not, and clearly distinguish H. pylori-negative subjects from H. pylori-positive subjects. Ingestion of urea or other labelled tracers is not required, nor is belching; and the sensor takes less than two minutes to reach a maximum response. The data provide good evidence that the chemiresistive detection of NH3 has considerable potential as a rapid, point-of-care diagnostic test for H. pylori infection.
Ammonia↗
Reliability and validity of diagnostic tests.
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Biomarkers↗
Identification, validation, and clinical implementation of tumor-associated biomarkers to improve therapy concepts, survival, and quality of life of cancer patients: tasks of the Receptor and Biomarker Group of the European Organization for Research and Treatment of Cancer.
Guiding principles are provided and discussed on how to inform the physician scientist and cancer researcher about quality control systems to enable a consistent assessment of the clinical value of tumor-associated biomarkers. Next to cancer research itself, the Receptor and Biomarker Group of the European Organization for Research and Treatment of Cancer (RBG-EORTC) advises on methodologies, test kits and test reagents utilized for tumor biomarker determination. Tumor-associated biomarkers are important and clinically useful tools which can aid the early diagnosis of cancer, determine prognosis, predict therapy response, and monitor disease. With regard to clinical use of tumor-associated bio-markers, quality assessment and quality assurance programs of the RBG-EORTC are crucially important issues. Test reagents, assays, and procedures for tumor sample collection and handling should be standardized. Furthermore, standard operating procedures (SOPs) should be developed for each type of tumor specimen. Assay formats and the quality of the tumor biomarker assay results have to be monitored by continuous within- and inter-laboratory proficiency testing. With this approach, a major step forward in the knowledge and understanding of the biological role and the clinical utility of tumor-associated biomarkers would be anticipated.
Biomarkers, Tumor↗
Increased breath markers of oxidative stress in normal pregnancy and in preeclampsia.
OBJECTIVES: The purpose of this study was to compare the intensity of oxidative stress in normal pregnancy, preeclampsia, and nonpregnant women using a breath test. STUDY DESIGN: We studied primiparous women in third trimester pregnancy (38 uncomplicated, 26 with preeclampsia) and 60 nonpregnant control subjects. Volatile organic compounds (VOCs) in alveolar breath were analyzed by gas chromatography/mass spectroscopy to construct the breath methylated alkane contour (BMAC), a 3-dimensional display of abundance of C4-C20 alkanes and monomethylated alkanes. RESULTS: The mean volume under curve (VUC) of the BMAC was significantly higher in preeclampsia patients than in normal pregnant women (P < .003) and nonpregnant control subjects (P < .005). A predictive model employing 5 VOCs distinguished preeclampsia from uncomplicated pregnancy (sensitivity = 92.3%, specificity = 89.7%; cross-validated sensitivity = 88.5%, specificity = 79.3%). CONCLUSION: A breath test significantly demonstrated greater oxidative stress in women with preeclampsia than in uncomplicated pregnancy and nonpregnant control subjects. The breath test accurately identified women with established preeclampsia, but further studies are required to determine if this test can predict the onset of disease.
Adult↗
[Diagnostics of occupational asthma: measurements of exhaled nitric oxide].
Nitric oxide (NO) is an endogenous, soluble gas whose highly reactive molecules are involved in many biological and pathophysiological organic processes. It is generated from arginine through the action of the enzyme nitric oxide synthase (NOS). Over the recent years, accurate and non-invasive diagnostic methods have been searched for illustrating the allergic airway inflammation. Lately, great hopes have been associated with the use of measurements of exhaled nitric oxide (FENO) in the estimation of bronchial inflammation in asthmatic subjects. This method is non-invasive and can be frequently repeated. Furthermore, positive correlation between FENO and blood eosinophilia and induced sputum in atopic children and asthmatic adults has been observed. A significant increase in FENO after specific challenge test has also been shown. Therefore, determination of this parameter can be an additional source of information useful in the interpretation of occupational challenge tests in cases with boderline functional changes.
Adult↗
Clonal evolution and progression of 20-methylcholanthrene-induced squamous cell carcinoma of mouse epidermis as revealed by DNA instability and other malignancy markers.
We examined the clonal evolution of skin malignant lesions by repeated topical applications of 20-methylcholanthrene (20-MC) to the skin, which induces hyperplastic epidermis, papillomatous lesion and invasive carcinoma in mice. The lesions were examined histologically and immunohistochemically with anti-single-stranded DNA after acid hydrolysis (DNA-instability test), p53, VEGF, DFF45, PCNA and AgNORs parameters analyses. Multiple clones with increased DNA instability comparable to that of invasive carcinoma were noted in early-stage (2-6 weeks) hyperplastic epidermis, and their number increased in middle (7-11 weeks), and late-stages (12-25 weeks) of hyperplastic epidermis, indicating that they belong to the malignancy category. All papillomatous lesions and invasive carcinomas showed a positive DNA-instability test. Positive immunostaining for various biomarkers and AgNORs parameters appeared in clones with a positive DNA-instability test in early-or middle-stage hyperplastic epidermis, and markedly increased in late-stage hyperplastic epidermis, papillomatous lesions and invasive carcinomas. The percentage of PCNA-positive vascular endothelial cells was significantly higher in VEGF-positive lesions with a positive DNA-instability test and became higher toward the late-stage of progression. Cut-woundings were made to papillomatous and invasive carcinoma lesions, and the regeneration activity of vascular endothelial cells was determined by using flash labeling with tritiated thymidine (3H-TdR). In small papillomatous lesions, vascular endothelial cells showed regenerative response, but the response was weak in large lesions. No such response was noted in invasive carcinomas; rather, cut-wounding induced collapse of blood vessels, which in turn induced massive coagulative necrosis of cancer cells. These responses can be interpreted to reflect exhausted vascular growth activity due to excessive stimulation by VEGF-overexpression, which was persistently seen from hyperplastic epidermis to invasive carcinoma.
Animals↗
Panel endorses limited role for CRP tests.
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Biomarkers↗
Design and testing of a disposable microfluidic chemiluminescent immunoassay for disease biomarkers in human serum samples.
This paper presents the development of a plastic microfluidic immunosensor for rapid, reliable and on-the-spot detection of disease biomarkers in human sera. The microfluidic chips were fabricated in cyclic polyolefin by hot-embossing with a silicon master mold. The master itself was made using photolithographic techniques and Deep Reactive Ion Etching (DRIE). As a platform model, serum concentrations of C-reactive protein (CRP), a cardiac and inflammation marker, was measured on-chip using chemiluminescence based immunoassay. The assay results were read via an on-board instant photographic film, and with an imager capable of detecting chemiluminescent signals. The on-board detection module obviates the need for any dedicated bench-top analyzer for reading the immunoassay results, and therefore makes the device self-sufficient for point-of-care diagnostics when simple positive/negative results are sought. The microfluidic chemiluminescence results were compared with standard microplate ELISA analysis to assess the accuracy of the developed microfluidic immunoassay. Screening of CRP in human serum samples showed good correlation with ELISA analysis and the mean difference between the two methods using the Bland and Altman method was -0.079 +/- 0.858 mg/L for hsCRP. With approximate assay times of 25 min, the developed microfluidic immunoassay approach shows great potential for rapid plus sensitive detection of disease markers at the point-of-care.
Biomarkers↗