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Sample records for cdt false positive

  1. Distinct Roles for CdtA and CdtC during Intoxication by Cytolethal Distending Toxins.

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    Shandee D Dixon

    Full Text Available Cytolethal distending toxins (CDTs are heterotrimeric protein exotoxins produced by a diverse array of Gram-negative pathogens. The enzymatic subunit, CdtB, possesses DNase and phosphatidylinositol 3-4-5 trisphosphate phosphatase activities that induce host cell cycle arrest, cellular distension and apoptosis. To exert cyclomodulatory and cytotoxic effects CDTs must be taken up from the host cell surface and transported intracellularly in a manner that ultimately results in localization of CdtB to the nucleus. However, the molecular details and mechanism by which CDTs bind to host cells and exploit existing uptake and transport pathways to gain access to the nucleus are poorly understood. Here, we report that CdtA and CdtC subunits of CDTs derived from Haemophilus ducreyi (Hd-CDT and enteropathogenic E. coli (Ec-CDT are independently sufficient to support intoxication by their respective CdtB subunits. CdtA supported CdtB-mediated killing of T-cells and epithelial cells that was nearly as efficient as that observed with holotoxin. In contrast, the efficiency by which CdtC supported intoxication was dependent on the source of the toxin as well as the target cell type. Further, CdtC was found to alter the subcellular trafficking of Ec-CDT as determined by sensitivity to EGA, an inhibitor of endosomal trafficking, colocalization with markers of early and late endosomes, and the kinetics of DNA damage response. Finally, host cellular cholesterol was found to influence sensitivity to intoxication mediated by Ec-CdtA, revealing a role for cholesterol or cholesterol-rich membrane domains in intoxication mediated by this subunit. In summary, data presented here support a model in which CdtA and CdtC each bind distinct receptors on host cell surfaces that direct alternate intracellular uptake and/or trafficking pathways.

  2. False Position, Double False Position and Cramer's Rule

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    Boman, Eugene

    2009-01-01

    We state and prove the methods of False Position (Regula Falsa) and Double False Position (Regula Duorum Falsorum). The history of both is traced from ancient Egypt and China through the work of Fibonacci, ending with a connection between Double False Position and Cramer's Rule.

  3. The Copenhagen Dependency Treebank (CDT)

    DEFF Research Database (Denmark)

    Høeg Müller, Henrik; Korzen, Iørn

    2014-01-01

    the fundamentals of how CDT is marked up with semantic relations in accordance with the dependency principles governing the annotation on the other levels of CDT. Specifically, focus will be on how Generative Lexicon (GL) theory has been incorporated into the unitary theoretical dependency framework of CDT....... An annotation scheme for lexical semantics has been designed so as to account for the lexico-semantic structure of complex NPs, and the four GL qualia also appear in some of the CDT discourse relation labels as a description of parallel semantic relations at this level....

  4. CDT meets Horava-Lifshitz gravity

    International Nuclear Information System (INIS)

    Ambjorn, J.; Goerlich, A.; Jordan, S.; Jurkiewicz, J.; Loll, R.

    2010-01-01

    The theory of causal dynamical triangulations (CDT) attempts to define a nonperturbative theory of quantum gravity as a sum over spacetime geometries. One of the ingredients of the CDT framework is a global time foliation, which also plays a central role in the quantum gravity theory recently formulated by Horava. We show that the phase diagram of CDT bears a striking resemblance with the generic Lifshitz phase diagram appealed to by Horava. We argue that CDT might provide a unifying nonperturbative framework for anisotropic as well as isotropic theories of quantum gravity.

  5. Proliferating Cell Nuclear Antigen-dependent Rapid Recruitment of Cdt1 and CRL4Cdt2 at DNA-damaged Sites after UV Irradiation in HeLa Cells*

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    Ishii, Takashi; Shiomi, Yasushi; Takami, Toshihiro; Murakami, Yusuke; Ohnishi, Naho; Nishitani, Hideo

    2010-01-01

    The licensing factor Cdt1 is degraded by CRL4Cdt2 ubiquitin ligase dependent on proliferating cell nuclear antigen (PCNA) during S phase and when DNA damage is induced in G1 phase. Association of both Cdt2 and PCNA with chromatin was observed in S phase and after UV irradiation. Here we used a micropore UV irradiation assay to examine Cdt2 accumulation at cyclobutane pyrimidine dimer-containing DNA-damaged sites in the process of Cdt1 degradation in HeLa cells. Cdt2, present in the nucleus throughout the cell cycle, accumulated rapidly at damaged DNA sites during G1 phase. The recruitment of Cdt2 is dependent on prior PCNA chromatin binding because Cdt2 association was prevented when PCNA was silenced. Cdt1 was also recruited to damaged sites soon after UV irradiation through its PIP-box. As Cdt1 was degraded, the Cdt2 signal at damaged sites was reduced, but PCNA, cyclobutane pyrimidine dimer, and XPA (xeroderma pigmentosum, complementation group A) signals remained at the same levels. These findings suggest that Cdt1 degradation following UV irradiation occurs rapidly at damaged sites due to PCNA chromatin loading and the recruitment of Cdt1 and CRL4Cdt2, before DNA damage repair is completed. PMID:20929861

  6. An Inactive Geminin Mutant That Binds Cdt1

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    Marissa Suchyta

    2015-05-01

    Full Text Available The initiation of DNA replication is tightly regulated in order to ensure that the genome duplicates only once per cell cycle. In vertebrate cells, the unstable regulatory protein Geminin prevents a second round of DNA replication by inhibiting the essential replication factor Cdt1. Cdt1 recruits mini-chromosome maintenance complex (MCM2-7, the replication helicase, into the pre-replication complex (pre-RC at origins of DNA replication. The mechanism by which Geminin inhibits MCM2-7 loading by Cdt1 is incompletely understood. The conventional model is that Geminin sterically hinders a direct physical interaction between Cdt1 and MCM2-7. Here, we describe an inactive missense mutant of Geminin, GemininAWA, which binds to Cdt1 with normal affinity yet is completely inactive as a replication inhibitor even when added in vast excess. In fact, GemininAWA can compete with GemininWT for binding to Cdt1 and prevent it from inhibiting DNA replication. GemininAWA does not inhibit the loading of MCM2-7 onto DNA in vivo, and in the presence of GemininAWA, nuclear DNA is massively over-replicated within a single S phase. We conclude that Geminin does not inhibit MCM loading by simple steric interference with a Cdt1-MCM2-7 interaction but instead works by a non-steric mechanism, possibly by inhibiting the histone acetyltransferase HBO1.

  7. CdtR Regulates TcdA and TcdB Production in Clostridium difficile.

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    Shelley A Lyon

    2016-07-01

    Full Text Available Clostridium difficile is a global health burden and the leading cause of antibiotic-associated diarrhoea worldwide, causing severe gastrointestinal disease and death. Three well characterised toxins are encoded by this bacterium in two genetic loci, specifically, TcdB (toxin B and TcdA (toxin A in the Pathogenicity Locus (PaLoc and binary toxin (CDT in the genomically distinct CDT locus (CdtLoc. Toxin production is controlled by regulators specific to each locus. The orphan response regulator, CdtR, encoded within the CdtLoc, up-regulates CDT production. Until now there has been no suggestion that CdtR influences TcdA and TcdB production since it is not carried by all PaLoc-containing strains and CdtLoc is not linked genetically to PaLoc. Here we show that, in addition to CDT, CdtR regulates TcdA and TcdB production but that this effect is strain dependent. Of clinical relevance, CdtR increased the production of TcdA, TcdB and CDT in two epidemic ribotype 027 human strains, modulating their virulence in a mouse infection model. Strains traditionally from animal lineages, notably ribotype 078 strains, are increasingly being isolated from humans and their genetic and phenotypic analysis is critical for future studies on this important pathogen. Here we show that CdtR-mediated toxin regulation did not occur in other strain backgrounds, including a ribotype 078 animal strain. The finding that toxin gene regulation is strain dependent highlights the regulatory diversity between C. difficile isolates and the importance of studying virulence regulation in diverse lineages and clinically relevant strains. Our work provides the first evidence that TcdA, TcdB and CDT production is linked by a common regulatory mechanism and that CdtR may act as a global regulator of virulence in epidemic 027 strains.

  8. The false positive exercise test

    International Nuclear Information System (INIS)

    Moritani, Kohshiro; Matsuda, Yasuo; Ozaki, Masaharu; Ogawa, Hiroshi; Ichiyama, Masaji; Matsuda, Masako; Kusukawa, Reizo

    1986-01-01

    Exercise tests with sublingual nitroglycerin were performed on 7 patients with true positive and 8 patients with false positive exercise test results. Four of 7 patients with true positive changes and 8 patients with false positive changes underwent exercise cardiac scintigraphy. Scintigrams showed perfusion defects in 4 patients with true positive outcomes, and no perfusion defect in 8 patients with false positive outcomes. Exercise tests with sublingual nitroglycerin were performed with the same load as that without nitroglycerin. In all 7 patients with true positive exercise test results, ST segment depression observed in the control exercise test was not observed in the nitroglycerin exercise test. In the false positive patients, ST segment depression observed in the control exercise test remained unchanged in 7 of 8 patients receiving nitroglycerin. Exercise tests with sublingual nitroglycerin as well as exercise cardiac scintigraphy are valuable tods in differentiating false positive from true positive patients. Furthermore, these data suggest that ST segment depression in the false positive patients may not be related to myocardial ischemia. (author)

  9. Cdt1 stabilizes an open MCM ring for helicase loading.

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    Frigola, Jordi; He, Jun; Kinkelin, Kerstin; Pye, Valerie E; Renault, Ludovic; Douglas, Max E; Remus, Dirk; Cherepanov, Peter; Costa, Alessandro; Diffley, John F X

    2017-06-23

    ORC, Cdc6 and Cdt1 act together to load hexameric MCM, the motor of the eukaryotic replicative helicase, into double hexamers at replication origins. Here we show that Cdt1 interacts with MCM subunits Mcm2, 4 and 6, which both destabilizes the Mcm2-5 interface and inhibits MCM ATPase activity. Using X-ray crystallography, we show that Cdt1 contains two winged-helix domains in the C-terminal half of the protein and a catalytically inactive dioxygenase-related N-terminal domain, which is important for MCM loading, but not for subsequent replication. We used these structures together with single-particle electron microscopy to generate three-dimensional models of MCM complexes. These show that Cdt1 stabilizes MCM in a left-handed spiral open at the Mcm2-5 gate. We propose that Cdt1 acts as a brace, holding MCM open for DNA entry and bound to ATP until ORC-Cdc6 triggers ATP hydrolysis by MCM, promoting both Cdt1 ejection and MCM ring closure.

  10. USP37 deubiquitinates Cdt1 and contributes to regulate DNA replication.

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    Hernández-Pérez, Santiago; Cabrera, Elisa; Amoedo, Hugo; Rodríguez-Acebes, Sara; Koundrioukoff, Stephane; Debatisse, Michelle; Méndez, Juan; Freire, Raimundo

    2016-10-01

    DNA replication control is a key process in maintaining genomic integrity. Monitoring DNA replication initiation is particularly important as it needs to be coordinated with other cellular events and should occur only once per cell cycle. Crucial players in the initiation of DNA replication are the ORC protein complex, marking the origin of replication, and the Cdt1 and Cdc6 proteins, that license these origins to replicate by recruiting the MCM2-7 helicase. To accurately achieve its functions, Cdt1 is tightly regulated. Cdt1 levels are high from metaphase and during G1 and low in S/G2 phases of the cell cycle. This control is achieved, among other processes, by ubiquitination and proteasomal degradation. In an overexpression screen for Cdt1 deubiquitinating enzymes, we isolated USP37, to date the first ubiquitin hydrolase controlling Cdt1. USP37 overexpression stabilizes Cdt1, most likely a phosphorylated form of the protein. In contrast, USP37 knock down destabilizes Cdt1, predominantly during G1 and G1/S phases of the cell cycle. USP37 interacts with Cdt1 and is able to de-ubiquitinate Cdt1 in vivo and, USP37 is able to regulate the loading of MCM complexes onto the chromatin. In addition, downregulation of USP37 reduces DNA replication fork speed. Taken together, here we show that the deubiquitinase USP37 plays an important role in the regulation of DNA replication. Whether this is achieved via Cdt1, a central protein in this process, which we have shown to be stabilized by USP37, or via additional factors, remains to be tested. Copyright © 2016 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  11. Cdt1 is differentially targeted for degradation by anticancer chemotherapeutic drugs.

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    Athanasia Stathopoulou

    Full Text Available BACKGROUND: Maintenance of genome integrity is crucial for the propagation of the genetic information. Cdt1 is a major component of the pre-replicative complex, which controls once per cell cycle DNA replication. Upon DNA damage, Cdt1 is rapidly targeted for degradation. This targeting has been suggested to safeguard genomic integrity and prevent re-replication while DNA repair is in progress. Cdt1 is deregulated in tumor specimens, while its aberrant expression is linked with aneuploidy and promotes tumorigenesis in animal models. The induction of lesions in DNA is a common mechanism by which many cytotoxic anticancer agents operate, leading to cell cycle arrest and apoptosis. METHODOLOGY/PRINCIPAL FINDING: In the present study we examine the ability of several anticancer drugs to target Cdt1 for degradation. We show that treatment of HeLa and HepG2 cells with MMS, Cisplatin and Doxorubicin lead to rapid proteolysis of Cdt1, whereas treatment with 5-Fluorouracil and Tamoxifen leave Cdt1 expression unaffected. Etoposide affects Cdt1 stability in HepG2 cells and not in HeLa cells. RNAi experiments suggest that Cdt1 proteolysis in response to MMS depends on the presence of the sliding clamp PCNA. CONCLUSION/SIGNIFICANCE: Our data suggest that treatment of tumor cells with commonly used chemotherapeutic agents induces differential responses with respect to Cdt1 proteolysis. Information on specific cellular targets in response to distinct anticancer chemotherapeutic drugs in different cancer cell types may contribute to the optimization of the efficacy of chemotherapy.

  12. A new functional site W115 in CdtA is critical for Aggregatibacter actinomycetemcomitans cytolethal distending toxin.

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    Lu Li

    Full Text Available Aggregatibacter actinomycetemcomitans, a specific pathogen of localized aggressive periodontitis, produces a cytolethal distending toxin (CDT that arrests eukaryotic cells irreversibly in G0/G1 or G2/M phase of the cell cycle. Although structural studies show that the aromatic patch region of CdtA plays an important role in its biological activity, the functional sites of CdtA have not been firmly established. In this study, site-specific mutagenesis strategy was employed for cdtA point mutations construction so as to examine the contributions of individual amino acids to receptor binding and the biological activity of holotoxin. The binding ability was reduced in CdtA(Y181ABC holotoxin and the biological function of CDT was not weaken in CdtA(Y105ABC, CdtA(Y125ABC, CdtA(F109ABC and CdtA(S106NBC holotoxin suggesting that these sites were not critical to CDT. But the binding activity and cell cycle arrest ability of holotoxin complexes were inhibited in CdtA(W115GBC. And this site did not affect the holotoxin assembly by size exclusion chromatography. Therefore, W115 might be a critical site of CdtA binding ability. These findings suggest that the functional sites of CdtA are not only in the aromatic patch region. W115, the new functional site is critical for receptor binding and cell cycle arrest, which provides potential targets for pharmacological disruption of CDT activity.

  13. Fijación de radioyodo en huesos maxilares simulando metástasis en pacientes con Carcinoma Diferenciado de Tiroides (CDT): False- Positive images in patients with Differentiated Thyroid Carcinoma. (DTC)

    OpenAIRE

    Degrossi, O. J.; Gutiérrez, S.; Fadel, A.; Degrossi, E. B.; Valdivieso, M. C.; Balbuena, R. L.; Alak, M. del C.; de Cabrejas, M.

    2008-01-01

    En estudios centellográficos con 131I (CCT) para seguimiento, postablación o tratamiento de pacientes portadores de carcinoma diferenciado de tiroides (CDT) se observan frecuentemente en tiempos precoces áreas de captación del radiotrazador en macizo facial. Estas áreas corresponden, generalmente, a glándulas salivares y extremo anterior de mucosa nasal y se mantienen durante las primeras 48 horas y no son observadas generalmente a las 72 horas. Pero con menor frecuencia se presentan otras qu...

  14. 2d CDT is 2d Horava-Lifshitz quantum gravity

    DEFF Research Database (Denmark)

    Ambjørn, J.; Glaser, L.; Sato, Y.

    2013-01-01

    Causal Dynamical Triangulations (CDT) is a lattice theory where aspects of quantum gravity can be studied. Two-dimensional CDT can be solved analytically and the continuum (quantum) Hamiltonian obtained. In this Letter we show that this continuum Hamiltonian is the one obtained by quantizing two......-dimensional projectable Horava-Lifshitz gravity....

  15. False Positives in Exoplanet Detection

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    Leuquire, Jacob; Kasper, David; Jang-Condell, Hannah; Kar, Aman; Sorber, Rebecca; Suhaimi, Afiq; KELT (Kilodegree Extremely Little Telescope)

    2018-06-01

    Our team at the University of Wyoming uses a 0.6 m telescope at RBO (Red Buttes Observatory) to help confirm results on potential exoplanet candidates from low resolution, wide field surveys shared by the KELT (Kilodegree Extremely Little Telescope) team. False positives are common in this work. We carry out transit photometry, and this method comes with special types of false positives. The most common false positive seen at the confirmation level is an EB (eclipsing binary). Low resolution images are great in detecting multiple sources for photometric dips in light curves, but they lack the precision to decipher single targets at an accurate level. For example, target star KC18C030621 needed RBO’s photometric precision to determine there was a nearby EB causing exoplanet type light curves. Identifying false positives with our telescope is important work because it helps eliminate the waste of time taken by more expensive telescopes trying to rule out negative candidate stars. It also furthers the identification of other types of photometric events, like eclipsing binaries, so they can be studied on their own.

  16. False Positive and False Negative Effects on Network Attacks

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    Shang, Yilun

    2018-01-01

    Robustness against attacks serves as evidence for complex network structures and failure mechanisms that lie behind them. Most often, due to detection capability limitation or good disguises, attacks on networks are subject to false positives and false negatives, meaning that functional nodes may be falsely regarded as compromised by the attacker and vice versa. In this work, we initiate a study of false positive/negative effects on network robustness against three fundamental types of attack strategies, namely, random attacks (RA), localized attacks (LA), and targeted attack (TA). By developing a general mathematical framework based upon the percolation model, we investigate analytically and by numerical simulations of attack robustness with false positive/negative rate (FPR/FNR) on three benchmark models including Erdős-Rényi (ER) networks, random regular (RR) networks, and scale-free (SF) networks. We show that ER networks are equivalently robust against RA and LA only when FPR equals zero or the initial network is intact. We find several interesting crossovers in RR and SF networks when FPR is taken into consideration. By defining the cost of attack, we observe diminishing marginal attack efficiency for RA, LA, and TA. Our finding highlights the potential risk of underestimating or ignoring FPR in understanding attack robustness. The results may provide insights into ways of enhancing robustness of network architecture and improve the level of protection of critical infrastructures.

  17. Analysis of false positive and false negative cytological diagnosis of breast lesions

    International Nuclear Information System (INIS)

    Jamal, Awtif A.; Mansoor, I.

    2001-01-01

    To study the reasons for interpretive errors in false negative and false positive diagnosis of breast carcinoma on fine needle aspiration cytology material. We reviewed only those cases in which cytohistological discrepancies were found, where the cytologic material was abnormal and to some extent misinterpreted or both. There was only one false negative case (false negative fraction 0.32%) proved histologically as ductal carcinoma and four false positive cases (false positive fraction 1.2%); 2 fibroadenoma; 1 fibrocystic disease; and 1 stromal fibrosis. Smears of the two false positive fibroadenoma cases showed very high cellularity, overcrowded clusters and frequent stripped nuclei. The fibrocystic case showed tight clusters of apocrine cells and sheets of loosely aggregated macrophages that were over interpreted. Smears of the false negative ductal carcinoma was hypocellular overall, and the cells showed minimal nuclear pleomorphism. Overcrowded clusters and hypercellular smears should be carefully assessed for uniformity of cells and detailed nuclear and cytomorphological features. If the full-blown malignant cytomorphological changes are not visible, a diagnosis of suspicious or inconclusive should be made and frozen section recommended before surgery. Hypocellularity and relatively nuclear monomorphism are the reasons for failure to diagnose malignant breast lesions. Careful attention should be paid to extreme nuclear monomorphism and absence of naked bipolar cells. A cytologically atypical or suspicious diagnosis together with positive radiological and clinical findings should suggest a diagnosis of malignancy. (author)

  18. The Cytolethal Distending Toxin Subunit CdtB of Helicobacter hepaticus Promotes Senescence and Endoreplication in Xenograft Mouse Models of Hepatic and Intestinal Cell Lines

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    Christelle Péré-Védrenne

    2017-06-01

    Full Text Available Cytolethal distending toxins (CDTs are common among pathogenic bacteria of the human and animal microbiota. CDTs exert cytopathic effets, via their active CdtB subunit. No clear description of those cytopathic effects has been reported at the cellular level in the target organs in vivo. In the present study, xenograft mouse models of colon and liver cell lines were set up to study the effects of the CdtB subunit of Helicobacter hepaticus. Conditional transgenic cell lines were established, validated in vitro and then engrafted into immunodeficient mice. After successful engraftment, mice were treated with doxycyclin to induce the expression of transgenes (red fluorescent protein, CdtB, and mutated CdtB. For both engrafted cell lines, results revealed a delayed tumor growth and a reduced tumor weight in CdtB-expressing tumors compared to controls. CdtB-derived tumors showed γ-H2AX foci formation, an increase in apoptosis, senescence, p21 and Ki-67 nuclear antigen expression. No difference in proliferating cells undergoing mitosis (phospho-histone H3 was observed. CdtB intoxication was also associated with an overexpression of cytokeratins in cells at the invasive front of the tumor as well as an increase in ploidy. All these features are hallmarks of endoreplication, as well as aggressiveness in cancer. These effects were dependent on the histidine residue at position 265 of the CdtB, underlying the importance of this residue in CdtB catalytic activity. Taken together, these data indicate that the CdtB triggers senescence and cell endoreplication leading to giant polyploid cells in these xenograft mouse models.

  19. Consequences of a false-positive mammography result

    DEFF Research Database (Denmark)

    von Euler-Chelpin, My; Bæksted, Christina; Vejborg, Ilse

    2016-01-01

    group used anxiolytic and antidepressant drugs. There was no difference in use of beta blockers. Hormone therapy was used more frequently by the false-positive, 36.6% versus 28.7%. The proportion of women using anxiolytic and antidepressant drugs increased with 19% from the before to the after period...... in the false-positive group, and with 16% in the normal group, resulting in an RRR of 1.02 (95% CI 0.92-1.14). RRR was 1.03 for beta blockers, 0.97 for hormone therapy. Conclusion(s): Drugs used to mitigate mood disorders were used more frequently by women with false-positive than by women with normal......Background: Previous research showed women experiencing false-positive mammograms to have greater anxiety about breast cancer than women with normal mammograms. To elucidate psychological effects of false-positive mammograms, we studied impact on drug intake.  Methods: We calculated the ratio...

  20. The problem of false positives and false negatives in violent video game experiments.

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    Ferguson, Christopher J

    The problem of false positives and negatives has received considerable attention in behavioral research in recent years. The current paper uses video game violence research as an example of how such issues may develop in a field. Despite decades of research, evidence on whether violent video games (VVGs) contribute to aggression in players has remained mixed. Concerns have been raised in recent years that experiments regarding VVGs may suffer from both "false positives" and "false negatives." The current paper examines this issue in three sets of video game experiments, two sets of video game experiments on aggression and prosocial behaviors identified in meta-analysis, and a third group of recent null studies. Results indicated that studies of VVGs and aggression appear to be particularly prone to false positive results. Studies of VVGs and prosocial behavior, by contrast are heterogeneous and did not demonstrate any indication of false positive results. However, their heterogeneous nature made it difficult to base solid conclusions on them. By contrast, evidence for false negatives in null studies was limited, and little evidence emerged that null studies lacked power in comparison those highlighted in past meta-analyses as evidence for effects. These results are considered in light of issues related to false positives and negatives in behavioral science more broadly. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Characterisation of false-positive observations in botanical surveys

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    Quentin J. Groom

    2017-05-01

    Full Text Available Errors in botanical surveying are a common problem. The presence of a species is easily overlooked, leading to false-absences; while misidentifications and other mistakes lead to false-positive observations. While it is common knowledge that these errors occur, there are few data that can be used to quantify and describe these errors. Here we characterise false-positive errors for a controlled set of surveys conducted as part of a field identification test of botanical skill. Surveys were conducted at sites with a verified list of vascular plant species. The candidates were asked to list all the species they could identify in a defined botanically rich area. They were told beforehand that their final score would be the sum of the correct species they listed, but false-positive errors counted against their overall grade. The number of errors varied considerably between people, some people create a high proportion of false-positive errors, but these are scattered across all skill levels. Therefore, a person’s ability to correctly identify a large number of species is not a safeguard against the generation of false-positive errors. There was no phylogenetic pattern to falsely observed species; however, rare species are more likely to be false-positive as are species from species rich genera. Raising the threshold for the acceptance of an observation reduced false-positive observations dramatically, but at the expense of more false negative errors. False-positive errors are higher in field surveying of plants than many people may appreciate. Greater stringency is required before accepting species as present at a site, particularly for rare species. Combining multiple surveys resolves the problem, but requires a considerable increase in effort to achieve the same sensitivity as a single survey. Therefore, other methods should be used to raise the threshold for the acceptance of a species. For example, digital data input systems that can verify

  2. CDT and the Big Bang

    OpenAIRE

    Ambjorn, J.; Watabiki, Y.

    2017-01-01

    We describe a CDT-like model where breaking of W3 symmetry will lead to the emergence of time and subsequently of space. Surprisingly the simplest such models which lead to higher dimensional spacetimes are based on the four "magical" Jordan algebras of 3x3 Hermitian matrices with real, complex, quaternion and octonion entries, respectively. The simplest symmetry breaking leads to universes with spacetime dimensions 3, 4, 6, and 10.

  3. False positive and false negative FDG-PET scans in various thoracic diseases

    International Nuclear Information System (INIS)

    Chang, Jung Min; Lee, Hyun Ju; Goo, Jin Mo; Lee, Ho Young; Lee, Jong Jin; Chung, June Key; Im, Jung Gi

    2006-01-01

    Fluorodeoxygucose (FDG)-positron emission tomography (PET) is being used more and more to differentiate benign form malignant focal lesions and it has been shown to be more efficacious than conventional chest computed tomography (CT). However, FDG is not a cancer-specific agent, and false positive findings in benign diseases have been reported. Infectious diseases (mycobacterial, fungal, bacterial infection), sarcoidosis, radiation pneumonitis and post-operative surgical conditions have shown intense uptake on PET scan. On the other hand, tumors with low glycolytic activity such as adenomas, bronchioloalveolar carcinomas, carcinoid tumors, low grade lymphomas and small sized tumors have revealed false negative findings on PET scan, Furthermore, in diseases located near the physiologic uptake sites (heart, bladder, kidney, and liver), FDG-PET should be complemented with other imaging modalities to confirm results and to minimize false negative findings. Familiarity with these false positive and negative findings will help radiologists interpret PET scans more accurately and also will help to determine the significance of the findings. In this review, we illustrate false positive and negative findings of PET scan in a variety of diseases

  4. Cdt1 revisited: complex and tight regulation during the cell cycle and consequences of deregulation in mammalian cells

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    Fujita Masatoshi

    2006-10-01

    Full Text Available Abstract In eukaryotic cells, replication of genomic DNA initiates from multiple replication origins distributed on multiple chromosomes. To ensure that each origin is activated precisely only once during each S phase, a system has evolved which features periodic assembly and disassembly of essential pre-replication complexes (pre-RCs at replication origins. The pre-RC assembly reaction involves the loading of a presumptive replicative helicase, the MCM2-7 complexes, onto chromatin by the origin recognition complex (ORC and two essential factors, CDC6 and Cdt1. The eukaryotic cell cycle is driven by the periodic activation and inactivation of cyclin-dependent kinases (Cdks and assembly of pre-RCs can only occur during the low Cdk activity period from late mitosis through G1 phase, with inappropriate re-assembly suppressed during S, G2, and M phases. It was originally suggested that inhibition of Cdt1 function after S phase in vertebrate cells is due to geminin binding and that Cdt1 hyperfunction resulting from Cdt1-geminin imbalance induces re-replication. However, recent progress has revealed that Cdt1 activity is more strictly regulated by two other mechanisms in addition to geminin: (1 functional and SCFSkp2-mediated proteolytic regulation through phosphorylation by Cdks; and (2 replication-coupled proteolysis mediated by the Cullin4-DDB1Cdt2 ubiquitin ligase and PCNA, an eukaryotic sliding clamp stimulating replicative DNA polymerases. The tight regulation implies that Cdt1 control is especially critical for the regulation of DNA replication in mammalian cells. Indeed, Cdt1 overexpression evokes chromosomal damage even without re-replication. Furthermore, deregulated Cdt1 induces chromosomal instability in normal human cells. Since Cdt1 is overexpressed in cancer cells, this could be a new molecular mechanism leading to carcinogenesis. In this review, recent insights into Cdt1 function and regulation in mammalian cells are discussed.

  5. Geminin deploys multiple mechanisms to regulate Cdt1 before cell division thus ensuring the proper execution of DNA replication

    DEFF Research Database (Denmark)

    Ballabeni, Andrea; Zamponi, Raffaella; Moore, Jodene K

    2013-01-01

    the accumulation of Cdt1 in mitosis, because decreasing the Geminin levels prevents Cdt1 accumulation and impairs DNA replication. Geminin is known to inhibit Cdt1 function; its depletion during G2 leads to DNA rereplication and checkpoint activation. Here we show that, despite rapid Cdt1 protein turnover in G2...

  6. Trees and spatial topology change in CDT

    DEFF Research Database (Denmark)

    Ambjorn, Jan; Budd, Timothy George

    2013-01-01

    Generalized causal dynamical triangulations (generalized CDT) is a model of two-dimensional quantum gravity in which a limited number of spatial topology changes is allowed to occur. We solve the model at the discretized level using bijections between quadrangulations and trees. In the continuum...

  7. Mutant analysis of Cdt1's function in suppressing nascent strand elongation during DNA replication in Xenopus egg extracts.

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    Nakazaki, Yuta; Tsuyama, Takashi; Azuma, Yutaro; Takahashi, Mikiko; Tada, Shusuke

    2017-09-02

    The initiation of DNA replication is strictly regulated by multiple mechanisms to ensure precise duplication of chromosomes. In higher eukaryotes, activity of the Cdt1 protein is temporally regulated during the cell cycle, and deregulation of Cdt1 induces DNA re-replication. In previous studies, we showed that excess Cdt1 inhibits DNA replication by suppressing progression of replication forks in Xenopus egg extracts. Here, we investigated the functional regions of Cdt1 that are required for the inhibition of DNA replication. We constructed a series of N-terminally or C-terminally deleted mutants of Cdt1 and examined their inhibitory effects on DNA replication in Xenopus egg extracts. Our results showed that the region spanning amino acids (a. a.) 255-620 is required for efficient inhibition of DNA replication, and that, within this region, a. a. 255-289 have a critical role in inhibition. Moreover, one of the Cdt1 mutants, Cdt1 R285A, was compromised with respect to the licensing activity but still inhibited DNA replication. This result suggests that Cdt1 has an unforeseen function in the negative regulation of DNA replication, and that this function is located within a molecular region that is distinct from those required for the licensing activity. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. ATM regulates Cdt1 stability during the unperturbed S phase to prevent re-replication

    Science.gov (United States)

    Iwahori, Satoko; Kohmon, Daisuke; Kobayashi, Junya; Tani, Yuhei; Yugawa, Takashi; Komatsu, Kenshi; Kiyono, Tohru; Sugimoto, Nozomi; Fujita, Masatoshi

    2014-01-01

    Ataxia-telangiectasia mutated (ATM) plays crucial roles in DNA damage responses, especially with regard to DNA double-strand breaks (DSBs). However, it appears that ATM can be activated not only by DSB, but also by some changes in chromatin architecture, suggesting potential ATM function in cell cycle control. Here, we found that ATM is involved in timely degradation of Cdt1, a critical replication licensing factor, during the unperturbed S phase. At least in certain cell types, degradation of p27Kip1 was also impaired by ATM inhibition. The novel ATM function for Cdt1 regulation was dependent on its kinase activity and NBS1. Indeed, we found that ATM is moderately phosphorylated at Ser1981 during the S phase. ATM silencing induced partial reduction in levels of Skp2, a component of SCFSkp2 ubiquitin ligase that controls Cdt1 degradation. Furthermore, Skp2 silencing resulted in Cdt1 stabilization like ATM inhibition. In addition, as reported previously, ATM silencing partially prevented Akt phosphorylation at Ser473, indicative of its activation, and Akt inhibition led to modest stabilization of Cdt1. Therefore, the ATM-Akt-SCFSkp2 pathway may partly contribute to the novel ATM function. Finally, ATM inhibition rendered cells hypersensitive to induction of re-replication, indicating importance for maintenance of genome stability. PMID:24280901

  9. False-positive 111In-pentetreotide Uptake in Gastritis

    International Nuclear Information System (INIS)

    Usmani, Sharjeel; Alshammari, Alshaima

    2013-01-01

    111 In-pentetreotide [ 111 In-octreoscan] is the most widely used radiolabeled somatostatin analog for evaluating neuroendocrine tumor overexpression of somatostatin receptors. False-positives studies of somatostatin receptor scintigraphy have been reported and often the cause is unexplained but assumed to be due to high number of somatostatin receptors in other pathologies. Causes of false-positives include visualization of the gallbladder, nasal mucosa and pulmonary hilar areas in respiratory infections, thyroid abnormalities, accessory spleens, recent Cerebrovascular accidents (CVA's) and activity at the site of a recent surgical incision. In infection or inflammation the cause of false-positive uptake is probably the result of tracer binding by somatostatin receptors on the inflammatory leukocytes. In this case report, we report, a 44-year-old male patient with false-positive 111 In-pentetreotide uptake due to gastritis

  10. 'False-positive' and 'false-negative' test results in clinical urine drug testing.

    Science.gov (United States)

    Reisfield, Gary M; Goldberger, Bruce A; Bertholf, Roger L

    2009-08-01

    The terms 'false-positive' and 'false-negative' are widely used in discussions of urine drug test (UDT) results. These terms are inadequate because they are used in different ways by physicians and laboratory professionals and they are too narrow to encompass the larger universe of potentially misleading, inappropriate and unexpected drug test results. This larger universe, while not solely comprised of technically 'true' or 'false' positive or negative test results, presents comparable interpretive challenges with corresponding clinical implications. In this review, we propose the terms 'potentially inappropriate' positive or negative test results in reference to UDT results that are ambiguous or unexpected and subject to misinterpretation. Causes of potentially inappropriate positive UDT results include in vivo metabolic conversions of a drug, exposure to nonillicit sources of a drug and laboratory error. Causes of potentially inappropriate negative UDT results include limited assay specificity, absence of drug in the urine, presence of drug in the urine, but below established assay cutoff, specimen manipulation and laboratory error. Clinical UDT interpretation is a complicated task requiring knowledge of recent prescription, over-the-counter and herbal drug administration, drug metabolism and analytical sensitivities and specificities.

  11. False-positive results in pharmacoepidemiology and pharmacovigilance.

    Science.gov (United States)

    Bezin, Julien; Bosco-Levy, Pauline; Pariente, Antoine

    2017-09-01

    False-positive constitute an important issue in scientific research. In the domain of drug evaluation, it affects all phases of drug development and assessment, from the very early preclinical studies to the late post-marketing evaluations. The core concern associated with this false-positive is the lack of replicability of the results. Aside from fraud or misconducts, false-positive is often envisioned from the statistical angle, which considers them as a price to pay for type I error in statistical testing, and its inflation in the context of multiple testing. If envisioning this problematic in the context of pharmacoepidemiology and pharmacovigilance however, that both evaluate drugs in an observational settings, information brought by statistical testing and the significance of such should only be considered as additional to the estimates provided and their confidence interval, in a context where differences have to be a clinically meaningful upon everything, and the results appear robust to the biases likely to have affected the studies. In the following article, we consequently illustrate these biases and their consequences in generating false-positive results, through studies and associations between drug use and health outcomes that have been widely disputed. Copyright © 2017 Société française de pharmacologie et de thérapeutique. Published by Elsevier Masson SAS. All rights reserved.

  12. Clostridium difficile toxin CDT induces formation of microtubule-based protrusions and increases adherence of bacteria.

    Directory of Open Access Journals (Sweden)

    Carsten Schwan

    2009-10-01

    Full Text Available Clostridium difficile causes antibiotic-associated diarrhea and pseudomembranous colitis by production of the Rho GTPase-glucosylating toxins A and B. Recently emerging hypervirulent Clostridium difficile strains additionally produce the binary ADP-ribosyltransferase toxin CDT (Clostridium difficile transferase, which ADP-ribosylates actin and inhibits actin polymerization. Thus far, the role of CDT as a virulence factor is not understood. Here we report by using time-lapse- and immunofluorescence microscopy that CDT and other binary actin-ADP-ribosylating toxins, including Clostridium botulinum C2 toxin and Clostridium perfringens iota toxin, induce redistribution of microtubules and formation of long (up to >150 microm microtubule-based protrusions at the surface of intestinal epithelial cells. The toxins increase the length of decoration of microtubule plus-ends by EB1/3, CLIP-170 and CLIP-115 proteins and cause redistribution of the capture proteins CLASP2 and ACF7 from microtubules at the cell cortex into the cell interior. The CDT-induced microtubule protrusions form a dense meshwork at the cell surface, which wrap and embed bacterial cells, thereby largely increasing the adherence of Clostridia. The study describes a novel type of microtubule structure caused by less efficient microtubule capture and offers a new perspective for the pathogenetic role of CDT and other binary actin-ADP-ribosylating toxins in host-pathogen interactions.

  13. An investigation of false positive dosimetry results

    International Nuclear Information System (INIS)

    Lewandowski, M.A.; Davis, S.A.; Goff, T.E.; Wu, C.F.

    1996-01-01

    The Waste Isolation Pilot Plant (WIPP) is a facility designed for the demonstration of the safe disposal of transuranic waste. Currently, the radiation source term is confined to sealed calibration and check sources since WIPP has not received waste for disposal. For several years the WIPP Dosimetry Group has operated a Harshaw Model 8800C reader to analyze Harshaw 8801-7776 thermoluminescent cards (3 TLD-700 and 1 TLD-600) with 8805 holder. The frequency of false positive results for quarterly dosimeter exchanges is higher than desired by the Dosimetry Group management. Initial observations suggested that exposure to intense ambient sunlight may be responsible for the majority of the false positive readings for element 3. A study was designed to investigate the possibility of light leaking through the holder and inducing a signal in element 3. This paper discusses the methods and results obtained, with special emphasis placed on recommendations to reduce the frequency of light-induced false positive readings

  14. Characterization of conserved arginine residues on Cdt1 that affect licensing activity and interaction with Geminin or Mcm complex.

    Science.gov (United States)

    You, Zhiying; Ode, Koji L; Shindo, Mayumi; Takisawa, Haruhiko; Masai, Hisao

    2016-05-02

    All organisms ensure once and only once replication during S phase through a process called replication licensing. Cdt1 is a key component and crucial loading factor of Mcm complex, which is a central component for the eukaryotic replicative helicase. In higher eukaryotes, timely inhibition of Cdt1 by Geminin is essential to prevent rereplication. Here, we address the mechanism of DNA licensing using purified Cdt1, Mcm and Geminin proteins in combination with replication in Xenopus egg extracts. We mutagenized the 223th arginine of mouse Cdt1 (mCdt1) to cysteine or serine (R-S or R-C, respectively) and 342nd and 346th arginines constituting an arginine finger-like structure to alanine (RR-AA). The RR-AA mutant of Cdt1 could not only rescue the DNA replication activity in Cdt1-depleted extracts but also its specific activity for DNA replication and licensing was significantly increased compared to the wild-type protein. In contrast, the R223 mutants were partially defective in rescue of DNA replication and licensing. Biochemical analyses of these mutant Cdt1 proteins indicated that the RR-AA mutation disabled its functional interaction with Geminin, while R223 mutations resulted in ablation in interaction with the Mcm2∼7 complex. Intriguingly, the R223 mutants are more susceptible to the phosphorylation-induced inactivation or chromatin dissociation. Our results show that conserved arginine residues play critical roles in interaction with Geminin and Mcm that are crucial for proper conformation of the complexes and its licensing activity.

  15. Human CDT1 associates with CDC7 and recruits CDC45 to chromatin during S phase

    DEFF Research Database (Denmark)

    Ballabeni, Andrea; Zamponi, Raffaela; Caprara, Greta

    2009-01-01

    The initiation of DNA replication is a tightly controlled process that involves the formation of distinct complexes at origins of DNA replication at specific periods of the cell cycle. Pre-Replicative Complexes are formed during telophase and early G1. They rearrange at the start of S phase to form...... pre-Initiation Complexes, which are a prerequisite for DNA replication. The CDT1 protein is required for the formation of the pre-Replicative Complexes. Here we show that human CDT1 associates with the CDC7 kinase and recruits CDC45 to chromatin. Moreover, we show that the amount of CDT1 bound...

  16. PyCDT: A Python toolkit for modeling point defects in semiconductors and insulators

    Science.gov (United States)

    Broberg, Danny; Medasani, Bharat; Zimmermann, Nils E. R.; Yu, Guodong; Canning, Andrew; Haranczyk, Maciej; Asta, Mark; Hautier, Geoffroy

    2018-05-01

    Point defects have a strong impact on the performance of semiconductor and insulator materials used in technological applications, spanning microelectronics to energy conversion and storage. The nature of the dominant defect types, how they vary with processing conditions, and their impact on materials properties are central aspects that determine the performance of a material in a certain application. This information is, however, difficult to access directly from experimental measurements. Consequently, computational methods, based on electronic density functional theory (DFT), have found widespread use in the calculation of point-defect properties. Here we have developed the Python Charged Defect Toolkit (PyCDT) to expedite the setup and post-processing of defect calculations with widely used DFT software. PyCDT has a user-friendly command-line interface and provides a direct interface with the Materials Project database. This allows for setting up many charged defect calculations for any material of interest, as well as post-processing and applying state-of-the-art electrostatic correction terms. Our paper serves as a documentation for PyCDT, and demonstrates its use in an application to the well-studied GaAs compound semiconductor. We anticipate that the PyCDT code will be useful as a framework for undertaking readily reproducible calculations of charged point-defect properties, and that it will provide a foundation for automated, high-throughput calculations.

  17. Diagnosing periprosthetic infection: false-positive intraoperative Gram stains.

    Science.gov (United States)

    Oethinger, Margret; Warner, Debra K; Schindler, Susan A; Kobayashi, Hideo; Bauer, Thomas W

    2011-04-01

    Intraoperative Gram stains have a reported low sensitivity but high specificity when used to help diagnose periprosthetic infections. In early 2008, we recognized an unexpectedly high frequency of apparent false-positive Gram stains from revision arthroplasties. The purpose of this report is to describe the cause of these false-positive test results. We calculated the sensitivity and specificity of all intraoperative Gram stains submitted from revision arthroplasty cases during a 3-month interval using microbiologic cultures of the same samples as the gold standard. Methods of specimen harvesting, handling, transport, distribution, specimen processing including tissue grinding/macerating, Gram staining, and interpretation were studied. After a test modification, results of specimens were prospectively collected for a second 3-month interval, and the sensitivity and specificity of intraoperative Gram stains were calculated. The retrospective review of 269 Gram stains submitted from revision arthroplasties indicated historic sensitivity and specificity values of 23% and 92%, respectively. Systematic analysis of all steps of the procedure identified Gram-stained but nonviable bacteria in commercial broth reagents used as diluents for maceration of periprosthetic membranes before Gram staining and culture. Polymerase chain reaction and sequencing showed mixed bacterial DNA. Evaluation of 390 specimens after initiating standardized Millipore filtering of diluent fluid revealed a reduced number of positive Gram stains, yielding 9% sensitivity and 99% specificity. Clusters of false-positive Gram stains have been reported in other clinical conditions. They are apparently rare related to diagnosing periprosthetic infections but have severe consequences if used to guide treatment. Even occasional false-positive Gram stains should prompt review of laboratory methods. Our observations implicate dead bacteria in microbiologic reagents as potential sources of false-positive Gram

  18. Accurate decisions in an uncertain world: collective cognition increases true positives while decreasing false positives.

    Science.gov (United States)

    Wolf, Max; Kurvers, Ralf H J M; Ward, Ashley J W; Krause, Stefan; Krause, Jens

    2013-04-07

    In a wide range of contexts, including predator avoidance, medical decision-making and security screening, decision accuracy is fundamentally constrained by the trade-off between true and false positives. Increased true positives are possible only at the cost of increased false positives; conversely, decreased false positives are associated with decreased true positives. We use an integrated theoretical and experimental approach to show that a group of decision-makers can overcome this basic limitation. Using a mathematical model, we show that a simple quorum decision rule enables individuals in groups to simultaneously increase true positives and decrease false positives. The results from a predator-detection experiment that we performed with humans are in line with these predictions: (i) after observing the choices of the other group members, individuals both increase true positives and decrease false positives, (ii) this effect gets stronger as group size increases, (iii) individuals use a quorum threshold set between the average true- and false-positive rates of the other group members, and (iv) individuals adjust their quorum adaptively to the performance of the group. Our results have broad implications for our understanding of the ecology and evolution of group-living animals and lend themselves for applications in the human domain such as the design of improved screening methods in medical, forensic, security and business applications.

  19. Risk of breast cancer after false-positive results in mammographic screening

    DEFF Research Database (Denmark)

    Roman, Marta; Castells, Xavier; Hofvind, Solveig

    2016-01-01

    risk (RR) of screen-detected cancer for women with false-positive versus negative results. We analyzed information from 1,935,093 women 50–69 years who underwent 6,094,515 screening exams. During an average 5.8 years of follow-up, 230,609 (11.9%) women received a false-positive result and 27,849 (1......Women with false-positive results are commonly referred back to routine screening. Questions remain regarding their long-term outcome of breast cancer. We assessed the risk of screen-detected breast cancer in women with false-positive results. We conducted a joint analysis using individual level.......4%) were diagnosed with screen-detected cancer. The adjusted RR of screen-detected cancer after a false-positive result was 2.01 (95% CI: 1.93–2.09). Women who tested false-positive at first screen had a RR of 1.86 (95% CI: 1.77–1.96), whereas those who tested false-positive at third screening had a RR...

  20. Risk factors for false positive and for false negative test results in screening with fecal occult blood testing

    NARCIS (Netherlands)

    Stegeman, Inge; de Wijkerslooth, Thomas R.; Stoop, Esther M.; van Leerdam, Monique; van Ballegooijen, M.; Kraaijenhagen, Roderik A.; Fockens, Paul; Kuipers, Ernst J.; Dekker, Evelien; Bossuyt, Patrick M.

    2013-01-01

    Differences in the risk of a false negative or a false positive fecal immunochemical test (FIT) across subgroups may affect optimal screening strategies. We evaluate whether subgroups are at increased risk of a false positive or a false negative FIT result, whether such variability in risk is

  1. Accounting for False Positive HIV Tests: Is Visceral Leishmaniasis Responsible?

    Science.gov (United States)

    Shanks, Leslie; Ritmeijer, Koert; Piriou, Erwan; Siddiqui, M Ruby; Kliescikova, Jarmila; Pearce, Neil; Ariti, Cono; Muluneh, Libsework; Masiga, Johnson; Abebe, Almaz

    2015-01-01

    Co-infection with HIV and visceral leishmaniasis is an important consideration in treatment of either disease in endemic areas. Diagnosis of HIV in resource-limited settings relies on rapid diagnostic tests used together in an algorithm. A limitation of the HIV diagnostic algorithm is that it is vulnerable to falsely positive reactions due to cross reactivity. It has been postulated that visceral leishmaniasis (VL) infection can increase this risk of false positive HIV results. This cross sectional study compared the risk of false positive HIV results in VL patients with non-VL individuals. Participants were recruited from 2 sites in Ethiopia. The Ethiopian algorithm of a tiebreaker using 3 rapid diagnostic tests (RDTs) was used to test for HIV. The gold standard test was the Western Blot, with indeterminate results resolved by PCR testing. Every RDT screen positive individual was included for testing with the gold standard along with 10% of all negatives. The final analysis included 89 VL and 405 non-VL patients. HIV prevalence was found to be 12.8% (47/ 367) in the VL group compared to 7.9% (200/2526) in the non-VL group. The RDT algorithm in the VL group yielded 47 positives, 4 false positives, and 38 negatives. The same algorithm for those without VL had 200 positives, 14 false positives, and 191 negatives. Specificity and positive predictive value for the group with VL was less than the non-VL group; however, the difference was not found to be significant (p = 0.52 and p = 0.76, respectively). The test algorithm yielded a high number of HIV false positive results. However, we were unable to demonstrate a significant difference between groups with and without VL disease. This suggests that the presence of endemic visceral leishmaniasis alone cannot account for the high number of false positive HIV results in our study.

  2. Accounting for False Positive HIV Tests: Is Visceral Leishmaniasis Responsible?

    Directory of Open Access Journals (Sweden)

    Leslie Shanks

    Full Text Available Co-infection with HIV and visceral leishmaniasis is an important consideration in treatment of either disease in endemic areas. Diagnosis of HIV in resource-limited settings relies on rapid diagnostic tests used together in an algorithm. A limitation of the HIV diagnostic algorithm is that it is vulnerable to falsely positive reactions due to cross reactivity. It has been postulated that visceral leishmaniasis (VL infection can increase this risk of false positive HIV results. This cross sectional study compared the risk of false positive HIV results in VL patients with non-VL individuals.Participants were recruited from 2 sites in Ethiopia. The Ethiopian algorithm of a tiebreaker using 3 rapid diagnostic tests (RDTs was used to test for HIV. The gold standard test was the Western Blot, with indeterminate results resolved by PCR testing. Every RDT screen positive individual was included for testing with the gold standard along with 10% of all negatives. The final analysis included 89 VL and 405 non-VL patients. HIV prevalence was found to be 12.8% (47/ 367 in the VL group compared to 7.9% (200/2526 in the non-VL group. The RDT algorithm in the VL group yielded 47 positives, 4 false positives, and 38 negatives. The same algorithm for those without VL had 200 positives, 14 false positives, and 191 negatives. Specificity and positive predictive value for the group with VL was less than the non-VL group; however, the difference was not found to be significant (p = 0.52 and p = 0.76, respectively.The test algorithm yielded a high number of HIV false positive results. However, we were unable to demonstrate a significant difference between groups with and without VL disease. This suggests that the presence of endemic visceral leishmaniasis alone cannot account for the high number of false positive HIV results in our study.

  3. Increased risk of breast cancer in women with false-positive test

    DEFF Research Database (Denmark)

    von Euler-Chelpin, My; Kuchiki, Megumi; Vejborg, Ilse

    2014-01-01

    of misclassification, i.e. women who were actually false-negatives instead of false-positives. METHOD: We used data from the Copenhagen Mammography Screening Programme, Denmark. The study population was the 295 women, out of 4743 recalled women from a total of 58,003 participants, with a false-positive test during...... the women with misclassified tests had been excluded, there was an excess risk of breast cancer of 27% (RR=1.27, 95% confidence interval (CI), 1.11-1.46) among the women with a false-positive test compared to women with only negative tests. Women with a false-positive test determined at assessment had...... an excess risk of 27%, while false-positives determined at surgery had an excess risk of 30%. CONCLUSIONS: The results indicate that the increased risk is not explained only by misclassification. The excess risk remains for false-positives determined at assessment as well as at surgery, which favours some...

  4. Risk of breast cancer after false-positive results in mammographic screening.

    Science.gov (United States)

    Román, Marta; Castells, Xavier; Hofvind, Solveig; von Euler-Chelpin, My

    2016-06-01

    Women with false-positive results are commonly referred back to routine screening. Questions remain regarding their long-term outcome of breast cancer. We assessed the risk of screen-detected breast cancer in women with false-positive results. We conducted a joint analysis using individual level data from the population-based screening programs in Copenhagen and Funen in Denmark, Norway, and Spain. Overall, 150,383 screened women from Denmark (1991-2008), 612,138 from Norway (1996-2010), and 1,172,572 from Spain (1990-2006) were included. Poisson regression was used to estimate the relative risk (RR) of screen-detected cancer for women with false-positive versus negative results. We analyzed information from 1,935,093 women 50-69 years who underwent 6,094,515 screening exams. During an average 5.8 years of follow-up, 230,609 (11.9%) women received a false-positive result and 27,849 (1.4%) were diagnosed with screen-detected cancer. The adjusted RR of screen-detected cancer after a false-positive result was 2.01 (95% CI: 1.93-2.09). Women who tested false-positive at first screen had a RR of 1.86 (95% CI: 1.77-1.96), whereas those who tested false-positive at third screening had a RR of 2.42 (95% CI: 2.21-2.64). The RR of breast cancer at the screening test after the false-positive result was 3.95 (95% CI: 3.71-4.21), whereas it decreased to 1.25 (95% CI: 1.17-1.34) three or more screens after the false-positive result. Women with false-positive results had a twofold risk of screen-detected breast cancer compared to women with negative tests. The risk remained significantly higher three or more screens after the false-positive result. The increased risk should be considered when discussing stratified screening strategies. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

  5. Implications of false-positive results for future cancer screenings.

    Science.gov (United States)

    Taksler, Glen B; Keating, Nancy L; Rothberg, Michael B

    2018-06-01

    False-positive cancer screening results may affect a patient's willingness to obtain future screening. The authors conducted logistic regression analysis of 450,484 person-years of electronic medical records (2006-2015) in 92,405 individuals aged 50 to 75 years. Exposures were false-positive breast, prostate, or colorectal cancer screening test results (repeat breast imaging or negative breast biopsy ≤3 months after screening mammography, repeat prostate-specific antigen [PSA] test ≤3 months after PSA test result ≥4.0 ng/mL or negative prostate biopsy ≤3 months after any PSA result, or negative colonoscopy [without biopsy/polypectomy] ≤6 months after a positive fecal occult blood test). Outcomes were up-to-date status with breast or colorectal cancer screening. Covariates included prior screening history, clinical information (eg, family history, obesity, and smoking status), comorbidity, and demographics. Women were more likely to be up to date with breast cancer screening if they previously had false-positive mammography findings (adjusted odds ratio [AOR], 1.43 [95% confidence interval, 1.34-1.51] without breast biopsy and AOR, 2.02 [95% confidence interval, 1.56-2.62] with breast biopsy; both Pfalse-positive PSA testing were more likely to be up to date with colorectal cancer screening (AOR, 1.22 [P = .039] without prostate imaging/biopsy and AOR, 1.60 [P = .028] with imaging/biopsy). Results were stronger for individuals with more false-positive results (all P≤.005). However, women with previous false-positive colorectal cancer fecal occult blood test screening results were found to be less likely to be up to date with breast cancer screening (AOR, 0.73; Pfalse-positive breast or prostate cancer screening test were more likely to engage in future screening. Cancer 2018;124:2390-8. © 2018 American Cancer Society. © 2018 American Cancer Society.

  6. Accurate decisions in an uncertain world: collective cognition increases true positives while decreasing false positives

    NARCIS (Netherlands)

    Wolf, M.; Kurvers, R.H.J.M.; Ward, A.J.W.; Krause, S.; Krause, J.

    2013-01-01

    In a wide range of contexts, including predator avoidance, medical decision-making and security screening, decision accuracy is fundamentally constrained by the trade-off between true and false positives. Increased true positives are possible only at the cost of increased false positives;

  7. Targeted ubiquitination of CDT1 by the DDB1-CUL4A-ROC1 ligase in response to DNA damage.

    Science.gov (United States)

    Hu, Jian; McCall, Chad M; Ohta, Tomohiko; Xiong, Yue

    2004-10-01

    Cullins assemble a potentially large number of ubiquitin ligases by binding to the RING protein ROC1 to catalyse polyubiquitination, as well as binding to various specificity factors to recruit substrates. The Cul4A gene is amplified in human breast and liver cancers, and loss-of-function of Cul4 results in the accumulation of the replication licensing factor CDT1 in Caenorhabditis elegans embryos and ultraviolet (UV)-irradiated human cells. Here, we report that human UV-damaged DNA-binding protein DDB1 associates stoichiometrically with CUL4A in vivo, and binds to an amino-terminal region in CUL4A in a manner analogous to SKP1, SOCS and BTB binding to CUL1, CUL2 and CUL3, respectively. As with SKP1-CUL1, the DDB1-CUL4A association is negatively regulated by the cullin-associated and neddylation-dissociated protein, CAND1. Recombinant DDB1 and CDT1 bind directly to each other in vitro, and ectopically expressed DDB1 bridges CDT1 to CUL4A in vivo. Silencing DDB1 prevented UV-induced rapid CDT1 degradation in vivo and CUL4A-mediated CDT1 ubiquitination in vitro. We suggest that DDB1 targets CDT1 for ubiquitination by a CUL4A-dependent ubiquitin ligase, CDL4A(DDB1), in response to UV irradiation.

  8. Coincidence of scintigraphic false positive and false negative findings in parathyroid and thyroid adenomas (case report)

    Energy Technology Data Exchange (ETDEWEB)

    Mana, O.; Zatta, G.; Boccolari, S.; Barbesti, S.; Tarolo, G.L.

    1987-04-01

    The subtractive double tracer scintigraphy with /sup 201/Tl and /sup 99m/Tc is a useful technique in studying parathyroid nodules; nevertheless, this method can give misleading informations especially in presence of thyroid nodules with false positive and false negative findings. In this case report the technique was applied in studying a patient with three nodules (two thyroid adenomas and one parathyroid adenoma), where both scintigraphic and echographic methods provided misleading informations. The selective uptake of /sup 201/Tl in the upper region of the right thyroid lobe gave a false positive finding, while the increased uptake of /sup 99m/Tc in a hyperfunctioning thyroid adenoma of left lobe masked the parathyroid adenoma laying below, giving a false negative finding.

  9. Fijación de radioyodo en huesos maxilares simulando metástasis en pacientes con Carcinoma Diferenciado de Tiroides (CDT): False- Positive images in patients with Differentiated Thyroid Carcinoma. (DTC) Uptake of 131-I in maxillary bones mimicking salivary glands

    OpenAIRE

    O. J. Degrossi; S. Gutiérrez; A. Fadel; E. B. Degrossi; M. C. Valdivieso; R. L. Balbuena; M. del C. Alak; M. de Cabrejas

    2008-01-01

    En estudios centellográficos con 131I (CCT) para seguimiento, postablación o tratamiento de pacientes portadores de carcinoma diferenciado de tiroides (CDT) se observan frecuentemente en tiempos precoces áreas de captación del radiotrazador en macizo facial. Estas áreas corresponden, generalmente, a glándulas salivares y extremo anterior de mucosa nasal y se mantienen durante las primeras 48 horas y no son observadas generalmente a las 72 horas. Pero con menor frecuencia se presentan otras qu...

  10. Inhibition of NEDD8-activating enzyme induces rereplication and apoptosis in human tumor cells consistent with deregulating CDT1 turnover.

    Science.gov (United States)

    Milhollen, Michael A; Narayanan, Usha; Soucy, Teresa A; Veiby, Petter O; Smith, Peter G; Amidon, Benjamin

    2011-04-15

    Loss of NEDD8-activating enzyme (NAE) function by siRNA knockdown or inhibition by the small molecule NAE inhibitor MLN4924 leads to increased steady-state levels of direct Cullin-RING ligase (CRL) substrates by preventing their ubiquitination and proteasome-dependent degradation. Many of these CRL substrates are involved in cell cycle progression, including a critical DNA replication licensing factor CDT1. Cell cycle analysis of asynchronous and synchronous cultures after NAE inhibition revealed effects on cell cycle distribution and activation of DNA break repair signaling pathways similar to that reported for CDT1 overexpression. The siRNA knockdown of cullins critical for the turnover of CDT1 recapitulated the aberrant rereplication phenotype while CDT1 knockdown was suppressing. Although NAE inhibition leads to deregulation of many CRL substrates, these data demonstrate that CDT1 accumulation mediates the DNA rereplication phenotype resulting from loss of NAE function. DNA rereplication is an unrecoverable cellular insult and the small molecule inhibitor MLN4924, currently in phase I trials, represents an unprecedented opportunity to explore this mechanism of cytotoxicity for the treatment of cancer. ©2011 AACR.

  11. Risk of breast cancer after false-positive test results in screening mammography

    DEFF Research Database (Denmark)

    von Euler-Chelpin, My Catarina; Risør, Louise Madeleine; Thorsted, Brian Larsen

    2012-01-01

    Screening for disease in healthy people inevitably leads to some false-positive tests in disease-free individuals. Normally, women with false-positive screening tests for breast cancer are referred back to routine screening. However, the long-term outcome for women with false-positive tests...

  12. Non-canonical CRL4A/4B(CDT2 interacts with RAD18 to modulate post replication repair and cell survival.

    Directory of Open Access Journals (Sweden)

    Sarah Sertic

    Full Text Available The Cullin-4(CDT2 E3 ubiquitin ligase plays an essential role in DNA replication origin licensing directing degradation of several licensing factors at the G1/S transition in order to prevent DNA re-replication. Recently a RAD18-independent role of Cullin-4(CDT2 in PCNA monoubiquitylation has been proposed. In an effort to better understand the function of Cullin-4(CDT2 E3 ubiquitin ligase in mammalian Post-Replication Repair during an unperturbed S-phase, we show that down-regulation of Cullin-4(CDT2 leads to two distinguishable independent phenotypes in human cells that unveil at least two independent roles of Cullin-4(CDT2 in S-phase. Apart from the re-replication preventing activity, we identified a non-canonical Cullin-4(CDT2 complex, containing both CUL4A and CUL4B, associated to the COP9 signalosome, that controls a RAD18-dependent damage avoidance pathway essential during an unperturbed S-phase. Indeed, we show that the non-canonical Cullin-4A/4B(CDT2 complex binds to RAD18 and it is required to modulate RAD18 protein levels onto chromatin and the consequent dynamics of PCNA monoubiquitylation during a normal S-phase. This function prevents replication stress, ATR hyper-signaling and, ultimately, apoptosis. A very similar PRR regulatory mechanism has been recently described for Spartan. Our findings uncover a finely regulated process in mammalian cells involving Post-Replication Repair factors, COP9 signalosome and a non-canonical Cullin4-based E3 ligase which is essential to tolerate spontaneous damage and for cell survival during physiological DNA replication.

  13. Use of finger-prick dried blood spots (fpDBS) and capillary electrophoresis for carbohydrate deficient transferrin (CDT) screening in forensic toxicology.

    Science.gov (United States)

    Bertaso, Anna; Sorio, Daniela; Vandoros, Anthula; De Palo, Elio F; Bortolotti, Federica; Tagliaro, Franco

    2016-10-01

    Continued progress in chronic alcohol abuse investigation requires the development of less invasive procedures for screening purposes. The application of finger-prick and related dried blood spots (fpDBS) for carbohydrate deficient transferrin (CDT) detection appears suitable for this aim. Therefore, the goal of this project was to develop a screening method for CDT using fpDBS with CZE analysis. Blood samples prepared by finger-prick were placed on DBS cards and left to air dry; each dried fpDBS disc was shredded into small pieces and suspended in acid solution (60 μL of HCl 120 mmol/L). After centrifugation (10 min at 1500 × g), the collected sample was adjusted to pH 3.5. After an overnight incubation, the pH was neutralised and an iron rich solution was added. After 1 h, CZE analysis was carried out. A group of 47 individuals was studied. Parallel serum samples were collected from each investigated subject and the %CDT for each sample was measured using HPLC and CZE techniques. The fpDBS transferrin sialo isoform electropherograms were similar to those obtained with serum. Moreover, fpDBS CZE CDT percentage levels demonstrated significant statistical correlation with those obtained from serum for both HPLC and CZE %CDT (p < 0.01; r 2 = 0.8913 and 0.8976, respectively), with %CDT from 0.8 to 13.7% for fpDBS and from 0.7 to 12.7% for serum. The newly developed fpDBS procedure for CDT analysis provides a simple and inexpensive tool for use in population screening. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Shear-wave elastography in the diagnosis of solid breast masses: what leads to false-negative or false-positive results?

    Science.gov (United States)

    Yoon, Jung Hyun; Jung, Hae Kyoung; Lee, Jong Tae; Ko, Kyung Hee

    2013-09-01

    To investigate the factors that have an effect on false-positive or false-negative shear-wave elastography (SWE) results in solid breast masses. From June to December 2012, 222 breast lesions of 199 consecutive women (mean age: 45.3 ± 10.1 years; range, 21 to 88 years) who had been scheduled for biopsy or surgical excision were included. Greyscale ultrasound and SWE were performed in all women before biopsy. Final ultrasound assessments and SWE parameters (pattern classification and maximum elasticity) were recorded and compared with histopathology results. Patient and lesion factors in the 'true' and 'false' groups were compared. Of the 222 masses, 175 (78.8 %) were benign, and 47 (21.2 %) were malignant. False-positive rates of benign masses were significantly higher than false-negative rates of malignancy in SWE patterns, 36.6 % to 6.4 % (P masses, factors showing significance among false SWE features were lesion size, breast thickness and lesion depth (all P breast masses had SWE images of good quality. False SWE features were more significantly seen in benign masses. Lesion size, breast thickness and lesion depth have significance in producing false results, and this needs consideration in SWE image acquisition. • Shear-wave elastography (SWE) is widely used during breast imaging • At SWE, false-positive rates were significantly higher than false-negative rates • Larger size, breast thickness, depth and fair quality influences false-positive SWE features • Smaller size, larger breast thickness and depth influences false-negative SWE features.

  15. Female False Positive Exercise Stress ECG Testing - Fact Verses Fiction.

    Science.gov (United States)

    Fitzgerald, Benjamin T; Scalia, William M; Scalia, Gregory M

    2018-03-07

    Exercise stress testing is a well validated cardiovascular investigation. Accuracy for treadmill stress electrocardiograph (ECG) testing has been documented at 60%. False positive stress ECGs (exercise ECG changes with non-obstructive disease on anatomical testing) are common, especially in women, limiting the effectiveness of the test. This study investigates the incidence and predictors of false positive stress ECG findings, referenced against stress echocardiography (SE) as a standard. Stress echocardiography was performed using the Bruce treadmill protocol. False positive stress ECG tests were defined as greater than 1mm of ST depression on ECG during exertion, without pain, with a normal SE. Potential causes for false positive tests were recorded before the test. Three thousand consecutive negative stress echocardiograms (1036 females, 34.5%) were analysed (age 59+/-14 years. False positive (F+) stress ECGs were documented in 565/3000 tests (18.8%). F+ stress ECGs were equally prevalent in females (194/1036, 18.7%) and males (371/1964, 18.9%, p=0.85 for the difference). Potential causes (hypertension, left ventricular hypertrophy, known coronary disease, arrhythmia, diabetes mellitus, valvular heart disease) were recorded in 36/194 (18.6%) of the female F+ ECG tests and 249/371 (68.2%) of the male F+ ECG tests (preinforce the value of stress imaging, particularly in women. Copyright © 2018 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). All rights reserved.

  16. Psychological effects of false-positive results in expanded newborn screening in China.

    Directory of Open Access Journals (Sweden)

    Wen-Jun Tu

    Full Text Available OBJECTIVES: As more families participate expanded newborn screening for metabolic disorders in China, the overall number of false positives increases. Our goal was to assess the potential impact on parental stress, perceptions of the child's health, and family relationships. METHODS: Parents of 49 infants with false-positive screening results for metabolic disorders in the expanded newborn screening panel were compared with parents of 42 children with normal screening results. Parents first completed structured interview using likert scales, closed and open questions. Parents also completed the parenting stress index. RESULTS: A total of 88 mothers and 41 fathers were interviewed. More mothers in the false-positive group reported that their children required extra parental care (21%, compared with 5% of mothers in the normal-screened group (P<0.001. 39% of mothers in the false-positive group reported that they worry about their child's future development, compared with 10% of mothers in the normal-screened group (P<0.001. Fathers in the false-positive group did not differ from fathers in the normal-screened group in reporting worry about their child's extra care requirements, and their child's future development. Children with false-positive results compared with children with normal results were triple as likely to experience hospitalization (27%vs 9%, respectively; P<0.001. CONCLUSIONS: The results showing false-positive screening results may affect parental stress and the parent-child relationship. Parental stress and anxiety can be reduced with improved education and communication to parents about false-positive results.

  17. Epidemiology, public health, and the rhetoric of false positives

    DEFF Research Database (Denmark)

    Blair, Aaron; Saracci, Rodolfo; Vineis, Paolo

    2009-01-01

    BACKGROUND: As an observational science, epidemiology is regarded by some researchers as inherently flawed and open to false results. In a recent paper, Boffetta et al. [Boffetta P, McLaughlin JK, LaVecchia C, Tarone RE, Lipworth L, Blot WJ. False-positive results in cancer epidemiology: a plea f...

  18. Diagnostic Invasiveness and Psychosocial Consequences of False-Positive Mammography

    DEFF Research Database (Denmark)

    Heleno, Bruno M.; Siersma, Volkert Dirk; Brodersen, John

    2015-01-01

    PURPOSE: We undertook a study to assess whether women with false-positivemammography have worse psychosocial consequences if managed with aworkup that involves a biopsy (invasive group) than if managed with only additional imaging (noninvasive group). METHODS: We performed subgroup analysis...... of a cohort study of 454 womenwith abnormal screening mammography and 908 matched control women withnormal results. Using a condition-specific questionnaire (Consequences of Screening in Breast Cancer), we assessed 12 psychosocial consequences at 5 time points (0, 1, 6, 18, and 36 months after final diagnosis......) and compared the 2 groups of women with false-positives (invasive and noninvasive management groups). RESULTS: Among the 252 women with false-positive mammography eligible forthis study, psychosocial consequences were similar for those managed invasivelyand those managed noninvasively during the 36 months...

  19. Addressing False Positives in Early Reading Assessment Using Intervention Response Data

    Science.gov (United States)

    McAlenney, Athena Lentini; Coyne, Michael D.

    2015-01-01

    The current study examined a solution to high false positive reading risk classification rates in early kindergarten by investigating a method of identifying students with possible false positive risk classifications and returning them to general classroom instruction. Researchers assessed kindergarten students (N = 105) identified as at risk who…

  20. False-positive results in mammographic screening for breast cancer in Europe

    DEFF Research Database (Denmark)

    Hofvind, Solveig; Ponti, Antonio; Patnick, Julietta

    2012-01-01

    To estimate the cumulative risk of a false-positive screening result in European mammographic screening programmes, and examine the rates and procedures of further assessment.......To estimate the cumulative risk of a false-positive screening result in European mammographic screening programmes, and examine the rates and procedures of further assessment....

  1. Detecting false positive sequence homology: a machine learning approach.

    Science.gov (United States)

    Fujimoto, M Stanley; Suvorov, Anton; Jensen, Nicholas O; Clement, Mark J; Bybee, Seth M

    2016-02-24

    Accurate detection of homologous relationships of biological sequences (DNA or amino acid) amongst organisms is an important and often difficult task that is essential to various evolutionary studies, ranging from building phylogenies to predicting functional gene annotations. There are many existing heuristic tools, most commonly based on bidirectional BLAST searches that are used to identify homologous genes and combine them into two fundamentally distinct classes: orthologs and paralogs. Due to only using heuristic filtering based on significance score cutoffs and having no cluster post-processing tools available, these methods can often produce multiple clusters constituting unrelated (non-homologous) sequences. Therefore sequencing data extracted from incomplete genome/transcriptome assemblies originated from low coverage sequencing or produced by de novo processes without a reference genome are susceptible to high false positive rates of homology detection. In this paper we develop biologically informative features that can be extracted from multiple sequence alignments of putative homologous genes (orthologs and paralogs) and further utilized in context of guided experimentation to verify false positive outcomes. We demonstrate that our machine learning method trained on both known homology clusters obtained from OrthoDB and randomly generated sequence alignments (non-homologs), successfully determines apparent false positives inferred by heuristic algorithms especially among proteomes recovered from low-coverage RNA-seq data. Almost ~42 % and ~25 % of predicted putative homologies by InParanoid and HaMStR respectively were classified as false positives on experimental data set. Our process increases the quality of output from other clustering algorithms by providing a novel post-processing method that is both fast and efficient at removing low quality clusters of putative homologous genes recovered by heuristic-based approaches.

  2. False-Positive Rate of AKI Using Consensus Creatinine-Based Criteria.

    Science.gov (United States)

    Lin, Jennie; Fernandez, Hilda; Shashaty, Michael G S; Negoianu, Dan; Testani, Jeffrey M; Berns, Jeffrey S; Parikh, Chirag R; Wilson, F Perry

    2015-10-07

    Use of small changes in serum creatinine to diagnose AKI allows for earlier detection but may increase diagnostic false-positive rates because of inherent laboratory and biologic variabilities of creatinine. We examined serum creatinine measurement characteristics in a prospective observational clinical reference cohort of 2267 adult patients with AKI by Kidney Disease Improving Global Outcomes creatinine criteria and used these data to create a simulation cohort to model AKI false-positive rates. We simulated up to seven successive blood draws on an equal population of hypothetical patients with unchanging true serum creatinine values. Error terms generated from laboratory and biologic variabilities were added to each simulated patient's true serum creatinine value to obtain the simulated measured serum creatinine for each blood draw. We determined the proportion of patients who would be erroneously diagnosed with AKI by Kidney Disease Improving Global Outcomes creatinine criteria. Within the clinical cohort, 75.0% of patients received four serum creatinine draws within at least one 48-hour period during hospitalization. After four simulated creatinine measurements that accounted for laboratory variability calculated from assay characteristics and 4.4% of biologic variability determined from the clinical cohort and publicly available data, the overall false-positive rate for AKI diagnosis was 8.0% (interquartile range =7.9%-8.1%), whereas patients with true serum creatinine ≥1.5 mg/dl (representing 21% of the clinical cohort) had a false-positive AKI diagnosis rate of 30.5% (interquartile range =30.1%-30.9%) versus 2.0% (interquartile range =1.9%-2.1%) in patients with true serum creatinine values false-positive rates caused by inherent variability of serum creatinine at higher baseline values, potentially misclassifying patients with CKD in AKI studies. Copyright © 2015 by the American Society of Nephrology.

  3. Cdt1p, through its interaction with Mcm6p, is required for the formation, nuclear accumulation and chromatin loading of the MCM complex.

    Science.gov (United States)

    Wu, Rentian; Wang, Jiafeng; Liang, Chun

    2012-01-01

    Regulation of DNA replication initiation is essential for the faithful inheritance of genetic information. Replication initiation is a multi-step process involving many factors including ORC, Cdt1p, Mcm2-7p and other proteins that bind to replication origins to form a pre-replicative complex (pre-RC). As a prerequisite for pre-RC assembly, Cdt1p and the Mcm2-7p heterohexameric complex accumulate in the nucleus in G1 phase in an interdependent manner in budding yeast. However, the nature of this interdependence is not clear, nor is it known whether Cdt1p is required for the assembly of the MCM complex. In this study, we provide the first evidence that Cdt1p, through its interaction with Mcm6p with the C-terminal regions of the two proteins, is crucial for the formation of the MCM complex in both the cytoplasm and nucleoplasm. We demonstrate that disruption of the interaction between Cdt1p and Mcm6p prevents the formation of the MCM complex, excludes Mcm2-7p from the nucleus, and inhibits pre-RC assembly and DNA replication. Our findings suggest a function for Cdt1p in promoting the assembly of the MCM complex and maintaining its integrity by interacting with Mcm6p.

  4. Positive events protect children from causal false memories for scripted events.

    Science.gov (United States)

    Melinder, Annika; Toffalini, Enrico; Geccherle, Eleonora; Cornoldi, Cesare

    2017-11-01

    Adults produce fewer inferential false memories for scripted events when their conclusions are emotionally charged than when they are neutral, but it is not clear whether the same effect is also found in children. In the present study, we examined this issue in a sample of 132 children aged 6-12 years (mean 9 years, 3 months). Participants encoded photographs depicting six script-like events that had a positively, negatively, or a neutral valenced ending. Subsequently, true and false recognition memory of photographs related to the observed scripts was tested as a function of emotionality. Causal errors-a type of false memory thought to stem from inferential processes-were found to be affected by valence: children made fewer causal errors for positive than for neutral or negative events. Hypotheses are proposed on why adults were found protected against inferential false memories not only by positive (as for children) but also by negative endings when administered similar versions of the same paradigm.

  5. Is there a positive bias in false recognition? Evidence from confabulating amnesia patients.

    Science.gov (United States)

    Alkathiri, Nura H; Morris, Robin G; Kopelman, Michael D

    2015-10-01

    Although there is some evidence for a positive emotional bias in the content of confabulations in brain damaged patients, findings have been inconsistent. The present study used the semantic-associates procedure to induce false recall and false recognition in order to examine whether a positive bias would be found in confabulating amnesic patients, relative to non-confabulating amnesic patients and healthy controls. Lists of positive, negative and neutral words were presented in order to induce false recall or false recognition of non-presented (but semantically associated) words. The latter were termed 'critical intrusions'. Thirteen confabulating amnesic patients, 13 non-confabulating amnesic patients and 13 healthy controls were investigated. Confabulating patients falsely recognised a higher proportion of positive (but unrelated) words, compared with non-confabulating patients and healthy controls. No differences were found for recall memory. Signal detection analysis, however, indicated that the positive bias for false recognition memory might reflect weaker memory in the confabulating amnesic group. This suggested that amnesia patients with weaker memory are more likely to confabulate and the content of these confabulations are more likely to be positive. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Study of false positives in 5-ALA induced photodynamic diagnosis of bladder carcinoma

    Science.gov (United States)

    Draga, Ronald O. P.; Grimbergen, Matthijs C. M.; Kok, Esther T.; Jonges, Trudy G. N.; Bosch, J. L. H. R.

    2009-02-01

    Photodynamic diagnosis (PDD) is a technique that enhances the detection of tumors during cystoscopy using a photosensitizer which accumulates primarily in cancerous cells and will fluoresce when illuminated by violetblue light. A disadvantage of PDD is the relatively low specificity. In this retrospective study we aimed to identify predictors for false positive findings in PDD. Factors such as gender, age, recent transurethral resection of bladder tumors (TURBT), previous intravesical therapy (IVT) and urinary tract infections (UTIs) were examined for association with the false positive rates in a multivariate analysis. Data of 366 procedures and 200 patients were collected. Patients were instilled with 5-aminolevulinic acid (5-ALA) intravesically and 1253 biopsies were taken from tumors and suspicious lesions. Female gender and TURBT are independent predictors of false positives in PDD. However, previous intravesical therapy with Bacille Calmette-Guérin is also an important predictor of false positives. The false positive rate decreases during the first 9-12 weeks after the latest TURBT and the latest intravesical chemotherapy. Although shortly after IVT and TURBT false positives increase, PDD improves the diagnostic sensitivity and results in more adequate treatment strategies in a significant number of patients.

  7. Look Again: An Investigation of False Positive Detections in Combat Models

    National Research Council Canada - National Science Library

    Wainwright, Ryan K

    2008-01-01

    .... Existing combat models tend to overlook or downplay false positive detections. Signal Detection Theory provides the framework for analysis of an observer's hits, misses, correct rejections, and false alarms...

  8. Categorizing Mistaken False Positives in Regulation of Human and Environmental Health

    DEFF Research Database (Denmark)

    Hansen, Steffen Foss; Krayer von Krauss, Martin Paul; Tickner, J.A.

    2007-01-01

    One of the concerns often voiced by critics of the precautionary principle is that a widespread regulatory application of the principle will lead to a large number of false positives (i.e., over-regulation of minor risks and regulation of nonexisting risks). The present article proposes a general......," including: real risks, "The jury is still out," nonregulated proclaimed risks, "Too narrow a definition of risk," and risk-risk tradeoffs. These categories are defined and examples are presented in order to illustrate their key characteristics. On the basis of our analysis, we were able to identify only...... four cases that could be defined as regulatory false positives in the light of today's knowledge and recognized uncertainty: the Southern Corn Leaf Blight, the Swine Flu, Saccharin, and Food Irradiation in relation to consumer health. We conclude that concerns about false positives do not represent...

  9. Participation behaviour following a false positive test in the Copenhagen mammography screening programme

    DEFF Research Database (Denmark)

    Andersen, Sune Bangsbøll; Vejborg, Ilse; von Euler-Chelpin, My

    2008-01-01

    women experiencing a negative screening test, regardless of whether the false positive statement was given following assessment or following surgery. The benign to malignant biopsy ratio, comparing the type B false positives to the true positives, was by the fifth round well below the desirable level...

  10. Skin irritation, false positives and the local lymph node assay: a guideline issue?

    Science.gov (United States)

    Basketter, David A; Kimber, Ian

    2011-10-01

    Since the formal validation and regulatory acceptance of the local lymph node assay (LLNA) there have been commentaries suggesting that the irritant properties of substances can give rise to false positives. As toxicology aspires to progress rapidly towards the age of in vitro alternatives, it is of increasing importance that issues relating to assay selectivity and performance are understood fully, and that true false positive responses are distinguished clearly from those that are simply unpalatable. In the present review, we have focused on whether skin irritation per se is actually a direct cause of true false positive results in the LLNA. The body of published work has been examined critically and considered in relation to our current understanding of the mechanisms of skin irritation and skin sensitisation. From these analyses it is very clear that, of itself, skin irritation is not a cause of false positive results. The corollary is, therefore, that limiting test concentrations in the LLNA for the purpose of avoiding skin irritation may lead, unintentionally, to false negatives. Where a substance is a true false positive in the LLNA, the classic example being sodium lauryl sulphate, explanations for that positivity will have to reach beyond the seductive, but incorrect, recourse to its skin irritation potential. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Evaluation of positive and false-positive results in syphilis screening of blood donors in Rio de Janeiro, Brazil.

    Science.gov (United States)

    Sandes, V S; Silva, S G C; Motta, I J F; Velarde, L G C; de Castilho, S R

    2017-06-01

    We propose to analyse the positive and false-positive results of treponemal and nontreponemal tests in blood donors from Brazil and to evaluate possible factors associated with the results of treponemal tests. Treponemal tests have been used widely for syphilis screening in blood banks. The introduction of these tests in donor screening has caused an impact and a loss of donors who need to be assessed. This was a retrospective cross-sectional study of syphilis screening and confirmatory test results of blood donors that were obtained before and after adopting a chemiluminescent immunoassay (CLIA). A comparative analysis was performed using a second sample drawn from positive donors. The possible factors associated with CLIA-positive or CLIA-false-positive results were investigated in a subgroup. Statistical tests were used to compare the proportions and adjusted estimates of association. The reactivity rate increased from 1·01% (N = 28 158) to 2·66% (N = 25 577) after introducing the new test. Among Venereal Disease Research Laboratory (VDRL)- and CLIA-confirmed results, the false-positive rates were 40·5% (N = 180) and 37·4% (N = 359), respectively (P = 0·5266). Older donors (OR = 1·04; P = 0·0010) and donors with lower education levels (OR = 6·59; P = 0·0029) were associated with a higher risk of positivity for syphilis. CLIA represents an improvement in blood bank serological screening. However, its use in a healthy population appears to result in high rates of false positives. Identifying which characteristics can predict false positives, however, remains a challenge. © 2017 British Blood Transfusion Society.

  12. THE XO PLANETARY SURVEY PROJECT: ASTROPHYSICAL FALSE POSITIVES

    International Nuclear Information System (INIS)

    Poleski, Radosaw; McCullough, Peter R.; Valenti, Jeff A.; Burke, Christopher J.; Machalek, Pavel; Janes, Kenneth

    2010-01-01

    Searches for planetary transits find many astrophysical false positives as a by-product. There are four main types analyzed in the literature: a grazing-incidence eclipsing binary (EB) star, an EB star with a small radius companion star, a blend of one or more stars with an unrelated EB star, and a physical triple star system. We present a list of 69 astrophysical false positives that had been identified as candidates of transiting planets of the on-going XO survey. This list may be useful in order to avoid redundant observation and characterization of these particular candidates that have been independently identified by other wide-field searches for transiting planets. The list may be useful for those modeling the yield of the XO survey and surveys similar to it. Subsequent observations of some of the listed stars may improve mass-radius relations, especially for low-mass stars. From the candidates exhibiting eclipses, we report three new spectroscopic double-line binaries and give mass function estimations for 15 single-line spectroscopic binaries.

  13. Reducing false positives of microcalcification detection systems by removal of breast arterial calcifications

    International Nuclear Information System (INIS)

    Mordang, Jan-Jurre; Gubern-Mérida, Albert; Karssemeijer, Nico; Heeten, Gerard den

    2016-01-01

    Purpose: In the past decades, computer-aided detection (CADe) systems have been developed to aid screening radiologists in the detection of malignant microcalcifications. These systems are useful to avoid perceptual oversights and can increase the radiologists’ detection rate. However, due to the high number of false positives marked by these CADe systems, they are not yet suitable as an independent reader. Breast arterial calcifications (BACs) are one of the most frequent false positives marked by CADe systems. In this study, a method is proposed for the elimination of BACs as positive findings. Removal of these false positives will increase the performance of the CADe system in finding malignant microcalcifications. Methods: A multistage method is proposed for the removal of BAC findings. The first stage consists of a microcalcification candidate selection, segmentation and grouping of the microcalcifications, and classification to remove obvious false positives. In the second stage, a case-based selection is applied where cases are selected which contain BACs. In the final stage, BACs are removed from the selected cases. The BACs removal stage consists of a GentleBoost classifier trained on microcalcification features describing their shape, topology, and texture. Additionally, novel features are introduced to discriminate BACs from other positive findings. Results: The CADe system was evaluated with and without BACs removal. Here, both systems were applied on a validation set containing 1088 cases of which 95 cases contained malignant microcalcifications. After bootstrapping, free-response receiver operating characteristics and receiver operating characteristics analyses were carried out. Performance between the two systems was compared at 0.98 and 0.95 specificity. At a specificity of 0.98, the sensitivity increased from 37% to 52% and the sensitivity increased from 62% up to 76% at a specificity of 0.95. Partial areas under the curve in the specificity

  14. Reducing false positives of microcalcification detection systems by removal of breast arterial calcifications

    Energy Technology Data Exchange (ETDEWEB)

    Mordang, Jan-Jurre, E-mail: Jan-Jurre.Mordang@radboudumc.nl; Gubern-Mérida, Albert; Karssemeijer, Nico [Diagnostic Image Analysis Group, Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen 6525 GA (Netherlands); Heeten, Gerard den [The National Training Centre for Breast Cancer Screening, Nijmegen 6503 GJ, The Netherlands and Department of Radiology, Amsterdam Medical Center, Amsterdam 1100 DD (Netherlands)

    2016-04-15

    Purpose: In the past decades, computer-aided detection (CADe) systems have been developed to aid screening radiologists in the detection of malignant microcalcifications. These systems are useful to avoid perceptual oversights and can increase the radiologists’ detection rate. However, due to the high number of false positives marked by these CADe systems, they are not yet suitable as an independent reader. Breast arterial calcifications (BACs) are one of the most frequent false positives marked by CADe systems. In this study, a method is proposed for the elimination of BACs as positive findings. Removal of these false positives will increase the performance of the CADe system in finding malignant microcalcifications. Methods: A multistage method is proposed for the removal of BAC findings. The first stage consists of a microcalcification candidate selection, segmentation and grouping of the microcalcifications, and classification to remove obvious false positives. In the second stage, a case-based selection is applied where cases are selected which contain BACs. In the final stage, BACs are removed from the selected cases. The BACs removal stage consists of a GentleBoost classifier trained on microcalcification features describing their shape, topology, and texture. Additionally, novel features are introduced to discriminate BACs from other positive findings. Results: The CADe system was evaluated with and without BACs removal. Here, both systems were applied on a validation set containing 1088 cases of which 95 cases contained malignant microcalcifications. After bootstrapping, free-response receiver operating characteristics and receiver operating characteristics analyses were carried out. Performance between the two systems was compared at 0.98 and 0.95 specificity. At a specificity of 0.98, the sensitivity increased from 37% to 52% and the sensitivity increased from 62% up to 76% at a specificity of 0.95. Partial areas under the curve in the specificity

  15. Open-ringed structure of the Cdt1-Mcm2-7 complex as a precursor of the MCM double hexamer.

    Science.gov (United States)

    Zhai, Yuanliang; Cheng, Erchao; Wu, Hao; Li, Ningning; Yung, Philip Yuk Kwong; Gao, Ning; Tye, Bik-Kwoon

    2017-03-01

    The minichromosome maintenance complex (MCM) hexameric complex (Mcm2-7) forms the core of the eukaryotic replicative helicase. During G1 phase, two Cdt1-Mcm2-7 heptamers are loaded onto each replication origin by the origin-recognition complex (ORC) and Cdc6 to form an inactive MCM double hexamer (DH), but the detailed loading mechanism remains unclear. Here we examine the structures of the yeast MCM hexamer and Cdt1-MCM heptamer from Saccharomyces cerevisiae. Both complexes form left-handed coil structures with a 10-15-Å gap between Mcm5 and Mcm2, and a central channel that is occluded by the C-terminal domain winged-helix motif of Mcm5. Cdt1 wraps around the N-terminal regions of Mcm2, Mcm6 and Mcm4 to stabilize the whole complex. The intrinsic coiled structures of the precursors provide insights into the DH formation, and suggest a spring-action model for the MCM during the initial origin melting and the subsequent DNA unwinding.

  16. Memory for media: investigation of false memories for negatively and positively charged public events.

    Science.gov (United States)

    Porter, Stephen; Taylor, Kristian; Ten Brinke, Leanne

    2008-01-01

    Despite a large body of false memory research, little has addressed the potential influence of an event's emotional content on susceptibility to false recollections. The Paradoxical Negative Emotion (PNE) hypothesis predicts that negative emotion generally facilitates memory but also heightens susceptibility to false memories. Participants were asked whether they could recall 20 "widely publicised" public events (half fictitious) ranging in emotional valence, with or without visual cues. Participants recalled a greater number of true negative events (M=3.31/5) than true positive (M=2.61/5) events. Nearly everyone (95%) came to recall at least one false event (M=2.15 false events recalled). Further, more than twice as many participants recalled any false negative (90%) compared to false positive (41.7%) events. Negative events, in general, were associated with more detailed memories and false negative event memories were more detailed than false positive event memories. Higher dissociation scores were associated with false recollections of negative events, specifically.

  17. False positive reduction in protein-protein interaction predictions using gene ontology annotations

    Directory of Open Access Journals (Sweden)

    Lin Yen-Han

    2007-07-01

    Full Text Available Abstract Background Many crucial cellular operations such as metabolism, signalling, and regulations are based on protein-protein interactions. However, the lack of robust protein-protein interaction information is a challenge. One reason for the lack of solid protein-protein interaction information is poor agreement between experimental findings and computational sets that, in turn, comes from huge false positive predictions in computational approaches. Reduction of false positive predictions and enhancing true positive fraction of computationally predicted protein-protein interaction datasets based on highly confident experimental results has not been adequately investigated. Results Gene Ontology (GO annotations were used to reduce false positive protein-protein interactions (PPI pairs resulting from computational predictions. Using experimentally obtained PPI pairs as a training dataset, eight top-ranking keywords were extracted from GO molecular function annotations. The sensitivity of these keywords is 64.21% in the yeast experimental dataset and 80.83% in the worm experimental dataset. The specificities, a measure of recovery power, of these keywords applied to four predicted PPI datasets for each studied organisms, are 48.32% and 46.49% (by average of four datasets in yeast and worm, respectively. Based on eight top-ranking keywords and co-localization of interacting proteins a set of two knowledge rules were deduced and applied to remove false positive protein pairs. The 'strength', a measure of improvement provided by the rules was defined based on the signal-to-noise ratio and implemented to measure the applicability of knowledge rules applying to the predicted PPI datasets. Depending on the employed PPI-predicting methods, the strength varies between two and ten-fold of randomly removing protein pairs from the datasets. Conclusion Gene Ontology annotations along with the deduced knowledge rules could be implemented to partially

  18. Image Watermarking Scheme for Specifying False Positive Probability and Bit-pattern Embedding

    Science.gov (United States)

    Sayama, Kohei; Nakamoto, Masayoshi; Muneyasu, Mitsuji; Ohno, Shuichi

    This paper treats a discrete wavelet transform(DWT)-based image watermarking with considering the false positive probability and bit-pattern embedding. We propose an iterative embedding algorithm of watermarking signals which are K sets pseudo-random numbers generated by a secret key. In the detection, K correlations between the watermarked DWT coefficients and watermark signals are computed by using the secret key. L correlations are made available for the judgment of the watermark presence with specified false positive probability, and the other K-L correlations are corresponding to the bit-pattern signal. In the experiment, we show the detection results with specified false positive probability and the bit-pattern recovery, and the comparison of the proposed method against JPEG compression, scaling down and cropping.

  19. Algorithm of reducing the false positives in IDS based on correlation Analysis

    Science.gov (United States)

    Liu, Jianyi; Li, Sida; Zhang, Ru

    2018-03-01

    This paper proposes an algorithm of reducing the false positives in IDS based on correlation Analysis. Firstly, the algorithm analyzes the distinguishing characteristics of false positives and real alarms, and preliminary screen the false positives; then use the method of attribute similarity clustering to the alarms and further reduces the amount of alarms; finally, according to the characteristics of multi-step attack, associated it by the causal relationship. The paper also proposed a reverse causation algorithm based on the attack association method proposed by the predecessors, turning alarm information into a complete attack path. Experiments show that the algorithm simplifies the number of alarms, improve the efficiency of alarm processing, and contribute to attack purposes identification and alarm accuracy improvement.

  20. False-positive Human Papillomavirus DNA tests in cervical screening

    DEFF Research Database (Denmark)

    Rebolj, Matejka; Pribac, Igor; Lynge, Elsebeth

    2011-01-01

    Based on data from randomised controlled trials (RCT) on primary cervical screening, it has been reported that the problem of more frequent false-positive tests in Human Papillomavirus (HPV) DNA screening compared to cytology could be overcome. However, these reports predominantly operated...

  1. Computer-Aided Detection in Digital Mammography: False-Positive Marks and Their Reproducibility in Negative Mammograms

    International Nuclear Information System (INIS)

    Kim, Seung Ja; Moon, Woo Kyung; Cho, Nariya; Chang, Jung Min; Seong, Min Hyun

    2009-01-01

    Background: There are relatively few studies reporting the frequency of false-positive computer-aided detection (CAD) marks and their reproducibility in normal cases. Purpose: To evaluate retrospectively the false-positive mark rate of a CAD system and the reproducibility of false-positive marks in two sets of negative digital mammograms. Material and Methods: Two sets of negative digital mammograms were obtained in 360 women (mean age 57 years, range 30-76 years) with an approximate interval of 1 year (mean time 343.7 days), and a CAD system was applied. False-positive CAD marks and the reproducibility were determined. Results: Of the 360 patients, 252 (70.0%) and 240 (66.7%) patients had 1-7 CAD marks on the initial and second mammograms, respectively. The false-positive CAD mark rate was 1.5 (1.1 for masses and 0.4 for calcifications) and 1.4 (1.0 for masses and 0.4 for calcifications) per examination in the initial and second mammograms, respectively. The reproducibility of the false-positive CAD marks was 12.0% for both mass (81/680) and microcalcification (33/278) marks. Conclusion: False-positive CAD marks were seen in approximately 70% of normal cases. However, the reproducibility was very low. Radiologists must be familiar with the findings of false-positive CAD marks, since they are very common and can increase the recall rate in screening

  2. The problem of false-positive human papillomavirus DNA tests in cervical screening

    DEFF Research Database (Denmark)

    Rebolj, Matejka; Pribac, Igor; Frederiksen, Maria Eiholm

    2013-01-01

    Human Papillomavirus (HPV) testing has been extensively studied in randomized controlled trials of primary cervical screening. Based on encouraging results concerning its high detection rates and a high negative predictive value for high-grade cervical intraepithelial neoplasia (CIN), HPV testing...... will probably replace cytology in future primary cervical screening. However, HPV testing is associated with more frequent false-positive tests compared to cytology. False-positive tests are defined as positive screening tests which are not subsequently confirmed with high-grade CIN. Several authors have...

  3. Sherlock Holmes and child psychopathology assessment approaches: the case of the false-positive.

    Science.gov (United States)

    Jensen, P S; Watanabe, H

    1999-02-01

    To explore the relative value of various methods of assessing childhood psychopathology, the authors compared 4 groups of children: those who met criteria for one or more DSM diagnoses and scored high on parent symptom checklists, those who met psychopathology criteria on either one of these two assessment approaches alone, and those who met no psychopathology assessment criterion. Parents of 201 children completed the Child Behavior Checklist (CBCL), after which children and parents were administered the Diagnostic Interview Schedule for Children (version 2.1). Children and parents also completed other survey measures and symptom report inventories. The 4 groups of children were compared against "external validators" to examine the merits of "false-positive" and "false-negative" cases. True-positive cases (those that met DSM criteria and scored high on the CBCL) differed significantly from the true-negative cases on most external validators. "False-positive" and "false-negative" cases had intermediate levels of most risk factors and external validators. "False-positive" cases were not normal per se because they scored significantly above the true-negative group on a number of risk factors and external validators. A similar but less marked pattern was noted for "false-negatives." Findings call into question whether cases with high symptom checklist scores despite no formal diagnoses should be considered "false-positive." Pending the availability of robust markers for mental illness, researchers and clinicians must resist the tendency to reify diagnostic categories or to engage in arcane debates about the superiority of one assessment approach over another.

  4. Application of a high throughput method of biomarker discovery to improvement of the EarlyCDT(®-Lung Test.

    Directory of Open Access Journals (Sweden)

    Isabel K Macdonald

    Full Text Available BACKGROUND: The National Lung Screening Trial showed that CT screening for lung cancer led to a 20% reduction in mortality. However, CT screening has a number of disadvantages including low specificity. A validated autoantibody assay is available commercially (EarlyCDT®-Lung to aid in the early detection of lung cancer and risk stratification in patients with pulmonary nodules detected by CT. Recent advances in high throughput (HTP cloning and expression methods have been developed into a discovery pipeline to identify biomarkers that detect autoantibodies. The aim of this study was to demonstrate the successful clinical application of this strategy to add to the EarlyCDT-Lung panel in order to improve its sensitivity and specificity (and hence positive predictive value, (PPV. METHODS AND FINDINGS: Serum from two matched independent cohorts of lung cancer patients were used (n = 100 and n = 165. Sixty nine proteins were initially screened on an abridged HTP version of the autoantibody ELISA using protein prepared on small scale by a HTP expression and purification screen. Promising leads were produced in shake flask culture and tested on the full assay. These results were analyzed in combination with those from the EarlyCDT-Lung panel in order to provide a set of re-optimized cut-offs. Five proteins that still displayed cancer/normal differentiation were tested for reproducibility and validation on a second batch of protein and a separate patient cohort. Addition of these proteins resulted in an improvement in the sensitivity and specificity of the test from 38% and 86% to 49% and 93% respectively (PPV improvement from 1 in 16 to 1 in 7. CONCLUSION: This is a practical example of the value of investing resources to develop a HTP technology. Such technology may lead to improvement in the clinical utility of the EarlyCDT--Lung test, and so further aid the early detection of lung cancer.

  5. APHRODITE: an Anomaly-based Architecture for False Positive Reduction

    NARCIS (Netherlands)

    Bolzoni, D.; Etalle, Sandro

    We present APHRODITE, an architecture designed to reduce false positives in network intrusion detection systems. APHRODITE works by detecting anomalies in the output traffic, and by correlating them with the alerts raised by the NIDS working on the input traffic. Benchmarks show a substantial

  6. Reducing false positives of microcalcification detection systems by removal of breast arterial calcifications.

    Science.gov (United States)

    Mordang, Jan-Jurre; Gubern-Mérida, Albert; den Heeten, Gerard; Karssemeijer, Nico

    2016-04-01

    In the past decades, computer-aided detection (CADe) systems have been developed to aid screening radiologists in the detection of malignant microcalcifications. These systems are useful to avoid perceptual oversights and can increase the radiologists' detection rate. However, due to the high number of false positives marked by these CADe systems, they are not yet suitable as an independent reader. Breast arterial calcifications (BACs) are one of the most frequent false positives marked by CADe systems. In this study, a method is proposed for the elimination of BACs as positive findings. Removal of these false positives will increase the performance of the CADe system in finding malignant microcalcifications. A multistage method is proposed for the removal of BAC findings. The first stage consists of a microcalcification candidate selection, segmentation and grouping of the microcalcifications, and classification to remove obvious false positives. In the second stage, a case-based selection is applied where cases are selected which contain BACs. In the final stage, BACs are removed from the selected cases. The BACs removal stage consists of a GentleBoost classifier trained on microcalcification features describing their shape, topology, and texture. Additionally, novel features are introduced to discriminate BACs from other positive findings. The CADe system was evaluated with and without BACs removal. Here, both systems were applied on a validation set containing 1088 cases of which 95 cases contained malignant microcalcifications. After bootstrapping, free-response receiver operating characteristics and receiver operating characteristics analyses were carried out. Performance between the two systems was compared at 0.98 and 0.95 specificity. At a specificity of 0.98, the sensitivity increased from 37% to 52% and the sensitivity increased from 62% up to 76% at a specificity of 0.95. Partial areas under the curve in the specificity range of 0.8-1.0 were

  7. Analyzing false positives of four questions in the Force Concept Inventory

    Science.gov (United States)

    Yasuda, Jun-ichiro; Mae, Naohiro; Hull, Michael M.; Taniguchi, Masa-aki

    2018-06-01

    In this study, we analyze the systematic error from false positives of the Force Concept Inventory (FCI). We compare the systematic errors of question 6 (Q.6), Q.7, and Q.16, for which clearly erroneous reasoning has been found, with Q.5, for which clearly erroneous reasoning has not been found. We determine whether or not a correct response to a given FCI question is a false positive using subquestions. In addition to the 30 original questions, subquestions were introduced for Q.5, Q.6, Q.7, and Q.16. This modified version of the FCI was administered to 1145 university students in Japan from 2015 to 2017. In this paper, we discuss our finding that the systematic errors of Q.6, Q.7, and Q.16 are much larger than that of Q.5 for students with mid-level FCI scores. Furthermore, we find that, averaged over the data sample, the sum of the false positives from Q.5, Q.6, Q.7, and Q.16 is about 10% of the FCI score of a midlevel student.

  8. False positive paediatric labelled white blood cell study

    International Nuclear Information System (INIS)

    Beveridge, N.; Bennett, E.; Thomas, P.

    2002-01-01

    Full text: An eight-month-old female presented for a technetium labelled white blood cell study (LWBC) to exclude an intra-abdominal abscess. Born premature, the child had surgery to repair a perforated bowel and had repeated presentations with diarrhoea, fevers, a tender right upper quadrant and a raised leucocyte count. Multiple imaging modalities failed to demonstrate recurrent bowel perforation, ischaemia or an intra-abdominal mass. A LWBC study was performed with whole body imaging at 1 and 5 hours post re-injection of the radiolabelled blood. No abnormal uptake was visualised in the abdomen but abnormal white cell accumulation was noted in the right hind foot and the length of the right lower leg. This activity appeared to lie along the course of the right tibia. Plain X-ray demonstrated no evidence of tibial osteomyelitis. Concern that the LWBC may be falsely negative in a patient on antibiotics, a gallium scan was immediately performed to re-examine the abdomen. The whole body gallium images demonstrated normal physiological uptake in the abdomen and no evidence of infection in the right leg. The patient had no clinical features to support right leg pathology. The abnormal LWBC localisation in the right lower leg/foot was therefore falsely positive. The most likely explanation is increased activation of the autologous LWBC by 'rough' handling during difficult venesection and re-injection through small veins and needles/cannulas. The slow flow through the veins draining the foot injection site would contribute to margination in these vessel walls. This is a potential cause for false positive LWBC studies- with significant implications for patient care. Copyright (2002) The Australian and New Zealand Society of Nuclear Medicine Inc

  9. False positive seroreactivity to brucellosis in tuberculosis patients: a prevalence study

    Directory of Open Access Journals (Sweden)

    Mojtaba Varshochi

    2011-03-01

    Full Text Available Mojtaba Varshochi1,2, Jafar Majidi2, Marjan Amini1, Kamyar Ghabili3, Mohammadali M Shoja31Department of Infectious Disease, Tabriz University of Medical Sciences, Tabriz, Iran; 2Infectious Disease and Tropical Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; 3Tuberculosis and Lung Disease Research Center, Tabriz University of Medical Sciences, Tabriz, IranBackground: The rising worldwide incidence of tuberculosis (TB increases the demand for knowledge about its potential seroreactivity with other microbial agents. A few reports and the authors’ experiences indicate that tuberculosis may result in a false-positive brucellosis serology. This may cause a diagnostic challenge because of the close clinical resemblance of these two infections.Objective: The aim of the present prevalence study was to elucidate brucellosis seroreactivity in patients with active TB.Methods: Ninety-eight patients with newly diagnosed and active TB were studied using an enzyme-linked immunosorbent assay (ELISA and Wright’s and Coombs–Wright’s tests. Seventy-five healthy individuals were used as controls. The patients showed signs of recovery after starting a standard anti-TB regimen and had no clinical evidence of brucellosis at a subsequent 6-month follow-up. The data were analyzed statistically by Fisher’s exact test using SPSS 11.0.Results: We found that 9.2% of TB patients versus 1.3% of healthy controls had positive results on the anti-Brucella IgG ELISA (P = 0.04. Five TB patients were found to have agglutination on Wright’s tests, while none of the controls showed agglutination.Conclusion: Active TB patients may have some seroreactivity with Brucella antigens, and Brucella IgG ELISA may give a false positive in these patients. Clinicians should consider false positive brucellosis seroreactivity in patients with active TB.Keywords: false positive serology, ELISA, diagnosis

  10. False positive acetaminophen concentrations in icteric serum

    Directory of Open Access Journals (Sweden)

    L. de Jong

    2016-04-01

    Full Text Available Introduction: Serum concentrations of acetaminophen are measured to predict the risk of hepatotoxicity in cases of acetaminophen overdose and to identify acetaminophen use in patients with acute liver injury without a known cause. The acetaminophen concentration determines if treatment with N-acetyl cysteine, the antidote for acetaminophen poisoning, is warranted. Description: A 49-year-old woman was admitted to our hospital with a hepatic encephalopathy and a total serum bilirubin concentration of 442 µmol/l. The acetaminophen concentration of 11.5 mg/l was measured with an enzymatic-colorimetric assay, thus treatment with N-acetyl cysteine was started. Interestingly, the acetaminophen concentration remained unchanged (11.5–12.3 mg/l during a period of 4 consecutive days. In contrast, the acetaminophen concentration measured by HPLC, a chromatographic technique, remained undetectable Discussion: In the presented case, elevated bilirubin was the most likely candidate to interfere with acetaminophen assay causing false positive results. Bilirubin has intense absorbance in the ultraviolet and visible regions of the electromagnetic spectrum and for that reason it causes interference in an enzymatic-colorimetric assay. Conclusion: False positive acetaminophen laboratory test results may be found in icteric serum, when enzymatic-colorimetric assays are used for determination of an acetaminophen concentration. Questionable acetaminophen results in icteric serum should be confirmed by a non-enzymatic method, by means of ultrafiltration of the serum, or by dilution studies. Keywords: Acetaminophen, Enzymatic-colorimetric assays, HPLC, Bilirubin, Interference, Paracetamol, Liver failure, Jaundice

  11. Evaluation of inadequate, indeterminate, false-negative and false-positive cases in cytological examination for breast cancer according to histological type

    Directory of Open Access Journals (Sweden)

    Yamaguchi Rin

    2012-05-01

    Full Text Available Abstract Background We previously investigated the current status of breast cytology cancer screening at seven institutes in our area of southern Fukuoka Prefecture, and found some differences in diagnostic accuracy among the institutions. In the present study, we evaluated the cases involved and noted possible reasons for their original cytological classification as inadequate, indeterminate, false-negative and false-positive according to histological type. Methods We evaluated the histological findings in 5693 individuals who underwent cytological examination for breast cancer (including inadequate, indeterminate, false-negative and false-positive cases, to determine the most common histological types and/or features in these settings and the usefulness/limitations of cytological examination for the diagnosis of breast cancer. Results Among 1152 cytologically inadequate cases, histology revealed that 75/173 (43.6% cases were benign, including mastopathy (fibrocystic disease in 38.6%, fibroadenoma in 24.0% and papilloma in 5.3%. Ninety-five of 173 (54.9% cases were histologically malignant, with scirrhous growing type, invasive ductal carcinoma (SIDC being significantly more frequent (49.5% than papillotubular growing type (Papi-tub (P P = 0.0001 and ductal carcinoma in situ (DCIS (P = 0.0001. Among 458 indeterminate cases, 54/139 (38.8% were histologically benign (mastopathy, 30.0%; fibroadenoma, 27.8%; papilloma, 26.0% and 73/139 (52.5% were malignant, with SIDC being the most frequent malignant tumor (37.0%. Among 52 false-negative cases, SIDC was significantly more frequent (42.3% than DCIS (P = 0.0049 and Papi-tub (P = 0.001. There were three false-positive cases, with one each of fibroadenoma, epidermal cyst and papilloma. Conclusions The inadequate, indeterminate, false-negative and false-positive cases showed similar histological types, notably SIDC for malignant tumors, and mastopathy, fibroadenoma and papilloma for

  12. PIP degron proteins, substrates of CRL4Cdt2, and not PIP boxes, interfere with DNA polymerase η and κ focus formation on UV damage.

    Science.gov (United States)

    Tsanov, Nikolay; Kermi, Chames; Coulombe, Philippe; Van der Laan, Siem; Hodroj, Dana; Maiorano, Domenico

    2014-04-01

    Proliferating cell nuclear antigen (PCNA) is a well-known scaffold for many DNA replication and repair proteins, but how the switch between partners is regulated is currently unclear. Interaction with PCNA occurs via a domain known as a PCNA-Interacting Protein motif (PIP box). More recently, an additional specialized PIP box has been described, the « PIP degron », that targets PCNA-interacting proteins for proteasomal degradation via the E3 ubiquitin ligase CRL4(Cdt2). Here we provide evidence that CRL4(Cdt2)-dependent degradation of PIP degron proteins plays a role in the switch of PCNA partners during the DNA damage response by facilitating accumulation of translesion synthesis DNA polymerases into nuclear foci. We show that expression of a nondegradable PIP degron (Cdt1) impairs both Pol η and Pol κ focus formation on ultraviolet irradiation and reduces cell viability, while canonical PIP box-containing proteins have no effect. Furthermore, we identify PIP degron-containing peptides from several substrates of CRL4(Cdt2) as efficient inhibitors of Pol η foci formation. By site-directed mutagenesis we show that inhibition depends on a conserved threonine residue that confers high affinity for PCNA-binding. Altogether these findings reveal an important regulative role for the CRL4(Cdt2) pathway in the switch of PCNA partners on DNA damage.

  13. Effect of radiologist experience on the risk of false-positive results in breast cancer screening programs

    International Nuclear Information System (INIS)

    Zubizarreta Alberdi, Raquel; Llanes, Ana B.F.; Ortega, Raquel Almazan; Exposito, Ruben Roman; Collado, Jose M.V.; Oliveres, Xavier Castells; Queiro Verdes, Teresa; Natal Ramos, Carmen; Sanz, Maria Ederra; Salas Trejo, Dolores

    2011-01-01

    To evaluate the effect of radiologist experience on the risk of false-positive results in population-based breast cancer screening programmes. We evaluated 1,440,384 single-read screening mammograms, corresponding to 471,112 women aged 45-69 years participating in four Spanish programmes between 1990 and 2006. The mammograms were interpreted by 72 radiologists. The overall percentage of false-positive results was 5.85% and that for false-positives resulting in an invasive procedure was 0.38%. Both the risk of false-positives overall and of false-positives leading to an invasive procedure significantly decreased (p 14,999 mammograms with respect to the reference category (<500). The risk of both categories of false-positives was also significantly reduced (p < 0.001) as radiologists' years of experience increased: OR 0.96 and OR 0.84, respectively, for 1 year's experience and OR 0.72 and OR 0.73, respectively, for more than 4 years' experience with regard to the category of <1 year's experience. Radiologist experience is a determining factor in the risk of a false-positive result in breast cancer screening. (orig.)

  14. C/EBPα regulates CRL4Cdt2-mediated degradation of p21 in response to UVB-induced DNA damage to control the G1/S checkpoint

    Science.gov (United States)

    Hall, Jonathan R; Bereman, Michael S; Nepomuceno, Angelito I; Thompson, Elizabeth A; Muddiman, David C; Smart, Robert C

    2014-01-01

    The bZIP transcription factor, C/EBPα is highly inducible by UVB and other DNA damaging agents in keratinocytes. C/EBPα-deficient keratinocytes fail to undergo cell cycle arrest in G1 in response to UVB-induced DNA damage and mice lacking epidermal C/EBPα are highly susceptible to UVB-induced skin cancer. The mechanism through which C/EBPα regulates the cell cycle checkpoint in response to DNA damage is unknown. Here we report untreated C/EBPα-deficient keratinocytes have normal levels of the cyclin-dependent kinase inhibitor, p21, however, UVB-treated C/EBPα-deficient keratinocytes fail to up-regulate nuclear p21 protein levels despite normal up-regulation of Cdkn1a mRNA levels. UVB-treated C/EBPα-deficient keratinocytes displayed a 4-fold decrease in nuclear p21 protein half-life due to the increased proteasomal degradation of p21 via the E3 ubiquitin ligase CRL4Cdt2. Cdt2 is the substrate recognition subunit of CRL4Cdt2 and Cdt2 mRNA and protein levels were up-regulated in UVB-treated C/EBPα-deficient keratinocytes. Knockdown of Cdt2 restored p21 protein levels in UVB-treated C/EBPα-deficient keratinocytes. Lastly, the failure to accumulate p21 in response to UVB in C/EBPα-deficient keratinocytes resulted in decreased p21 interactions with critical cell cycle regulatory proteins, increased CDK2 activity, and inappropriate entry into S-phase. These findings reveal C/EBPα regulates G1/S cell cycle arrest in response to DNA damage via the control of CRL4Cdt2 mediated degradation of p21. PMID:25483090

  15. Improving computer-aided detection assistance in breast cancer screening by removal of obviously false-positive findings

    NARCIS (Netherlands)

    Mordang, Jan-Jurre; Gubern-Merida, Albert; Bria, Alessandro; Tortorella, Francesco; den Heeten, Gerard; Karssemeijer, Nico

    2017-01-01

    Purpose: Computer-aided detection (CADe) systems for mammography screening still mark many false positives. This can cause radiologists to lose confidence in CADe, especially when many false positives are obviously not suspicious to them. In this study, we focus on obvious false positives generated

  16. Improving computer-aided detection assistance in breast cancer screening by removal of obviously false-positive findings

    NARCIS (Netherlands)

    Mordang, J.J.; Gubern Merida, A.; Bria, A.; Tortorella, F.; Heeten, G.; Karssemeijer, N.

    2017-01-01

    PURPOSE: Computer-aided detection (CADe) systems for mammography screening still mark many false positives. This can cause radiologists to lose confidence in CADe, especially when many false positives are obviously not suspicious to them. In this study, we focus on obvious false positives generated

  17. Waiting time and the psychosocial consequences of false-positive mammography

    DEFF Research Database (Denmark)

    Heleno, Bruno M.; Siersma, Volkert; Brodersen, John

    2015-01-01

    Background: There is wide variation in the psychosocial response to false-positive mammography. We aimed to assess whether women having to wait longer to exclude cancer had increased psychosocial consequences that persisted after cancer was ruled out. Findings: We selected women with false......-positive mammography (n = 272), screened for breast cancer in Copenhagen and Funen (Denmark) over a 1-year period. We measured psychosocial consequences immediately before women attended their recall visit and 1, 6, 18 and 36 months after women received their final diagnosis. After women were told that cancer had been...... ruled out, adverse psychosocial consequences decreased with time. We found no statistically significant differences between women who had cancer ruled out immediately at the recall visit (waiting time of 0) and women who had to wait longer before cancer was ruled out (waiting times 1-30, 30...

  18. Reducing false-positive incidental findings with ensemble genotyping and logistic regression based variant filtering methods.

    Science.gov (United States)

    Hwang, Kyu-Baek; Lee, In-Hee; Park, Jin-Ho; Hambuch, Tina; Choe, Yongjoon; Kim, MinHyeok; Lee, Kyungjoon; Song, Taemin; Neu, Matthew B; Gupta, Neha; Kohane, Isaac S; Green, Robert C; Kong, Sek Won

    2014-08-01

    As whole genome sequencing (WGS) uncovers variants associated with rare and common diseases, an immediate challenge is to minimize false-positive findings due to sequencing and variant calling errors. False positives can be reduced by combining results from orthogonal sequencing methods, but costly. Here, we present variant filtering approaches using logistic regression (LR) and ensemble genotyping to minimize false positives without sacrificing sensitivity. We evaluated the methods using paired WGS datasets of an extended family prepared using two sequencing platforms and a validated set of variants in NA12878. Using LR or ensemble genotyping based filtering, false-negative rates were significantly reduced by 1.1- to 17.8-fold at the same levels of false discovery rates (5.4% for heterozygous and 4.5% for homozygous single nucleotide variants (SNVs); 30.0% for heterozygous and 18.7% for homozygous insertions; 25.2% for heterozygous and 16.6% for homozygous deletions) compared to the filtering based on genotype quality scores. Moreover, ensemble genotyping excluded > 98% (105,080 of 107,167) of false positives while retaining > 95% (897 of 937) of true positives in de novo mutation (DNM) discovery in NA12878, and performed better than a consensus method using two sequencing platforms. Our proposed methods were effective in prioritizing phenotype-associated variants, and an ensemble genotyping would be essential to minimize false-positive DNM candidates. © 2014 WILEY PERIODICALS, INC.

  19. False-positive buprenorphine EIA urine toxicology results due to high dose morphine: a case report.

    Science.gov (United States)

    Tenore, Peter L

    2012-01-01

    In monitoring a patient with chronic pain who was taking high-dose morphine and oxycodone with weekly urine enzymatic immunoassay (EIA) toxicology testing, the authors noted consistent positives for buprenorphine. The patient was not taking buprenorphine, and gas chromatography/mass spectroscopy (GCMS) testing on multiple samples revealed no buprenorphine, indicating a case of false-positive buprenorphine EIAs in a high-dose opiate case. The authors discontinued oxycodone for a period of time and then discontinued morphine. Urine monitoring with EIAs and GCMS revealed false-positive buprenorphine EIAs, which remained only when the patient was taking morphine. When taking only oxycodone and no morphine, urine samples became buprenorphine negative. When morphine was reintroduced, false-positive buprenorphine results resumed. Medical practitioners should be aware that high-dose morphine (with morphine urine levels turning positive within the 15,000 to 28,000 mg/mL range) may produce false-positive buprenorphine EIAs with standard urine EIA toxicology testing.

  20. The OGCleaner: filtering false-positive homology clusters.

    Science.gov (United States)

    Fujimoto, M Stanley; Suvorov, Anton; Jensen, Nicholas O; Clement, Mark J; Snell, Quinn; Bybee, Seth M

    2017-01-01

    Detecting homologous sequences in organisms is an essential step in protein structure and function prediction, gene annotation and phylogenetic tree construction. Heuristic methods are often employed for quality control of putative homology clusters. These heuristics, however, usually only apply to pairwise sequence comparison and do not examine clusters as a whole. We present the Orthology Group Cleaner (the OGCleaner), a tool designed for filtering putative orthology groups as homology or non-homology clusters by considering all sequences in a cluster. The OGCleaner relies on high-quality orthologous groups identified in OrthoDB to train machine learning algorithms that are able to distinguish between true-positive and false-positive homology groups. This package aims to improve the quality of phylogenetic tree construction especially in instances of lower-quality transcriptome assemblies. https://github.com/byucsl/ogcleaner CONTACT: sfujimoto@gmail.comSupplementary information: Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  1. A Demonstration of Regression False Positive Selection in Data Mining

    Science.gov (United States)

    Pinder, Jonathan P.

    2014-01-01

    Business analytics courses, such as marketing research, data mining, forecasting, and advanced financial modeling, have substantial predictive modeling components. The predictive modeling in these courses requires students to estimate and test many linear regressions. As a result, false positive variable selection ("type I errors") is…

  2. A CDT-Based Heuristic Zone Design Approach for Economic Census Investigators

    Directory of Open Access Journals (Sweden)

    Changixu Cheng

    2015-01-01

    Full Text Available This paper addresses a special zone design problem for economic census investigators that is motivated by a real-world application. This paper presented a heuristic multikernel growth approach via Constrained Delaunay Triangulation (CDT. This approach not only solved the barriers problem but also dealt with the polygon data in zoning procedure. In addition, it uses a new heuristic method to speed up the zoning process greatly on the premise of the required quality of zoning. At last, two special instances for economic census were performed, highlighting the performance of this approach.

  3. Long-term psychosocial consequences of false-positive screening mammography

    DEFF Research Database (Denmark)

    Brodersen, John; Siersma, Volkert Dirk

    2013-01-01

    Cancer screening programs have the potential of intended beneficial effects, but they also inevitably have unintended harmful effects. In the case of screening mammography, the most frequent harm is a false-positive result. Prior efforts to measure their psychosocial consequences have been limite...... by short-term follow-up, the use of generic survey instruments, and the lack of a relevant benchmark-women with breast cancer....

  4. Effect of radiologist experience on the risk of false-positive results in breast cancer screening programs

    Energy Technology Data Exchange (ETDEWEB)

    Zubizarreta Alberdi, Raquel [Galician Breast Cancer Screening Programme, Public Health and Planning Directorate, Health Office, Galicia (Spain); Edificio Administrativo da Conselleria de Sanidade, Servicio de Programas Poboacionais de Cribado, Direccion Xeral de Saude Publica e Planificacion, Santiago de Compostela, Galicia (Spain); Llanes, Ana B.F.; Ortega, Raquel Almazan [Galician Breast Cancer Screening Programme, Public Health and Planning Directorate, Health Office, Galicia (Spain); Exposito, Ruben Roman; Collado, Jose M.V.; Oliveres, Xavier Castells [Department of Epidemiology and Evaluation, Institut Municipal d' Investigacio Medica-Parc de Salut Mar. CIBERESP, Barcelona (Spain); Queiro Verdes, Teresa [Galician Agency for Health Technology Assessment, Public Health and Planning Directorate, Health Office, Galicia (Spain); Natal Ramos, Carmen [Principality of Asturias Breast Cancer Screening Programme, Principality of Asturias (Spain); Sanz, Maria Ederra [Public Health Institute, Navarra Breast Cancer Screening Programme, Pamplona (Spain); Salas Trejo, Dolores [General Directorate Public Health and Centre for Public Health Research (CSISP), Valencia Breast Cancer Screening Programme, Valencia (Spain)

    2011-10-15

    To evaluate the effect of radiologist experience on the risk of false-positive results in population-based breast cancer screening programmes. We evaluated 1,440,384 single-read screening mammograms, corresponding to 471,112 women aged 45-69 years participating in four Spanish programmes between 1990 and 2006. The mammograms were interpreted by 72 radiologists. The overall percentage of false-positive results was 5.85% and that for false-positives resulting in an invasive procedure was 0.38%. Both the risk of false-positives overall and of false-positives leading to an invasive procedure significantly decreased (p < 0.001) with greater reading volume in the previous year: OR 0.77 and OR 0.78, respectively, for a reading volume 500-1,999 mammograms and OR 0.59 and OR 0.60 for a reading volume of >14,999 mammograms with respect to the reference category (<500). The risk of both categories of false-positives was also significantly reduced (p < 0.001) as radiologists' years of experience increased: OR 0.96 and OR 0.84, respectively, for 1 year's experience and OR 0.72 and OR 0.73, respectively, for more than 4 years' experience with regard to the category of <1 year's experience. Radiologist experience is a determining factor in the risk of a false-positive result in breast cancer screening. (orig.)

  5. Heterophilic antibodies interfering with radioimmunoassay. A false-positive pregnancy test

    Energy Technology Data Exchange (ETDEWEB)

    Vladutiu, A.O.; Sulewski, J.M.; Pudlak, K.A.; Stull, C.G.

    1982-11-19

    A young woman with amenorrhea had a consistently positive pregnancy test result (serum radioimmunoassay measurement of ..beta..-human chorionic gonadotropin hormone). No fetal or placental tissue was found after uterine curettage and exploratory laparotomy. The false-positive pregnancy test result was due to heterophilic antibovine and antigoat antibodies in the patient's serum. These antibodies interfered with radioimmunoassays using goat antibodies. This case shows that serum heterophilic antibodies can interfere with immunoassays and result in unnecessary diagnostic procedures and/or unnecessary treatment.

  6. Heterophilic antibodies interfering with radioimmunoassay. A false-positive pregnancy test

    International Nuclear Information System (INIS)

    Vladutiu, A.O.; Sulewski, J.M.; Pudlak, K.A.; Stull, C.G.

    1982-01-01

    A young woman with amenorrhea had a consistently positive pregnancy test result (serum radioimmunoassay measurement of #betta#-human chorionic gonadotropin hormone). No fetal or placental tissue was found after uterine curettage and exploratory laparotomy. The false-positive pregnancy test result was due to heterophilic antibovine and antigoat antibodies in the patient's serum. These antibodies interfered with radioimmunoassays using goat antibodies. This case shows that serum heterophilic antibodies can interfere with immunoassays and result in unnecessary diagnostic procedures and/or unnecessary treatment

  7. Assessment of potential false positives via orbitrap-based untargeted lipidomics from rat tissues.

    Science.gov (United States)

    Xu, Lina; Wang, Xueying; Jiao, Yupei; Liu, Xiaohui

    2018-02-01

    Untargeted lipidomics is increasingly popular due to the broad coverage of lipid species. Data dependent MS/MS acquisition is commonly used in order to acquire sufficient information for confident lipid assignment. However, although lipids are identified based on MS/MS confirmation, a number of false positives are still observed. Here, we discuss several causes of introducing lipid false identifications in untargeted analysis. Phosphotidylcholines and cholesteryl esters generate in-source fragmentation to produce dimethylated phosphotidylethanolamine and free cholesterol. Dimerization of fatty acid results in false identification of fatty acid ester of hydroxyl fatty acid. Realizing these false positives is able to improve confidence of results acquired from untargeted analysis. Besides, thresholds are established for lipids identified using LipidSearch v4.1.16 software to reduce unreliable results. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Comparison of cumulative false-positive risk of screening mammography in the United States and Denmark

    DEFF Research Database (Denmark)

    Jacobsen, Katja Kemp

    2015-01-01

    INTRODUCTION: In the United States (US), about one-half of women screened with annual mammography have at least one false-positive test after ten screens. The estimate for European women screened ten times biennially is much lower. We evaluate to what extent screening interval, mammogram type......=400,204), between 1991-2012 and 1993-2013, respectively. Model-based cumulative false-positive risks were computed for the entire sample, using two statistical methods (Hubbard Njor) previously used to estimate false-positive risks in the US and Europe. RESULTS: Empirical cumulative risk of at least...... one false-positive test after eight (annual or biennial) screens was 41.9% in BCSC, 16.1% in Copenhagen, and 7.4% in Funen. Variation in screening interval and mammogram type did not explain the differences by country. Using the Hubbard method, the model-based cumulative risks after eight screens...

  9. When are false-positive and false-negative 18F'FDG PET scans really false?

    International Nuclear Information System (INIS)

    Binns, D.S.; Hicks, R.J.; Fawcett, M.E.

    1999-01-01

    Full text: A 61-year-old male presented with locally advanced squamous cell carcinoma of the base of tongue. In the absence of wider metastatic disease on conventional staging, he was enrolled in a phase I, dose escalation chemoradiotherapy trial. In this study, therapeutic response to radiotherapy combined with cisplatin and a chemotherapeutic agent which specifically targets hypoxic cells (tirapazamine) was evaluated with serial 18 F-FDG PET scans. Baseline 18 F-FDG PET confirmed locally advanced disease, although a previously undetected lower cervical lymph node was identified and included in the radiotherapy portal. Whole-body PET revealed a small metabolically active area adjacent to the right hemidiaphragm. Respiratory gated, high-resolution helical CT failed to find structural evidence of disease and, as a result, the patient was enrolled in the 7 week therapy regime on the assumption that the PET finding was a false-positive result. Repeat 18 F-FDG PET scans at the middle, end and 12 weeks post-treatment showed excellent therapeutic response in the head and neck which was discordant with clinical and CT findings, and resolution of the metabolically active chest lesion. Despite the negative PET scan, persistent clinical and CT evidence of a residual tumour mass suggested a false-negative result and resulted in a neck lymph node dissection. This showed no evidence of malignant cells. Five months following treatment, the patient presented with pleural effusion at the base on the right lung. Subsequent CT scanning showed a small pleural lesion at the site of initial 18 F-FDG uptake. Biopsy confirmed metastatic disease. The apparent transient resolution of 18 F-FDG uptake in the pleural lesion with treatment presumably reflected a combination of reduced metabolic activity and size due to the partial, but not complete, cytotoxic effects of cisplatin. In conclusion, this case emphasizes the importance of pathological review and clinical follow-up in reconciling

  10. Evaluation of false positivity and cross reactivity in the investigation ...

    African Journals Online (AJOL)

    This study evaluated the causes of false positive Human Immunodeficiency Virus test results (F+HIV), cross reactivity of HIV antibodies with other non HIV antibodies, and efficiency of the serial and parallel testing algorithms. 100 blood samples randomly collected from clients attending the Heart to Heart HIV counseling and ...

  11. Consensus-based identification of factors related to false-positives in ultrasound scanning of synovitis and tenosynovitis.

    Science.gov (United States)

    Ikeda, Kei; Narita, Akihiro; Ogasawara, Michihiro; Ohno, Shigeru; Kawahito, Yutaka; Kawakami, Atsushi; Ito, Hiromu; Matsushita, Isao; Suzuki, Takeshi; Misaki, Kenta; Ogura, Takehisa; Kamishima, Tamotsu; Seto, Yohei; Nakahara, Ryuichi; Kaneko, Atsushi; Nakamura, Takayuki; Henmi, Mihoko; Fukae, Jun; Nishida, Keiichiro; Sumida, Takayuki; Koike, Takao

    2016-01-01

    We aimed to identify causes of false-positives in ultrasound scanning of synovial/tenosynovial/bursal inflammation and provide corresponding imaging examples. We first performed systematic literature review to identify previously reported causes of false-positives. We next determined causes of false-positives and corresponding example images for educational material through Delphi exercises and discussion by 15 experts who were an instructor and/or a lecturer in the 2013 advanced course for musculoskeletal ultrasound organized by Japan College of Rheumatology Committee for the Standardization of Musculoskeletal Ultrasonography. Systematic literature review identified 11 articles relevant to sonographic false-positives of synovial/tenosynovial inflammation. Based on these studies, 21 candidate causes of false-positives were identified in the consensus meeting. Of these items, 11 achieved a predefined consensus (≥ 80%) in Delphi exercise and were classified as follows: (I) Gray-scale assessment [(A) non-specific synovial findings and (B) normal anatomical structures which can mimic synovial lesions due to either their low echogenicity or anisotropy]; (II) Doppler assessment [(A) Intra-articular normal vessels and (B) reverberation)]. Twenty-four corresponding examples with 49 still and 23 video images also achieved consensus. Our study provides a set of representative images that can help sonographers to understand false-positives in ultrasound scanning of synovitis and tenosynovitis.

  12. The risk factor of false-negative and false-positive for T-SPOT.TB in active tuberculosis.

    Science.gov (United States)

    Di, Li; Li, Yan

    2018-02-01

    T-SPOT.TB is a promising diagnosis tool to identify both pulmonary tuberculosis and extrapulmonary tuberculosis, as well as latent tuberculosis; however, the factors that affect the results of T-SPOT.TB remains unclear. In this study, we aim to figure out the risk factor of T-SPOT.TB for active TB. A total of 349 patients were recruited between January 1st, 2016 and January 22st, 2017 at Renmin Hospital of Wuhan University, including 98 subjects with TB and 251 subjects with non-TB disease, and received T-SPOT.TB (Oxford Immunotec Ltd). Statistics were analyzed by SPSS 19.0 using logistic regression. The overall specificity and sensitivity of the T-SPOT.TB was 92.83% (233/251; 95%CI 0.8872-0.9557) and 83.67% (82/98; 95%CI 0.7454-0.9010), respectively. Patients with tuberculous meningitis were more likely to have false-negative results (OR 17.4, 95%CI 3.068-98.671; P.05). Tuberculous meningitis was a risk factor of false-negative for T-SPOT.TB, while cured TB was a risk factor of false-positive. © 2017 Wiley Periodicals, Inc.

  13. Break-induced ATR and Ddb1-Cul4(Cdt)² ubiquitin ligase-dependent nucleotide synthesis promotes homologous recombination repair in fission yeast

    DEFF Research Database (Denmark)

    Moss, Jennifer; Tinline-Purvis, Helen; Walker, Carol A

    2010-01-01

    Nucleotide synthesis is a universal response to DNA damage, but how this response facilitates DNA repair and cell survival is unclear. Here we establish a role for DNA damage-induced nucleotide synthesis in homologous recombination (HR) repair in fission yeast. Using a genetic screen, we found...... the Ddb1-Cul4(Cdt)² ubiquitin ligase complex and ribonucleotide reductase (RNR) to be required for HR repair of a DNA double-strand break (DSB). The Ddb1-Cul4(Cdt)² ubiquitin ligase complex is required for degradation of Spd1, an inhibitor of RNR in fission yeast. Accordingly, deleting spd1(+) suppressed...

  14. Performance quantification of clustering algorithms for false positive removal in fMRI by ROC curves

    Directory of Open Access Journals (Sweden)

    André Salles Cunha Peres

    Full Text Available Abstract Introduction Functional magnetic resonance imaging (fMRI is a non-invasive technique that allows the detection of specific cerebral functions in humans based on hemodynamic changes. The contrast changes are about 5%, making visual inspection impossible. Thus, statistic strategies are applied to infer which brain region is engaged in a task. However, the traditional methods like general linear model and cross-correlation utilize voxel-wise calculation, introducing a lot of false-positive data. So, in this work we tested post-processing cluster algorithms to diminish the false-positives. Methods In this study, three clustering algorithms (the hierarchical cluster, k-means and self-organizing maps were tested and compared for false-positive removal in the post-processing of cross-correlation analyses. Results Our results showed that the hierarchical cluster presented the best performance to remove the false positives in fMRI, being 2.3 times more accurate than k-means, and 1.9 times more accurate than self-organizing maps. Conclusion The hierarchical cluster presented the best performance in false-positive removal because it uses the inconsistency coefficient threshold, while k-means and self-organizing maps utilize a priori cluster number (centroids and neurons number; thus, the hierarchical cluster avoids clustering scattered voxels, as the inconsistency coefficient threshold allows only the voxels to be clustered that are at a minimum distance to some cluster.

  15. False-Positive TDxFLx urine Amphetamine/Metamphetamine II assay from Ofloxacin

    International Nuclear Information System (INIS)

    Nomier, Mahmoud A.; Al-Huseini, Hani K.

    2004-01-01

    Immunoassays are widely used in testing urine for illicit drugs. Ofloaxcin and a number of other quinolones were found to induce false-positive opiates (OP) urine immunoassays. This can result in misleading conclusions in the concept of drug abuse The aim of present study was to evaluate the effects of ofloxacin in theraputic doses on the induction of false-positive urine immunoassays for common drugs of abuse in healthy male volunteers. The study was conducted on 6 healthy male volunteers, aging between 35-45 years. Two doses of 400 mg ofloxacin each, were given orally to each volunteer at 12 hours interval and urine samples were collected before ofloaxcin administration and 5-7.5 hours after the second dose. Urine samples were subjected for OP, amphetamine/methamphetamine II (AM/MA II), cocaine and cannabinoids assays on TDxFLx analyzer. Ofloxacin produced significant increase (P cutoff) for AM/MA II assays, were found in all volunteers after ofloaxcin administration. The study recomends strongly the confirmation of positive urine immunoassay results for drugs of abuseby a more specific methodology e.g. gas chromatography/ mass spectroscopy (GC/MS). (author)

  16. On minimizing assignment errors and the trade-off between false positives and negatives in parentage analysis

    KAUST Repository

    Harrison, Hugo B.

    2013-11-04

    Genetic parentage analyses provide a practical means with which to identify parent-offspring relationships in the wild. In Harrison et al.\\'s study (2013a), we compare three methods of parentage analysis and showed that the number and diversity of microsatellite loci were the most important factors defining the accuracy of assignments. Our simulations revealed that an exclusion-Bayes theorem method was more susceptible to false-positive and false-negative assignments than other methods tested. Here, we analyse and discuss the trade-off between type I and type II errors in parentage analyses. We show that controlling for false-positive assignments, without reporting type II errors, can be misleading. Our findings illustrate the need to estimate and report both the rate of false-positive and false-negative assignments in parentage analyses. © 2013 John Wiley & Sons Ltd.

  17. On minimizing assignment errors and the trade-off between false positives and negatives in parentage analysis

    KAUST Repository

    Harrison, Hugo B.; Saenz Agudelo, Pablo; Planes, Serge; Jones, Geoffrey P.; Berumen, Michael L.

    2013-01-01

    Genetic parentage analyses provide a practical means with which to identify parent-offspring relationships in the wild. In Harrison et al.'s study (2013a), we compare three methods of parentage analysis and showed that the number and diversity of microsatellite loci were the most important factors defining the accuracy of assignments. Our simulations revealed that an exclusion-Bayes theorem method was more susceptible to false-positive and false-negative assignments than other methods tested. Here, we analyse and discuss the trade-off between type I and type II errors in parentage analyses. We show that controlling for false-positive assignments, without reporting type II errors, can be misleading. Our findings illustrate the need to estimate and report both the rate of false-positive and false-negative assignments in parentage analyses. © 2013 John Wiley & Sons Ltd.

  18. Prevalence, antibiogram, and cdt genes of toxigenic Campylobacter jejuni in salad style vegetables (ulam) at farms and retail outlets in Terengganu.

    Science.gov (United States)

    Khalid, Mohd Ikhsan; Tang, John Yew Huat; Baharuddin, Nabila Huda; Rahman, Nasiha Shakina; Rahimi, Nurul Faizzah; Radu, Son

    2015-01-01

    The present study was conducted to investigate the prevalence and antibiotic resistance among Campylobacter jejuni in ulam at farms and retail outlets located in Kuala Terengganu, Malaysia. A total of 526 samples (ulam, soil, and fertilizer) were investigated for the presence of C. jejuni and the gene for cytolethal distending toxin (cdt) by using a multiplex PCR method. Antibiotic susceptibility to 10 types of antibiotics was determined using the disk diffusion method for 33 C. jejuni isolates. The average prevalence of contaminated samples from farms, wet markets, and supermarkets was 35.29, 52.66, and 69.88%, respectively. The cdt gene was not detected in 24 of the 33 C. jejuni isolates, but 9 isolates harbored cdtC. Antibiotic resistance in C. jejuni isolates was highest to penicillin G (96.97% of isolates) followed by vancomycin (87.88%), ampicillin (75.76%), erythromycin (60.61%), tetracycline (9.09%), amikacin (6.06%), and norfloxacin (3.03%); none of the isolates were resistant to ciprofloxacin, enrofloxacin, and gentamicin. In this study, C. jejuni was present in ulam, and some isolates were highly resistant to some antibiotics but not to quinolones. Thus, appropriate attention and measures are required to prevent C. jejuni contamination on farms and at retail outlets.

  19. Evaluation of inadequate, indeterminate, false-negative and false-positive cases in cytological examination for breast cancer according to histological type

    Science.gov (United States)

    2012-01-01

    Background We previously investigated the current status of breast cytology cancer screening at seven institutes in our area of southern Fukuoka Prefecture, and found some differences in diagnostic accuracy among the institutions. In the present study, we evaluated the cases involved and noted possible reasons for their original cytological classification as inadequate, indeterminate, false-negative and false-positive according to histological type. Methods We evaluated the histological findings in 5693 individuals who underwent cytological examination for breast cancer (including inadequate, indeterminate, false-negative and false-positive cases), to determine the most common histological types and/or features in these settings and the usefulness/limitations of cytological examination for the diagnosis of breast cancer. Results Among 1152 cytologically inadequate cases, histology revealed that 75/173 (43.6%) cases were benign, including mastopathy (fibrocystic disease) in 38.6%, fibroadenoma in 24.0% and papilloma in 5.3%. Ninety-five of 173 (54.9%) cases were histologically malignant, with scirrhous growing type, invasive ductal carcinoma (SIDC) being significantly more frequent (49.5%) than papillotubular growing type (Papi-tub) (P breast disease. In particular, several inadequate, indeterminate and false-negative cases with samples collected by aspiration were diagnosed as SIDC. These findings should encourage the use of needle biopsy rather than aspiration when this histological type is identified on imaging. Namely, good communication between clinicians and pathological staff, and triple assessment (i.e., clinical, pathological and radiological assessment), are important for accurate diagnosis of aspiration samples. Virtual slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7349809170055423 PMID:22607447

  20. False-positive findings in Cochrane meta-analyses with and without application of trial sequential analysis

    DEFF Research Database (Denmark)

    Imberger, Georgina; Thorlund, Kristian; Gluud, Christian

    2016-01-01

    outcome, a negative result and sufficient power. We defined a negative result as one where the 95% CI for the effect included 1.00, a positive result as one where the 95% CI did not include 1.00, and sufficient power as the required information size for 80% power, 5% type 1 error, relative risk reduction...... of 10% or number needed to treat of 100, and control event proportion and heterogeneity taken from the included studies. We re-conducted the meta-analyses, using conventional cumulative techniques, to measure how many false positives would have occurred if these meta-analyses had been updated after each...... new trial. For each false positive, we performed TSA, using three different approaches. RESULTS: We screened 4736 systematic reviews to find 100 meta-analyses that fulfilled our inclusion criteria. Using conventional cumulative meta-analysis, false positives were present in seven of the meta...

  1. Suture Granuloma Showing False-Positive Findings on FDG-PET

    Directory of Open Access Journals (Sweden)

    Kohei Takahara

    2013-01-01

    Full Text Available We report a case of a 33-year-old male with a mixed germ-cell testicular tumor. Postoperative follow-up FDG-PET revealed concentration of FDG in the left inguinal area which is not tumor metastasis or local recurrence but suture reactivity granuloma. In this paper, we reviewed suture granulomas associated with false-positive findings on FDG-PET after surgery. If FDG-PET will be used more frequently in the future, it will be necessary to refrain from using silk thread in order to prevent any unnecessary surgery.

  2. Generating false negatives and false positives for As and Mo concentrations in groundwater due to well installation.

    Science.gov (United States)

    Wallis, Ilka; Pichler, Thomas

    2018-08-01

    Groundwater monitoring relies on the acquisition of 'representative' groundwater samples, which should reflect the ambient water quality at a given location. However, drilling of a monitoring well for sample acquisition has the potential to perturb groundwater conditions to a point that may prove to be detrimental to the monitoring objective. Following installation of 20 monitoring wells in close geographic proximity in central Florida, opposing concentration trends for As and Mo were observed. In the first year after well installation As and Mo concentrations increased in some wells by a factor of 2, while in others As and Mo concentrations decreased by a factor of up to 100. Given this relatively short period of time, a natural change in groundwater composition of such magnitude is not expected, leaving well installation itself as the likely cause for the observed concentration changes. Hence, initial concentrations were identified as 'false negatives' if concentrations increased with time or as 'false positives' if concentrations decreased. False negatives were observed if concentrations were already high, i.e., the As or Mo were present at the time of drilling. False positives were observed if concentrations were relatively lower, i.e., As or Mo were present at low concentrations of approximately 1 to 2μg/L before drilling, but then released from the aquifer matrix as a result of drilling. Generally, As and Mo were present in the aquifer matrix in either pyrite or organic matter, both of which are susceptible to dissolution if redox conditions change due to the addition of oxygen. Thus, introduction of an oxidant into an anoxic aquifer through use of an oxygen saturated drilling fluid served as the conceptual model for the trends where concentrations decreased with time. Mixing between drilling fluid and groundwater (i.e., dilution) was used as the conceptual model for scenarios where increasing trends were observed. Conceptual models were successfully tested

  3. Newly formed skeletal muscle fibers are prone to false positive immunostaining by rabbit antibodies

    DEFF Research Database (Denmark)

    Andersen, Ditte C; Kliem, Anette; Schrøder, Henrik Daa

    2011-01-01

    rely on controls that reveal non-specific binding by the secondary antibody and neglect that the primary rabbit antibody itself may cause false positive staining of the muscle. We suggest that reliable immuno-based protein detection in newly formed muscle fibers at least requires a nonsense rabbit......Reports on muscle biology and regeneration often implicate immuno(cyto/histo)chemical protein characterization using rabbit polyclonal antibodies. In this study we demonstrate that newly formed myofibers are especially prone to false positive staining by rabbit antibodies and this unwanted staining...

  4. The Role of the CRL4Cdt2 Target Spd1 in Chromosome Segregation in Fission Yeast

    DEFF Research Database (Denmark)

    Landvad, Katrine

    Ddb1, a component of the E3 ubiquitin ligase CRL4Cdt2, is needed for proper chromosome segregation in fission yeast as ddb1 deleted cells show unequal distribution of DNA to daughter cells and sensitivity to the microtubule destabilising drug TBZ. In this study we show that Δddb1 cells have...

  5. PRE-SPECTROSCOPIC FALSE-POSITIVE ELIMINATION OF KEPLER PLANET CANDIDATES

    International Nuclear Information System (INIS)

    Batalha, Natalie M.; Rowe, Jason F.; Borucki, William J.; Koch, David G.; Lissauer, Jack J.; Gilliland, Ronald L.; Jenkins, Jon J.; Caldwell, Douglas; Dunham, Edward W.; Gautier, Thomas N.; Howell, Steve B.; Latham, David W.; Marcy, Geoff W.; Prsa, Andrej

    2010-01-01

    Ten days of commissioning data (Quarter 0) and 33 days of science data (Quarter 1) yield instrumental flux time series of ∼150,000 stars that were combed for transit events, termed threshold crossing events(TCE), each having a total detection statistic above 7.1σ. TCE light curves are modeled as star+planet systems. Those returning a companion radius smaller than 2R J are assigned a Kepler Object of Interest (KOI) number. The raw flux, pixel flux, and flux-weighted centroids of every KOI are scrutinized to assess the likelihood of being an astrophysical false positive versus the likelihood of being a planetary companion. This vetting using Kepler data is referred to as data validation (DV). Herein, we describe the DV metrics and graphics used to identify viable planet candidates amongst the KOIs. Light curve modeling tests for (1) the difference in depth of the odd- versus even-numbered transits, (2) evidence of ellipsoidal variations, and (3) evidence of a secondary eclipse event at phase = 0.5. Flux-weighted centroids are used to test for signals correlated with transit events with a magnitude and direction indicative of a background eclipsing binary. Centroid time series are complimented by analysis of images taken in-transit versus out-of-transit, the difference often revealing the pixel contributing the most to the flux change during transit. Examples are shown to illustrate each test. Candidates passing DV are submitted to ground-based observers for further false-positive elimination or confirmation/characterization.

  6. ST-Segment Depression in Hyperventilation Indicates a False Positive Exercise Test in Patients with Mitral Valve Prolapse

    Directory of Open Access Journals (Sweden)

    Andreas P. Michaelides

    2010-01-01

    Full Text Available Objectives. Mitral valve prolapse (MVP is a known cause for false positive exercise test (ET. The purpose of this study was to establish additional electrocardiographic criteria to distinguish the false positive exercise results in patients with MVP. Methods. We studied 218 consecutive patients ( years, 103 males with MVP (according to echocardiographic study, and positive treadmill ET was performed due to multiple cardiovascular risk factors or angina-like symptoms. A coronary angiography was performed to detect coronary artery disease (CAD. Results. From 218 patients, 90 (group A presented with normal coronary arteries according to the angiography (false positive ET while the rest 128 (group B presented with CAD. ST-segment depression in hyperventilation phase was present in 54 patients of group A (60% while only in 14 patients of group B (11%, . Conclusions. Presence of ST-segment depression in hyperventilation phase favors a false positive ET in patients with MVP.

  7. Proteins interacting with cloning scars: a source of false positive protein-protein interactions.

    Science.gov (United States)

    Banks, Charles A S; Boanca, Gina; Lee, Zachary T; Florens, Laurence; Washburn, Michael P

    2015-02-23

    A common approach for exploring the interactome, the network of protein-protein interactions in cells, uses a commercially available ORF library to express affinity tagged bait proteins; these can be expressed in cells and endogenous cellular proteins that copurify with the bait can be identified as putative interacting proteins using mass spectrometry. Control experiments can be used to limit false-positive results, but in many cases, there are still a surprising number of prey proteins that appear to copurify specifically with the bait. Here, we have identified one source of false-positive interactions in such studies. We have found that a combination of: 1) the variable sequence of the C-terminus of the bait with 2) a C-terminal valine "cloning scar" present in a commercially available ORF library, can in some cases create a peptide motif that results in the aberrant co-purification of endogenous cellular proteins. Control experiments may not identify false positives resulting from such artificial motifs, as aberrant binding depends on sequences that vary from one bait to another. It is possible that such cryptic protein binding might occur in other systems using affinity tagged proteins; this study highlights the importance of conducting careful follow-up studies where novel protein-protein interactions are suspected.

  8. Protein complex prediction via dense subgraphs and false positive analysis.

    Directory of Open Access Journals (Sweden)

    Cecilia Hernandez

    Full Text Available Many proteins work together with others in groups called complexes in order to achieve a specific function. Discovering protein complexes is important for understanding biological processes and predict protein functions in living organisms. Large-scale and throughput techniques have made possible to compile protein-protein interaction networks (PPI networks, which have been used in several computational approaches for detecting protein complexes. Those predictions might guide future biologic experimental research. Some approaches are topology-based, where highly connected proteins are predicted to be complexes; some propose different clustering algorithms using partitioning, overlaps among clusters for networks modeled with unweighted or weighted graphs; and others use density of clusters and information based on protein functionality. However, some schemes still require much processing time or the quality of their results can be improved. Furthermore, most of the results obtained with computational tools are not accompanied by an analysis of false positives. We propose an effective and efficient mining algorithm for discovering highly connected subgraphs, which is our base for defining protein complexes. Our representation is based on transforming the PPI network into a directed acyclic graph that reduces the number of represented edges and the search space for discovering subgraphs. Our approach considers weighted and unweighted PPI networks. We compare our best alternative using PPI networks from Saccharomyces cerevisiae (yeast and Homo sapiens (human with state-of-the-art approaches in terms of clustering, biological metrics and execution times, as well as three gold standards for yeast and two for human. Furthermore, we analyze false positive predicted complexes searching the PDBe (Protein Data Bank in Europe database in order to identify matching protein complexes that have been purified and structurally characterized. Our analysis shows

  9. Easy fix for clinical laboratories for the false-positive defect with the Abbott AxSym total beta-hCG test.

    Science.gov (United States)

    Cole, Laurence A; Khanlian, Sarah A

    2004-05-01

    False-positive hCG results can lead to erroneous diagnoses and needless chemotherapy and surgery. In the last 2 years, eight publications described cases involving false-positive hCG tests; all eight involved the AxSym test. We investigated the source of this abundance of cases and a simple fix that may be used by clinical laboratories. False-positive hCG was primarily identified by absence of hCG in urine and varying or negative hCG results in alternative tests. Seventeen false-positive serum samples in the AxSym test were evaluated undiluted and at twofold dilution with diluent containing excess goat serum or immunoglobulin. We identified 58 patients with false-positive hCG, 47 of 58 due to the Abbott AxSym total hCGbeta test (81%). Sixteen of 17 of these "false-positive" results (mean 100 mIU/ml) became undetectable when tested again after twofold dilution. A simple twofold dilution with this diluent containing excess goat serum or immunoglobulin completely protected 16 of 17 samples from patients having false-positive results. It is recommended that laboratories using this test use twofold dilution as a minimum to prevent false-positive results.

  10. False-positive reduction in CAD mass detection using a competitive classification strategy

    International Nuclear Information System (INIS)

    Li Lihua; Zheng Yang; Zhang Lei; Clark, Robert A.

    2001-01-01

    High false-positive (FP) rate remains to be one of the major problems to be solved in CAD study because too many false-positively cued signals will potentially degrade the performance of detecting true-positive regions and increase the call-back rate in CAD environment. In this paper, we proposed a novel classification method for FP reduction, where the conventional 'hard' decision classifier is cascaded with a 'soft' decision classification with the objective to reduce false-positives in the cases with multiple FPs retained after the 'hard' decision classification. The 'soft' classification takes a competitive classification strategy in which only the 'best' ones are selected from the pre-classified suspicious regions as the true mass in each case. A neural network structure is designed to implement the proposed competitive classification. Comparative studies of FP reduction on a database of 79 images by a 'hard' decision classification and a combined 'hard'-'soft' classification method demonstrated the efficiency of the proposed classification strategy. For example, for the high FP sub-database which has only 31.7% of total images but accounts for 63.5% of whole FPs generated in single 'hard' classification, the FPs can be reduced for 56% (from 8.36 to 3.72 per image) by using the proposed method at the cost of 1% TP loss (from 69% to 68%) in whole database, while it can only be reduced for 27% (from 8.36 to 6.08 per image) by simply increasing the threshold of 'hard' classifier with a cost of TP loss as high as 14% (from 69% to 55%). On the average in whole database, the FP reduction by hybrid 'hard'-'soft' classification is 1.58 per image as compared to 1.11 by 'hard' classification at the TP costs described above. Because the cases with high dense tissue are of higher risk of cancer incidence and false-negative detection in mammogram screening, and usually generate more FPs in CAD detection, the method proposed in this paper will be very helpful in improving

  11. Potential for false positive HIV test results with the serial rapid HIV testing algorithm.

    Science.gov (United States)

    Baveewo, Steven; Kamya, Moses R; Mayanja-Kizza, Harriet; Fatch, Robin; Bangsberg, David R; Coates, Thomas; Hahn, Judith A; Wanyenze, Rhoda K

    2012-03-19

    Rapid HIV tests provide same-day results and are widely used in HIV testing programs in areas with limited personnel and laboratory infrastructure. The Uganda Ministry of Health currently recommends the serial rapid testing algorithm with Determine, STAT-PAK, and Uni-Gold for diagnosis of HIV infection. Using this algorithm, individuals who test positive on Determine, negative to STAT-PAK and positive to Uni-Gold are reported as HIV positive. We conducted further testing on this subgroup of samples using qualitative DNA PCR to assess the potential for false positive tests in this situation. Of the 3388 individuals who were tested, 984 were HIV positive on two consecutive tests, and 29 were considered positive by a tiebreaker (positive on Determine, negative on STAT-PAK, and positive on Uni-Gold). However, when the 29 samples were further tested using qualitative DNA PCR, 14 (48.2%) were HIV negative. Although this study was not primarily designed to assess the validity of rapid HIV tests and thus only a subset of the samples were retested, the findings show a potential for false positive HIV results in the subset of individuals who test positive when a tiebreaker test is used in serial testing. These findings highlight a need for confirmatory testing for this category of individuals.

  12. Adrenocortical Carcinoma: False Positive in an I-123 Metaiodobenzylguanidine Scan

    Energy Technology Data Exchange (ETDEWEB)

    Rey, Cristina Rodriguez; Candil, Aida Ortega; Galvan, Eliseo Vano; Martin, Maria Nieves Cabrera; Delgado, Jose Luis Carreras [Clinico San Carlos Hospital, Madrid (Spain)

    2016-06-15

    A 55-year-old man with a personal his history of left pheochromocytoma 2 years previously presented with an abdominal ultrasound showed a large left upper quadrant solid mass (calipers), with heterogeneous echogenicity and central cystic degeneration areas or necrosis. F-18 Fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT was performed as ACC was suspected. ACC is an uncommon malignant neoplasm of unknown cause; however, smoking and oral contraceptives may be risk factors. Patients usually present with advanced-stage disease and have poor prognosis, with a 2-year recurrence rate that ranges form 73 to 86 %. An MIBG scan was performed after injection of 185 MBq of I-123 MIBG intravenously. Single photon emission tomography (SPECT)/CT scan showed abnormal isotope accumulation in the tumor region. The patient underwent total resection of the tumor. The histology was of ACC, with areas of necrosis and cystic areas, so the result of the MIBG scan was a false positive. Authors divided false-positive MIBG studies into three categories. The first category is neuroendocrine lesions other than pheochromocytomas (tumors of the APUD series). the second category consists in adrenal lesions other than pheochromocytomas (adenomas, ACC) the reasons for this abnormal uptake are unclear. The third category consists of tracer uptake adjacent to the adrenal due to abnormalities in the route of excretion.

  13. False-positive findings in mammography screening induces short-term distress - breast cancer-specific concern prevails longer

    DEFF Research Database (Denmark)

    Aro, A R; Pilvikki Absetz, S; van Elderen, T M

    2000-01-01

    -ups at 2 and 12 months postscreening. At 2 months, there was a moderate multivariate effect of group on distress; and intrusive thinking and worry about breast cancer, in particular, were most frequent amongst the false positives. Intrusive thinking still prevailed at 12 months, in addition to a higher...... findings (n=1407), false-positive findings (n=492) and referents from outside the screening programme (n=1718, age 48-49 years). Distress was measured as illness worry, anxiety, depression, cancer beliefs and early detection behaviour. Measurements were one month before screening invitation with follow...... perceived breast cancer risk and susceptibility. Distress related to screening and false-positive findings seems to be moderate, but prevailing cancer-specific concerns call for improvements in screening programmes....

  14. [Evaluation of performance and false positivity of Mediace RPR test that uses a chemistry autoanalyzer].

    Science.gov (United States)

    Noh, Jaekwang; Ko, Hak Hyun; Yun, Yeomin; Choi, Young Sook; Lee, Sang Gon; Shin, Sue; Han, Kyou Sup; Song, Eun Young

    2008-08-01

    We evaluated the performance and false positive rate of Mediace RPR test (Sekisui, Japan), a newly introduced nontreponemal test using a chemistry autoanalyzer. The sensitivity of Mediace RPR test was analyzed using sera from 50 patients with syphilis in different stages (8 primary, 7 secondary, and 35 latent), 14 sera positive with fluorescent treponemal antibody absorption (FTA-ABS) IgM, and 74 sera positive with conventional rapid plasma regain (RPR) card test (Asan, Korea) and also positive with Treponema pallidum hemagglutination (TPHA) test or FTA-ABS IgG test. The specificity was analyzed on 108 healthy blood donors. We also performed RPR card test on 302 sera that had been tested positive with Mediace RPR test and also performed TPHA or FTA-ABS IgG test to analyze the false positive rate of Mediace RPR test. A cutoff value of 0.5 R.U. (RPR unit) was used for Mediace RPR test. Mediace RPR test on syphilitic sera of different stages (primary, secondary, and latent stages) and FTA-ABS IgM positive sera showed a sensitivity of 100%, 100%, 82.9% and 100%, respectively. Among the 74 sera positive with conventional RPR card test and TPHA or FTA-ABS IgG test, 55 were positive with Mediace test. The specificity of Mediace RPR test on blood donors was 97.2%. Among the 302 sera positive with Mediace RPR test, 137 sera (45.4%) were negative by RPR card and TPHA/FTA-ABS IgG tests. Although the sensitivities of Mediace RPR were good for primary and secondary syphilis, due to its high negative rate of Mediace RPR over the conventional RPR positive samples, further studies are necessary whether it can replace conventional nontreponemal test for screening purpose. Moreover, in view of the high false positive rate, positive results by Mediace RPR test should be confirmed with treponemal tests.

  15. The illusion of the positive: the impact of natural and induced mood on older adults' false recall.

    Science.gov (United States)

    Emery, Lisa; Hess, Thomas M; Elliot, Tonya

    2012-11-01

    Recent research suggests that affective and motivational processes can influence age differences in memory. In the current study, we examine the impact of both natural and induced mood state on age differences in false recall. Older and younger adults performed a version of the Deese-Roediger-McDermott (DRM; Roediger & McDermott, 1995 , Journal of Experimental Psychology: Learning, Memory, and Cognition, 21, 803) false memory paradigm in either their natural mood state or after a positive or negative mood induction. Results indicated that, after accounting for age differences in basic cognitive function, age-related differences in positive mood during the testing session were related to increased false recall in older adults. Inducing older adults into a positive mood also exacerbated age differences in false memory. In contrast, veridical recall did not appear to be systematically influenced by mood. Together, these results suggest that positive mood states can impact older adults' information processing and potentially increase underlying cognitive age differences.

  16. Potential for false positive HIV test results with the serial rapid HIV testing algorithm

    Directory of Open Access Journals (Sweden)

    Baveewo Steven

    2012-03-01

    Full Text Available Abstract Background Rapid HIV tests provide same-day results and are widely used in HIV testing programs in areas with limited personnel and laboratory infrastructure. The Uganda Ministry of Health currently recommends the serial rapid testing algorithm with Determine, STAT-PAK, and Uni-Gold for diagnosis of HIV infection. Using this algorithm, individuals who test positive on Determine, negative to STAT-PAK and positive to Uni-Gold are reported as HIV positive. We conducted further testing on this subgroup of samples using qualitative DNA PCR to assess the potential for false positive tests in this situation. Results Of the 3388 individuals who were tested, 984 were HIV positive on two consecutive tests, and 29 were considered positive by a tiebreaker (positive on Determine, negative on STAT-PAK, and positive on Uni-Gold. However, when the 29 samples were further tested using qualitative DNA PCR, 14 (48.2% were HIV negative. Conclusion Although this study was not primarily designed to assess the validity of rapid HIV tests and thus only a subset of the samples were retested, the findings show a potential for false positive HIV results in the subset of individuals who test positive when a tiebreaker test is used in serial testing. These findings highlight a need for confirmatory testing for this category of individuals.

  17. Characteristics of the new phase in CDT

    Energy Technology Data Exchange (ETDEWEB)

    Ambjoern, J. [Copenhagen University, The Niels Bohr Institute, Copenhagen Oe (Denmark); Radboud University, Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Nijmegen (Netherlands); Gizbert-Studnicki, J.; Jurkiewicz, J. [Jagiellonian University, Institute of Physics, Krakow (Poland); Goerlich, A. [Copenhagen University, The Niels Bohr Institute, Copenhagen Oe (Denmark); Jagiellonian University, Institute of Physics, Krakow (Poland); Klitgaard, N.; Loll, R. [Radboud University, Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Nijmegen (Netherlands)

    2017-03-15

    The approach of Causal Dynamical Triangulations (CDT), a candidate theory of nonperturbative quantum gravity in 4D, turns out to have a rich phase structure. We investigate the recently discovered bifurcation phase C{sub b} and relate some of its characteristics to the presence of singular vertices of very high order. The transition lines separating this phase from the ''time-collapsed'' B-phase and the de Sitter phase C{sub dS} are of great interest when searching for physical scaling limits. The work presented here sheds light on the mechanisms behind these transitions. First, we study how the B-C{sub b} transition signal depends on the volume fixing implemented in the simulations, and find results compatible with the previously determined second-order character of the transition. The transition persists in a transfer matrix formulation, where the system's time extension is taken to be minimal. Second, we relate the new C{sub b}-C{sub dS} transition to the appearance of singular vertices, which leads to a direct physical interpretation in terms of a breaking of the homogeneity and isotropy observed in the de Sitter phase when crossing from C{sub dS} to the bifurcation phase C{sub b}. (orig.)

  18. Buffer substitution in malaria rapid diagnostic tests causes false-positive results

    Directory of Open Access Journals (Sweden)

    Van den Ende Jef

    2010-07-01

    Full Text Available Abstract Background Malaria rapid diagnostic tests (RDTs are kits that generally include 20 to 25 test strips or cassettes, but only a single buffer vial. In field settings, laboratory staff occasionally uses saline, distilled water (liquids for parenteral drugs dilution or tap water as substitutes for the RDT kit's buffer to compensate for the loss of a diluent bottle. The present study assessed the effect of buffer substitution on the RDT results. Methods Twenty-seven RDT brands were run with EDTA-blood samples of five malaria-free subjects, who were negative for rheumatoid factor and antinuclear antibodies. Saline, distilled water and tap water were used as substitute liquids. RDTs were also run with distilled water, without adding blood. Results were compared to those obtained with the RDT kit's buffer and Plasmodium positive samples. Results Only eight cassettes (in four RDT brands showed no control line and were considered invalid. Visible test lines occurred for at least one malaria-free sample and one of the substitutes in 20/27 (74% RDT brands (saline: n = 16; distilled water: n = 17; and tap water: n = 20, and in 15 RDTs which were run with distilled water only. They occurred for all Plasmodium antigens and RDT formats (two-, three- and four-band RDTs. Clearance of the background of the strip was excellent except for saline. The aspects (colour, intensity and crispness of the control and the false-positive test lines were similar to those obtained with the RDT kits' buffer and Plasmodium positive samples. Conclusion Replacement of the RDT kit's dedicated buffer by saline, distilled water and tap water can cause false-positive test results.

  19. Clinical evaluation of false-positive scintigraphic lesions of the left lobe in portal hypertension

    International Nuclear Information System (INIS)

    Takayasu, Kenichi; Moriyama, Noriyuki; Suzuki, Masao; Yamada, Tatsuya; Fukutake, Toshio.

    1982-01-01

    sup(99m)Tc-phytate liver scan and percutaneous transhepatic portography (PTP) were performed in 33 patients with portal hypertension due to various hepatic diseases. A defect or space occupying lesion in the left lobe on the scan in these patients was analysed with reference to portographic changes of the pars umbilicus of the left portal vein and the following results were obtained. 1) A false-positive defect on the scintigram was found in 6 (18.2%) of 33 patients, and portal vein pressure (PVP) was above 200 mmH 2 O in all 6 which constituted 21.4% of 28 with PVP above 200 mmH 2 O. 2) In five out of 6 patients with false-positive scan findings, the pars umbilicus was dilated to more than 25 x 15 mm in size, and it was huge and tortuous in 3 of them. 3) The mean PVP in the group with a false-positive scan tended to be higher than that in patients with no abnormalities on the scintigram. It was concluded that in reading of liver scintigrams in patients with portal hypertension, a dilated pars umbilicus and huge para-umbilical vein should be considered. (author)

  20. Commercial radioimmunoassay for beta subunit of human chorionic gonadotropin: falsely positive determinations due to elevated serum luteinizing hormone

    International Nuclear Information System (INIS)

    Fowler, J.E. Jr.; Platoff, G.E.; Kubrock, C.A.; Stuzman, R.E.

    1982-01-01

    Among 17 men who had received seemingly curative treatment for unilateral non-seminomatous germ cell tumors for the testis and who had consistently normal serum human chorionic gonadotropin (HCG) levels at a reference laboratory, 7 (41%) had at least one falsely positive commercial serum HCG determination. To investigate the cause of these falsely positive determinations the authors measured the cross reactivity of luteinizing hormone (LH) and follicle stimulating hormone (FSH) standards in the commercial HCG assay, and studied the relationships between commercial HCG levels and serum LH levels, serum FSH levels and gonadal status in men with and without normal gonadal function. The falsely positive HCG determinations appeared to be due to elevated serum LH levels and cross reactivity of LH in the commercial HCG assay because: 1) there was substantial cross reactivity of the LH standards in the commercial assay, 2) the serum LH was elevated in four of six men with solitary testes, 3) there was a striking correlation between elevated serum LH levels and falsely elevated commercial HCG levels in ten men with solitary or absent testes, and 4) there were no falsely positive HCG determinations in 13 normal men but there were falsely positive HCG determinations in seven of ten anorchid men

  1. The Binary Toxin CDT of Clostridium difficile as a Tool for Intracellular Delivery of Bacterial Glucosyltransferase Domains

    Directory of Open Access Journals (Sweden)

    Lara-Antonia Beer

    2018-06-01

    Full Text Available Binary toxins are produced by several pathogenic bacteria. Examples are the C2 toxin from Clostridium botulinum, the iota toxin from Clostridium perfringens, and the CDT from Clostridium difficile. All these binary toxins have ADP-ribosyltransferases (ADPRT as their enzymatically active component that modify monomeric actin in their target cells. The binary C2 toxin was intensively described as a tool for intracellular delivery of allogenic ADPRTs. Here, we firstly describe the binary toxin CDT from C. difficile as an effective tool for heterologous intracellular delivery. Even 60 kDa glucosyltransferase domains of large clostridial glucosyltransferases can be delivered into cells. The glucosyltransferase domains of five tested large clostridial glucosyltransferases were successfully introduced into cells as chimeric fusions to the CDTa adapter domain (CDTaN. Cell uptake was demonstrated by the analysis of cell morphology, cytoskeleton staining, and intracellular substrate glucosylation. The fusion toxins were functional only when the adapter domain of CDTa was N-terminally located, according to its native orientation. Thus, like other binary toxins, the CDTaN/b system can be used for standardized delivery systems not only for bacterial ADPRTs but also for a variety of bacterial glucosyltransferase domains.

  2. Limited agreement of independent RNAi screens for virus-required host genes owes more to false-negative than false-positive factors.

    Directory of Open Access Journals (Sweden)

    Linhui Hao

    Full Text Available Systematic, genome-wide RNA interference (RNAi analysis is a powerful approach to identify gene functions that support or modulate selected biological processes. An emerging challenge shared with some other genome-wide approaches is that independent RNAi studies often show limited agreement in their lists of implicated genes. To better understand this, we analyzed four genome-wide RNAi studies that identified host genes involved in influenza virus replication. These studies collectively identified and validated the roles of 614 cell genes, but pair-wise overlap among the four gene lists was only 3% to 15% (average 6.7%. However, a number of functional categories were overrepresented in multiple studies. The pair-wise overlap of these enriched-category lists was high, ∼19%, implying more agreement among studies than apparent at the gene level. Probing this further, we found that the gene lists implicated by independent studies were highly connected in interacting networks by independent functional measures such as protein-protein interactions, at rates significantly higher than predicted by chance. We also developed a general, model-based approach to gauge the effects of false-positive and false-negative factors and to estimate, from a limited number of studies, the total number of genes involved in a process. For influenza virus replication, this novel statistical approach estimates the total number of cell genes involved to be ∼2,800. This and multiple other aspects of our experimental and computational results imply that, when following good quality control practices, the low overlap between studies is primarily due to false negatives rather than false-positive gene identifications. These results and methods have implications for and applications to multiple forms of genome-wide analysis.

  3. The probability of false positives in zero-dimensional analyses of one-dimensional kinematic, force and EMG trajectories.

    Science.gov (United States)

    Pataky, Todd C; Vanrenterghem, Jos; Robinson, Mark A

    2016-06-14

    A false positive is the mistake of inferring an effect when none exists, and although α controls the false positive (Type I error) rate in classical hypothesis testing, a given α value is accurate only if the underlying model of randomness appropriately reflects experimentally observed variance. Hypotheses pertaining to one-dimensional (1D) (e.g. time-varying) biomechanical trajectories are most often tested using a traditional zero-dimensional (0D) Gaussian model of randomness, but variance in these datasets is clearly 1D. The purpose of this study was to determine the likelihood that analyzing smooth 1D data with a 0D model of variance will produce false positives. We first used random field theory (RFT) to predict the probability of false positives in 0D analyses. We then validated RFT predictions via numerical simulations of smooth Gaussian 1D trajectories. Results showed that, across a range of public kinematic, force/moment and EMG datasets, the median false positive rate was 0.382 and not the assumed α=0.05, even for a simple two-sample t test involving N=10 trajectories per group. The median false positive rate for experiments involving three-component vector trajectories was p=0.764. This rate increased to p=0.945 for two three-component vector trajectories, and to p=0.999 for six three-component vectors. This implies that experiments involving vector trajectories have a high probability of yielding 0D statistical significance when there is, in fact, no 1D effect. Either (a) explicit a priori identification of 0D variables or (b) adoption of 1D methods can more tightly control α. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Reporting instructions significantly impact false positive rates when reading chest radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, John W.; Brennan, Patrick C.; Mello-Thoms, Claudia; Lewis, Sarah J. [The University of Sydney, Medical Image Optimisation and Perception Group, Discipline of Medical Radiation Sciences, Faculty of Health Sciences, Lidcombe, NSW (Australia)

    2016-10-15

    To determine the impact of specific reporting tasks on the performance of radiologists when reading chest radiographs. Ten experienced radiologists read a set of 40 postero-anterior (PA) chest radiographs: 21 nodule free and 19 with a proven solitary nodule. There were two reporting conditions: an unframed task (UFT) to report any abnormality and a framed task (FT) reporting only lung nodule/s. Jackknife free-response operating characteristic (JAFROC) figure of merit (FOM), specificity, location sensitivity and number of true positive (TP), false positive (FP), true negative (TN) and false negative (FN) decisions were used for analysis. JAFROC FOM for tasks showed a significant reduction in performance for framed tasks (P = 0.006) and an associated decrease in specificity (P = 0.011) but no alteration to the location sensitivity score. There was a significant increase in number of FP decisions made during framed versus unframed tasks for nodule-containing (P = 0.005) and nodule-free (P = 0.011) chest radiographs. No significant differences in TP were recorded. Radiologists report more FP decisions when given specific reporting instructions to search for nodules on chest radiographs. The relevance of clinical history supplied to radiologists is called into question and may induce a negative effect. (orig.)

  5. Reporting instructions significantly impact false positive rates when reading chest radiographs

    International Nuclear Information System (INIS)

    Robinson, John W.; Brennan, Patrick C.; Mello-Thoms, Claudia; Lewis, Sarah J.

    2016-01-01

    To determine the impact of specific reporting tasks on the performance of radiologists when reading chest radiographs. Ten experienced radiologists read a set of 40 postero-anterior (PA) chest radiographs: 21 nodule free and 19 with a proven solitary nodule. There were two reporting conditions: an unframed task (UFT) to report any abnormality and a framed task (FT) reporting only lung nodule/s. Jackknife free-response operating characteristic (JAFROC) figure of merit (FOM), specificity, location sensitivity and number of true positive (TP), false positive (FP), true negative (TN) and false negative (FN) decisions were used for analysis. JAFROC FOM for tasks showed a significant reduction in performance for framed tasks (P = 0.006) and an associated decrease in specificity (P = 0.011) but no alteration to the location sensitivity score. There was a significant increase in number of FP decisions made during framed versus unframed tasks for nodule-containing (P = 0.005) and nodule-free (P = 0.011) chest radiographs. No significant differences in TP were recorded. Radiologists report more FP decisions when given specific reporting instructions to search for nodules on chest radiographs. The relevance of clinical history supplied to radiologists is called into question and may induce a negative effect. (orig.)

  6. A deep 3D residual CNN for false-positive reduction in pulmonary nodule detection.

    Science.gov (United States)

    Jin, Hongsheng; Li, Zongyao; Tong, Ruofeng; Lin, Lanfen

    2018-05-01

    The automatic detection of pulmonary nodules using CT scans improves the efficiency of lung cancer diagnosis, and false-positive reduction plays a significant role in the detection. In this paper, we focus on the false-positive reduction task and propose an effective method for this task. We construct a deep 3D residual CNN (convolution neural network) to reduce false-positive nodules from candidate nodules. The proposed network is much deeper than the traditional 3D CNNs used in medical image processing. Specifically, in the network, we design a spatial pooling and cropping (SPC) layer to extract multilevel contextual information of CT data. Moreover, we employ an online hard sample selection strategy in the training process to make the network better fit hard samples (e.g., nodules with irregular shapes). Our method is evaluated on 888 CT scans from the dataset of the LUNA16 Challenge. The free-response receiver operating characteristic (FROC) curve shows that the proposed method achieves a high detection performance. Our experiments confirm that our method is robust and that the SPC layer helps increase the prediction accuracy. Additionally, the proposed method can easily be extended to other 3D object detection tasks in medical image processing. © 2018 American Association of Physicists in Medicine.

  7. Parental knowledge reduces long term anxiety induced by false-positive test results after newborn screening for cystic fibrosis

    NARCIS (Netherlands)

    Vernooij-van Langen, A.M.M.; Pal, S.M. van der; Reijntjens, A.J.T.; Loeber, J.G.; Dompeling, E.; Dankert-Roelse, J.E.

    2014-01-01

    Background: False-positive screening results in newborn screening for cystic fibrosis may lead to parental stress, family relationship problems and a changed perception of the child's health. Aim of the study: To evaluate whether parental anxiety induced by a false positive screening result

  8. Optimization of CDT-1 and XYL1 Expression for Balanced Co-Production of Ethanol and Xylitol from Cellobiose and Xylose by Engineered Saccharomyces cerevisiae

    Science.gov (United States)

    Zha, Jian; Li, Bing-Zhi; Shen, Ming-Hua; Hu, Meng-Long; Song, Hao; Yuan, Ying-Jin

    2013-01-01

    Production of ethanol and xylitol from lignocellulosic hydrolysates is an alternative to the traditional production of ethanol in utilizing biomass. However, the conversion efficiency of xylose to xylitol is restricted by glucose repression, causing a low xylitol titer. To this end, we cloned genes CDT-1 (encoding a cellodextrin transporter) and gh1-1 (encoding an intracellular β-glucosidase) from Neurospora crassa and XYL1 (encoding a xylose reductase that converts xylose into xylitol) from Scheffersomyces stipitis into Saccharomyces cerevisiae, enabling simultaneous production of ethanol and xylitol from a mixture of cellobiose and xylose (main components of lignocellulosic hydrolysates). We further optimized the expression levels of CDT-1 and XYL1 by manipulating their promoters and copy-numbers, and constructed an engineered S. cerevisiae strain (carrying one copy of PGK1p-CDT1 and two copies of TDH3p-XYL1), which showed an 85.7% increase in xylitol production from the mixture of cellobiose and xylose than that from the mixture of glucose and xylose. Thus, we achieved a balanced co-fermentation of cellobiose (0.165 g/L/h) and xylose (0.162 g/L/h) at similar rates to co-produce ethanol (0.36 g/g) and xylitol (1.00 g/g). PMID:23844185

  9. Optimization of CDT-1 and XYL1 expression for balanced co-production of ethanol and xylitol from cellobiose and xylose by engineered Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Jian Zha

    Full Text Available Production of ethanol and xylitol from lignocellulosic hydrolysates is an alternative to the traditional production of ethanol in utilizing biomass. However, the conversion efficiency of xylose to xylitol is restricted by glucose repression, causing a low xylitol titer. To this end, we cloned genes CDT-1 (encoding a cellodextrin transporter and gh1-1 (encoding an intracellular β-glucosidase from Neurospora crassa and XYL1 (encoding a xylose reductase that converts xylose into xylitol from Scheffersomyces stipitis into Saccharomyces cerevisiae, enabling simultaneous production of ethanol and xylitol from a mixture of cellobiose and xylose (main components of lignocellulosic hydrolysates. We further optimized the expression levels of CDT-1 and XYL1 by manipulating their promoters and copy-numbers, and constructed an engineered S. cerevisiae strain (carrying one copy of PGK1p-CDT1 and two copies of TDH3p-XYL1, which showed an 85.7% increase in xylitol production from the mixture of cellobiose and xylose than that from the mixture of glucose and xylose. Thus, we achieved a balanced co-fermentation of cellobiose (0.165 g/L/h and xylose (0.162 g/L/h at similar rates to co-produce ethanol (0.36 g/g and xylitol (1.00 g/g.

  10. Reduction of false-positive recalls using a computerized mammographic image feature analysis scheme

    Science.gov (United States)

    Tan, Maxine; Pu, Jiantao; Zheng, Bin

    2014-08-01

    The high false-positive recall rate is one of the major dilemmas that significantly reduce the efficacy of screening mammography, which harms a large fraction of women and increases healthcare cost. This study aims to investigate the feasibility of helping reduce false-positive recalls by developing a new computer-aided diagnosis (CAD) scheme based on the analysis of global mammographic texture and density features computed from four-view images. Our database includes full-field digital mammography (FFDM) images acquired from 1052 recalled women (669 positive for cancer and 383 benign). Each case has four images: two craniocaudal (CC) and two mediolateral oblique (MLO) views. Our CAD scheme first computed global texture features related to the mammographic density distribution on the segmented breast regions of four images. Second, the computed features were given to two artificial neural network (ANN) classifiers that were separately trained and tested in a ten-fold cross-validation scheme on CC and MLO view images, respectively. Finally, two ANN classification scores were combined using a new adaptive scoring fusion method that automatically determined the optimal weights to assign to both views. CAD performance was tested using the area under a receiver operating characteristic curve (AUC). The AUC = 0.793  ±  0.026 was obtained for this four-view CAD scheme, which was significantly higher at the 5% significance level than the AUCs achieved when using only CC (p = 0.025) or MLO (p = 0.0004) view images, respectively. This study demonstrates that a quantitative assessment of global mammographic image texture and density features could provide useful and/or supplementary information to classify between malignant and benign cases among the recalled cases, which may eventually help reduce the false-positive recall rate in screening mammography.

  11. Prospective assessment of the false positive rate of the Australian snake venom detection kit in healthy human samples.

    Science.gov (United States)

    Nimorakiotakis, Vasilios Bill; Winkel, Kenneth D

    2016-03-01

    The Snake Venom Detection Kit (SVDK; bioCSL Pty Ltd, Australia) distinguishes venom from the five most medically significant snake immunotypes found in Australia. This study assesses the rate of false positives that, by definition, refers to a positive assay finding in a sample from someone who has not been bitten by a venomous snake. Control unbroken skin swabs, simulated bite swabs and urine specimens were collected from 61 healthy adult volunteers [33 males and 28 females] for assessment. In all controls, simulated bite site and urine samples [a total of 183 tests], the positive control well reacted strongly within one minute and no test wells reacted during the ten minute incubation period. However, in two urine tests, the negative control well gave a positive reaction (indicating an uninterpretable test). A 95% confidence interval for the false positive rate, on a per-patient rate, derived from the findings of this study, would extend from 0% to 6% and, on a per-test basis, it would be 0-2%. It appears to be a very low incidence (0-6%) of intrinsic true false positives for the SVDK. The clinical impresssion of a high SVDK false positive rate may be mostly related to operator error. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  12. Multilevel Contextual 3-D CNNs for False Positive Reduction in Pulmonary Nodule Detection.

    Science.gov (United States)

    Dou, Qi; Chen, Hao; Yu, Lequan; Qin, Jing; Heng, Pheng-Ann

    2017-07-01

    False positive reduction is one of the most crucial components in an automated pulmonary nodule detection system, which plays an important role in lung cancer diagnosis and early treatment. The objective of this paper is to effectively address the challenges in this task and therefore to accurately discriminate the true nodules from a large number of candidates. We propose a novel method employing three-dimensional (3-D) convolutional neural networks (CNNs) for false positive reduction in automated pulmonary nodule detection from volumetric computed tomography (CT) scans. Compared with its 2-D counterparts, the 3-D CNNs can encode richer spatial information and extract more representative features via their hierarchical architecture trained with 3-D samples. More importantly, we further propose a simple yet effective strategy to encode multilevel contextual information to meet the challenges coming with the large variations and hard mimics of pulmonary nodules. The proposed framework has been extensively validated in the LUNA16 challenge held in conjunction with ISBI 2016, where we achieved the highest competition performance metric (CPM) score in the false positive reduction track. Experimental results demonstrated the importance and effectiveness of integrating multilevel contextual information into 3-D CNN framework for automated pulmonary nodule detection in volumetric CT data. While our method is tailored for pulmonary nodule detection, the proposed framework is general and can be easily extended to many other 3-D object detection tasks from volumetric medical images, where the targeting objects have large variations and are accompanied by a number of hard mimics.

  13. A False Positive I-131 Metastatic Survey Caused by Radioactive Iodine Uptake by a Benign Thymic Cyst

    Directory of Open Access Journals (Sweden)

    Avneet K. Singh

    2017-01-01

    Full Text Available Thyroid carcinoma is the most common endocrine malignancy in the United States with increasing incidence and diagnosis but stable mortality. Differentiated thyroid cancer rarely presents with distant metastases and is associated with a low risk of morbidity and mortality. Despite this, current protocols recommend remnant ablation with radioactive iodine and evaluation for local and distant metastasis in some patients with higher risk disease. There are several case reports of false positive results of metastatic surveys that are either normal physiologic variants or other pathological findings. Most false positive findings are associated with tissue that has physiologic increased uptake of I-131, such as breast tissue or lung tissue; pathological findings such as thymic cysts are also known to have increased uptake. Our case describes a rare finding of a thymic cyst found on a false positive I-131 metastatic survey. The patient was taken for surgical excision and the final pathology was a benign thymic cyst. Given that pulmonary metastases of differentiated thyroid cancer are rare, thymic cysts, though also rare, must be part of the differential diagnosis for false positive findings on an I-131 survey.

  14. Human geminin promotes pre-RC formation and DNA replication by stabilizing CDT1 in mitosis

    DEFF Research Database (Denmark)

    Ballabeni, Andrea; Melixetian, Marina; Zamponi, Raffaella

    2004-01-01

    -mediated degradation by inhibiting its ubiquitination. In particular, Geminin ensures basal levels of CDT1 during S phase and its accumulation during mitosis. Consistently, inhibition of Geminin synthesis during M phase leads to impairment of pre-RC formation and DNA replication during the following cell cycle....... Moreover, we show that inhibition of CDK1 during mitosis, and not Geminin depletion, is sufficient for premature formation of pre-RCs, indicating that CDK activity is the major mitotic inhibitor of licensing in human cells. Taken together with recent data from our laboratory, our results demonstrate...

  15. Interval Breast Cancer Rates and Histopathologic Tumor Characteristics after False-Positive Findings at Mammography in a Population-based Screening Program.

    Science.gov (United States)

    Hofvind, Solveig; Sagstad, Silje; Sebuødegård, Sofie; Chen, Ying; Roman, Marta; Lee, Christoph I

    2018-04-01

    Purpose To compare rates and tumor characteristics of interval breast cancers (IBCs) detected after a negative versus false-positive screening among women participating in the Norwegian Breast Cancer Screening Program. Materials and Methods The Cancer Registry Regulation approved this retrospective study. Information about 423 445 women aged 49-71 years who underwent 789 481 full-field digital mammographic screening examinations during 2004-2012 was extracted from the Cancer Registry of Norway. Rates and odds ratios of IBC among women with a negative (the reference group) versus a false-positive screening were estimated by using logistic regression models adjusted for age at diagnosis and county of residence. Results A total of 1302 IBCs were diagnosed after 789 481 screening examinations, of which 7.0% (91 of 1302) were detected among women with a false-positive screening as the most recent breast imaging examination before detection. By using negative screening as the reference, adjusted odds ratios of IBCs were 3.3 (95% confidence interval [CI]: 2.6, 4.2) and 2.8 (95% CI: 1.8, 4.4) for women with a false-positive screening without and with needle biopsy, respectively. Women with a previous negative screening had a significantly lower proportion of tumors that were 10 mm or less (14.3% [150 of 1049] vs 50.0% [seven of 14], respectively; P false-positive screening with benign biopsy. A retrospective review of the screening mammographic examinations identified 42.9% (39 of 91) of the false-positive cases to be the same lesion as the IBC. Conclusion By using a negative screening as the reference, a false-positive screening examination increased the risk of an IBC three-fold. The tumor characteristics of IBC after a negative screening were less favorable compared with those detected after a previous false-positive screening. © RSNA, 2017 Online supplemental material is available for this article.

  16. Center not liable for defamation from false-positive hepatitis test.

    Science.gov (United States)

    1997-04-18

    The Nebraska Court of Appeals ruled that [name removed] does not have a cause of action against the Lincoln Plasma Center in Lincoln, NE. The center blacklisted him as a carrier of hepatitis B virus; subsequent tests proved [name removed] was uninfected. [Name removed], a paid plasma donator, was placed on an ineligible list after he tested positive for the hepatitis B surface antigen. [Name removed] sued, alleging that Lincoln defamed him by publishing false information to blood banks about his eligibility to donate. The Court of Appeals upheld a trial court's directed verdict because there was no evidence that the plasma center acted in malice.

  17. The cumulative risk of false-positive screening results across screening centres in the Norwegian Breast Cancer Screening Program

    Energy Technology Data Exchange (ETDEWEB)

    Roman, M., E-mail: Marta.Roman@kreftregisteret.no [Cancer Registry of Norway, Oslo (Norway); Department of Women and Children’s Health, Oslo University Hospital, Oslo (Norway); Skaane, P., E-mail: PERSK@ous-hf.no [Department of Radiology, Oslo University Hospital Ullevaal, University of Oslo, Oslo (Norway); Hofvind, S., E-mail: Solveig.Hofvind@kreftregisteret.no [Cancer Registry of Norway, Oslo (Norway); Oslo and Akershus University College of Applied Sciences, Faculty of Health Science, Oslo (Norway)

    2014-09-15

    Highlights: • We found variation in early performance measures across screening centres. • Radiologists’ performance may play a key role in the variability. • Potential to improve the effectiveness of breast cancer screening programs. • Continuous surveillance of screening centres and radiologists is essential. - Abstract: Background: Recall for assessment in mammographic screening entails an inevitable number of false-positive screening results. This study aimed to investigate the variation in the cumulative risk of a false positive screening result and the positive predictive value across the screening centres in the Norwegian Breast Cancer Screening Program. Methods: We studied 618,636 women aged 50–69 years who underwent 2,090,575 screening exams (1996–2010. Recall rate, positive predictive value, rate of screen-detected cancer, and the cumulative risk of a false positive screening result, without and with invasive procedures across the screening centres were calculated. Generalized linear models were used to estimate the probability of a false positive screening result and to compute the cumulative false-positive risk for up to ten biennial screening examinations. Results: The cumulative risk of a false-positive screening exam varied from 10.7% (95% CI: 9.4–12.0%) to 41.5% (95% CI: 34.1–48.9%) across screening centres, with a highest to lowest ratio of 3.9 (95% CI: 3.7–4.0). The highest to lowest ratio for the cumulative risk of undergoing an invasive procedure with a benign outcome was 4.3 (95% CI: 4.0–4.6). The positive predictive value of recall varied between 12.0% (95% CI: 11.0–12.9%) and 19.9% (95% CI: 18.3–21.5%), with a highest to lowest ratio of 1.7 (95% CI: 1.5–1.9). Conclusions: A substantial variation in the performance measures across the screening centres in the Norwegian Breast Cancer Screening Program was identified, despite of similar administration, procedures, and quality assurance requirements. Differences in the

  18. The cumulative risk of false-positive screening results across screening centres in the Norwegian Breast Cancer Screening Program

    International Nuclear Information System (INIS)

    Roman, M.; Skaane, P.; Hofvind, S.

    2014-01-01

    Highlights: • We found variation in early performance measures across screening centres. • Radiologists’ performance may play a key role in the variability. • Potential to improve the effectiveness of breast cancer screening programs. • Continuous surveillance of screening centres and radiologists is essential. - Abstract: Background: Recall for assessment in mammographic screening entails an inevitable number of false-positive screening results. This study aimed to investigate the variation in the cumulative risk of a false positive screening result and the positive predictive value across the screening centres in the Norwegian Breast Cancer Screening Program. Methods: We studied 618,636 women aged 50–69 years who underwent 2,090,575 screening exams (1996–2010. Recall rate, positive predictive value, rate of screen-detected cancer, and the cumulative risk of a false positive screening result, without and with invasive procedures across the screening centres were calculated. Generalized linear models were used to estimate the probability of a false positive screening result and to compute the cumulative false-positive risk for up to ten biennial screening examinations. Results: The cumulative risk of a false-positive screening exam varied from 10.7% (95% CI: 9.4–12.0%) to 41.5% (95% CI: 34.1–48.9%) across screening centres, with a highest to lowest ratio of 3.9 (95% CI: 3.7–4.0). The highest to lowest ratio for the cumulative risk of undergoing an invasive procedure with a benign outcome was 4.3 (95% CI: 4.0–4.6). The positive predictive value of recall varied between 12.0% (95% CI: 11.0–12.9%) and 19.9% (95% CI: 18.3–21.5%), with a highest to lowest ratio of 1.7 (95% CI: 1.5–1.9). Conclusions: A substantial variation in the performance measures across the screening centres in the Norwegian Breast Cancer Screening Program was identified, despite of similar administration, procedures, and quality assurance requirements. Differences in the

  19. Biological false-positive venereal disease research laboratory test in cerebrospinal fluid in the diagnosis of neurosyphilis - a case-control study.

    Science.gov (United States)

    Zheng, S; Lin, R J; Chan, Y H; Ngan, C C L

    2018-03-01

    There is no clear consensus on the diagnosis of neurosyphilis. The Venereal Disease Research Laboratory (VDRL) test from cerebrospinal fluid (CSF) has traditionally been considered the gold standard for diagnosing neurosyphilis but is widely known to be insensitive. In this study, we compared the clinical and laboratory characteristics of true-positive VDRL-CSF cases with biological false-positive VDRL-CSF cases. We retrospectively identified cases of true and false-positive VDRL-CSF across a 3-year period received by the Immunology and Serology Laboratory, Singapore General Hospital. A biological false-positive VDRL-CSF is defined as a reactive VDRL-CSF with a non-reactive Treponema pallidum particle agglutination (TPPA)-CSF and/or negative Line Immuno Assay (LIA)-CSF IgG. A true-positive VDRL-CSF is a reactive VDRL-CSF with a concordant reactive TPPA-CSF and/or positive LIA-CSF IgG. During the study period, a total of 1254 specimens underwent VDRL-CSF examination. Amongst these, 60 specimens from 53 patients tested positive for VDRL-CSF. Of the 53 patients, 42 (79.2%) were true-positive cases and 11 (20.8%) were false-positive cases. In our setting, a positive non-treponemal serology has 97.6% sensitivity, 100% specificity, 100% positive predictive value and 91.7% negative predictive value for a true-positive VDRL-CSF based on our laboratory definition. HIV seropositivity was an independent predictor of a true-positive VDRL-CSF. Biological false-positive VDRL-CSF is common in a setting where patients are tested without first establishing a serological diagnosis of syphilis. Serological testing should be performed prior to CSF evaluation for neurosyphilis. © 2017 European Academy of Dermatology and Venereology.

  20. One Hundred False-Positive Amphetamine Specimens Characterized by Liquid Chromatography Time-of-Flight Mass Spectrometry.

    Science.gov (United States)

    Marin, Stephanie J; Doyle, Kelly; Chang, Annie; Concheiro-Guisan, Marta; Huestis, Marilyn A; Johnson-Davis, Kamisha L

    2016-01-01

    Some amphetamine (AMP) and ecstacy (MDMA) urine immunoassay (IA) kits are prone to false-positive results due to poor specificity of the antibody. We employed two techniques, high-resolution mass spectrometry (HRMS) and an in silico structure search, to identify compounds likely to cause false-positive results. Hundred false-positive IA specimens for AMP and/or MDMA were analyzed by an Agilent 6230 time-of-flight (TOF) mass spectrometer. Separately, SciFinder (Chemical Abstracts) was used as an in silico structure search to generate a library of compounds that are known to cross-react with AMP/MDMA IAs. Chemical formulas and exact masses of 145 structures were then compared against masses identified by TOF. Compounds known to have cross-reactivity with the IAs were identified in the structure-based search. The chemical formulas and exact masses of 145 structures (of 20 chemical formulas) were compared against masses identified by TOF. Urine analysis by HRMS correlates accurate mass with chemical formulae, but provides little information regarding compound structure. Structural data of targeted antigens can be utilized to correlate HRMS-derived chemical formulas with structural analogs. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. A false-positive detection bias as a function of state and trait schizotypy in interaction with intelligence

    Directory of Open Access Journals (Sweden)

    Phillip eGrant

    2014-09-01

    Full Text Available Hallucinatory experiences are by far not limited to patients with clinical psychosis. A number of internal and external factors may bring about such experiences in healthy individuals, whereby the personality trait of (positive schizotypy is a major mediator of individual differences. Psychotic experiences are defined as associating abnormal meaning to real but objectively irrelevant perceptions. Especially the ambiguity of a stimulus correlates positively with the likelihood of abnormal interpretation, and intelligence is believed to have an important influence and act as protective against clinical psychosis in highly schizotypic individuals.In this study we presented 131 healthy participants with 216 15-letter strings containing either a word, a non-word or only random letters and asked them to report, whether or not they believed to have seen a word. The aim was to replicate findings that participants with high values in positive schizotypy on the trait-level make more false-positive errors and assess the role of stimulus-ambiguity and verbal intelligence. Additionally, we wanted to examine whether the same effect could be shown for indices of state schizotypy.Our results support findings that both state and trait positive schizotypy explain significant variance in seeing things that are not there and that the properties of individual stimuli have additional strong effects on the false-positive hit rates. Finally, we found that verbal intelligence and positive schizotypy interact with stimulus-ambiguity in the production of false-positive perceptions.

  2. A false-positive detection bias as a function of state and trait schizotypy in interaction with intelligence.

    Science.gov (United States)

    Grant, Phillip; Balser, Mona; Munk, Aisha Judith Leila; Linder, Jens; Hennig, Juergen

    2014-01-01

    Hallucinatory experiences are by far not limited to patients with clinical psychosis. A number of internal and external factors may bring about such experiences in healthy individuals, whereby the personality trait of (positive) schizotypy is a major mediator of individual differences. Psychotic experiences are defined as associating abnormal meaning to real but objectively irrelevant perceptions. Especially, the ambiguity of a stimulus correlates positively with the likelihood of abnormal interpretation, and intelligence is believed to have an important influence and act as protective against clinical psychosis in highly schizotypic individuals. In this study, we presented 131 healthy participants with 216 15-letter strings containing either a word, a non-word, or only random letters and asked them to report, whether or not they believed to have seen a word. The aim was to replicate findings that participants with high values in positive schizotypy on the trait-level make more false-positive errors and assess the role of stimulus-ambiguity and verbal intelligence. Additionally, we wanted to examine whether the same effect could be shown for indices of state schizotypy. Our results support findings that both state and trait positive schizotypy explain significant variance in "seeing things that are not there" and that the properties of individual stimuli have additional strong effects on the false-positive hit rates. Finally, we found that verbal intelligence and positive schizotypy interact with stimulus-ambiguity in the production of false-positive perceptions.

  3. Hemorrhoids detected at colonoscopy: an infrequent cause of false-positive fecal immunochemical test results.

    NARCIS (Netherlands)

    Turenhout, S.T. van; Oort, F.A.; Terhaar sive Droste, J.S.; Coupe, V.M.; Hulst, R.W. van der; Loffeld, R.J.; Scholten, P.; Depla, A.C.; Bouman, A.A.; Meijer, G.A.; Mulder, C.J.; Rossum, L.G.M. van

    2012-01-01

    BACKGROUND: Colorectal cancer screening by fecal immunochemical tests (FITs) is hampered by frequent false-positive (FP) results and thereby the risk of complications and strain on colonoscopy capacity. Hemorrhoids might be a plausible cause of FP results. OBJECTIVE: To determine the contribution of

  4. False Advertising

    OpenAIRE

    Rhodes, Andrew; Wilson, Chris M

    2016-01-01

    There is widespread evidence that some firms use false advertising to overstate the value of their products. We consider a model in which a policymaker is able to punish such false claims. We characterize an equilibrium where false advertising actively influences rational buyers, and analyze the effects of policy under different welfare objectives. We establish precise conditions where policy optimally permits a positive level of false advertising, and show how these conditions vary intuitive...

  5. Malaria rapid diagnostic tests: Plasmodium falciparum infections with high parasite densities may generate false positive Plasmodium vivax pLDH lines

    Directory of Open Access Journals (Sweden)

    van Esbroeck Marjan

    2010-07-01

    Full Text Available Abstract Background Most malaria rapid diagnostic tests (RDTs detect Plasmodium falciparum and an antigen common to the four species. Plasmodium vivax-specific RDTs target P. vivax-specific parasite lactate dehydrogenase (Pv-pLDH. Previous observations of false positive Pv-pLDH test lines in P. falciparum samples incited to the present study, which assessed P. vivax-specific RDTs for the occurrence of false positive Pv-pLDH lines in P. falciparum samples. Methods Nine P. vivax-specific RDTs were tested with 85 P. falciparum samples of high (≥2% parasite density. Mixed P. falciparum/P. vivax infections were ruled out by real-time PCR. The RDTs included two-band (detecting Pv-pLDH, three-band (detecting P. falciparum-antigen and Pv-pLDH and four-band RDTs (detecting P. falciparum, Pv-pLDH and pan-pLDH. Results False positive Pv-pLDH lines were observed in 6/9 RDTs (including two- three- and four-band RDTs. They occurred in the individual RDT brands at frequencies ranging from 8.2% to 29.1%. For 19/85 samples, at least two RDT brands generated a false positive Pv-pLDH line. Sixteen of 85 (18.8% false positive lines were of medium or strong line intensity. There was no significant relation between false positive results and parasite density or geographic origin of the samples. Conclusion False positive Pv-pLDH lines in P. falciparum samples with high parasite density occurred in 6/9 P. vivax-specific RDTs. This is of concern as P. falciparum and P. vivax are co-circulating in many regions. The diagnosis of life-threatening P. falciparum malaria may be missed (two-band Pv-pLDH RDT, or the patient may be treated incorrectly with primaquine (three- or four-band RDTs.

  6. False positive rate of carbon monoxide saturation by pulse oximetry of emergency department patients.

    Science.gov (United States)

    Weaver, Lindell K; Churchill, Susan K; Deru, Kayla; Cooney, Darryl

    2013-02-01

    Symptoms of carbon monoxide (CO) poisoning are non-specific. Diagnosis requires suspicion of exposure, confirmed by measuring ambient CO levels or carboxyhemoglobin (COHb). An FDA-approved pulse oximeter (Rad-57) can measure CO saturation (S(pCO)). The device accuracy has implications for clinical decision-making. From April 1 to August 15, 2008, study personnel measured S(pCO) and documented demographic factors at time of clinical blood draw, in a convenience sample of 1,363 subjects presenting to the emergency department at Intermountain Medical Center, Murray, Utah. The technician then assayed COHb. COHb and S(pCO) values were compared by subject; false positive or negative values were defined as S(pCO) at least 3 percentage points greater or less than COHb level, reported by the manufacturer to be ± 1 SD in performance. In 1,363 subjects, 613 (45%) were male, 1,141 (84%) were light-skinned, 14 in shock, 4 with CO poisoning, and 122 (9%) met the criteria for a false positive value (range 3-19 percentage points), while 247 (18%) met the criteria for a false negative value (-13 to -3 percentage points). Risks for a false positive S(pCO) reading included being female and having a lower perfusion index. Methemoglobin, body temperature, and blood pressure also appear to influence the S(pCO) accuracy. There was variability among monitors, possibly related to technician technique, as rotation of monitors among technicians was not enforced. While the Rad-57 pulse oximeter functioned within the manufacturer's specifications, clinicians using the Rad-57 should expect some S(pCO) readings to be significantly higher or lower than COHb measurements, and should not use S(pCO) to direct triage or patient management. An elevated S(pCO) could broaden the diagnosis of CO poisoning in patients with non-specific symptoms. However, a negative S(pCO) level in patients suspected of having CO poisoning should never rule out CO poisoning, and should always be confirmed by COHb. © 2013

  7. False-Positive Rate Determination of Protein Target Discovery using a Covalent Modification- and Mass Spectrometry-Based Proteomics Platform

    Science.gov (United States)

    Strickland, Erin C.; Geer, M. Ariel; Hong, Jiyong; Fitzgerald, Michael C.

    2014-01-01

    Detection and quantitation of protein-ligand binding interactions is important in many areas of biological research. Stability of proteins from rates of oxidation (SPROX) is an energetics-based technique for identifying the proteins targets of ligands in complex biological mixtures. Knowing the false-positive rate of protein target discovery in proteome-wide SPROX experiments is important for the correct interpretation of results. Reported here are the results of a control SPROX experiment in which chemical denaturation data is obtained on the proteins in two samples that originated from the same yeast lysate, as would be done in a typical SPROX experiment except that one sample would be spiked with the test ligand. False-positive rates of 1.2-2.2 % and analysis of the isobaric mass tag (e.g., iTRAQ®) reporter ions used for peptide quantitation. Our results also suggest that technical replicates can be used to effectively eliminate such false positives that result from this random error, as is demonstrated in a SPROX experiment to identify yeast protein targets of the drug, manassantin A. The impact of ion purity in the tandem mass spectral analyses and of background oxidation on the false-positive rate of protein target discovery using SPROX is also discussed.

  8. False-positive ethyl glucuronide immunoassay screening caused by a propyl alcohol-based hand sanitizer.

    Science.gov (United States)

    Arndt, Torsten; Grüner, Joachim; Schröfel, Stefanie; Stemmerich, Karsten

    2012-11-30

    Urine ethyl glucuronide (EtG) is considered as a specific marker of recent ethanol consumption. We describe false-positive DRI(®) EIA EtG enzyme immunoassay results caused by propyl glucuronides in urine after using a propanol-based hand sanitizer. EtG screening was done with the DRI(®) EIA EtG assay (Microgenics), using a cut-off of 0.5 mg/L as recommended by the manufacturer and of 0.1 mg/L as demanded by the German Regulations for Reissuing Drivers Licenses. Confirmatory EtG analysis was done with the ClinMass(®) EtG LC-MS/MS testkit (Recipe), extended by the mass transitions 235.1→75.1, 235.1→85.1, and 235.1→113.1 for the detection of the 1- and 2-propyl glucuronides. Self-experiments were done by staff members of our lab (n=7), using 3 mL Sterillium(®) Classic Pure (30 g/100 g 1-propanol and 45 g/100 g 2-propanol) for hand sanitation every quarter of an hour for 8 h according to DIN EN 1500:2011-05 with and without an exhauster and by passive inhalation of the sanitizer vapor. Spot urine samples were taken immediately before and up to 24 h after the first sanitizer use. False-positive immunoassay results of up to 4 mg/L or 2.3 mg/g creatinine were obtained after normal use of the sanitizer and also after passive inhalation of the sanitizer vapor (up to 0.89 mg/L or 0.61 mg/g). Immunoassay results were positive even after 4-fold use of the sanitizer (up to 0.14 mg/L or 0.38 mg/g) and up to 6 h after the last sanitizer contact (maximum 0.63 mg/L and 0.33 mg/g for sanitizer users and 0.25 mg/g after passive inhalation). Spiking of EtG-free urine with 1-propyl glucuronide (Athena Environmental Sciences) between 0.05 and 10 mg/L clearly demonstrated a cross reaction of the immunoassay of approx. 10% as compared to EtG. LC-MS/MS of urines with a positive immunoassay EtG result did not show EtG signals, but distinct signals of 1-propyl glucuronide (n-propyl glucuronide) and 2-propyl glucuronide (iso-propyl glucuronide). An exhauster effectively prevented

  9. Early Disseminated Lyme Disease Causing False-Positive Serology for Primary Epstein-Barr Virus Infection: Report of 2 Cases.

    Science.gov (United States)

    Pavletic, Adriana J; Marques, Adriana R

    2017-07-15

    False-positive serology for Lyme disease was reported in patients with acute infectious mononucleosis. Here we describe 2 patients with early disseminated Lyme disease who were misdiagnosed with infectious mononucleosis based on false-positive tests for primary Epstein-Barr virus infection. Published by Oxford University Press for the Infectious Diseases Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  10. False memories, but not false beliefs, affect implicit attitudes for food preferences.

    Science.gov (United States)

    Howe, David; Anderson, Rachel J; Dewhurst, Stephen A

    2017-09-01

    Previous studies have found that false memories and false beliefs of childhood experiences can have attitudinal consequences. Previous studies have, however, focused exclusively on explicit attitude measures without exploring whether implicit attitudes are similarly affected. Using a false feedback/imagination inflation paradigm, false memories and beliefs of enjoying a certain food as a child were elicited in participants, and their effects were assessed using both explicit attitude measures (self-report questionnaires) and implicit measures (a Single-Target Implicit Association Test). Positive changes in explicit attitudes were observed both in participants with false memories and participants with false beliefs. In contrast, only participants with false memories exhibited more positive implicit attitudes. The findings are discussed in terms of theories of explicit and implicit attitudes. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Restricted Boltzmann machines based oversampling and semi-supervised learning for false positive reduction in breast CAD.

    Science.gov (United States)

    Cao, Peng; Liu, Xiaoli; Bao, Hang; Yang, Jinzhu; Zhao, Dazhe

    2015-01-01

    The false-positive reduction (FPR) is a crucial step in the computer aided detection system for the breast. The issues of imbalanced data distribution and the limitation of labeled samples complicate the classification procedure. To overcome these challenges, we propose oversampling and semi-supervised learning methods based on the restricted Boltzmann machines (RBMs) to solve the classification of imbalanced data with a few labeled samples. To evaluate the proposed method, we conducted a comprehensive performance study and compared its results with the commonly used techniques. Experiments on benchmark dataset of DDSM demonstrate the effectiveness of the RBMs based oversampling and semi-supervised learning method in terms of geometric mean (G-mean) for false positive reduction in Breast CAD.

  12. Distinguishing Binders from False Positives by Free Energy Calculations: Fragment Screening Against the Flap Site of HIV Protease

    Science.gov (United States)

    2015-01-01

    Molecular docking is a powerful tool used in drug discovery and structural biology for predicting the structures of ligand–receptor complexes. However, the accuracy of docking calculations can be limited by factors such as the neglect of protein reorganization in the scoring function; as a result, ligand screening can produce a high rate of false positive hits. Although absolute binding free energy methods still have difficulty in accurately rank-ordering binders, we believe that they can be fruitfully employed to distinguish binders from nonbinders and reduce the false positive rate. Here we study a set of ligands that dock favorably to a newly discovered, potentially allosteric site on the flap of HIV-1 protease. Fragment binding to this site stabilizes a closed form of protease, which could be exploited for the design of allosteric inhibitors. Twenty-three top-ranked protein–ligand complexes from AutoDock were subject to the free energy screening using two methods, the recently developed binding energy analysis method (BEDAM) and the standard double decoupling method (DDM). Free energy calculations correctly identified most of the false positives (≥83%) and recovered all the confirmed binders. The results show a gap averaging ≥3.7 kcal/mol, separating the binders and the false positives. We present a formula that decomposes the binding free energy into contributions from the receptor conformational macrostates, which provides insights into the roles of different binding modes. Our binding free energy component analysis further suggests that improving the treatment for the desolvation penalty associated with the unfulfilled polar groups could reduce the rate of false positive hits in docking. The current study demonstrates that the combination of docking with free energy methods can be very useful for more accurate ligand screening against valuable drug targets. PMID:25189630

  13. Factors associated with false-positive self-reported adherence to antihypertensive drugs.

    Science.gov (United States)

    Tedla, Y G; Bautista, L E

    2017-05-01

    Self-reported medication adherence is known to overestimate true adherence. However, little is known about patient factors that may contribute to the upward bias in self-reported medication adherence. The objective of this study is to examine whether demographic, behavioral, medication and mood factors are associated with being a false-positive self-reported adherer (FPA) to antihypertensive drug treatment. We studied 175 patients (mean age: 50 years; 57% men) from primary-care clinics starting antihypertensive drug treatment. Self-reported adherence (SRA) was measured with the Medication Adherence Report Scale (MARS) and by the number of drug doses missed in the previous week/month, and compared with pill count adherence ratio (PCAR) as gold standard. Data on adherence, demographic, behavioral, medication and mood factors were collected at baseline and every 3 months up to 1 year. FPA was defined as being a non-adherer by PCAR and an adherer by self-report. Mixed effect logistic regression was used for the analysis. Twenty percent of participants were FPA. Anxiety increased (odds ratio (OR): 3.00; P=0.01), whereas smoking (OR: 0.40; P=0.03) and drug side effects (OR: 0.46, P=0.03) decreased the probability for FPA by MARS. Education below high-school completion increased the probability of being an FPA as measured by missing doses in the last month (OR: 1.66; P=0.04) and last week (OR: 1.88; P=0.02). The validity of SRA varies significantly according to drug side effects, behavioral factors and patient's mood. Careful consideration should be given to the use of self-reported measures of adherence among patients likely to be false-positive adherers.

  14. Advanced gestational age increases serum carbohydrate-deficient transferrin levels in abstinent pregnant women.

    Science.gov (United States)

    Bakhireva, Ludmila N; Cano, Sandra; Rayburn, William F; Savich, Renate D; Leeman, Lawrence; Anton, Raymond F; Savage, Daniel D

    2012-01-01

    Carbohydrate-deficient transferrin (%CDT) is a well-established and highly specific biomarker for sustained heavy consumption of alcohol. However, in pregnant women, the specificity of this biomarker might be affected by advanced gestational age, even after accounting for increased transferrin concentrations in pregnancy. The goal of this prospective study was to assess the variability in %CDT during pregnancy among alcohol-abstaining patients. Patients were recruited during one of the first prenatal care visits and followed-up to term. Abstinence was confirmed by maternal self-report and by alcohol biomarkers. Biomarkers assessed in the mother included serum gamma-glutamyltranspeptidase, urine ethyl glucuronide and ethyl sulfate, and whole blood phosphatidylethanol (PEth). In addition, PEth was measured in a dry blood spot card obtained from a newborn. For %CDT analysis, serum samples were collected at baseline and at term and analyzed by an internationally validated high-performance liquid chromatography and spectrophotometric detection method. At recruitment (mean gestational age 22.6 ± 7.3 weeks), the mean %CDT concentration was 1.49 ± 0.30%, while at term, it increased to 1.67 ± 0.28% (P = 0.001). Using a conventional cutoff concentration %CDT >1.7%, 22.9 and 45.7% of the sample would be classified as 'positive' for this biomarker at recruitment and at term, respectively (P = 0.011 ). These results suggest that a conventional cutoff of 1.7% might be too low for pregnant women and would generate false-positive results. We propose that %CDT >2.0% be used as a cutoff concentration indicative of alcohol exposure in pregnant women. The sensitivity of %CDT at this cutoff for heavy drinking during pregnancy needs to be assessed further.

  15. Data from Paper “False-Positive Psychology: Undisclosed Flexibility in Data Collection and Analysis Allows Presenting Anything as Significant”

    Directory of Open Access Journals (Sweden)

    Joseph P Simmons

    2014-02-01

    Full Text Available The data includes measures collected for the two experiments reported in “False-Positive Psychology” [1] where listening to a randomly assigned song made people feel younger (Study 1 or actually be younger (Study 2. These data are useful because they illustrate inflations of false positive rates due to flexibility in data collection, analysis, and reporting of results. Data are useful for educational purposes.

  16. Detecção dos genes codificantes da toxina CDT, e pesquisa de fatores que influenciam na produção de hemolisinas em amostras de Campylobacter jejuni de origem avícola

    Directory of Open Access Journals (Sweden)

    Michele M. Trindade

    2015-08-01

    Full Text Available Resumo: Membros termofílicos do gênero Campylobacter são reconhecidos como importantes enteropatógenos para o ser humano e animais. A grande diversidade ecológica destes micro-organismos em diferentes habitats tais como água, animais e alimentos predispõem ao aparecimento de novos fatores de virulência. Este trabalho teve por objetivo detectar os genes codificantes da Toxina Distensiva Citoletal (CDT por meio da técnica de PCR, pesquisar a atividade de hemolisinas e a influência de soluções quelantes e de íons nesta atividade. Foram utilizadas 45 amostras de Campylobacter jejuni de origem avícola para pesquisa de atividade hemolítica, cultivadas em Caldo Triptona de Soja (TSB. Após o crescimento bacteriano, as amostras foram semeadas em Ágar tríptico de soja (TSA contendo 5% de sangue de ovino. Para verificar a influência de agentes quelantes e solução de íons na atividade hemolítica, as amostras de C. jejuni foram cultivadas em TSB contendo separadamente os quelantes EDTA, ácido acético, soluções de íons CaCl2, MgCl2 e FeCl3, em atmosfera de microaerofilia. Quanto à atividade de hemolisina de C. jejuni em placas de TSA - sangue ovino foi possível observar que houve hemólise em 40% das amostras analisadas apenas com caldo TSB. Somente o ácido acético apresentou ação quelante sobre a atividade de hemolisinas em amostras de C. jejuni semeadas em placas de TSA - sangue ovino. Para detecção dos genes cdtA, cdtB e cdtC através da técnica da Reação em Cadeia da Polimerase (PCR foram utilizadas 119 amostras de C. jejuni de origem avícola. Foi possível observar que 37,8% possuíam o perfil de genes cdtABC. Os resultados demonstraram em amostras avícolas a presença de cepas de C. jejuni com potencial virulento, devido à presença dos genes da toxina CDT e potencial hemolítico, que apresentou ação reduzida in vitro com ácido acético.

  17. PIPIDA scintigraphy for cholecystitis: false positives in alcoholism and total parenteral nutrition

    International Nuclear Information System (INIS)

    Shuman, W.P.; Gibbs, P.; Rudd, T.G.; Mack, L.A.

    1982-01-01

    A review of gallbladder scintigraphy in patients with potentially compromised hepatobiliary function revealed two groups in whom cholecystitis might be mistakenly diagnosed. In 200 consecutive hospitalized patients studied with technetium-99m-PIPIDA for acute cholecystitis or cholestasis, there were 41 alcoholics and 17 patients on total parenteral nutrition. In 60% of the alcoholics and 92% of those on parenteral nutrition, absent or delayed visualization of the gallbladder occurred without physical or clinical evidence of cholecystitis. A cholecystagogue, sincalide, did not prevent the false-positive features which presumably are due to altered bile flow kinetics related to alcoholism and parenteral nutrition. Four patients on parenteral nutrition undergoing cholecystectomy for suspected cholecystitis had normal gallbladders filled with jellylike viscous thick bile. A positive (nonvisualized or delayed visualized) gallbladder PIPIDA scintigram in these two populations should not be interpreted as indicating a need for cholecystectomy

  18. Inflammatory disorders mimicking periprosthetic joint infections may result in false positive α-defensin.

    Science.gov (United States)

    Plate, Andreas; Stadler, Laura; Sutter, Reto; Anagnostopoulos, Alexia; Frustaci, Dario; Zbinden, Reinhard; Fucentese, Sandro F; Zinkernagel, Annelies S; Zingg, Patrick O; Achermann, Yvonne

    2018-02-26

    The antimicrobial peptide α-defensin has recently been introduced as potential "single" biomarker with a high sensitivity and specificity for the preoperative diagnosis of periprosthetic joint infections (PJIs). However, most studies assessed the benefits of the test with exclusion of patients with rheumatic diseases. We aimed to evaluate the α-defensin test in a cohort study without exclusion of cases with inflammatory diseases. Between June 2016 and June 2017, we prospectively included cases with a suspected PJI and an available lateral flow test α-defensin (Synovasure®) in synovial fluid. We compared the test result to the diagnostic criteria for PJIs published by an International Consensus Group in 2013. We included 109 cases (49 hips, 60 knees) in which preoperative α-defensin tests had been performed. Thereof, 20 PJIs (16 hips, 4 knees) were diagnosed. Preoperative α-defensin tests were positive in 25 cases (22.9%) with a test sensitivity and specificity of 90% and 92.1% (95% confidence interval [CI], 68.3 - 98.8% and 84.5 - 96.8%, respectively), and a high negative predictive value of 97.6% (95% CI, 91.7 - 99.4%). We interpreted seven α-defensin tests as false positive, mainly in cases with inflammatory rheumatic diseases, including crystal deposition diseases. A negative synovial α-defensin test can reliably rule out a PJI. However, the test can be false positive in conjunction with an underlying non-infectious inflammatory disease. We therefore propose to use the α-defensin test only in addition to MSIS criteria and assessment for crystals in synovial aspirates. Copyright © 2018. Published by Elsevier Ltd.

  19. Are Hemorrhoids Associated with False-Positive Fecal Immunochemical Test Results?

    Science.gov (United States)

    Kim, Nam Hee; Park, Jung Ho; Park, Dong Il; Sohn, Chong Il; Choi, Kyuyong; Jung, Yoon Suk

    2017-01-01

    False-positive (FP) results of fecal immunochemical tests (FITs) conducted in colorectal cancer (CRC) screening could lead to performing unnecessary colonoscopies. Hemorrhoids are a possible cause of FP FIT results; however, studies on this topic are extremely rare. We investigated whether hemorrhoids are associated with FP FIT results. A retrospective study was conducted at a university hospital in Korea from June 2013 to May 2015. Of the 34547 individuals who underwent FITs, 3946 aged ≥50 years who underwent colonoscopies were analyzed. Logistic regression analysis was performed to determine factors associated with FP FIT results. Among 3946 participants, 704 (17.8%) showed positive FIT results and 1303 (33.0%) had hemorrhoids. Of the 704 participants with positive FIT results, 165 had advanced colorectal neoplasia (ACRN) and 539 had no ACRN (FP results). Of the 1303 participants with hemorrhoids, 291 showed FP results, of whom 81 showed FP results because of hemorrhoids only. Participants with hemorrhoids had a higher rate of FP results than those without hemorrhoids (291/1176, 24.7% vs. 248/2361, 10.5%; phemorrhoids as the only abnormality had a higher rate of FP results than those experiencing no such abnormalities (81/531, 15.3% vs. 38/1173, 3.2%; phemorrhoids was identified as an independent predictor of FP results (adjusted odds ratio, 2.76; 95% confidence interval, 2.24-3.40; pHemorrhoids are significantly associated with FP FIT results. Their presence seemed to be a non-negligible contributor of FP results in FIT-based CRC screening programs.

  20. Cross-reactive Carbohydrate Determinant Contributes to the False Positive IgE Antibody to Peanut

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    Komei Ito

    2005-01-01

    Conclusions: Social education about the features of peanut allergy is needed in Japan. Anti-CCD IgE antibody was suggested to be one of the mechanisms contributing to the false positive detection of peanut IgE. Detection of anti-HRP or anti-bromelain IgE can be a useful tool to recognize the presence of anti-CCD antibodies.

  1. Classification of radiological errors in chest radiographs, using support vector machine on the spatial frequency features of false- negative and false-positive regions

    Science.gov (United States)

    Pietrzyk, Mariusz W.; Donovan, Tim; Brennan, Patrick C.; Dix, Alan; Manning, David J.

    2011-03-01

    Aim: To optimize automated classification of radiological errors during lung nodule detection from chest radiographs (CxR) using a support vector machine (SVM) run on the spatial frequency features extracted from the local background of selected regions. Background: The majority of the unreported pulmonary nodules are visually detected but not recognized; shown by the prolonged dwell time values at false-negative regions. Similarly, overestimated nodule locations are capturing substantial amounts of foveal attention. Spatial frequency properties of selected local backgrounds are correlated with human observer responses either in terms of accuracy in indicating abnormality position or in the precision of visual sampling the medical images. Methods: Seven radiologists participated in the eye tracking experiments conducted under conditions of pulmonary nodule detection from a set of 20 postero-anterior CxR. The most dwelled locations have been identified and subjected to spatial frequency (SF) analysis. The image-based features of selected ROI were extracted with un-decimated Wavelet Packet Transform. An analysis of variance was run to select SF features and a SVM schema was implemented to classify False-Negative and False-Positive from all ROI. Results: A relative high overall accuracy was obtained for each individually developed Wavelet-SVM algorithm, with over 90% average correct ratio for errors recognition from all prolonged dwell locations. Conclusion: The preliminary results show that combined eye-tracking and image-based features can be used for automated detection of radiological error with SVM. The work is still in progress and not all analytical procedures have been completed, which might have an effect on the specificity of the algorithm.

  2. Evaluation of Patients with an Apparent False Positive Stool DNA Test: The Role of Repeat Stool DNA Testing.

    Science.gov (United States)

    Cooper, Gregory S; Markowitz, Sanford D; Chen, Zhengyi; Tuck, Missy; Willis, Joseph E; Berger, Barry M; Brenner, Dean E; Li, Li

    2018-03-07

    There is uncertainty as to the appropriate follow-up of patients who test positive on multimarker stool DNA (sDNA) testing and have a colonoscopy without neoplasia. To determine the prevalence of missed colonic or occult upper gastrointestinal neoplasia in patients with an apparent false positive sDNA. We prospectively identified 30 patients who tested positive with a commercially available sDNA followed by colonoscopy without neoplastic lesions. Patients were invited to undergo repeat sDNA at 11-29 months after the initial test followed by repeat colonoscopy and upper endoscopy. We determined the presence of neoplastic lesions on repeat evaluation stratified by results of repeat sDNA. Twelve patients were restudied. Seven patients had a negative second sDNA test and a normal second colonoscopy and upper endoscopy. In contrast, 5 of 12 subjects had a persistently positive second sDNA test, and 3 had positive findings, including a 3-cm sessile transverse colon adenoma with high-grade dysplasia, a 2-cm right colon sessile serrated adenoma with dysplasia, and a nonadvanced colon adenoma (p = 0.045). These corresponded to a positive predictive value of 0.60 (95% CI 0.17-1.00) and a negative predictive value of 1.00 (95% CI 1.00-1.00) for the second sDNA test. In addition, the medical records of all 30 subjects with apparent false positive testing were reviewed and no documented cases of malignant tumors were recorded. Repeat positive sDNA testing may identify a subset of patients with missed or occult colorectal neoplasia after negative colonoscopy for an initially positive sDNA. High-quality colonoscopy with careful attention to the right colon in patients with positive sDNA is critically important and may avoid false negative colonoscopy.

  3. False-positive head-impulse test in cerebellar ataxia

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    Olympia eKremmyda

    2012-11-01

    Full Text Available Abstract:The objective of this study was to compare the findings of the bedside head impulse test (HIT, passive head rotation gain, and caloric irrigation in patients with cerebellar ataxia (CA. In 16 patients with CA and bilaterally pathological bedside HIT, VOR gains were measured during HIT and passive head rotation by scleral search coil technique. Eight of the patients had pathologically reduced caloric responsiveness, while the other eight had normal caloric responses. Those with normal calorics showed a slightly reduced HIT gain (mean±SD: 0.73±0.15. In those with pathological calorics, gains 80ms and 100 ms after the HIT as well as the passive rotation VOR gains were significantly lower. The corrective saccade after head turn occurred earlier in patients with pathological calorics (111±62 ms after onset of the HIT than in those with normal calorics. (191±17 ms, p=0.0064 We indentified two groups of patients with CA: those with an isolated moderate HIT deficit only, probably due to floccular dysfunction, and those with combined HIT, passive rotation and caloric deficit, probably due to a peripheral vestibular deficit. From a clinical point of view, these results show that the bedside HIT alone can be false positive for establishing a diagnosis of a bilateral peripheral vestibular deficit in patients with CA.

  4. A FALSE POSITIVE FOR OCEAN GLINT ON EXOPLANETS: THE LATITUDE-ALBEDO EFFECT

    International Nuclear Information System (INIS)

    Cowan, Nicolas B.; Abbot, Dorian S.; Voigt, Aiko

    2012-01-01

    Identifying liquid water on the surface of planets is a high priority, as this traditionally defines habitability. One proposed signature of oceans is specular reflection ('glint'), which increases the apparent albedo of a planet at crescent phases. We post-process a global climate model of an Earth-like planet to simulate reflected light curves. Significantly, we obtain glint-like phase variations even though we do not include specular reflection in our model. This false positive is the product of two generic properties: (1) for modest obliquities, a planet's poles receive less orbit-averaged stellar flux than its equator, so the poles are more likely to be covered in highly reflective snow and ice; and (2) we show that reflected light from a modest-obliquity planet at crescent phases probes higher latitudes than at gibbous phases, therefore a planet's apparent albedo will naturally increase at crescent phase. We suggest that this 'latitude-albedo effect' will operate even for large obliquities: in that case the equator receives less orbit-averaged flux than the poles, and the equator is preferentially sampled at crescent phase. Using rotational and orbital color variations to map the surfaces of directly imaged planets and estimate their obliquity will therefore be a necessary pre-condition for properly interpreting their reflected phase variations. The latitude-albedo effect is a particularly convincing glint false positive for zero-obliquity planets, and such worlds are not amenable to latitudinal mapping. This effect severely limits the utility of specular reflection for detecting oceans on exoplanets.

  5. A new sample treatment for asialo-Tf determination with capillary electrophoresis: an added value to the analysis of CDT.

    Science.gov (United States)

    Porpiglia, Nadia Maria; De Palo, Elio Franco; Savchuk, Sergey Alexandrovich; Appolonova, Svetlana Alexandrovna; Bortolotti, Federica; Tagliaro, Franco

    2018-05-10

    The non-glycosylated glycoform of transferrin (Tf), known as asialo-Tf, was not selected (in favor of disialo-Tf) as the measurand for the standardization of carbohydrate deficient transferrin (CDT) determination because of a lower diagnostic sensitivity provided with the currently available analytical procedures for sera. However, asialo-Tf could provide an additional value to disialo-Tf in the CDT analysis employed in forensic toxicology contexts. The present work aimed at developing an easy sample preparation based on PEG precipitation in order to improve the detectability of asialo-Tf in capillary electrophoresis (CE). Equal volumes (35 μL) of serum and of 30% PEG-8000 were mixed and briefly vortexed. After centrifugation, the supernatant was iron saturated with a ferric solution (1:1, v/v). The mixture was analyzed in CE for asialo-Tf and disialo-Tf determination. PEG-8000 precipitation allowed the improvement of the baseline in the electropherograms in terms of interferences reduction particularly in the asialo-Tf migration region. The detection of asialo-Tf was possible in 89% of samples with disialo-Tf above the cut-off limit, whereas only 16% of them showed asialo-Tf by employing the traditional sample preteatment. Asialo-Tf represents an additional value to disialo-Tf as a biomarker of alcohol abuse in forensic toxicology. Copyright © 2018. Published by Elsevier B.V.

  6. Reduction of false positives in the detection of architectural distortion in mammograms by using a geometrically constrained phase portrait model

    International Nuclear Information System (INIS)

    Ayres, Fabio J.; Rangayyan, Rangaraj M.

    2007-01-01

    Objective One of the commonly missed signs of breast cancer is architectural distortion. We have developed techniques for the detection of architectural distortion in mammograms, based on the analysis of oriented texture through the application of Gabor filters and a linear phase portrait model. In this paper, we propose constraining the shape of the general phase portrait model as a means to reduce the false-positive rate in the detection of architectural distortion. Material and methods The methods were tested with one set of 19 cases of architectural distortion and 41 normal mammograms, and with another set of 37 cases of architectural distortion. Results Sensitivity rates of 84% with 4.5 false positives per image and 81% with 10 false positives per image were obtained for the two sets of images. Conclusion The adoption of a constrained phase portrait model with a symmetric matrix and the incorporation of its condition number in the analysis resulted in a reduction in the false-positive rate in the detection of architectural distortion. The proposed techniques, dedicated for the detection and localization of architectural distortion, should lead to efficient detection of early signs of breast cancer. (orig.)

  7. EGA Protects Mammalian Cells from Clostridium difficile CDT, Clostridium perfringens Iota Toxin and Clostridium botulinum C2 Toxin.

    Science.gov (United States)

    Schnell, Leonie; Mittler, Ann-Katrin; Sadi, Mirko; Popoff, Michel R; Schwan, Carsten; Aktories, Klaus; Mattarei, Andrea; Azarnia Tehran, Domenico; Montecucco, Cesare; Barth, Holger

    2016-04-01

    The pathogenic bacteria Clostridium difficile, Clostridium perfringens and Clostridium botulinum produce the binary actin ADP-ribosylating toxins CDT, iota and C2, respectively. These toxins are composed of a transport component (B) and a separate enzyme component (A). When both components assemble on the surface of mammalian target cells, the B components mediate the entry of the A components via endosomes into the cytosol. Here, the A components ADP-ribosylate G-actin, resulting in depolymerization of F-actin, cell-rounding and eventually death. In the present study, we demonstrate that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone (EGA), a compound that protects cells from multiple toxins and viruses, also protects different mammalian epithelial cells from all three binary actin ADP-ribosylating toxins. In contrast, EGA did not inhibit the intoxication of cells with Clostridium difficile toxins A and B, indicating a possible different entry route for this toxin. EGA does not affect either the binding of the C2 toxin to the cells surface or the enzyme activity of the A components of CDT, iota and C2, suggesting that this compound interferes with cellular uptake of the toxins. Moreover, for C2 toxin, we demonstrated that EGA inhibits the pH-dependent transport of the A component across cell membranes. EGA is not cytotoxic, and therefore, we propose it as a lead compound for the development of novel pharmacological inhibitors against clostridial binary actin ADP-ribosylating toxins.

  8. EGA Protects Mammalian Cells from Clostridium difficile CDT, Clostridium perfringens Iota Toxin and Clostridium botulinum C2 Toxin

    Science.gov (United States)

    Schnell, Leonie; Mittler, Ann-Katrin; Sadi, Mirko; Popoff, Michel R.; Schwan, Carsten; Aktories, Klaus; Mattarei, Andrea; Tehran, Domenico Azarnia; Montecucco, Cesare; Barth, Holger

    2016-01-01

    The pathogenic bacteria Clostridium difficile, Clostridium perfringens and Clostridium botulinum produce the binary actin ADP-ribosylating toxins CDT, iota and C2, respectively. These toxins are composed of a transport component (B) and a separate enzyme component (A). When both components assemble on the surface of mammalian target cells, the B components mediate the entry of the A components via endosomes into the cytosol. Here, the A components ADP-ribosylate G-actin, resulting in depolymerization of F-actin, cell-rounding and eventually death. In the present study, we demonstrate that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone (EGA), a compound that protects cells from multiple toxins and viruses, also protects different mammalian epithelial cells from all three binary actin ADP-ribosylating toxins. In contrast, EGA did not inhibit the intoxication of cells with Clostridium difficile toxins A and B, indicating a possible different entry route for this toxin. EGA does not affect either the binding of the C2 toxin to the cells surface or the enzyme activity of the A components of CDT, iota and C2, suggesting that this compound interferes with cellular uptake of the toxins. Moreover, for C2 toxin, we demonstrated that EGA inhibits the pH-dependent transport of the A component across cell membranes. EGA is not cytotoxic, and therefore, we propose it as a lead compound for the development of novel pharmacological inhibitors against clostridial binary actin ADP-ribosylating toxins. PMID:27043629

  9. Prenatal ultrasound screening: false positive soft markers may alter maternal representations and mother-infant interaction.

    Directory of Open Access Journals (Sweden)

    Sylvie Viaux-Savelon

    Full Text Available In up to 5% of pregnancies, ultrasound screening detects a "soft marker" (SM that places the foetus at risk for a severe abnormality. In most cases, prenatal diagnostic work-up rules out a severe defect. We aimed to study the effects of false positive SM on maternal emotional status, maternal representations of the infant, and mother-infant interaction.Utilizing an extreme-case prospective case control design, we selected from a group of 244 women undergoing ultrasound, 19 pregnant women whose foetus had a positive SM screening and a reassuring diagnostic work up, and 19 controls without SM matched for age and education. In the third trimester of pregnancy, within one week after delivery, and 2 months postpartum, we assessed anxiety, depression, and maternal representations. Mother-infant interactions were videotaped during feeding within one week after delivery and again at 2 months postpartum and coded blindly using the Coding Interactive Behavior (CIB scales. Anxiety and depression scores were significantly higher at all assessment points in the SM group. Maternal representations were also different between SM and control groups at all study time. Perturbations to early mother-infant interactions were observed in the SM group. These dyads showed greater dysregulation, lower maternal sensitivity, higher maternal intrusive behaviour and higher infant avoidance. Multivariate analysis showed that maternal representation and depression at third trimester predicted mother-infant interaction.False positive ultrasound screenings for SM are not benign and negatively affect the developing maternal-infant attachment. Medical efforts should be directed to minimize as much as possible such false diagnoses, and to limit their psychological adverse consequences.

  10. Reduction of lymph tissue false positives in pulmonary embolism detection

    Science.gov (United States)

    Ghanem, Bernard; Liang, Jianming; Bi, Jinbo; Salganicoff, Marcos; Krishnan, Arun

    2008-03-01

    Pulmonary embolism (PE) is a serious medical condition, characterized by the partial/complete blockage of an artery within the lungs. We have previously developed a fast yet effective approach for computer aided detection of PE in computed topographic pulmonary angiography (CTPA),1 which is capable of detecting both acute and chronic PEs, achieving a benchmark performance of 78% sensitivity at 4 false positives (FPs) per volume. By reviewing the FPs generated by this system, we found the most dominant type of FP, roughly one third of all FPs, to be lymph/connective tissue. In this paper, we propose a novel approach that specifically aims at reducing this FP type. Our idea is to explicitly exploit the anatomical context configuration of PE and lymph tissue in the lungs: a lymph FP connects to the airway and is located outside the artery, while a true PE should not connect to the airway and must be inside the artery. To realize this idea, given a detected candidate (i.e. a cluster of suspicious voxels), we compute a set of contextual features, including its distance to the airway based on local distance transform and its relative position to the artery based on fast tensor voting and Hessian "vesselness" scores. Our tests on unseen cases show that these features can reduce the lymph FPs by 59%, while improving the overall sensitivity by 3.4%.

  11. Efficient detection of human circulating tumor cells without significant production of false-positive cells by a novel conditionally replicating adenovirus

    Directory of Open Access Journals (Sweden)

    Fuminori Sakurai

    2016-01-01

    Full Text Available Circulating tumor cells (CTCs are promising biomarkers in several cancers, and thus methods and apparatuses for their detection and quantification in the blood have been actively pursued. A novel CTC detection system using a green fluorescence protein (GFP–expressing conditionally replicating adenovirus (Ad (rAd-GFP was recently developed; however, there is concern about the production of false-positive cells (GFP-positive normal blood cells when using rAd-GFP, particularly at high titers. In addition, CTCs lacking or expressing low levels of coxsackievirus–adenovirus receptor (CAR cannot be detected by rAd-GFP, because rAd-GFP is constructed based on Ad serotype 5, which recognizes CAR. In order to suppress the production of false-positive cells, sequences perfectly complementary to blood cell–specific microRNA, miR-142-3p, were incorporated into the 3′-untranslated region of the E1B and GFP genes. In addition, the fiber protein was replaced with that of Ad serotype 35, which recognizes human CD46, creating rAdF35-142T-GFP. rAdF35-142T-GFP efficiently labeled not only CAR-positive tumor cells but also CAR-negative tumor cells with GFP. The numbers of false-positive cells were dramatically lower for rAdF35-142T-GFP than for rAd-GFP. CTCs in the blood of cancer patients were detected by rAdF35-142T-GFP with a large reduction in false-positive cells.

  12. An analysis of true- and false-positive results of vocal fold uptake in positron emission tomography-computed tomography imaging.

    Science.gov (United States)

    Seymour, N; Burkill, G; Harries, M

    2018-03-01

    Positron emission tomography-computed tomography with fluorine-18 fluorodeoxy-D-glucose has a major role in the investigation of head and neck cancers. Fluorine-18 fluorodeoxy-D-glucose is not a tumour-specific tracer and can also accumulate in benign pathology. Therefore, positron emission tomography-computed tomography scan interpretation difficulties are common in the head and neck, which can produce false-positive results. This study aimed to investigate patients detected as having abnormal vocal fold uptake on fluorine-18 fluorodeoxy-D-glucose positron emission tomography-computed tomography. Positron emission tomography-computed tomography scans were identified over a 15-month period where reports contained evidence of unilateral vocal fold uptake or vocal fold pathology. Patients' notes and laryngoscopy results were analysed. Forty-six patients were identified as having abnormal vocal fold uptake on positron emission tomography-computed tomography. Twenty-three patients underwent positron emission tomography-computed tomography and flexible laryngoscopy: 61 per cent of patients had true-positive positron emission tomography-computed tomography scans and 39 per cent had false-positive scan results. Most patients referred to ENT for abnormal findings on positron emission tomography-computed tomography scans had true-positive findings. Asymmetrical fluorine-18 fluorodeoxy-D-glucose uptake should raise suspicion of vocal fold pathology, accepting a false-positive rate of approximately 40 per cent.

  13. Using ELISPOT to expose false positive skin test conversion in tuberculosis contacts.

    Directory of Open Access Journals (Sweden)

    Philip C Hill

    2007-01-01

    Full Text Available Repeat tuberculin skin tests may be false positive due to boosting of waned immunity to past mycobacterial exposure. We evaluated whether an ELISPOT test could identify tuberculosis (TB contacts with boosting of immunity to non-tuberculous mycobacterial exposure.We conducted tuberculin and ELISPOT tests in 1665 TB contacts: 799 were tuberculin test negative and were offered a repeat test after three months. Those with tuberculin test conversion had an ELISPOT, chest X-ray and sputum analysis if appropriate. We compared converters with non-converters, assessed the probability of each of four combinations of ELISPOT results over the two time points and estimated boosting with adjustment for ELISPOT sensitivity and specificity. 704 (72% contacts had a repeat tuberculin test; 176 (25% had test conversion, which increased with exposure to a case (p = 0.002, increasing age (p = 0.0006 and BCG scar (p = 0.06. 114 tuberculin test converters had ELISPOT results: 16(14% were recruitment positive/follow-up positive, 9 (8% positive/negative, 34 (30% negative/positive, and 55 (48% were negative/negative. There was a significant non-linear effect of age for ELISPOT results in skin test converters (p = 0.038. Estimates of boosting ranged from 32%-41% of skin test converters with increasing age. Three converters were diagnosed with TB, two had ELISPOT results: both were positive, including one at recruitment.We estimate that approximately one third of tuberculin skin test conversion in Gambian TB case contacts is due to boosting of immunity to non-tuberculous mycobacterial exposure. Further longitudinal studies are required to confirm whether ELISPOT can reliably identify case contacts with tuberculin test conversion that would benefit most from prophylactic treatment.

  14. Prevalence and pathogenicity of binary toxin–positive Clostridium difficile strains that do not produce toxins A and B

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    C. Eckert

    2015-01-01

    Full Text Available Clostridium difficile causes antibiotic-associated diarrhoea and pseudomembranous colitis. The main virulence factors of C. difficile are the toxins A (TcdA and B (TcdB. A third toxin, called binary toxin (CDT, can be detected in 17% to 23% of strains, but its role in human disease has not been clearly defined. We report six independent cases of patients with diarrhoea suspected of having C. difficile infection due to strains from toxinotype XI/PCR ribotype 033 or 033-like, an unusual toxinotype/PCR ribotype positive for CDT but negative for TcdA and TcdB. Four patients were considered truly infected by clinicians and were specifically treated with oral metronidazole. One of the cases was identified during a prevalence study of A−B−CDT+ strains. In this study, we screened a French collection of 220 nontoxigenic strains and found only one (0.5% toxinotype XI/PCR ribotype 033 or 033-like strain. The description of such strains raises the question of the role of binary toxin as a virulence factor and could have implications for laboratory diagnostics that currently rarely include testing for binary toxin.

  15. Shape based automated detection of pulmonary nodules with surface feature based false positive reduction

    International Nuclear Information System (INIS)

    Nomura, Y.; Itoh, H.; Masutani, Y.; Ohtomo, K.; Maeda, E.; Yoshikawa, T.; Hayashi, N.

    2007-01-01

    We proposed a shape based automated detection of pulmonary nodules with surface feature based false positive (FP) reduction. In the proposed system, the FP existing in internal of vessel bifurcation is removed using extracted surface of vessels and nodules. From the validation with 16 chest CT scans, we find that the proposed CAD system achieves 18.7 FPs/scan at 90% sensitivity, and 7.8 FPs/scan at 80% sensitivity. (orig.)

  16. False-positive axillary lymph node on F-18 FDG PET/CT due to moxibustion therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Shin Young; Lee, Sang Woo; Ahn, Byeong Cheol; Lee, Jae Tae [Kyungpook National University Hospital, Daegu (Korea, Republic of); Seo, Ji Hyoung [Inje University Haeundae Paik Hospital, Busan (Korea, Republic of)

    2010-12-15

    A 30-year-old female was diagnosed with papillary thyroid cancer and underwent total thyroidectomy and high-dose radioiodine ablation. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for recurrence detection of thyroid carcinoma was performed at 3 years after total thyroidectomy. Moxibustion is a traditional Chinese medicine therapy using moxa or the mugwort herb. Moxibustion is the burning of a small, thimble-sized, smoldering plug of dried leaves such as moxa or mugwort on the skin at an acupuncture point. Acupuncture and moxibustion induce hyperemia and a local inflammatory reaction. Complications associated with moxibustion such as skin bums or infection of the site have been reported previously. False-positive FDG uptake in PET may result from inflammation, infection, and variations in physiological uptake. In the present case, the hypermetabolic axillary lymph node disappeared without any treatment. Well-known of false-positive FDG uptake in axillary lymph noes such as arthritis of the upper extremity, extravasation of injected FDG, and vaccination were not found. Thus, left axillary lymph node uptake was

  17. False-positive axillary lymph node on F-18 FDG PET/CT due to moxibustion therapy

    International Nuclear Information System (INIS)

    Jeong, Shin Young; Lee, Sang Woo; Ahn, Byeong Cheol; Lee, Jae Tae; Seo, Ji Hyoung

    2010-01-01

    A 30-year-old female was diagnosed with papillary thyroid cancer and underwent total thyroidectomy and high-dose radioiodine ablation. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for recurrence detection of thyroid carcinoma was performed at 3 years after total thyroidectomy. Moxibustion is a traditional Chinese medicine therapy using moxa or the mugwort herb. Moxibustion is the burning of a small, thimble-sized, smoldering plug of dried leaves such as moxa or mugwort on the skin at an acupuncture point. Acupuncture and moxibustion induce hyperemia and a local inflammatory reaction. Complications associated with moxibustion such as skin bums or infection of the site have been reported previously. False-positive FDG uptake in PET may result from inflammation, infection, and variations in physiological uptake. In the present case, the hypermetabolic axillary lymph node disappeared without any treatment. Well-known of false-positive FDG uptake in axillary lymph noes such as arthritis of the upper extremity, extravasation of injected FDG, and vaccination were not found. Thus, left axillary lymph node uptake was

  18. Robust Correlation Analyses: False Positive and Power Validation Using a New Open Source Matlab Toolbox

    Science.gov (United States)

    Pernet, Cyril R.; Wilcox, Rand; Rousselet, Guillaume A.

    2012-01-01

    Pearson’s correlation measures the strength of the association between two variables. The technique is, however, restricted to linear associations and is overly sensitive to outliers. Indeed, a single outlier can result in a highly inaccurate summary of the data. Yet, it remains the most commonly used measure of association in psychology research. Here we describe a free Matlab(R) based toolbox (http://sourceforge.net/projects/robustcorrtool/) that computes robust measures of association between two or more random variables: the percentage-bend correlation and skipped-correlations. After illustrating how to use the toolbox, we show that robust methods, where outliers are down weighted or removed and accounted for in significance testing, provide better estimates of the true association with accurate false positive control and without loss of power. The different correlation methods were tested with normal data and normal data contaminated with marginal or bivariate outliers. We report estimates of effect size, false positive rate and power, and advise on which technique to use depending on the data at hand. PMID:23335907

  19. Robust correlation analyses: false positive and power validation using a new open source matlab toolbox.

    Science.gov (United States)

    Pernet, Cyril R; Wilcox, Rand; Rousselet, Guillaume A

    2012-01-01

    Pearson's correlation measures the strength of the association between two variables. The technique is, however, restricted to linear associations and is overly sensitive to outliers. Indeed, a single outlier can result in a highly inaccurate summary of the data. Yet, it remains the most commonly used measure of association in psychology research. Here we describe a free Matlab((R)) based toolbox (http://sourceforge.net/projects/robustcorrtool/) that computes robust measures of association between two or more random variables: the percentage-bend correlation and skipped-correlations. After illustrating how to use the toolbox, we show that robust methods, where outliers are down weighted or removed and accounted for in significance testing, provide better estimates of the true association with accurate false positive control and without loss of power. The different correlation methods were tested with normal data and normal data contaminated with marginal or bivariate outliers. We report estimates of effect size, false positive rate and power, and advise on which technique to use depending on the data at hand.

  20. False-positive cryptococcal antigen test associated with use of BBL Port-a-Cul transport vials.

    Science.gov (United States)

    Wilson, Deborah A; Sholtis, Mary; Parshall, Sharon; Hall, Gerri S; Procop, Gary W

    2011-02-01

    A total of 52 residual CSF and serum specimens, which were originally negative with the Cryptococcal Antigen Latex Agglutination System (CALAS), were shown to become falsely positive after placement in BBL Port-A-Cul anaerobic transport vials. This transport device, although excellent for specimen transportation for subsequent culture, should not be used if cryptococcal antigen testing is needed.

  1. With sadness comes accuracy; with happiness, false memory: mood and the false memory effect.

    Science.gov (United States)

    Storbeck, Justin; Clore, Gerald L

    2005-10-01

    The Deese-Roediger-McDermott paradigm lures people to produce false memories. Two experiments examined whether induced positive or negative moods would influence this false memory effect. The affect-as-information hypothesis predicts that, on the one hand, positive affective cues experienced as task-relevant feedback encourage relational processing during encoding, which should enhance false memory effects. On the other hand, negative affective cues are hypothesized to encourage item-specific processing at encoding, which should discourage such effects. The results of Experiment 1 are consistent with these predictions: Individuals in negative moods were significantly less likely to show false memory effects than those in positive moods or those whose mood was not manipulated. Experiment 2 introduced inclusion instructions to investigate whether moods had their effects at encoding or retrieval. The results replicated the false memory finding of Experiment 1 and provide evidence that moods influence the accessibility of lures at encoding, rather than influencing monitoring at retrieval of whether lures were actually presented.

  2. False-Positive Cryptococcal Antigen Test Associated with Use of BBL Port-A-Cul Transport Vials▿

    Science.gov (United States)

    Wilson, Deborah A.; Sholtis, Mary; Parshall, Sharon; Hall, Gerri S.; Procop, Gary W.

    2011-01-01

    A total of 52 residual CSF and serum specimens, which were originally negative with the Cryptococcal Antigen Latex Agglutination System (CALAS), were shown to become falsely positive after placement in BBL Port-A-Cul anaerobic transport vials. This transport device, although excellent for specimen transportation for subsequent culture, should not be used if cryptococcal antigen testing is needed. PMID:21159939

  3. IS HCI THAT IS USED AS A PRESERVATIVE CREATING FALSE POSITIVES FOR TBA IN GROUND WATER

    Science.gov (United States)

    Will hydrochloric acid produce false positives for TBA? Yes, if you heat the sample to get a lower detection limit for TBA. Conventional purge and trap methods at ambient temperature have a reporting limit for TBA between 50 and 100 g/liter. This is higher than the provisiona...

  4. Empirical methods for controlling false positives and estimating confidence in ChIP-Seq peaks

    Directory of Open Access Journals (Sweden)

    Courdy Samir J

    2008-12-01

    Full Text Available Abstract Background High throughput signature sequencing holds many promises, one of which is the ready identification of in vivo transcription factor binding sites, histone modifications, changes in chromatin structure and patterns of DNA methylation across entire genomes. In these experiments, chromatin immunoprecipitation is used to enrich for particular DNA sequences of interest and signature sequencing is used to map the regions to the genome (ChIP-Seq. Elucidation of these sites of DNA-protein binding/modification are proving instrumental in reconstructing networks of gene regulation and chromatin remodelling that direct development, response to cellular perturbation, and neoplastic transformation. Results Here we present a package of algorithms and software that makes use of control input data to reduce false positives and estimate confidence in ChIP-Seq peaks. Several different methods were compared using two simulated spike-in datasets. Use of control input data and a normalized difference score were found to more than double the recovery of ChIP-Seq peaks at a 5% false discovery rate (FDR. Moreover, both a binomial p-value/q-value and an empirical FDR were found to predict the true FDR within 2–3 fold and are more reliable estimators of confidence than a global Poisson p-value. These methods were then used to reanalyze Johnson et al.'s neuron-restrictive silencer factor (NRSF ChIP-Seq data without relying on extensive qPCR validated NRSF sites and the presence of NRSF binding motifs for setting thresholds. Conclusion The methods developed and tested here show considerable promise for reducing false positives and estimating confidence in ChIP-Seq data without any prior knowledge of the chIP target. They are part of a larger open source package freely available from http://useq.sourceforge.net/.

  5. False positive results occurring in a radioimmunoassay for hepatitis A IgM antibody of the IgM class

    Energy Technology Data Exchange (ETDEWEB)

    Bucens, M R; Pietroboni, G R; Harnett, G B [Virus Lab., Combined Microbiology Service, Queen Elizabeth II Medical Centre, Perth, Western Australia

    1983-12-01

    The diagnosis of hepatitis A infection is usually based on the presence of hepatitis A specific IgM in a single serum sample. The fortuitous observation in one patient that this reactivity was apparently still present 19 mth after her original illness led to the discovery that the ABBOTT HAVAB-M kit method may produce false positive results. A series of patients who had previously had hepatitis A was retested and false positive results were found in 6% of this group. Control groups consisted of patients with other acute and chronic liver disorders and other acute viral diseases. No reactivity was detected in the control sera. Sucrose gradient fractionation revealed that the factor responsible for the false positive results was associated only with serum fractions containing IgA and IgG and that it could be removed by absorption of sera with staphylococcal protein A but not by absorption with streptococcus AR1 or by 2-mercaptoethanol treatment. It was concluded that following hepatitis A infection some patients produce a rheumatoid factor-like substance (not of IgM class) which is cleared from the serum in 2-3 yr. The presence of this factor may lead to a misdiagnosis in patients presenting with jaundice.

  6. Usefulness of exercise ECG test with nitroglycerin and exercise cardiac scintigraphy in patients with false positive exercise ECG test

    International Nuclear Information System (INIS)

    Moritani, Kohshiro

    1984-01-01

    The purpose of this study is to evaluate the clinical usefulness of exercise (Ex) ECG test with sublingual nitroglycerin (NTG) and Ex cardiac scintigraphy in differentiating false positive responses from true positive responses of Ex ECG test. We examined 7 pts (age : 46+-7 years) with true positive Ex ECG test (TP) and 8 pts (age : 55+-10 years) with false positive Ex ECG test (FP). TP had significant coronary artery disease and FP did not. Ex test was done by multistage ergometer test. In 5 pts of TP and all pts of FP, Ex cardiac scintigraphy was performed. In TP, Ex cardiac scintigraphy revealed reversible perfusion deficit, but not in FP. NTG was administered 3 minutes before Ex test was started. Ex test with NTG was terminated at the same load as Ex test without NTG. Pressure-rate products at the end point of Ex test did not show significant difference between Ex test without NTG and that with NTG (TP: 203x10 2 , 213x10 2 , FP: 196x10 2 , 206x10 2 , respectively). In 7 pts of FP, ST depression in Ex test without NTG was not improved in Ex test with NTG. On the other hand, in all pts of TP, ST depression seen in Ex test without NTG, was not observed in Ex test with NTG. It may be concluded that Ex cardiac scintigraphy is diagnostic for differentiation of false positive responses from true positive responses of Ex ECG test, as well as Ex ECG test with NTG is. (author)

  7. Evaluation of false positive responses by mass spectrometry and ion mobility spectrometry for the detection of trace explosives in complex samples

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C.L., E-mail: clcrawf@sandia.gov; Hill, H.H.

    2013-09-17

    Graphical abstract: -- Highlights: •First study to use (−)SESI-IM-TOFMS to analyze complex mixtures of personal care products. •The study demonstrated, by identifying mobility and mass interferents with explosive signatures, which, if used separately, neither IMS nor MS alone would prevent every false positive for explosives when detected in the presence of a complex sample matrix. •Ingredients in common household cleaning products were shown to either enhance or suppress the ionization of explosives in a SESI-IM-TOFMS analysis. •Mobility separation provided real-time separation of ion species that indicated overlapping isotope peak patterns -- Abstract: Secondary electrospray ionization-ion mobility-time of flight mass spectrometry (SESI-IM-TOFMS) was used to evaluate common household products and food ingredients for any mass or mobility responses that produced false positives for explosives. These products contained ingredients which shared the same mass and mobility drift time ranges as the analyte ions for common explosives. The results of this study showed that the vast array of compounds in these products can cause either mass or mobility false positive responses. This work also found that two ingredients caused either enhanced or reduced ionization of the target analytes. Another result showed that an IMS can provide real-time separation of ion species that impede accurate mass identifications due to overlapping isotope peak patterns. The final result of this study showed that, when mass and mobility values were used to identify an ion, no false responses were found for the target explosives. The wider implication of these results is that the possibility exists for even greater occurrences of false responses from complex mixtures found in common products. Neither IMS nor MS alone can provide 100% assurance from false responses. IMS, due to its low cost, ease of operation, rugged reliability, high sensitivity and tunable selectivity, will remain

  8. False positive indium-111 white blood cell scan in a closed clavicle fracture

    International Nuclear Information System (INIS)

    Friedman, R.J.; Gordon, L.

    1988-01-01

    Aggressive treatment of the multiply injured patient often requires early fixation of many fractures, some of which may be open. Often, patients develop postoperative fevers requiring a thorough workup to rule out infection. Recently, indium-111 white blood cell (WBC) imaging has become a valuable adjunct in the diagnosis of acute infection. The patient described had a simple, closed clavicle fracture with markedly increased activity on an indium-111 WBC scan obtained for fever workup. This subsequently proved to be a normal, healing, noninfected fracture by other diagnostic techniques. Noninfected, simple closed fractures should be added to the list of causes for a false-positive indium-111 WBC scan

  9. Detecting and avoiding likely false-positive findings - a practical guide.

    Science.gov (United States)

    Forstmeier, Wolfgang; Wagenmakers, Eric-Jan; Parker, Timothy H

    2017-11-01

    Recently there has been a growing concern that many published research findings do not hold up in attempts to replicate them. We argue that this problem may originate from a culture of 'you can publish if you found a significant effect'. This culture creates a systematic bias against the null hypothesis which renders meta-analyses questionable and may even lead to a situation where hypotheses become difficult to falsify. In order to pinpoint the sources of error and possible solutions, we review current scientific practices with regard to their effect on the probability of drawing a false-positive conclusion. We explain why the proportion of published false-positive findings is expected to increase with (i) decreasing sample size, (ii) increasing pursuit of novelty, (iii) various forms of multiple testing and researcher flexibility, and (iv) incorrect P-values, especially due to unaccounted pseudoreplication, i.e. the non-independence of data points (clustered data). We provide examples showing how statistical pitfalls and psychological traps lead to conclusions that are biased and unreliable, and we show how these mistakes can be avoided. Ultimately, we hope to contribute to a culture of 'you can publish if your study is rigorous'. To this end, we highlight promising strategies towards making science more objective. Specifically, we enthusiastically encourage scientists to preregister their studies (including a priori hypotheses and complete analysis plans), to blind observers to treatment groups during data collection and analysis, and unconditionally to report all results. Also, we advocate reallocating some efforts away from seeking novelty and discovery and towards replicating important research findings of one's own and of others for the benefit of the scientific community as a whole. We believe these efforts will be aided by a shift in evaluation criteria away from the current system which values metrics of 'impact' almost exclusively and towards a system

  10. False-positive positron emission tomography appearance with 18F-fluorodeoxyglucose after definitive radiotherapy for cancer of the mobile tongue.

    Science.gov (United States)

    Ariji, Y; Fuwa, N; Kodaira, T; Tachibana, H; Nakamura, T; Satoh, Y; Ariji, E

    2009-01-01

    (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) is an effective tool for evaluating the results of radiotherapy. However, some false-positive appearances caused by physiological or pathological accumulation are reported. We report on three patients who showed a high accumulation of FDG in the lingual muscles but had no recurrent tumour after definitive radiotherapy for the mobile tongue. All patients had squamous cell carcinoma of the tongue and received interstitial radiotherapy with small sources. High uptake was seen in the lingual muscles without recurrence or inflammation, based on physical and MR examinations. This false-positive appearance is thought to relate to ill-balanced high activity of the lingual muscles after definitive radiotherapy.

  11. Placing symptoms in context: the role of contextual criteria in reducing false positives in Diagnostic and Statistical Manual of Mental Disorders diagnoses.

    Science.gov (United States)

    Wakefield, Jerome C; First, Michael B

    2012-02-01

    The Diagnostic and Statistical Manual of Mental Disorders (DSM) definition of mental disorder requires that symptoms be caused by a dysfunction in the individual; when dysfunction is absent, symptoms represent normal-range distress or eccentricity and, if diagnosed as a mental disorder, are false positives. We hypothesized that because of psychiatry's lack of direct laboratory tests to distinguish dysfunction from normal-range distress, the context in which symptoms occur (eg, lack of imminent danger in a panic attack) is often essential to determining whether symptoms are caused by a dysfunction. If this is right, then the DSM diagnostic criteria should include many contextual criteria added to symptom syndromes to prevent dysfunction false positives. Despite their potential importance, such contextual criteria have not been previously reviewed. We, thus, systematically reviewed DSM categories to establish the extent of such uses of contextual criteria and created a typology of such uses. Of 111 sampled categories, 68 (61%) used context to prevent dysfunction false positives. Contextual criteria fell into 7 types: (1) exclusion of specific false-positive scenarios; (2) requiring that patients experience preconditions for normal responses (eg, requiring that individuals experience adequate sexual stimulation before being diagnosed with sexual dysfunctions); (3) requiring that symptoms be disproportionate relative to circumstances; (4) for childhood disorders, requiring that symptoms be developmentally inappropriate; (5) requiring that symptoms occur in multiple contexts; (6) requiring a substantial discrepancy between beliefs and reality; and (7) a residual category. Most DSM categories include contextual criteria to eliminate false-positive diagnoses and increase validity of descriptive criteria. Future revisions should systematically evaluate each category's need for contextual criteria. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Likelihood of early detection of breast cancer in relation to false-positive risk in life-time mammographic screening: population-based cohort study.

    Science.gov (United States)

    Otten, J D M; Fracheboud, J; den Heeten, G J; Otto, S J; Holland, R; de Koning, H J; Broeders, M J M; Verbeek, A L M

    2013-10-01

    Women require balanced, high-quality information when making an informed decision on screening benefits and harms before attending biennial mammographic screening. The cumulative risk of a false-positive recall and/or (small) screen-detected or interval cancer over 13 consecutive screening examinations for women aged 50 from the start of screening were estimated using data from the Nijmegen programme, the Netherlands. Women who underwent 13 successive screens in the period 1975-1976 had a 5.3% cumulative chance of a screen-detected cancer, with a 4.2% risk of at least one false-positive recall. The risk of being diagnosed with interval cancer was 3.7%. Two decades later, these estimates were 6.9%, 7.3% and 2.9%, respectively. The chance of detection of a small, favourable invasive breast cancer, anticipating a normal life-expectancy, rose from 2.3% to 3.7%. Extrapolation to digital screening mammography indicates that the proportion of false-positive results will rise to 16%. Dutch women about to participate in the screening programme can be reassured that the chance of false-positive recall in the Netherlands is relatively low. A new screening policy and improved mammography have increased the detection of an early screening carcinoma and lowering the risk of interval carcinoma.

  13. Interpreting the results of the Semmes-Weinstein monofilament test: accounting for false-positive answers in the international consensus on the diabetic foot protocol by a new model.

    Science.gov (United States)

    Slater, Robert A; Koren, Shlomit; Ramot, Yoram; Buchs, Andreas; Rapoport, Micha J

    2014-01-01

    The Semmes-Weinstein monofilament is the most widely used test to diagnose the loss of protective sensation. The commonly used protocol of the International Consensus on the Diabetic Foot includes a 'sham' application that allows for false-positive answers. We sought to study the heretofore unexamined significance of false-positive answers. Forty-five patients with diabetes and a history of pedal ulceration (Group I) and 81 patients with diabetes but no history of ulceration (Group II) were studied. The three original sites of the International Consensus on the Diabetic Foot at the hallux, 1st metatarsal and 5th metatarsal areas were used. At each location, the test was performed three times: 2 actual and 1 "sham" applications. Scores were graded from 0 to 3 based upon correct responses. Determination of loss of protective sensation was performed with and without calculating a false-positive answer as a minus 1 score. False-positive responses were found in a significant percentage of patients with and without history of ulceration. Introducing false-positive results as minus 1 into the test outcome significantly increased the number of patients diagnosed with loss of protective sensation in both groups. False-positive answers can significantly affect Semmes-Weinstein monofilament test results and the diagnosis of LOPS. A model that accounts for false-positive answers is offered. Copyright © 2013 John Wiley & Sons, Ltd.

  14. Decisions to shoot in a weapon identification task: The influence of cultural stereotypes and perceived threat on false positive errors.

    Science.gov (United States)

    Fleming, Kevin K; Bandy, Carole L; Kimble, Matthew O

    2010-01-01

    The decision to shoot a gun engages executive control processes that can be biased by cultural stereotypes and perceived threat. The neural locus of the decision to shoot is likely to be found in the anterior cingulate cortex (ACC), where cognition and affect converge. Male military cadets at Norwich University (N=37) performed a weapon identification task in which they made rapid decisions to shoot when images of guns appeared briefly on a computer screen. Reaction times, error rates, and electroencephalogram (EEG) activity were recorded. Cadets reacted more quickly and accurately when guns were primed by images of Middle-Eastern males wearing traditional clothing. However, cadets also made more false positive errors when tools were primed by these images. Error-related negativity (ERN) was measured for each response. Deeper ERNs were found in the medial-frontal cortex following false positive responses. Cadets who made fewer errors also produced deeper ERNs, indicating stronger executive control. Pupil size was used to measure autonomic arousal related to perceived threat. Images of Middle-Eastern males in traditional clothing produced larger pupil sizes. An image of Osama bin Laden induced the largest pupil size, as would be predicted for the exemplar of Middle East terrorism. Cadets who showed greater increases in pupil size also made more false positive errors. Regression analyses were performed to evaluate predictions based on current models of perceived threat, stereotype activation, and cognitive control. Measures of pupil size (perceived threat) and ERN (cognitive control) explained significant proportions of the variance in false positive errors to Middle-Eastern males in traditional clothing, while measures of reaction time, signal detection response bias, and stimulus discriminability explained most of the remaining variance.

  15. A high false positive rate for Kepler planetary candidates of giant stars using asterodensity profiling

    International Nuclear Information System (INIS)

    Sliski, David H.; Kipping, David M.

    2014-01-01

    Asterodensity profiling (AP) is a relatively new technique for studying transit light curves. By comparing the mean stellar density derived from the transit light curve to that found through an independent method, AP provides information on several useful properties such as orbital eccentricity and blended light. We present an AP survey of 41 Kepler Objects of Interest (KOIs), with a single transiting candidate, for which the target star's mean stellar density has been measured using asteroseismology. The ensemble distribution of the AP measurements for the 31 dwarf stars in our sample shows excellent agreement with the spread expected if the KOIs were genuine and have realistic eccentricities. In contrast, the same test for the 10 giants in our sample reveals significant incompatibility at >4σ confidence. While extreme eccentricities could be invoked, this hypothesis requires four of the KOIs to contact their host star at periastron passage, including the recently claimed confirmation of Kepler-91b. After carefully examining several hypotheses, we conclude that the most plausible explanation is that the transiting objects orbit a different star to that measured with asteroseismology—cases we define as false-positives. Based on the AP distribution, we estimate a false-positive rate (FPR) for Kepler's giant stars with a single transiting object of FPR ≅ 70% ± 30%.

  16. False-positive indium-111 labeled leukocyte scintigram in a patient with a painful hip prosthesis

    International Nuclear Information System (INIS)

    Feldman, N.; Makler, P.T. Jr.; Alavi, A.

    1986-01-01

    A Tronzo hip prosthesis is designed to elicit an inflammatory reaction in order to promote prosthesis stability. A three-phased bone scan and Ga-67 imaging in conjunction with physical examination and laboratory findings failed to demonstrate evidence for osteomyelitis in a patient with a painful hip prosthesis, in whom images obtained with In-111-labeled leukocytes were positive. This observation demonstrated that the interpretation of the latter technique in demonstrating inflammation can cause a false impression of an infectious process

  17. False positive localisation of C-11 methionine in a colloid nodule

    International Nuclear Information System (INIS)

    Mahajan, Sonia; Tripathi, Madhavi; Jaimini, Abhinav; Dinesh, Anant

    2011-01-01

    A 45-year-old female diagnosed with carcinoma of the left breast on histopathological examination underwent both 18 F-flourodeoxyglucose (FDG) and 11C-methionine (MET) positron emission tomography/computed tomography (PET/CT) as part of a protocol comparing the utility of these tracers for predicting a response to neoadjuvant chemotherapy in breast carcinoma. Abnormal FDG and MET accumulation was noted in the left breast primary, left axillary lymph nodes, and also in a well-defined nodule present in the left lobe of the thyroid gland. Keeping in mind the possibility of thyroid neoplasm/metastasis, the patient was referred for fine needle aspiration cytology (FNAC) from the thyroid nodule that revealed features of a simple colloid nodule. Focal thyroid lesions incidentally found on 18 F-FDG PET/CT have a high risk of thyroid malignancy. Non-specific accumulation of FDG in thyroid adenomas is also known. This case highlights a potential cause for false positive on C-11 MET PET/CT in colloid adenomas, which should be kept in mind while using this tracer for oncological indications

  18. False-positive findings in mammography screening induces short-term distress - breast cancer-specific concern prevails longer

    DEFF Research Database (Denmark)

    Aro, A R; Pilvikki Absetz, S; van Elderen, T M

    2000-01-01

    The aim of this study was to examine psychological distress in a mammography screening process as a consequence of screening after adjusting for background, personality and prescreening distress. Subjects, aged 50 years, were invitees at their first screening. There were three groups; normal find...... perceived breast cancer risk and susceptibility. Distress related to screening and false-positive findings seems to be moderate, but prevailing cancer-specific concerns call for improvements in screening programmes....

  19. Multi-scale textural feature extraction and particle swarm optimization based model selection for false positive reduction in mammography.

    Science.gov (United States)

    Zyout, Imad; Czajkowska, Joanna; Grzegorzek, Marcin

    2015-12-01

    The high number of false positives and the resulting number of avoidable breast biopsies are the major problems faced by current mammography Computer Aided Detection (CAD) systems. False positive reduction is not only a requirement for mass but also for calcification CAD systems which are currently deployed for clinical use. This paper tackles two problems related to reducing the number of false positives in the detection of all lesions and masses, respectively. Firstly, textural patterns of breast tissue have been analyzed using several multi-scale textural descriptors based on wavelet and gray level co-occurrence matrix. The second problem addressed in this paper is the parameter selection and performance optimization. For this, we adopt a model selection procedure based on Particle Swarm Optimization (PSO) for selecting the most discriminative textural features and for strengthening the generalization capacity of the supervised learning stage based on a Support Vector Machine (SVM) classifier. For evaluating the proposed methods, two sets of suspicious mammogram regions have been used. The first one, obtained from Digital Database for Screening Mammography (DDSM), contains 1494 regions (1000 normal and 494 abnormal samples). The second set of suspicious regions was obtained from database of Mammographic Image Analysis Society (mini-MIAS) and contains 315 (207 normal and 108 abnormal) samples. Results from both datasets demonstrate the efficiency of using PSO based model selection for optimizing both classifier hyper-parameters and parameters, respectively. Furthermore, the obtained results indicate the promising performance of the proposed textural features and more specifically, those based on co-occurrence matrix of wavelet image representation technique. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. THE POSSIBLE MOON OF KEPLER-90g IS A FALSE POSITIVE

    Energy Technology Data Exchange (ETDEWEB)

    Kipping, D. M.; Torres, G.; Buchhave, L. A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Huang, X.; Bakos, G. Á. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 05844 (United States); Nesvorný, D. [Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States); Schmitt, A. R., E-mail: dkipping@cfa.harvard.edu

    2015-01-20

    The discovery of an exomoon would provide deep insights into planet formation and the habitability of planetary systems, with transiting examples being particularly sought after. Of the hundreds of Kepler planets now discovered, the seven-planet system Kepler-90 is unusual for exhibiting an unidentified transit-like signal in close proximity to one of the transits of the long-period gas-giant Kepler-90g, as noted by Cabrera et al. As part of the ''Hunt for Exomoons with Kepler'' project, we investigate this possible exomoon signal and find it passes all conventional photometric, dynamical, and centroid diagnostic tests. However, pixel-level light curves indicate that the moon-like signal occurs on nearly all of the target's pixels, which we confirm using a novel way of examining pixel-level data which we dub the ''transit centroid''. This test reveals that the possible exomoon to Kepler-90g is likely a false positive, perhaps due to a cosmic ray induced sudden pixel sensitivity dropout. This work highlights the extreme care required for seeking non-periodic low-amplitude transit signals, such as exomoons.

  1. A mode of error: Immunoglobulin binding protein (a subset of anti-citrullinated proteins can cause false positive tuberculosis test results in rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Maria Greenwald

    2017-12-01

    Full Text Available Citrullinated Immunoglobulin Binding Protein (BiP is a newly described autoimmune target in rheumatoid arthritis (RA, one of many cyclic citrullinated peptides(CCP or ACPA. BiP is over-expressed in RA patients causing T cell expansion and increased interferon levels during incubation for the QuantiFERON-Gold tuberculosis test (QFT-G TB. The QFT-G TB has never been validated where interferon is increased by underlying disease, as for example RA.Of ACPA-positive RA patients (n = 126, we found a 13% false-positive TB test rate by QFT-G TB. Despite subsequent biologic therapy for 3 years of all 126 RA patients, none showed evidence of TB without INH. Most of the false-positive RA patients after treatment with biologic therapy reverted to a negative QFT-G test. False TB tests correlated with ACPA level (p < 0.02.Three healthy women without arthritis or TB exposure had negative QFT-G TB. In vitro, all three tested positive every time for TB correlating to the dose of BiP or anti-BiP added, at 2 ug/ml, 5 ug/ml, 10 ug/ml, and 20 ug/ml.BiP naturally found in the majority of ACPA-positive RA patients can result in a false positive QFT-G TB. Subsequent undertreatment of RA, if biologic therapy is withheld, and overtreatment of presumed latent TB may harm patients. Keywords: Tuberculosis, IGRA, Rheumatoid arthritis, Interferon, Anti-citrullinated peptide antibody (ACPA, Immunoglobulin binding protein (BiP

  2. [False positive results or what's the probability that a significant P-value indicates a true effect?

    Science.gov (United States)

    Cucherat, Michel; Laporte, Silvy

    2017-09-01

    The use of statistical test is central in the clinical trial. At the statistical level, obtaining a Pinformation about the plausibility of the existence of treatment effect. With "Pfalse positive is very high. This is the case if the power is low, if there is an inflation of the alpha risk or if the result is exploratory or chance discoveries. This possibility is important to take into consideration when interpreting the results of clinical trials in order to avoid pushing ahead significant results in appearance, but which are likely to be actually false positive results. Copyright © 2017 Société française de pharmacologie et de thérapeutique. Published by Elsevier Masson SAS. All rights reserved.

  3. False positive or negative results of shear-wave elastography in differentiating benign from malignant breast masses: analysis of clinical and ultrasonographic characteristics.

    Science.gov (United States)

    Kim, Mi Young; Choi, Nami; Yang, Jung-Hyun; Yoo, Young Bum; Park, Kyoung Sik

    2015-10-01

    Shear-wave elastography (SWE) has the potential to improve diagnostic performance of conventional ultrasound (US) in differentiating benign from malignant breast masses. To investigate false positive or negative results of SWE in differentiating benign from malignant breast masses and to analyze clinical and imaging characteristics of the masses with false SWE findings. From May to October 2013, 166 breast lesions of 164 consecutive women (mean age, 45.3 ± 10.1 years) who had been scheduled for biopsy were included. Conventional US and SWE were performed in all women before biopsy. Clinical, ultrasonographic morphologic features and SWE parameters (pattern classification and standard deviation [SD]) were recorded and compared with the histopathology results. Patient and lesion factors in the "true" and "false" groups were compared. Of the 166 masses, 118 (71.1%) were benign and 48 (28.9%) were malignant. False SWE features were more frequently observed in benign masses. False positive rates of benign masses and false negative rates of malignancy were 53% and 8.2%, respectively, using SWE pattern analysis and were 22.4% and 10.3%, respectively, using SD values. A lesion boundary of the masses on US (P = 0.039) and younger patient age (P = 0.047) were significantly associated with false SWE findings. These clinical and ultrasonographic features need to be carefully evaluated in performance and interpretation of SWE examinations. © The Foundation Acta Radiologica 2014.

  4. LOW FALSE POSITIVE RATE OF KEPLER CANDIDATES ESTIMATED FROM A COMBINATION OF SPITZER AND FOLLOW-UP OBSERVATIONS

    International Nuclear Information System (INIS)

    Désert, Jean-Michel; Brown, Timothy M.; Charbonneau, David; Torres, Guillermo; Fressin, François; Ballard, Sarah; Latham, David W.; Bryson, Stephen T.; Borucki, William J.; Knutson, Heather A.; Batalha, Natalie M.; Deming, Drake; Ford, Eric B.; Fortney, Jonathan J.; Gilliland, Ronald L.; Seager, Sara

    2015-01-01

    NASA’s Kepler mission has provided several thousand transiting planet candidates during the 4 yr of its nominal mission, yet only a small subset of these candidates have been confirmed as true planets. Therefore, the most fundamental question about these candidates is the fraction of bona fide planets. Estimating the rate of false positives of the overall Kepler sample is necessary to derive the planet occurrence rate. We present the results from two large observational campaigns that were conducted with the Spitzer Space Telescope during the the Kepler mission. These observations are dedicated to estimating the false positive rate (FPR) among the Kepler candidates. We select a sub-sample of 51 candidates, spanning wide ranges in stellar, orbital, and planetary parameter space, and we observe their transits with Spitzer at 4.5 μm. We use these observations to measures the candidate’s transit depths and infrared magnitudes. An authentic planet produces an achromatic transit depth (neglecting the modest effect of limb darkening). Conversely a bandpass-dependent depth alerts us to the potential presence of a blending star that could be the source of the observed eclipse: a false positive scenario. For most of the candidates (85%), the transit depths measured with Kepler are consistent with the transit depths measured with Spitzer as expected for planetary objects, while we find that the most discrepant measurements are due to the presence of unresolved stars that dilute the photometry. The Spitzer constraints on their own yield FPRs between 5% and depending on the Kepler Objects of Interest. By considering the population of the Kepler field stars, and by combining follow-up observations (imaging) when available, we find that the overall FPR of our sample is low. The measured upper limit on the FPR of our sample is 8.8% at a confidence level of 3σ. This observational result, which uses the achromatic property of planetary transit signals that is not investigated

  5. LOW FALSE POSITIVE RATE OF KEPLER CANDIDATES ESTIMATED FROM A COMBINATION OF SPITZER AND FOLLOW-UP OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Désert, Jean-Michel; Brown, Timothy M. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Charbonneau, David; Torres, Guillermo; Fressin, François; Ballard, Sarah; Latham, David W. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bryson, Stephen T.; Borucki, William J. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Knutson, Heather A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Batalha, Natalie M. [San Jose State University, San Jose, CA 95192 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Ford, Eric B. [University of Florida, Gainesville, FL 32611 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Gilliland, Ronald L. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Seager, Sara, E-mail: desert@colorado.edu [Massachusetts Institute of Technology, Cambridge, MA 02159 (United States)

    2015-05-01

    NASA’s Kepler mission has provided several thousand transiting planet candidates during the 4 yr of its nominal mission, yet only a small subset of these candidates have been confirmed as true planets. Therefore, the most fundamental question about these candidates is the fraction of bona fide planets. Estimating the rate of false positives of the overall Kepler sample is necessary to derive the planet occurrence rate. We present the results from two large observational campaigns that were conducted with the Spitzer Space Telescope during the the Kepler mission. These observations are dedicated to estimating the false positive rate (FPR) among the Kepler candidates. We select a sub-sample of 51 candidates, spanning wide ranges in stellar, orbital, and planetary parameter space, and we observe their transits with Spitzer at 4.5 μm. We use these observations to measures the candidate’s transit depths and infrared magnitudes. An authentic planet produces an achromatic transit depth (neglecting the modest effect of limb darkening). Conversely a bandpass-dependent depth alerts us to the potential presence of a blending star that could be the source of the observed eclipse: a false positive scenario. For most of the candidates (85%), the transit depths measured with Kepler are consistent with the transit depths measured with Spitzer as expected for planetary objects, while we find that the most discrepant measurements are due to the presence of unresolved stars that dilute the photometry. The Spitzer constraints on their own yield FPRs between 5% and depending on the Kepler Objects of Interest. By considering the population of the Kepler field stars, and by combining follow-up observations (imaging) when available, we find that the overall FPR of our sample is low. The measured upper limit on the FPR of our sample is 8.8% at a confidence level of 3σ. This observational result, which uses the achromatic property of planetary transit signals that is not investigated

  6. False-positive results after environmental pinworm PCR testing due to Rhabditid nematodes in Corncob bedding.

    Science.gov (United States)

    Leblanc, Mathias; Berry, Kristina; Graciano, Sandy; Becker, Brandon; Reuter, Jon D

    2014-11-01

    Modern rodent colonies are housed in individually ventilated cages to protect the animals from contamination with adventitious pathogens. Standard health monitoring through soiled-bedding sentinels does not always detect infections, especially in the context of low pathogen prevalence. Recently proposed alternatives include analyzing environmental samples from the cages or rack exhaust by PCR to improve the detection of rodent pathogens but optimal sampling strategies have not yet been established for different microorganisms. Although generally very sensitive and specific, these molecular assays are not foolproof and subject to false-positive and -negative results and should always be interpreted cautiously with an overall understanding of the intrinsic controls and all the variables that may affect the results. Here, we report a limited Aspiculuris tetraptera outbreak in a mouse barrier facility that was detected by fecal PCR in sentinels and confirmed by fecal flotation and direct cecal examination of both sentinels and colony animals. The outbreak led to a widespread survey of all facilities for pinworms by using environmental PCR from ventilated rack exhaust plenums. Environmental PCR suggested an unexpected widespread contamination of all ventilated racks holding nonautoclaved cages, but results could not be confirmed in sentinel or colony animals by fecal flotation, cecal and colonic examination, or cage PCR testing. After additional investigation, the unexpected environmental PCR results were confirmed as false-positive findings due to the nonspecificity of the assay, leading to the amplification of rhabditid nematodes, which are not infectious in rodents but which contaminated the corncob bedding.

  7. Recurrent/metastatic thyroid carcinomas false negative for serum thyroglobulin but positive by posttherapy I-131 whole body scans

    International Nuclear Information System (INIS)

    Park, Eun-Kyung; Lee, Dong Soo; Lee, Myung Chul; Chung, June-Key; Lim, Il Han; Park, Do Joon; Cho, Bo Youn

    2009-01-01

    Serum Tg and I-131 WBS have been used to detect recurrent and metastatic thyroid cancers postoperatively. Tg is known to be more sensitive than I-131 WBS, and therefore, false-negative WBS cases with elevated Tg levels are frequently found. However, the clinical characteristics of false-negative Tg cases with positive WBS have not been clarified. The authors evaluated 824 postoperative patients with differentiated thyroid carcinoma who underwent post-ablation/therapy I-131 WBS. Tg negativity was defined as a Tg level of ≤2 ng/mL without TgAb under thyroid-stimulating hormone stimulation. Remission, recurrence, and metastasis were confirmed using pathologic or clinically findings. Fifty-two patients (6.3%) with functioning metastasis and negativity for TgAb were Tg-negative and posttherapy I-131 WBS-positive (TgN group), and 128 patients with functioning metastases were Tg positive and WBS positive (TgP group). The TgN group consisted of 45 cases of cervical/mediastinal lymph node metastases (86.5%) and seven cases of distant metastasis to lung or bone by follow-up WBS. The TgN group demonstrated significantly higher profiles of regional involvement than the TgP group (P < 0.029). In 47 patients in the TgN group, metastatic uptake disappeared in 33, ameliorated in four, and persisted in ten during follow-up. A significant number of differentiated thyroid cancer patients were Tg-/TgAb-negative despite a positive WBS finding. Cervical and mediastinal lymph nodes were predominant sites of metastasis in the TgN group. WBS should be undertaken routinely as a complementary modality to detect functioning recurrence and metastasis regardless of serum Tg results. (orig.)

  8. Avoiding false positive antigen detection by flow cytometry on blood cell derived microparticles: the importance of an appropriate negative control.

    Directory of Open Access Journals (Sweden)

    Emerence Crompot

    Full Text Available Microparticles (MPs, also called microvesicles (MVs are plasma membrane-derived fragments with sizes ranging from 0.1 to 1μm. Characterization of these MPs is often performed by flow cytometry but there is no consensus on the appropriate negative control to use that can lead to false positive results.We analyzed MPs from platelets, B-cells, T-cells, NK-cells, monocytes, and chronic lymphocytic leukemia (CLL B-cells. Cells were purified by positive magnetic-separation and cultured for 48h. Cells and MPs were characterized using the following monoclonal antibodies (CD19,20 for B-cells, CD3,8,5,27 for T-cells, CD16,56 for NK-cells, CD14,11c for monocytes, CD41,61 for platelets. Isolated MPs were stained with annexin-V-FITC and gated between 300nm and 900nm. The latex bead technique was then performed for easy detection of MPs. Samples were analyzed by Transmission (TEM and Scanning Electron microscopy (SEM.Annexin-V positive events within a gate of 300-900nm were detected and defined as MPs. Our results confirmed that the characteristic antigens CD41/CD61 were found on platelet-derived-MPs validating our technique. However, for MPs derived from other cell types, we were unable to detect any antigen, although they were clearly expressed on the MP-producing cells in the contrary of several data published in the literature. Using the latex bead technique, we confirmed detection of CD41,61. However, the apparent expression of other antigens (already deemed positive in several studies was determined to be false positive, indicated by negative controls (same labeling was used on MPs from different origins.We observed that mother cell antigens were not always detected on corresponding MPs by direct flow cytometry or latex bead cytometry. Our data highlighted that false positive results could be generated due to antibody aspecificity and that phenotypic characterization of MPs is a difficult field requiring the use of several negative controls.

  9. False-positive result when a diphenylcarbazide spot test is used on trivalent chromium-passivated zinc surfaces

    DEFF Research Database (Denmark)

    Reveko, Valeriia; Lampert, Felix; Din, Rameez Ud

    2018-01-01

    chromium passivation on zinc; however, subsequent analysis by XPS could not confirm the presence of chromium in a hexavalent state. Conclusions Unintended oxidation of DPC induced by atmospheric corrosion is suggested as a possible reason for the false-positive reaction of the DPC test on a trivalent......A colorimetric 1,5-diphenylcarbazide (DPC)-based spot test can be used to identify hexavalent chromium on various metallic and leather surfaces. DPC testing on trivalent chromium-passivated zinc surfaces has unexpectedly given positive results in some cases, apparently indicating the presence...... of hexavalent chromium; however, the presence of hexavalent chromium has never been confirmed with more sensitive and accurate test methods. Objectives To examine the presence of hexavalent chromium on trivalent chromium-passivated zinc surfaces with a DPC-based spot test. Methods A colorimetric DPC spot test...

  10. The effect of information about false negative and false positive rates on people's attitudes towards colorectal cancer screening using faecal occult blood testing (FOBt).

    Science.gov (United States)

    Miles, Anne; Rodrigues, Vania; Sevdalis, Nick

    2013-11-01

    To examine the impact of numeric risk information about false negative (FN) and false positive (FP) rates in faecal occult blood testing (FOBt) on attitudes towards screening. 95 people aged 45-59, living in England, read 6 hypothetical vignettes presented online about the use of FOB testing to detect bowel cancer, in which information about FN and FP rates was systematically varied. Both verbal and numeric FN risk information reduced people's interest in screening compared with no FN information. Numeric FN risk information reduced people's perceptions of screening effectiveness and lowered perceived trust in the results of screening compared with both verbal FN information and no FN information. FP information did not affect attitudes towards FOB testing. There was limited evidence that FN information reduced interest and perceptions of screening effectiveness more in educated groups. Numeric FN risk information decreased people's perceptions of screening effectiveness and trust in the results of screening but did not affect people's interest in screening anymore than verbal FN risk information. Numeric FN information could be added to patient information without affecting interest in screening, although this needs to be replicated in a larger, more representative sample. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  11. Impact of intermediate mammography assessment on the likelihood of false-positive results in breast cancer screening programmes

    International Nuclear Information System (INIS)

    Ascunce, Nieves; Ederra, Maria; Delfrade, Josu; Erdozain, Nieves; Baroja, Araceli; Zubizarreta, Raquel; Salas, Dolores; Castells, Xavier

    2012-01-01

    Breast cancer screening is offered to 100% of the target population in Spain and intermediate mammograms (IMs) are sometimes indicated. This study was aimed at analysing the frequency of IMs, the factors determining their recommendation, and their impact on the risk of false-positive results and the detection rate. Data from 3,471,307 mammograms from Spanish breast cancer screening programmes were included. 3.36% of the mammograms were IMs. The factors associated with the use of IMs were age, initial screening, previous invasive tests, a familial history of breast cancer and use of hormone replacement therapy. In screening episodes with an IM, the probability of a false-positive result was 13.74% (95% CI: 13.43-14.05), almost double that in episodes without IMs (6.02%, 95% CI 5.99-6.05). In young women with previous invasive procedures, a familial history of breast cancer or hormone replacement therapy use who were undergoing their initial screen, this probability was lower when IMs were performed. IMs always increased the detection rate. The factors prompting IMs should be characterised so that radiologists can systematise their recommendations according to the presence of the factors maximising the benefits and minimising the adverse effects of this procedure. (orig.)

  12. Impact of intermediate mammography assessment on the likelihood of false-positive results in breast cancer screening programmes

    Energy Technology Data Exchange (ETDEWEB)

    Ascunce, Nieves [Public Health Institute, CIBERESP, Navarra Breast Cancer Screening Programme, Pamplona (Spain); Instituto de Salud Publica, Navarra Breast Cancer Screening Programme, Pamplona (Spain); Ederra, Maria; Delfrade, Josu; Erdozain, Nieves [Public Health Institute, CIBERESP, Navarra Breast Cancer Screening Programme, Pamplona (Spain); Baroja, Araceli [Fundacion Rioja Salud, Logrono (Spain); Zubizarreta, Raquel [Public Health and Planning Directorate, Health Office, Galician Breast Cancer Screening Programme, Galicia (Spain); Salas, Dolores [General Directorate Public Health and Centre for Public Health Research (CSISP), Valencia (Spain); Castells, Xavier [Mar Teaching Hospital, CIBERESP, Department of Clinical Epidemiology, Barcelona (Spain)

    2012-02-15

    Breast cancer screening is offered to 100% of the target population in Spain and intermediate mammograms (IMs) are sometimes indicated. This study was aimed at analysing the frequency of IMs, the factors determining their recommendation, and their impact on the risk of false-positive results and the detection rate. Data from 3,471,307 mammograms from Spanish breast cancer screening programmes were included. 3.36% of the mammograms were IMs. The factors associated with the use of IMs were age, initial screening, previous invasive tests, a familial history of breast cancer and use of hormone replacement therapy. In screening episodes with an IM, the probability of a false-positive result was 13.74% (95% CI: 13.43-14.05), almost double that in episodes without IMs (6.02%, 95% CI 5.99-6.05). In young women with previous invasive procedures, a familial history of breast cancer or hormone replacement therapy use who were undergoing their initial screen, this probability was lower when IMs were performed. IMs always increased the detection rate. The factors prompting IMs should be characterised so that radiologists can systematise their recommendations according to the presence of the factors maximising the benefits and minimising the adverse effects of this procedure. (orig.)

  13. The uterine blush. A potential false-positive in Meckel's scan interpretation

    International Nuclear Information System (INIS)

    Fink-Bennett, D.

    1982-01-01

    To determine the presence, prevalence, and clinical importance of /sup 99m/Tc pertechnetate uterine uptake, this retrospective analysis of 71 Meckel's scans was undertaken. Specifically, each study was evaluated for the presence of a focal accumulation of radiotracer cephalad to the bladder. Patients received an intravenous dose of 150 microCi/kg of /sup 99m/Tc pertechnetate. Each study consisted of 15 one minute anterior serial gamma camera images, and a 15, 30, and 60 minute anterior, right lateral and posterior scintiscan. Menstrual histories were obtained from all patients except two. No males (33/33), nor premenstrual (13/13), menopausal (4/4) or posthysterectomy (2/2) patients revealed a uterine blush. Eleven of 15 patients (73%) with regular menses demonstrated a uterine blush. They were in the menstrual or secretory phases of their cycle. Four demonstrated no uterine uptake, had regular periods, but were in the proliferative phase of their cycle. Two with irregular periods, and one with no recorded menstrual history, manifested the blush. Radiotracer should be expected in the uterus during the menstrual and secretory phases of the menstrual cycle. It is a manifestation of a normal physiologic phenomenon, and must be recognized to prevent false-positive Meckel's scan interpretations

  14. Combination of RNA- and exome-sequencing efficiently eliminates false-positive somatic point mutations and indels – exemplified by cases of CN-AML

    DEFF Research Database (Denmark)

    Herborg, Laura Laine; Hansen, Marcus Celik; Roug, Anne Stidsholt

    Thorough annotation as a means of detecting highly relevant mutations, and aberrated genes, is becoming more feasible as the evidence of biological pathways underlying malignant transformation compiles. However, there is a continuous risk of misinterpretating both true and false positive observat......Thorough annotation as a means of detecting highly relevant mutations, and aberrated genes, is becoming more feasible as the evidence of biological pathways underlying malignant transformation compiles. However, there is a continuous risk of misinterpretating both true and false positive...... in the workflow, not only provides information on malignant expression profiles excluded here, but importantly help to capture the, often very few somatic mutations of myeloid leukaemia....

  15. Detection of seven virulence and toxin genes of Campylobacter jejuni isolates from Danish turkeys by PCR and cytolethal distending toxin production of the isolates

    DEFF Research Database (Denmark)

    Bang, Dang Duong; Borck, Birgitte; Nielsen, Eva Møller

    2004-01-01

    A total of 117 Campylobacter jejuni isolates from Danish turkeys were tested for the presence of seven virulence and toxin genes by PCR. One hundred seventeen (100%) isolates were positive for flaA, cadF, and ceuE gene primers. One hundred three (88%) isolates were positive for cdt gene cluster PCR.......7%) in Colon 205 assays, and 109 (93.2%) in chicken embryo cell assays. The CDT titers were determined in Vero cell assays. Of 117 isolates, 50 (42.7%) produced a CDT titer of 1:100, 29 (24.8%) of 1:50, and 27 (23%) of 1:5 to 1:10; 8 (6.8%) produced a CDT titer at undiluted supernatants and 3 (2.6%) produced...

  16. PIP degron proteins, substrates of CRL4Cdt2, and not PIP boxes, interfere with DNA polymerase η and κ focus formation on UV damage

    OpenAIRE

    Tsanov, Nikolay; Kermi, Chames; Coulombe, Philippe; Van der Laan, Siem; Hodroj, Dana; Maiorano, Domenico

    2014-01-01

    Proliferating cell nuclear antigen (PCNA) is a well-known scaffold for many DNA replication and repair proteins, but how the switch between partners is regulated is currently unclear. Interaction with PCNA occurs via a domain known as a PCNA-Interacting Protein motif (PIP box). More recently, an additional specialized PIP box has been described, the « PIP degron », that targets PCNA-interacting proteins for proteasomal degradation via the E3 ubiquitin ligase CRL4Cdt2. Here we provide evidence...

  17. Occurrence of false positive results for the detection of carbapenemases in carbapenemase-negative Escherichia coli and Klebsiella pneumoniae isolates.

    Directory of Open Access Journals (Sweden)

    Peng Wang

    Full Text Available Adequate detection of the production of carbapenemase in Enterobacteriaceae isolates is crucial for infection control measures and the appropriate choice of antimicrobial therapy. In this study, we investigated the frequency of false positive results for the detection of carbapenemases in carbapenemase-negative Escherichia coli and Klebsiella pneumoniae clinical isolates by the modified Hodge test (MHT. Three hundred and one E. coli and K. pneumoniae clinical isolates were investigated. All produced extended spectrum β-lactamases (ESBLs but were susceptible to carbapenems. Antimicrobial susceptibility testing was performed by the disk diffusion and agar dilution methods. The MHT was performed using the standard inoculum of test organisms recommended by the CLSI. Genes that encoded ESBLs and carbapenemases were identified by PCR and DNA sequencing. Among the 301 clinical isolates, none of the isolates conformed to the criteria for carbapenemase screening recommended by the CLSI. The susceptibility rates for imipenem, meropenem, and ertapenem all were 100.0%, 100.0%, and 100.0%, respectively. Of the 301 E. coli and K. pneumoniae isolates, none produced carbapenemase. The MHT gave a positive result for 3.3% (10/301 of the isolates. False positive results can occur when the MHT is used to detect carbapenemase in ESBL-producing isolates and clinical laboratories must be aware of this fact.

  18. False Positive Radioiodinated Metaiodobenzylguanidine (123I-MIBG Uptake in Undifferentiated Adrenal Malignant Tumor

    Directory of Open Access Journals (Sweden)

    Hee Soo Jung

    2015-01-01

    Full Text Available 123I-Metaiodobenzylguanidine (123I-MIBG scintigraphy is a widely used functional imaging tool with a high degree of sensitivity and specificity in diagnosis of pheochromocytoma. However, rare cases of false positive reactions have been reported. A 67-year-old male patient was admitted with epigastric pain. Abdominal computed tomography (CT revealed a heterogeneous left adrenal mass 6 cm in diameter; following hormone testing, 123I-MIBG scintigraphy was performed to determine the presence of pheochromocytoma, which confirmed eccentric uptake by a large left adrenal gland mass. Chest CT and PET-CT confirmed metastatic lymphadenopathy; therefore, endobronchial ultrasound transbronchial needle aspiration was performed. Metastatic carcinoma of unknown origin was suspected from a lymph node biopsy, and surgical resection was performed for definitive diagnosis and correction of excess hormonal secretion. A final diagnosis of undifferentiated adrenal malignant tumor was rendered, instead of histologically malignant pheochromocytoma, despite the uptake of 123I-MIBG demonstrated by scintigraphy.

  19. Working memory affects false memory production for emotional events.

    Science.gov (United States)

    Mirandola, Chiara; Toffalini, Enrico; Ciriello, Alfonso; Cornoldi, Cesare

    2017-01-01

    Whereas a link between working memory (WM) and memory distortions has been demonstrated, its influence on emotional false memories is unclear. In two experiments, a verbal WM task and a false memory paradigm for negative, positive or neutral events were employed. In Experiment 1, we investigated individual differences in verbal WM and found that the interaction between valence and WM predicted false recognition, with negative and positive material protecting high WM individuals against false remembering; the beneficial effect of negative material disappeared in low WM participants. In Experiment 2, we lowered the WM capacity of half of the participants with a double task request, which led to an overall increase in false memories; furthermore, consistent with Experiment 1, the increase in negative false memories was larger than that of neutral or positive ones. It is concluded that WM plays a critical role in determining false memory production, specifically influencing the processing of negative material.

  20. Massive training artificial neural network (MTANN) for reduction of false positives in computerized detection of lung nodules in low-dose computed tomography

    International Nuclear Information System (INIS)

    Suzuki, Kenji; Armato, Samuel G. III; Li, Feng; Sone, Shusuke; Doi, Kunio

    2003-01-01

    In this study, we investigated a pattern-recognition technique based on an artificial neural network (ANN), which is called a massive training artificial neural network (MTANN), for reduction of false positives in computerized detection of lung nodules in low-dose computed tomography (CT) images. The MTANN consists of a modified multilayer ANN, which is capable of operating on image data directly. The MTANN is trained by use of a large number of subregions extracted from input images together with the teacher images containing the distribution for the 'likelihood of being a nodule'. The output image is obtained by scanning an input image with the MTANN. The distinction between a nodule and a non-nodule is made by use of a score which is defined from the output image of the trained MTANN. In order to eliminate various types of non-nodules, we extended the capability of a single MTANN, and developed a multiple MTANN (Multi-MTANN). The Multi-MTANN consists of plural MTANNs that are arranged in parallel. Each MTANN is trained by using the same nodules, but with a different type of non-nodule. Each MTANN acts as an expert for a specific type of non-nodule, e.g., five different MTANNs were trained to distinguish nodules from various-sized vessels; four other MTANNs were applied to eliminate some other opacities. The outputs of the MTANNs were combined by using the logical AND operation such that each of the trained MTANNs eliminated none of the nodules, but removed the specific type of non-nodule with which the MTANN was trained, and thus removed various types of non-nodules. The Multi-MTANN consisting of nine MTANNs was trained with 10 typical nodules and 10 non-nodules representing each of nine different non-nodule types (90 training non-nodules overall) in a training set. The trained Multi-MTANN was applied to the reduction of false positives reported by our current computerized scheme for lung nodule detection based on a database of 63 low-dose CT scans (1765

  1. Prime time news: the influence of primed positive and negative emotion on susceptibility to false memories.

    Science.gov (United States)

    Porter, Stephen; ten Brinke, Leanne; Riley, Sean N; Baker, Alysha

    2014-01-01

    We examined the relation between emotion and susceptibility to misinformation using a novel paradigm, the ambiguous stimuli affective priming (ASAP) paradigm. Participants (N = 88) viewed ambiguous neutral images primed either at encoding or retrieval to be interpreted as either highly positive or negative (or neutral/not primed). After viewing the images, they either were asked misleading or non-leading questions. Following a delay, memory accuracy for the original images was assessed. Results indicated that any emotional priming at encoding led to a higher susceptibility to misinformation relative to priming at recall. In particular, inducing a negative interpretation of the image at encoding led to an increased susceptibility of false memories for major misinformation (an entire object not actually present in the scene). In contrast, this pattern was reversed when priming was used at recall; a negative reinterpretation of the image decreased memory distortion relative to unprimed images. These findings suggest that, with precise experimental control, the experience of emotion at event encoding, in particular, is implicated in false memory susceptibility.

  2. The semantics of emotion in false memory.

    Science.gov (United States)

    Brainerd, C J; Bookbinder, S H

    2018-03-26

    The emotional valence of target information has been a centerpiece of recent false memory research, but in most experiments, it has been confounded with emotional arousal. We sought to clarify the results of such research by identifying a shared mathematical relation between valence and arousal ratings in commonly administered normed materials. That relation was then used to (a) decide whether arousal as well as valence influences false memory when they are confounded and to (b) determine whether semantic properties that are known to affect false memory covary with valence and arousal ratings. In Study 1, we identified a quadratic relation between valence and arousal ratings of words and pictures that has 2 key properties: Arousal increases more rapidly as function of negative valence than positive valence, and hence, a given level of negative valence is more arousing than the same level of positive valence. This quadratic function predicts that if arousal as well as valence affects false memory when they are confounded, false memory data must have certain fine-grained properties. In Study 2, those properties were absent from norming data for the Cornell-Cortland Emotional Word Lists, indicating that valence but not arousal affects false memory in those norms. In Study 3, we tested fuzzy-trace theory's explanation of that pattern: that valence ratings are positively related to semantic properties that are known to increase false memory, but arousal ratings are not. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  3. Audit of the autoantibody test, EarlyCDT®-lung, in 1600 patients: an evaluation of its performance in routine clinical practice.

    Science.gov (United States)

    Jett, James R; Peek, Laura J; Fredericks, Lynn; Jewell, William; Pingleton, William W; Robertson, John F R

    2014-01-01

    EarlyCDT(®)-Lung may enhance detection of early stage lung cancer by aiding physicians in assessing high-risk patients through measurement of biological markers (i.e., autoantibodies). The test's performance characteristics in routine clinical practice were evaluated by auditing clinical outcomes of 1613 US patients deemed at high risk for lung cancer by their physician, who ordered the EarlyCDT-Lung test for their patient. Clinical outcomes for all 1613 patients who provided HIPAA authorization are reported. Clinical data were collected from each patient's treating physician. Pathology reports when available were reviewed for diagnostic classification. Staging was assessed on histology, otherwise on imaging. Six month follow-up for the positives/negatives was 99%/93%. Sixty-one patients (4%) were identified with lung cancer, 25 of whom tested positive by EarlyCDT-Lung (sensitivity=41%). A positive EarlyCDT-Lung test on the current panel was associated with a 5.4-fold increase in lung cancer incidence versus a negative. Importantly, 57% (8/14) of non-small cell lung cancers detected as positive (where stage was known) were stage I or II. EarlyCDT-Lung has been extensively tested and validated in case-control settings and has now been shown in this audit to perform in routine clinical practice as predicted. EarlyCDT-Lung may be a complementary tool to CT for detection of early lung cancer. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  4. Physical and biological data collected with CDT, fluorometer, and SeaSoar aboard the ship WECOMA as part of Global Ocean Ecosystem Dynamics (GLOBEC) in the North Pacific Ocean from May 30 to June 16 2000 (NODC Accession 0000986)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical and biological data collected with CDT, fluorometer, and SeaSoar aboard the ship WECOMA in the North Pacific Ocean from May 30 to June 16 2000. These data...

  5. How does negative emotion cause false memories?

    Science.gov (United States)

    Brainerd, C J; Stein, L M; Silveira, R A; Rohenkohl, G; Reyna, V F

    2008-09-01

    Remembering negative events can stimulate high levels of false memory, relative to remembering neutral events. In experiments in which the emotional valence of encoded materials was manipulated with their arousal levels controlled, valence produced a continuum of memory falsification. Falsification was highest for negative materials, intermediate for neutral materials, and lowest for positive materials. Conjoint-recognition analysis produced a simple process-level explanation: As one progresses from positive to neutral to negative valence, false memory increases because (a) the perceived meaning resemblance between false and true items increases and (b) subjects are less able to use verbatim memories of true items to suppress errors.

  6. False Memories for Affective Information in Schizophrenia.

    Science.gov (United States)

    Fairfield, Beth; Altamura, Mario; Padalino, Flavia A; Balzotti, Angela; Di Domenico, Alberto; Mammarella, Nicola

    2016-01-01

    Studies have shown a direct link between memory for emotionally salient experiences and false memories. In particular, emotionally arousing material of negative and positive valence enhanced reality monitoring compared to neutral material since emotional stimuli can be encoded with more contextual details and thereby facilitate the distinction between presented and imagined stimuli. Individuals with schizophrenia appear to be impaired in both reality monitoring and memory for emotional experiences. However, the relationship between the emotionality of the to-be-remembered material and false memory occurrence has not yet been studied. In this study, 24 patients and 24 healthy adults completed a false memory task with everyday episodes composed of 12 photographs that depicted positive, negative, or neutral outcomes. Results showed how patients with schizophrenia made a higher number of false memories than normal controls ( p  false memories ( p  > 0.05) resulting from erroneous inferences but did interact with plausible, script consistent errors in patients (i.e., neutral episodes yielded a higher degree of errors than positive and negative episodes). Affective information reduces the probability of generating causal errors in healthy adults but not in patients suggesting that emotional memory impairments may contribute to deficits in reality monitoring in schizophrenia when affective information is involved.

  7. False Memories for Affective Information in Schizophrenia

    Science.gov (United States)

    Fairfield, Beth; Altamura, Mario; Padalino, Flavia A.; Balzotti, Angela; Di Domenico, Alberto; Mammarella, Nicola

    2016-01-01

    Studies have shown a direct link between memory for emotionally salient experiences and false memories. In particular, emotionally arousing material of negative and positive valence enhanced reality monitoring compared to neutral material since emotional stimuli can be encoded with more contextual details and thereby facilitate the distinction between presented and imagined stimuli. Individuals with schizophrenia appear to be impaired in both reality monitoring and memory for emotional experiences. However, the relationship between the emotionality of the to-be-remembered material and false memory occurrence has not yet been studied. In this study, 24 patients and 24 healthy adults completed a false memory task with everyday episodes composed of 12 photographs that depicted positive, negative, or neutral outcomes. Results showed how patients with schizophrenia made a higher number of false memories than normal controls (p false memories (p > 0.05) resulting from erroneous inferences but did interact with plausible, script consistent errors in patients (i.e., neutral episodes yielded a higher degree of errors than positive and negative episodes). Affective information reduces the probability of generating causal errors in healthy adults but not in patients suggesting that emotional memory impairments may contribute to deficits in reality monitoring in schizophrenia when affective information is involved. PMID:27965600

  8. Radiodine administration under suppression of TSH for identification of false positive receptions in patients with thyroid differentiated carcinoma (TDC): utility of the potassium perchlorate

    International Nuclear Information System (INIS)

    Santangelo, L.A.; Pitoia, F.; Sanz, C.; Niepomniszcze, H.; El Tamer, Elias

    2004-01-01

    The total body scan, after a dose of 131 I correlated with the measurement of stimulated Tg, constitute the principal pillars in follow-up of patients with TDC (thyroid differentiated carcinoma). A bibliographical search revealed more than 70 situations that can cause false total body scans positive. The examination is essential to avoid unnecessary treatment with radioiodine. The object is to evaluate the effectiveness of the radioiodine administration under hormonal therapy thyroid suppressive (THST) to eliminate the possibility of a false total body scan positive in five patients with TDC with stimulated Tg <1ng/ml

  9. Effects of depressive disorder on false memory for emotional information.

    Science.gov (United States)

    Yeh, Zai-Ting; Hua, Mau-Sun

    2009-01-01

    This study explored with a false memory paradigm whether (1) depressed patients revealed more false memories and (2) whether more negative false than positive false recognition existed in subjects with depressive disorders. Thirty-two patients suffering from a major depressive episode (DSM-IV criteria), and 30 age- and education-matched normal control subjects participated in this study. After the presentation of a list of positive, negative, and neutral association items in the learning phase, subjects were asked to give a yes/no response in the recognition phase. They were also asked to rate 81 recognition items with emotional valence scores. The results revealed more negative false memories in the clinical depression group than in the normal control group; however, we did not find more negative false memories than positive ones in patients. When compared with the normal group, a more conservative response criterion for positive items was evident in patient groups. It was also found that when compared with the normal group, the subjects in the depression group perceived the positive items as less positive. On the basis of present results, it is suggested that depressed subjects judged the emotional information with criteria different from normal individuals, and patients' emotional memory intensity is attenuated by their mood.

  10. Breast cancer risk is increased in the years following false-positive breast cancer screening.

    Science.gov (United States)

    Goossens, Mathijs C; De Brabander, Isabel; De Greve, Jacques; Vaes, Evelien; Van Ongeval, Chantal; Van Herck, Koen; Kellen, Eliane

    2017-09-01

    A small number of studies have investigated breast cancer (BC) risk among women with a history of false-positive recall (FPR) in BC screening, but none of them has used time-to-event analysis while at the same time quantifying the effect of false-negative diagnostic assessment (FNDA). FNDA occurs when screening detects BC, but this BC is missed on diagnostic assessment (DA). As a result of FNDA, screenings that detected cancer are incorrectly classified as FPR. Our study linked data recorded in the Flemish BC screening program (women aged 50-69 years) to data from the national cancer registry. We used Cox proportional hazards models on a retrospective cohort of 298 738 women to assess the association between FPR and subsequent BC, while adjusting for potential confounders. The mean follow-up was 6.9 years. Compared with women without recall, women with a history of FPR were at an increased risk of developing BC [hazard ratio=2.10 (95% confidence interval: 1.92-2.31)]. However, 22% of BC after FPR was due to FNDA. The hazard ratio dropped to 1.69 (95% confidence interval: 1.52-1.87) when FNDA was excluded. Women with FPR have a subsequently increased BC risk compared with women without recall. The risk is higher for women who have a FPR BI-RADS 4 or 5 compared with FPR BI-RADS 3. There is room for improvement of diagnostic assessment: 41% of the excess risk is explained by FNDA after baseline screening.

  11. Proportion of false-positive lesions at interim and end-of-treatment FDG-PET in lymphoma as determined by histology: Systematic review and meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Hugo J.A., E-mail: h.j.a.adams@gmail.com; Kwee, Thomas C.

    2016-11-15

    Purpose: To systematically review and meta-analyze the proportion of false-positive lesions at interim and end-of-treatment {sup 18}F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) in lymphoma using biopsy as reference standard. Materials and methods: Medline was searched for original studies. Methodological quality of included studies was evaluated, and results were meta-analytically summarized using random effects (in case of interstudy heterogeneity [I{sup 2} ≤ 50%]) or fixed effects (in case of no interstudy heterogeneity [I{sup 2} > 50%]). Results: Eleven studies, comprising 139 patients who underwent biopsy of an FDG-avid lesion during or after completion of antilymphoma treatment, were included. Overall methodological quality was moderate. The proportion of false-positive results among all biopsied FDG-avid lesions at PET performed during of after completion of treatment ranged between 7.7% and 90.5% (the vast majority was due to inflammatory changes), with a weighted summary proportion (random effects, I{sup 2} = 75.7%) of 55.7% (95% confidence interval [CI]: 32.6–76.6%). There were no available studies on interim FDG-PET in Hodgkin lymphoma. The pooled summary false-positive proportions were 83.0% (95% CI: 72.0%–90.2%) for interim FDG-PET in non-Hodgkin lymphoma (fixed effects, I{sup 2} = 27.7%), 23.1% (95% CI: 4.7%–64.5%) for end-of-treatment FDG-PET in Hodgkin lymphoma (random effects; I{sup 2} = 67.1%), and 31.5% (95% CI: 3.9%–83.9%) for end-of-treatment FDG-PET in non-Hodgkin lymphoma (random effects, I{sup 2} = 68.3%). Conclusion: Both interim and end-of-treatment FDG-PET scans in patients with lymphoma suffer from a very high number of false-positive FDG-avid lesions. This finding, in combination with the previously reported high number of false-negative FGD-PET scans for residual disease detection, suggests that the role of interim and end-of-treatment FDG-PET should be reconsidered.

  12. Improved accuracy of cell surface shaving proteomics in Staphylococcus aureus using a false-positive control

    DEFF Research Database (Denmark)

    Solis, Nestor; Larsen, Martin Røssel; Cordwell, Stuart J

    2010-01-01

    Proteolytic treatment of intact bacterial cells is an ideal means for identifying surface-exposed peptide epitopes and has potential for the discovery of novel vaccine targets. Cell stability during such treatment, however, may become compromised and result in the release of intracellular proteins...... that complicate the final analysis. Staphylococcus aureus is a major human pathogen, causing community and hospital-acquired infections, and is a serious healthcare concern due to the increasing prevalence of multiple antibiotic resistances amongst clinical isolates. We employed a cell surface "shaving" technique...... to trypsin and three identified in the control. The use of a subtracted false-positive strategy improved enrichment of surface-exposed peptides in the trypsin data set to approximately 80% (124/155 peptides). Predominant surface proteins were those associated with methicillin resistance-surface protein SACOL...

  13. Potential Bedside Utility of the Clock-Drawing Test in Evaluating Rapid Therapeutic Response in the Natural Course of Schizophrenia: A Preliminary Study.

    Science.gov (United States)

    Ransing, Ramdas Sarjerao; Khairkar, Praveen Homdeorao; Mishra, Kshirod; Sakekar, Gajanan

    2017-01-01

    The Clock-Drawing Test (CDT) is a brief, relatively time-efficient, easy to administer at bedside, and well-proven cognitive screening test that assesses a broad range of cognitive abilities in stroke, delirium, and dementia. However, challenges of comprehensive therapeutic outcome evaluations in schizophrenia can also be potentially overcome using CDT. The authors aimed to measure the therapeutic outcome using CDT in 101 schizophrenia patients, irrespective of their diagnostic subtypes. A repeated measures analysis of variance found that improvements on CDT and the Positive and Negative Syndrome Scale were closely correlated, reflecting critical information about therapeutic response measures in schizophrenia.

  14. Suppressor Analysis of CRL4Cdt2 Defective and cdc48-353 Temperature Sensitive Mutants in Fission Yeast

    DEFF Research Database (Denmark)

    Marinova, Irina Nikolaeva

    chaperone-like complex involved in numerous cellular processes, including protein degradation, cell cycle control, DNA repair, and vesicle fusion. The cdc48 gene is essential in fission yeast and mutations or changes in Cdc48/p97 protein expression have been linked to neurological disorders and cancer......SummaryPart 1CRL4Cdt2 E3 ligase is a key regulator of cellular proliferation and genome integrity, as it promotes the degradation of proteins involved in cell cycle progression, DNA replication and repair. In fission yeast the small intrinsically disordered protein Spd1 is targeted for degradation...... that these mutations alleviate the checkpoint dependency, the DNA damage sensitivity and the meiotic defects associated with Spd1 accumulation. Further analysis showed that whereas the V40G and S43L substitutions do not have a significant impact on Suc22R2 nuclear import function of Spd1, they affect the interaction...

  15. Carbohydrate-deficient transferrin--a valid marker of alcoholism in population studies? Results from the Copenhagen City Heart Study

    DEFF Research Database (Denmark)

    Grønbaek, M; Becker, U; Henriksen, Jens Henrik Sahl

    1995-01-01

    Carbohydrate-deficient transferrin (CDT) was analyzed by a modified radioimmunoassay test in a random population sample of 400 individuals, and results were compared with reported alcohol intake derived from a structured questionnaire. Among the 180 men, the test was found to be acceptable...... with respect to detecting harmful alcohol intake (> 35 beverages/week) and alcohol intake above the recommended level (21 beverages/week), although the positive predictive values were low. Among the 220 women, the test was invalid with low predictive values. CDT was compared with other known markers of high...... alcohol intake, and it was observed that CDT had higher sensitivity and specificity than AST and short Michigan Alcoholism Screening Test (sMAST) in men, whereas the positive and negative predictive values were low in all tests. A combination of CDT and AST proved to be a better marker of both harmful...

  16. The False Premises and False Promises of the Movement to Privatize Public Education.

    Science.gov (United States)

    Hawley, Willis D.

    1995-01-01

    Argues that the movement to provide parents with financial incentives to send students to private schools will increase the racial, ethnic, and socioeconomic homogeneity of American schools. Six common assumptions about the positive effects of privatizing education are examined and deemed false. Probable costs of tuition vouchers for private…

  17. [EXPERIENCE OF STUDY AND POSSIBLE WAYS OF ELIMINATION OF FALSE POSITIVE AND FALSE NEGATIVE RESULTS DURING EXECUTION OF POLYMERASE CHAIN REACTION ON AN EXAMPLE OF JUNIN VIRUS RNA DETECTION].

    Science.gov (United States)

    Sizikova, T E; Lebedev, V N; Pantyukhov, V B; Borisevich, S V; Merkulov, V A

    2015-01-01

    Experience of study and possible ways of elimination of false positive and false negative results during execution of polymerase chain reaction on an example of Junin virus RNA detection. MATERIALSS AND METHODS: Junin virus--causative agent of Argentine hemorrhagic fever (AHF) strain XJpR37/5787 was obtained from the State collection of pathogenicity group I causative agents of the 48th Central Research Institute. Reagent kit for detection of Junin virus RNA by RT-PCR was developed in the Institute and consists of 4 sets: for isolation of RNA, execution of reverse-transcription reaction, execution of PCR and electrophoretic detection of PCR products. RT-PCR was carried out by a standard technique. Continuous cell cultures of African green monkey Vero B, GMK-AH-1(D) were obtained from the museum of cell culture department of the Centre. An experimental study of the effect of various factors of impact on the sample under investigation ("thawing-freezing", presence of formaldehyde, heparin) on the obtaining of false negative results during Junin virus RNA detection by using RT-PCR was studied. Addition of 0.01% heparin to the samples was shown to completely inhibit PCR. Addition of 0.05% formaldehyde significantly reduces sensitivity of the method. A possibility of reduction of analysis timeframe from 15 to 5 days was shown during detection of the causative agent in samples with low concentration of the latter by growing the samples and subsequent analysis of the material obtained by using RT-PCR. During detection of causative agent by using RT-PCR false negative results could appear in the presence of formaldehyde and heparin in the sample. A possibility of elimination of false negative PCR results due to concentration of the causative agent in the sample under investigation at a level below sensitivity threshold was shown on the example of Junin virus RNA detection by using growing of the pathogen in appropriate accumulation system with subsequent analysis of the

  18. Emotions and false memories: valence or arousal?

    Science.gov (United States)

    Corson, Yves; Verrier, Nadège

    2007-03-01

    The effects of mood on false memories have not been studied systematically until recently. Some results seem to indicate that negative mood may reduce false recall and thus suggest an influence of emotional valence on false memory. The present research tested the effects of both valence and arousal on recall and recognition and indicates that the effect is actually due to arousal. In fact, whether participants' mood is positive, negative, or neutral, false memories are significantly more frequent under conditions of high arousal than under conditions of low arousal.

  19. False positive results using calcitonin as a screening method for medullary thyroid carcinoma

    Directory of Open Access Journals (Sweden)

    Rafael Loch Batista

    2013-01-01

    Full Text Available The role of serum calcitonin as part of the evaluation of thyroid nodules has been widely discussed in literature. However there still is no consensus of measurement of calcitonin in the initial evaluation of a patient with thyroid nodule. Problems concerning cost-benefit, lab methods, false positive and low prevalence of medullary thyroid carcinoma (MTC are factors that limit this approach. We have illustrated two cases where serum calcitonin was used in the evaluation of thyroid nodule and rates proved to be high. A stimulation test was performed, using calcium as secretagogue, and calcitonin hyper-stimulation was confirmed, but anatomopathologic examination did not evidence medullar neoplasia. Anatomopathologic diagnosis detected Hashimoto thyroiditis in one case and adenomatous goiter plus an occult papillary thyroid carcinoma in the other one. Recommendation for routine use of serum calcitonin in the initial diagnostic evaluation of a thyroid nodule, followed by a confirming stimulation test if basal serum calcitonin is showed to be high, is the most currently recommended approach, but questions concerning cost-benefit and possibility of diagnosis error make the validity of this recommendation discussible.

  20. False memories for affective information in Schizophrenia

    Directory of Open Access Journals (Sweden)

    Beth Fairfield

    2016-11-01

    Full Text Available Studies have shown a direct link between memory for emotionally salient experiences and false memories. In particular, emotionally arousing material of negative and positive valence enhanced reality monitoring compared to neutral material since emotional stimuli can be encoded with more contextual details and thereby facilitate the distinction between presented and imagined stimuli. Individuals with schizophrenia appear to be impaired in both reality monitoring and memory for emotional experiences. However, the relationship between the emotionality of the-to-be-remembered material and false memory occurrence has not yet been studied. In this study, twenty-four patients and twenty-four healthy adults completed a false memory task with everyday episodes composed of 12 photographs that depicted positive, negative or neutral outcomes. Results showed how patients with schizophrenia made a higher number of false memories than normal controls (p0.05 resulting from erroneous inferences but did interact with plausible, script consistent errors in patients (i.e. neutral episodes yielded a higher degree of errors than positive and negative episodes. Affective information reduces the probability of generating causal errors in healthy adults but not in patients suggesting that emotional memory impairments may contribute to deficits in reality monitoring in schizophrenia when affective information is involved.

  1. Next-generation sequencing indicates false-positive MRD results and better predicts prognosis after SCT in patients with childhood ALL.

    Science.gov (United States)

    Kotrova, M; van der Velden, V H J; van Dongen, J J M; Formankova, R; Sedlacek, P; Brüggemann, M; Zuna, J; Stary, J; Trka, J; Fronkova, E

    2017-07-01

    Minimal residual disease (MRD) monitoring via quantitative PCR (qPCR) detection of Ag receptor gene rearrangements has been the most sensitive method for predicting prognosis and making post-transplant treatment decisions for patients with ALL. Despite the broad clinical usefulness and standardization of this method, we and others have repeatedly reported the possibility of false-positive MRD results caused by massive B-lymphocyte regeneration after stem cell transplantation (SCT). Next-generation sequencing (NGS) enables precise and sensitive detection of multiple Ag receptor rearrangements, thus providing a more specific readout compared to qPCR. We investigated two cohorts of children with ALL who underwent SCT (30 patients and 228 samples). The first cohort consisted of 17 patients who remained in long-term CR after SCT despite having low MRD positivity (SCT monitoring using qPCR. Only one of 27 qPCR-positive samples was confirmed to be positive by NGS. Conversely, 10 of 15 samples with low qPCR-detected MRD positivity from 13 patients who subsequently relapsed were also confirmed to be positive by NGS (P=0.002). These data show that NGS has a better specificity in post-SCT ALL management and indicate that treatment interventions aimed at reverting impending relapse should not be based on qPCR only.

  2. Myositis ossificans: a false positive of malignancy in PET - CT F.D.G. and in osseous scintigraphy with HMDP 99Tc

    International Nuclear Information System (INIS)

    Hassler, S.; Bourahla, K.

    2010-01-01

    Myositis ossificans is a difficult differential diagnosis and a false positive for malignancy in both 99m Tc H.M.D.P. (hydroxy-methylene diphosphonate) scintigraphy and in exploration PET-F.D.G. This hypothesis should be mentioned in case of young patients, despite the unusual scintigraphic appearance in a benign process. (N.C.)

  3. False-positive liver scans due to portal hypertension: correlation with percutaneous transhepatic portograms in 33 patients

    International Nuclear Information System (INIS)

    Takayasu, K.; Moriyama, N.; Suzuki, M.; Yamada, T.; Fukutake, T.; Shima, Y.; Kobayashi, C.; Musha, H.; Okuda, K.

    1983-01-01

    Tc-99m-phytate scanning of the liver and percutaneous transhepatic catheterization of the portal vein were performed in 33 patients--26 with cirrhosis, 3 with chronic active hepatitis, 2 with idiopathic portal hypertension, and 2 with unresolved acute hepatitis. A discrete defect in the porta hepatis area was seen in 6 of 28 patients who had portal vein pressure above 200 mm H2O. In 5 of the 6 patients with a false-positive scan, the umbilical portion of the left portal vein branch was dilated (larger than 25 x 20 mm) on the portogram, with or without a patent paraumbilical vein. The anatomical basis of this phenomenon is discussed, and it is suggested that this area be given special attention

  4. High prevalence of human anti-bovine IgG antibodies as the major cause of false positive reactions in two-site immunoassays based on monoclonal antibodies

    DEFF Research Database (Denmark)

    Andersen, Ditte C; Koch, Claus; Jensen, Charlotte H

    2004-01-01

    were purified by protein G affinity chromatography from culture supernatant containing 10% (v/v) fetal calf serum (FCS). Human anti-animal IgG (bovine, mouse, horse, and swine) antibodies and human anti-bovine serum albumin antibodies were measured using an ELISA design, with direct bridging...... of the solid phase and biotinylated antigens. The false positive reactions were abolished by addition of 1% (v/v) bovine serum to the dilution buffer (DB). Human anti-bovine IgG antibodies (HABIA) were detected in 99 out of 104 sera from blood donors (50 females; 54 males). HABIA levels in male sera (n = 54......) were positively correlated to the false positive signals in the PP14 ELISA (r = 0.923; p detected in the donor sera, but levels and frequencies were lower compared to that of HABIA. Furthermore, HABIA were...

  5. Too Good to be False : Nonsignificant Results Revisited

    NARCIS (Netherlands)

    Hartgerink, Chris H J; Wicherts, Jelte M.; Van Assen, M. A. L. M.

    2017-01-01

    Due to its probabilistic nature, Null Hypothesis Significance Testing (NHST) is subject to decision errors. The concern for false positives has overshadowed the concern for false negatives in the recent debates in psychology. This might be unwarranted, since reported statistically nonsignificant

  6. False Positive Findings on I-131 WBS and SPECT/CT in Patients with History of Thyroid Cancer: Case Series

    Directory of Open Access Journals (Sweden)

    Zeina C. Hannoush

    2017-01-01

    Full Text Available Introduction. Although whole body scan (WBS with I-131 is a highly sensitive tool for detecting normal thyroid tissue and metastasis of differentiated thyroid cancer (DTC, it is not specific. Additional information, provided by single photon emission computed tomography combined with X-ray computed tomography (SPECT/CT and by the serum thyroglobulin level, is extremely useful for the interpretation of findings. Case Presentation. We report four cases of false positive WBS in patients with DTC: ovarian uptake corresponding to an endometrioma, scrotal uptake due to a spermatocele, rib-cage uptake due to an old fracture, and hepatic and renal uptake secondary to a granuloma and simple cyst, respectively. Conclusions. Trapping, organification, and storage of iodine are more prominent in thyroid tissue but not specific. Physiologic sodium-iodine symporter expression in other tissues explains some, but not all, of the WBS false positive cases. Other proposed etiologies are accumulation of radioiodine in inflamed organs, metabolism of radiodinated thyroid hormone, presence of radioiodine in body fluids, and contamination. In our cases nonthyroidal pathologies were suspected since the imaging findings were not corroborated by an elevated thyroglobulin level, which is considered a reliable tumor marker for most well-differentiated thyroid cancers. Clinicians should be aware of the potential pitfalls of WBS in DTC to avoid incorrect management.

  7. The uterine blush. A potential false-positive in Meckel's scan interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Fink-Bennett, D.

    1982-10-01

    To determine the presence, prevalence, and clinical importance of /sup 99m/Tc pertechnetate uterine uptake, this retrospective analysis of 71 Meckel's scans was undertaken. Specifically, each study was evaluated for the presence of a focal accumulation of radiotracer cephalad to the bladder. Patients received an intravenous dose of 150 microCi/kg of /sup 99m/Tc pertechnetate. Each study consisted of 15 one minute anterior serial gamma camera images, and a 15, 30, and 60 minute anterior, right lateral and posterior scintiscan. Menstrual histories were obtained from all patients except two. No males (33/33), nor premenstrual (13/13), menopausal (4/4) or posthysterectomy (2/2) patients revealed a uterine blush. Eleven of 15 patients (73%) with regular menses demonstrated a uterine blush. They were in the menstrual or secretory phases of their cycle. Four demonstrated no uterine uptake, had regular periods, but were in the proliferative phase of their cycle. Two with irregular periods, and one with no recorded menstrual history, manifested the blush. Radiotracer should be expected in the uterus during the menstrual and secretory phases of the menstrual cycle. It is a manifestation of a normal physiologic phenomenon, and must be recognized to prevent false-positive Meckel's scan interpretations.

  8. Trial sequential analysis reveals insufficient information size and potentially false positive results in many meta-analyses

    DEFF Research Database (Denmark)

    Brok, J.; Thorlund, K.; Gluud, C.

    2008-01-01

    in 80% (insufficient information size). TSA(15%) and TSA(LBHIS) found that 95% and 91% had absence of evidence. The remaining nonsignificant meta-analyses had evidence of lack of effect. CONCLUSION: TSA reveals insufficient information size and potentially false positive results in many meta......OBJECTIVES: To evaluate meta-analyses with trial sequential analysis (TSA). TSA adjusts for random error risk and provides the required number of participants (information size) in a meta-analysis. Meta-analyses not reaching information size are analyzed with trial sequential monitoring boundaries...... analogous to interim monitoring boundaries in a single trial. STUDY DESIGN AND SETTING: We applied TSA on meta-analyses performed in Cochrane Neonatal reviews. We calculated information sizes and monitoring boundaries with three different anticipated intervention effects of 30% relative risk reduction (TSA...

  9. Minimotif Miner 3.0: database expansion and significantly improved reduction of false-positive predictions from consensus sequences.

    Science.gov (United States)

    Mi, Tian; Merlin, Jerlin Camilus; Deverasetty, Sandeep; Gryk, Michael R; Bill, Travis J; Brooks, Andrew W; Lee, Logan Y; Rathnayake, Viraj; Ross, Christian A; Sargeant, David P; Strong, Christy L; Watts, Paula; Rajasekaran, Sanguthevar; Schiller, Martin R

    2012-01-01

    Minimotif Miner (MnM available at http://minimotifminer.org or http://mnm.engr.uconn.edu) is an online database for identifying new minimotifs in protein queries. Minimotifs are short contiguous peptide sequences that have a known function in at least one protein. Here we report the third release of the MnM database which has now grown 60-fold to approximately 300,000 minimotifs. Since short minimotifs are by their nature not very complex we also summarize a new set of false-positive filters and linear regression scoring that vastly enhance minimotif prediction accuracy on a test data set. This online database can be used to predict new functions in proteins and causes of disease.

  10. Clinical evaluation of false-positive scintigraphic lesions of the left lobe in portal hypertension. Comparison with portographic findings of the pars umbilicus of the portal vein

    Energy Technology Data Exchange (ETDEWEB)

    Takayasu, Kenichi; Moriyama, Noriyuki; Suzuki, Masao; Yamada, Tatsuya [National Cancer Center, Tokyo (Japan). Hospital; Fukutake, Toshio

    1982-09-01

    sup(99m)Tc-phytate liver scan and percutaneous transhepatic portography (PTP) were performed in 33 patients with portal hypertension due to various hepatic diseases. A defect or space occupying lesion in the left lobe on the scan in these patients was analysed with reference to portographic changes of the pars umbilicus of the left portal vein and the following results were obtained. 1) A false-positive defect on the scintigram was found in 6 (18.2%) of 33 patients, and portal vein pressure (PVP) was above 200 mmH/sub 2/O in all 6 which constituted 21.4% of 28 with PVP above 200 mmH/sub 2/O. 2) In five out of 6 patients with false-positive scan findings, the pars umbilicus was dilated to more than 25 x 15 mm in size, and it was huge and tortuous in 3 of them. 3) The mean PVP in the group with a false-positive scan tended to be higher than that in patients with no abnormalities on the scintigram. It was concluded that in reading of liver scintigrams in patients with portal hypertension, a dilated pars umbilicus and huge para-umbilical vein should be considered.

  11. [False positive serum des-gamma-carboxy prothrombin after resection of hepatocellular carcinoma].

    Science.gov (United States)

    Hiramatsu, Kumiko; Tanaka, Yasuhito; Takagi, Kazumi; Iida, Takayasu; Takasaka, Yoshimitsu; Mizokami, Masashi

    2007-04-01

    Measurements of serum concentrations of des-gamma-carboxy-prothrombin (PIVKA-II) are widely used for diagnosing hepatocellular carcinoma (HCC). Recently, when we evaluated the correlation of PIVKA-II between two commercially available PIVKA-II immunoassay kits (Lumipulse f vs. Picolumi) to introduce it in our hospital, false high values of PIVKA-II were observed in Lumipulse assay. Four(4%) of 100 serum samples showed false high values, and all of them were obtained from patients less than 2 month after curative resection of HCC. Examining additional 7 patients with HCC resection, serum samples from the 5 patients had the same trend. To elucidate the non-specific reaction by Lumipulse assay which utilized alkaline phosphatase (ALP) enzymatic reaction, inhibition assays by various absorbents such as inactive ALP and IgM antibodies were performed. Excess of inactive ALP reduced the high values of PIVKA-II. Note that anti-bleeding sheets (fibrinogen combined drug), which included bovine thrombin, were directly attached on liver of all patients with HCC resection in this study. As the sheets also contaminate ALP and probably produce IgM antibodies to ALP, the IgM may cross-react with anti-PIVKA-II antibodies directly. Taken together, it was suggested that produced antibodies against ALP derived from anti-bleeding sheets led false high values of PIVKA-II in the patients with HCC resection.

  12. Psychoactive drugs and false memory: comparison of dextroamphetamine and delta-9-tetrahydrocannabinol on false recognition

    Science.gov (United States)

    Ballard, Michael E.; Gallo, David A.; de Wit, Harriet

    2014-01-01

    Rationale Several psychoactive drugs are known to influence episodic memory. However, these drugs’ effects on false memory, or the tendency to incorrectly remember nonstudied information, remain poorly understood. Objectives Here, we examined the effects of two commonly used psychoactive drugs, one with memory-enhancing properties (dextroamphetamine; AMP), and another with memory-impairing properties (Δ9-tetrahydrocannabinol; THC), on false memory using the Deese/Roediger–McDermott (DRM) illusion. Methods Two parallel studies were conducted in which healthy volunteers received either AMP (0, 10, and 20 mg) or THC (0, 7.5, and 15 mg) in within-subjects, randomized, double-blind designs. Participants studied DRM word lists under the influence of the drugs, and their recognition memory for the studied words was tested 2 days later, under sober conditions. Results As expected, AMP increased memory of studied words relative to placebo, and THC reduced memory of studied words. Although neither drug significantly affected false memory relative to placebo, AMP increased false memory relative to THC. Across participants, both drugs’ effects on true memory were positively correlated with their effects on false memory. Conclusions Our results indicate that AMP and THC have opposing effects on true memory, and these effects appear to correspond to similar, albeit more subtle, effects on false memory. These findings are consistent with previous research using the DRM illusion and provide further evidence that psychoactive drugs can affect the encoding processes that ultimately result in the creation of false memories. PMID:21647577

  13. Psychoactive drugs and false memory: comparison of dextroamphetamine and δ-9-tetrahydrocannabinol on false recognition.

    Science.gov (United States)

    Ballard, Michael E; Gallo, David A; de Wit, Harriet

    2012-01-01

    Several psychoactive drugs are known to influence episodic memory. However, these drugs' effects on false memory, or the tendency to incorrectly remember nonstudied information, remain poorly understood. Here, we examined the effects of two commonly used psychoactive drugs, one with memory-enhancing properties (dextroamphetamine; AMP), and another with memory-impairing properties (Δ(9)-tetrahydrocannabinol; THC), on false memory using the Deese/Roediger-McDermott (DRM) illusion. Two parallel studies were conducted in which healthy volunteers received either AMP (0, 10, and 20 mg) or THC (0, 7.5, and 15 mg) in within-subjects, randomized, double-blind designs. Participants studied DRM word lists under the influence of the drugs, and their recognition memory for the studied words was tested 2 days later, under sober conditions. As expected, AMP increased memory of studied words relative to placebo, and THC reduced memory of studied words. Although neither drug significantly affected false memory relative to placebo, AMP increased false memory relative to THC. Across participants, both drugs' effects on true memory were positively correlated with their effects on false memory. Our results indicate that AMP and THC have opposing effects on true memory, and these effects appear to correspond to similar, albeit more subtle, effects on false memory. These findings are consistent with previous research using the DRM illusion and provide further evidence that psychoactive drugs can affect the encoding processes that ultimately result in the creation of false memories.

  14. Benign thyroid and neck lesions mimicking malignancy with false positive findings on positron emission tomography-computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Ye Ri; Kim, Shin Young; Lee, Sang Mi [Soonchunhyang University Cheonan Hospital, Cheonan (Korea, Republic of); Lee, Deuk Young [Dept. of Surgery, Younsei Angelot Women' s Clinic, Cheonan (Korea, Republic of)

    2017-02-15

    The increasing use of positron emission tomography-computed tomography (PET/CT) has led to the frequent detection of incidental thyroid and neck lesions with increased 18F-deoxyglucose (FDG) uptake. Although lesions with increased FDG uptake are commonly assumed to be malignant, benign lesions may also exhibit increased uptake. The purpose of this pictorial essay is to demonstrate that benign thyroid and neck lesions can produce false-positive findings on PET/CT, and to identify various difficulties in interpretation. It is crucial to be aware that differentiating between benign and malignant lesions is difficult in a considerable proportion of cases, when relying only on PET/CT findings. Correlation of PET/CT findings with additional imaging modalities is essential to avoid misdiagnosis.

  15. Evaluation of HIV testing algorithms in Ethiopia: the role of the tie-breaker algorithm and weakly reacting test lines in contributing to a high rate of false positive HIV diagnoses.

    Science.gov (United States)

    Shanks, Leslie; Siddiqui, M Ruby; Kliescikova, Jarmila; Pearce, Neil; Ariti, Cono; Muluneh, Libsework; Pirou, Erwan; Ritmeijer, Koert; Masiga, Johnson; Abebe, Almaz

    2015-02-03

    In Ethiopia a tiebreaker algorithm using 3 rapid diagnostic tests (RDTs) in series is used to diagnose HIV. Discordant results between the first 2 RDTs are resolved by a third 'tiebreaker' RDT. Médecins Sans Frontières uses an alternate serial algorithm of 2 RDTs followed by a confirmation test for all double positive RDT results. The primary objective was to compare the performance of the tiebreaker algorithm with a serial algorithm, and to evaluate the addition of a confirmation test to both algorithms. A secondary objective looked at the positive predictive value (PPV) of weakly reactive test lines. The study was conducted in two HIV testing sites in Ethiopia. Study participants were recruited sequentially until 200 positive samples were reached. Each sample was re-tested in the laboratory on the 3 RDTs and on a simple to use confirmation test, the Orgenics Immunocomb Combfirm® (OIC). The gold standard test was the Western Blot, with indeterminate results resolved by PCR testing. 2620 subjects were included with a HIV prevalence of 7.7%. Each of the 3 RDTs had an individual specificity of at least 99%. The serial algorithm with 2 RDTs had a single false positive result (1 out of 204) to give a PPV of 99.5% (95% CI 97.3%-100%). The tiebreaker algorithm resulted in 16 false positive results (PPV 92.7%, 95% CI: 88.4%-95.8%). Adding the OIC confirmation test to either algorithm eliminated the false positives. All the false positives had at least one weakly reactive test line in the algorithm. The PPV of weakly reacting RDTs was significantly lower than those with strongly positive test lines. The risk of false positive HIV diagnosis in a tiebreaker algorithm is significant. We recommend abandoning the tie-breaker algorithm in favour of WHO recommended serial or parallel algorithms, interpreting weakly reactive test lines as indeterminate results requiring further testing except in the setting of blood transfusion, and most importantly, adding a confirmation test

  16. An audit to investigate the impact of false positive breast screening results and diagnostic work-up on re-engagement with subsequent routine screening

    International Nuclear Information System (INIS)

    Nightingale, Julie M.; Borgen, Rita; Porter-Bennett, Lisa; Szczepura, Katy

    2015-01-01

    Introduction: Women attending breast screening may have suspicious mammographic findings that are subsequently found at assessment clinic to be normal (false positive, FP). A false positive diagnosis is not harmless, with short and long term negative psychosocial consequences reported. Women are at increased relative risk of breast cancer therefore their attendance at subsequent screening is essential. Aims: To assess the impact of FP breast screening diagnosis and diagnostic work-up on re-attendance rates across four consecutive screening rounds at a typical breast screening centre. Method: Diagnostic interventions and screening re-attendance rates at one prior and two consecutive rounds were analysed for women receiving an FP diagnosis between 2004 and 2006. Results: 397 women (5.57%) were referred for further assessment, including 228 (57.43%) false positives. 34 eligible women failed to re-attend routine screening (+3 years), with 17 failing to re-attend subsequently (+6 years). 70.6% (24/34) of non-attenders had attended at least two screening rounds prior to FP assessment. 75% of FP women had an imaging-only assessment with 17.5% (30/171) failing to re-attend, and 25% received a biopsy, with 7% (4/57) failing to re-attend subsequently. Conclusion: This study is unique as it follows FP women through four consecutive screening rounds. FP non-attendance rates were considerably lower compared to the general screening population, with diagnostic work-up having limited influence. FP non-attendance may appear insignificant in comparison to total screened population, but these women are at greater risk of subsequent cancer so should be actively encouraged to re-engage with the screening programme

  17. Affective valence influences participant's susceptibility to false memories and illusory recollection.

    Science.gov (United States)

    Dehon, Hedwige; Larøi, Frank; Van der Linden, Martial

    2010-10-01

    This study examined the influence of emotional valence on the production of DRM false memories (Roediger & McDermott, 1995). Participants were presented with neutral, positive, or negative DRM lists for a later recognition (Experiment 1) or recall (Experiment 2) test. In both experiments, confidence and recollective experience (i.e., "Remember-Know" judgments; Tulving, 1985) were also assessed. Results consistently showed that, compared with neutral lists, affective lists induced more false recognition and recall of nonpresented critical lures. Moreover, although confidence ratings did not differ between the false remembering from the different kinds of lists, "Remember" responses were more often associated with negative than positive and neutral false remembering of the critical lures. In contrast, positive false remembering of the critical lures was more often associated with "Know" responses. These results are discussed in light of the Paradoxical Negative Emotion (PNE) hypothesis (Porter, Taylor, & ten Bricke, 2008). (PsycINFO Database Record (c) 2010 APA, all rights reserved).

  18. Initiation and termination of DNA replication during S phase in relation to cyclins D1, E and A, p21WAF1, Cdt1 and the p12 subunit of DNA polymerase δ revealed in individual cells by cytometry.

    Science.gov (United States)

    Darzynkiewicz, Zbigniew; Zhao, Hong; Zhang, Sufang; Lee, Marietta Y W T; Lee, Ernest Y C; Zhang, Zhongtao

    2015-05-20

    During our recent studies on mechanism of the regulation of human DNA polymerase δ in preparation for DNA replication or repair, multiparameter imaging cytometry as exemplified by laser scanning cytometry (LSC) has been used to assess changes in expression of the following nuclear proteins associated with initiation of DNA replication: cyclin A, PCNA, Ki-67, p21(WAF1), DNA replication factor Cdt1 and the smallest subunit of DNA polymerase δ, p12. In the present review, rather than focusing on Pol δ, we emphasize the application of LSC in these studies and outline possibilities offered by the concurrent differential analysis of DNA replication in conjunction with expression of the nuclear proteins. A more extensive analysis of the data on a correlation between rates of EdU incorporation, likely reporting DNA replication, and expression of these proteins, is presently provided. New data, specifically on the expression of cyclin D1 and cyclin E with respect to EdU incorporation as well as on a relationship between expression of cyclin A vs. p21(WAF1) and Ki-67 vs. Cdt1, are also reported. Of particular interest is the observation that this approach makes it possible to assess the temporal sequence of degradation of cyclin D1, p21(WAF1), Cdt1 and p12, each with respect to initiation of DNA replication and with respect to each other. Also the sequence or reappearance of these proteins in G2 after termination of DNA replication is assessed. The reviewed data provide a more comprehensive presentation of potential markers, whose presence or absence marks the DNA replicating cells. Discussed is also usefulness of these markers as indicators of proliferative activity in cancer tissues that may bear information on tumor progression and have a prognostic value.

  19. Diagnosis of Clostridium difficile-associated disease: examination of multiple algorithms using toxin EIA, glutamate dehydrogenase EIA and loop-mediated isothermal amplification.

    Science.gov (United States)

    Bamber, A I; Fitzsimmons, K; Cunniffe, J G; Beasor, C C; Mackintosh, C A; Hobbs, G

    2012-01-01

    The laboratory diagnosis of Clostridium difficile infection (CDI) needs to be accurate and timely to ensure optimal patient management, infection control and reliable surveillance. Three methods are evaluated using 810 consecutive stool samples against toxigenic culture: CDT TOX A/B Premier enzyme immunoassay (EIA) kit (Meridian Bioscience, Europe), Premier EIA for C. difficile glutamate dehydrogenase (GDH) (Meridian Bioscience, Europe) and the Illumigene kit (Meridian Bioscience, Europe), both individually and within combined testing algorithms. The study revealed that the CDT TOX A/B Premier EIA gave rise to false-positive and false-negative results and demonstrated poor sensitivity (56.47%), compared to Premier EIA for C. difficile GDH (97.65%), suggesting this GDH EIA can be a useful negative screening method. Results for the Illumigene assay alone showed sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of 91.57%, 98.07%, 99.03% and 84.44%, respectively. A two-stage algorithm using Premier EIA for C. difficile GDH/Illumigene assay yielded superior results compared with other testing algorithms (91.57%, 98.07%, 99.03% and 84.44%, respectively), mirroring the Illumigene performance. However, Illumigene is approximately half the cost of current polymerase chain reaction (PCR) methods, has a rapid turnaround time and requires no specialised skill base, making it an attractive alternative to assays such as the Xpert C. difficile assay (Cepheid, Sunnyvale, CA). A three-stage algorithm offered no improvement and would hamper workflow.

  20. False positive of the scintigraphy with octreoscan: a diagnosis of elimination; Faux positif de la scintigraphie a l'octreoscan: un diagnostic d'elimination

    Energy Technology Data Exchange (ETDEWEB)

    Charrier, N.; Brenot-Rossi, I.; Chuto, G.; Giovannini, M.; Delpero, J.R. [Institut Paoli-Calmettes, Marseille, (France)

    2009-05-15

    The imaging of receptors with somatostatin analogs by the pentetreotide-indium 111 (octreoscan) allows the detection of endocrine tumors essentially according to the density of S.S.T.2 receptors at the tumor level. The sensitivity of octreoscan for the detection of intestine endocrine tumors is included between 80 and 100% in the different studies. The clinical case presented here enlightens a case of false positive.We concluded to a physiological elimination of pentetreotide-indium 111 with intra pancreatic biliary stasis (perhaps a dysfunction of sphincter of ampulla of bile duct) and to the lack of tumor centre. It is here a diagnosis of elimination, supported by the different results of examination. all normal. This case of false positive induced expensive and traumatic explorations for the patient. (N.C.)

  1. False-Positive Rate of AKI Using Consensus Creatinine–Based Criteria

    Science.gov (United States)

    Lin, Jennie; Fernandez, Hilda; Shashaty, Michael G.S.; Negoianu, Dan; Testani, Jeffrey M.; Berns, Jeffrey S.; Parikh, Chirag R.

    2015-01-01

    Background and objectives Use of small changes in serum creatinine to diagnose AKI allows for earlier detection but may increase diagnostic false–positive rates because of inherent laboratory and biologic variabilities of creatinine. Design, setting, participants, & measurements We examined serum creatinine measurement characteristics in a prospective observational clinical reference cohort of 2267 adult patients with AKI by Kidney Disease Improving Global Outcomes creatinine criteria and used these data to create a simulation cohort to model AKI false–positive rates. We simulated up to seven successive blood draws on an equal population of hypothetical patients with unchanging true serum creatinine values. Error terms generated from laboratory and biologic variabilities were added to each simulated patient’s true serum creatinine value to obtain the simulated measured serum creatinine for each blood draw. We determined the proportion of patients who would be erroneously diagnosed with AKI by Kidney Disease Improving Global Outcomes creatinine criteria. Results Within the clinical cohort, 75.0% of patients received four serum creatinine draws within at least one 48-hour period during hospitalization. After four simulated creatinine measurements that accounted for laboratory variability calculated from assay characteristics and 4.4% of biologic variability determined from the clinical cohort and publicly available data, the overall false–positive rate for AKI diagnosis was 8.0% (interquartile range =7.9%–8.1%), whereas patients with true serum creatinine ≥1.5 mg/dl (representing 21% of the clinical cohort) had a false–positive AKI diagnosis rate of 30.5% (interquartile range =30.1%–30.9%) versus 2.0% (interquartile range =1.9%–2.1%) in patients with true serum creatinine values false–positive rates caused by inherent variability of serum creatinine at higher baseline values, potentially misclassifying patients with CKD in AKI studies. PMID

  2. Unique thermal record in False Bay

    CSIR Research Space (South Africa)

    Grundlingh, ML

    1993-10-01

    Full Text Available Over the past decade False Bay has assumed a prime position in terms of research in to large South African bays. This is manifested by investigations that cover flow conditions modelling, thermal structure, management, biology and nutrients, geology...

  3. Arousal-But Not Valence-Reduces False Memories at Retrieval.

    Science.gov (United States)

    Mirandola, Chiara; Toffalini, Enrico

    2016-01-01

    Mood affects both memory accuracy and memory distortions. However, some aspects of this relation are still poorly understood: (1) whether valence and arousal equally affect false memory production, and (2) whether retrieval-related processes matter; the extant literature typically shows that mood influences memory performance when it is induced before encoding, leaving unsolved whether mood induced before retrieval also impacts memory. We examined how negative, positive, and neutral mood induced before retrieval affected inferential false memories and related subjective memory experiences. A recognition-memory paradigm for photographs depicting script-like events was employed. Results showed that individuals in both negative and positive moods-similar in arousal levels-correctly recognized more target events and endorsed fewer false memories (and these errors were linked to remember responses less frequently), compared to individuals in neutral mood. This suggests that arousal (but not valence) predicted memory performance; furthermore, we found that arousal ratings provided by participants were more adequate predictors of memory performance than their actual belonging to either positive, negative or neutral mood groups. These findings suggest that arousal has a primary role in affecting memory, and that mood exerts its power on true and false memory even when induced at retrieval.

  4. Intellectual factors in false memories of patients with schizophrenia.

    Science.gov (United States)

    Zhu, Bi; Chen, Chuansheng; Loftus, Elizabeth F; Dong, Qi; Lin, Chongde; Li, Jun

    2018-07-01

    The current study explored the intellectual factors in false memories of 139 patients with schizophrenia, using a recognition task and an IQ test. The full-scale IQ score of the participants ranged from 57 to 144 (M = 100, SD = 14). The full IQ score had a negative correlation with false recognition in patients with schizophrenia, and positive correlations with high-confidence true recognition and discrimination rates. Further analyses with the subtests' scores revealed that false recognition was negatively correlated with scores of performance IQ (and one of its subtests: picture arrangement), whereas true recognition was positively correlated with scores of verbal IQ (and two of its subtests: information and digit span). High-IQ patients had less false recognition (overall or high-confidence false recognition), more high-confidence true recognition, and higher discrimination abilities than those with low IQ. These findings contribute to a better understanding of the cognitive mechanism in false memory of patients with schizophrenia, and are of practical relevance to the evaluation of memory reliability in patients with different intellectual levels. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Motivated reconstruction: The effect of brand commitment on false memories.

    Science.gov (United States)

    Montgomery, Nicole Votolato; Rajagopal, Priyali

    2018-06-01

    Across 5 studies, we examine the effect of prior brand commitment on the creation of false memories about product experience after reading online product reviews. We find that brand commitment and the valence of reviews to which consumers are exposed, interact to affect the incidence of false memories. Thus, highly committed consumers are more susceptible to the creation of false experience memories on exposure to positive versus negative reviews, whereas low commitment consumers exhibit similar levels of false memories in response to both positive and negative reviews. Further, these differences across brand commitment are attenuated when respondents are primed with an accuracy motivation, suggesting that the biasing effects of commitment are likely because of the motivation to defend the committed brand. Finally, we find that differences in false memories subsequently lead to differences in intentions to spread word-of-mouth (e.g., recommend the product to friends), suggesting that the consequences of false product experience memories can be significant for marketers and consumers. Our findings contribute to the literatures in false memory and marketing by documenting a motivated bias in false memories because of brand commitment. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  6. Different percentages of false-positive results obtained using five methods for the calculation of reference change values based on simulated normal and ln-normal distributions of data

    DEFF Research Database (Denmark)

    Lund, Flemming; Petersen, Per Hyltoft; Fraser, Callum G

    2016-01-01

    a homeostatic set point that follows a normal (Gaussian) distribution. This set point (or baseline in steady-state) should be estimated from a set of previous samples, but, in practice, decisions based on reference change value are often based on only two consecutive results. The original reference change value......-positive results. The aim of this study was to investigate false-positive results using five different published methods for calculation of reference change value. METHODS: The five reference change value methods were examined using normally and ln-normally distributed simulated data. RESULTS: One method performed...... best in approaching the theoretical false-positive percentages on normally distributed data and another method performed best on ln-normally distributed data. The commonly used reference change value method based on two results (without use of estimated set point) performed worst both on normally...

  7. Neural Network Target Identification System for False Alarm Reduction

    Science.gov (United States)

    Ye, David; Edens, Weston; Lu, Thomas T.; Chao, Tien-Hsin

    2009-01-01

    A multi-stage automated target recognition (ATR) system has been designed to perform computer vision tasks with adequate proficiency in mimicking human vision. The system is able to detect, identify, and track targets of interest. Potential regions of interest (ROIs) are first identified by the detection stage using an Optimum Trade-off Maximum Average Correlation Height (OT-MACH) filter combined with a wavelet transform. False positives are then eliminated by the verification stage using feature extraction methods in conjunction with neural networks. Feature extraction transforms the ROIs using filtering and binning algorithms to create feature vectors. A feed forward back propagation neural network (NN) is then trained to classify each feature vector and remove false positives. This paper discusses the test of the system performance and parameter optimizations process which adapts the system to various targets and datasets. The test results show that the system was successful in substantially reducing the false positive rate when tested on a sonar image dataset.

  8. The Lifetime Economic Burden of Inaccurate HER2 Testing: Estimating the Costs of False-Positive and False-Negative HER2 Test Results in US Patients with Early-Stage Breast Cancer.

    Science.gov (United States)

    Garrison, Louis P; Babigumira, Joseph B; Masaquel, Anthony; Wang, Bruce C M; Lalla, Deepa; Brammer, Melissa

    2015-06-01

    Patients with breast cancer whose tumors test positive for human epidermal growth factor receptor 2 (HER2) are treated with HER2-targeted therapies such as trastuzumab, but limitations with HER2 testing may lead to false-positive (FP) or false-negative (FN) results. To develop a US-level model to estimate the effect of tumor misclassification on health care costs and patient quality-adjusted life-years (QALYs). Decision analysis was used to estimate the number of patients with early-stage breast cancer (EBC) whose HER2 status was misclassified in 2012. FP results were assumed to generate unnecessary trastuzumab costs and unnecessary cases of trastuzumab-related cardiotoxicity. FN results were assumed to save money on trastuzumab, but with a loss of QALYs and greater risk of disease recurrence and its associated costs. QALYs were valued at $100,000 under a net monetary benefit approach. Among 226,870 women diagnosed with EBC in 2012, 3.12% (n = 7,070) and 2.18% (n = 4,955) were estimated to have had FP and FN test results, respectively. Approximately 8400 QALYs (discounted, lifetime) were lost among women not receiving trastuzumab because of FN results. The estimated incremental per-patient lifetime burden of FP or FN results was $58,900 and $116,000, respectively. The implied incremental losses to society were $417 million and $575 million, respectively. HER2 tests result in misclassification and nonoptimal treatment of approximately 12,025 US patients with EBC annually. The total economic societal loss of nearly $1 billion suggests that improvements in HER2 testing accuracy are needed and that further clinical and economic studies are warranted. Copyright © 2015 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  9. Arousal—But Not Valence—Reduces False Memories at Retrieval

    Science.gov (United States)

    Mirandola, Chiara; Toffalini, Enrico

    2016-01-01

    Mood affects both memory accuracy and memory distortions. However, some aspects of this relation are still poorly understood: (1) whether valence and arousal equally affect false memory production, and (2) whether retrieval-related processes matter; the extant literature typically shows that mood influences memory performance when it is induced before encoding, leaving unsolved whether mood induced before retrieval also impacts memory. We examined how negative, positive, and neutral mood induced before retrieval affected inferential false memories and related subjective memory experiences. A recognition-memory paradigm for photographs depicting script-like events was employed. Results showed that individuals in both negative and positive moods–similar in arousal levels–correctly recognized more target events and endorsed fewer false memories (and these errors were linked to remember responses less frequently), compared to individuals in neutral mood. This suggests that arousal (but not valence) predicted memory performance; furthermore, we found that arousal ratings provided by participants were more adequate predictors of memory performance than their actual belonging to either positive, negative or neutral mood groups. These findings suggest that arousal has a primary role in affecting memory, and that mood exerts its power on true and false memory even when induced at retrieval. PMID:26938737

  10. Arousal-But Not Valence-Reduces False Memories at Retrieval.

    Directory of Open Access Journals (Sweden)

    Chiara Mirandola

    Full Text Available Mood affects both memory accuracy and memory distortions. However, some aspects of this relation are still poorly understood: (1 whether valence and arousal equally affect false memory production, and (2 whether retrieval-related processes matter; the extant literature typically shows that mood influences memory performance when it is induced before encoding, leaving unsolved whether mood induced before retrieval also impacts memory. We examined how negative, positive, and neutral mood induced before retrieval affected inferential false memories and related subjective memory experiences. A recognition-memory paradigm for photographs depicting script-like events was employed. Results showed that individuals in both negative and positive moods-similar in arousal levels-correctly recognized more target events and endorsed fewer false memories (and these errors were linked to remember responses less frequently, compared to individuals in neutral mood. This suggests that arousal (but not valence predicted memory performance; furthermore, we found that arousal ratings provided by participants were more adequate predictors of memory performance than their actual belonging to either positive, negative or neutral mood groups. These findings suggest that arousal has a primary role in affecting memory, and that mood exerts its power on true and false memory even when induced at retrieval.

  11. Compound danshen tablet ameliorated aβ25-35-induced spatial memory impairment in mice via rescuing imbalance between cytokines and neurotrophins.

    Science.gov (United States)

    Teng, Yan; Zhang, Meng-Qi; Wang, Wen; Liu, Li-Tao; Zhou, Li-Ming; Miao, Shi-Kun; Wan, Li-Hong

    2014-01-14

    Compound Danshen Tablet (CDT), a Traditional Chinese Medicine, has recently been reported to improve spatial cognition in a rat model of Alzheimer's disease. However, in vivo neuroprotective mechanism of the CDT in models of spatial memory impairment is not yet evaluated. The present study is aimed to elucidate the cellular mechanism of CDT on Aβ25-35-induced cognitive impairment in mice. Mice were randomly divided into 5 groups: the control group (sham operated), the Aβ25-35 treated group, the positive drug group, and large and small dosage of the CDT groups, respectively. CDT was administered at a dose of 0.81 g/kg and 0.405 g/kg for 3 weeks. The mice in the positive drug group were treated with 0.4 mg/kg of Huperzine A, whereas the mice of the control and Aβ25-35 treated groups were administrated orally with equivalent saline. After 7 days of preventive treatment, mice were subjected to lateral ventricle injection of Aβ25-35 to establish the mice model of Alzheimer's disease. Spatial memory impairment was evaluated by Morris water maze test. Choline acetyltransferase (ChAT) contents in hippocampus and cortex were quantified by ELISA. The levels of cytokines, receptor of activated protein kinase C1 (RACK1) and brain-derived neurotrophic factor (BDNF) in hippocampus were measured by RT-PCR and ELISA. The results showed that Aβ25-35 caused spatial memory impairment as demonstrated by performance in the Morris water maze test. CDT was able to confer a significant improvement in spatial memory, and protect mice from Aβ25-35-induced neurotoxicity. Additionally, CDT also inhibited the increase of TNF-α and IL-6 level, and increased the expression of choline acetyltransferase (ChAT), receptor of activated protein kinase C1 (RACK1) and brain-derived neurotrophic factor (BDNF) in brain as compared to model mice. These findings strongly implicate that CDT may be a useful treatment against learning and memory deficits in mice by rescuing imbalance between cytokines

  12. Recursive belief manipulation and second-order false-beliefs

    DEFF Research Database (Denmark)

    Braüner, Torben; Blackburn, Patrick Rowan; Polyanskaya, Irina

    2016-01-01

    it indicate that a more fundamental *conceptual change* has taken place? In this paper we extend Braüner's hybrid-logical analysis of first-order false-belief tasks to the second-order case, and argue that our analysis supports a version of the conceptual change position.......The literature on first-order false-belief is extensive, but less is known about the second-order case. The ability to handle second-order false-beliefs correctly seems to mark a cognitively significant step, but what is its status? Is it an example of *complexity only* development, or does...

  13. Underpowered samples, false negatives, and unconscious learning.

    Science.gov (United States)

    Vadillo, Miguel A; Konstantinidis, Emmanouil; Shanks, David R

    2016-02-01

    The scientific community has witnessed growing concern about the high rate of false positives and unreliable results within the psychological literature, but the harmful impact of false negatives has been largely ignored. False negatives are particularly concerning in research areas where demonstrating the absence of an effect is crucial, such as studies of unconscious or implicit processing. Research on implicit processes seeks evidence of above-chance performance on some implicit behavioral measure at the same time as chance-level performance (that is, a null result) on an explicit measure of awareness. A systematic review of 73 studies of contextual cuing, a popular implicit learning paradigm, involving 181 statistical analyses of awareness tests, reveals how underpowered studies can lead to failure to reject a false null hypothesis. Among the studies that reported sufficient information, the meta-analytic effect size across awareness tests was d z = 0.31 (95 % CI 0.24-0.37), showing that participants' learning in these experiments was conscious. The unusually large number of positive results in this literature cannot be explained by selective publication. Instead, our analyses demonstrate that these tests are typically insensitive and underpowered to detect medium to small, but true, effects in awareness tests. These findings challenge a widespread and theoretically important claim about the extent of unconscious human cognition.

  14. HAMS: High-Affinity Mass Spectrometry Screening. A High-Throughput Screening Method for Identifying the Tightest-Binding Lead Compounds for Target Proteins with No False Positive Identifications.

    Science.gov (United States)

    Imaduwage, Kasun P; Go, Eden P; Zhu, Zhikai; Desaire, Heather

    2016-11-01

    A major challenge in drug discovery is the identification of high affinity lead compounds that bind a particular target protein; these leads are typically identified by high throughput screens. Mass spectrometry has become a detection method of choice in drug screening assays because the target and the ligand need not be modified. Label-free assays are advantageous because they can be developed more rapidly than assays requiring labels, and they eliminate the risk of the label interfering with the binding event. However, in commonly used MS-based screening methods, detection of false positives is a major challenge. Here, we describe a detection strategy designed to eliminate false positives. In this approach, the protein and the ligands are incubated together, and the non-binders are separated for detection. Hits (protein binders) are not detectable by MS after incubation with the protein, but readily identifiable by MS when the target protein is not present in the incubation media. The assay was demonstrated using three different proteins and hundreds of non-inhibitors; no false positive hits were identified in any experiment. The assay can be tuned to select for ligands of a particular binding affinity by varying the quantity of protein used and the immobilization method. As examples, the method selectively detected inhibitors that have K i values of 0.2 μM, 50 pM, and 700 pM. These findings demonstrate that the approach described here compares favorably with traditional MS-based screening methods. Graphical Abstract ᅟ.

  15. Analysis of false results in a series of 835 fine needle aspirates of breast lesions.

    Science.gov (United States)

    Willis, S L; Ramzy, I

    1995-01-01

    To analyze cases of false diagnoses from a large series to help increase the accuracy of fine needle aspiration of palpable breast lesions. The results of FNA of 835 palpable breast lesions were analyzed to determine the reasons for false positive, false negative and false suspicious diagnoses. Of the 835 aspirates, 174 were reported as positive, 549 as negative and 66 as suspicious or atypical but not diagnostic of malignancy. Forty-six cases were considered unsatisfactory. Tissue was available for comparison in 286 cases. The cytologic diagnoses in these cases were reported as follows: positive, 125 (43.7%); suspicious, 33 (11.5%); atypical, 18 (6.2%); negative, 92 (32%); and unsatisfactory, 18 (6.2%). There was one false positive diagnosis, yielding a false positive rate of 0.8%. This lesion was a case of fibrocystic change with hyperplasia, focal fat necrosis and reparative atypia. There were 14 false negative cases, resulting in a false negative rate of 13.2%. Nearly all these cases were sampling errors and included infiltrating ductal carcinomas (9), ductal carcinomas in situ (2), infiltrating lobular carcinomas (2) and tubular carcinoma (1). Most of the suspicious and atypical lesions proved to be carcinomas (35/50). The remainder were fibroadenomas (6), fibrocystic change (4), gynecomastia (2), adenosis (2) and granulomatous mastitis (1). A positive diagnosis of malignancy by FNA is reliable in establishing the diagnosis and planning the treatment of breast cancer. The false-positive rate is very low, with only a single case reported in 835 aspirates. Most false negatives are due to sampling and not to interpretive difficulties. The category "suspicious but not diagnostic of malignancy" serves a useful purpose in management of patients with breast lumps.

  16. False Memory in Adults With ADHD: A Comparison Between Subtypes and Normal Controls.

    Science.gov (United States)

    Soliman, Abdrabo Moghazy; Elfar, Rania Mohamed

    2017-10-01

    To examine the performance on the Deese-Roediger-McDermott task of adults divided into ADHD subtypes and compares their performance to that of healthy controls to examine whether adults with ADHD are more susceptible to the production of false memories under experimental conditions. A total of 128 adults with ADHD (50% females), classified into three Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV-TR) subtypes, were compared with 48 controls. The results indicated that the ADHD participants recalled and recognized fewer studied words than the controls, the ADHD groups produced more false memories than the control group, no differences in either the false positives or the false negatives. The ADHD-combined (ADHD-CT) group recognized significantly more critical words than the control, ADHD-predominantly inattentive (ADHD-IA), and ADHD-predominantly hyperactive-impulsive (ADHD-HI) groups. The ADHD groups recalled and recognized more false positives, were more confident in their false responses, and displayed more knowledge corruption than the controls. The ADHD-CT group recalled and recognized more false positives than the other ADHD groups. The adults with ADHD have more false memories than the controls and that false memory formation varied with the ADHD subtypes.

  17. The Relations Between False Positive and Negative Screens and Smoking Cessation and Relapse in the National Lung Screening Trial: Implications for Public Health.

    Science.gov (United States)

    Clark, Melissa A; Gorelick, Jeremy J; Sicks, JoRean D; Park, Elyse R; Graham, Amanda L; Abrams, David B; Gareen, Ilana F

    2016-01-01

    Lung screening is an opportunity for smoking cessation and relapse prevention, but smoking behaviors may differ across screening results. Changes in smoking were evaluated among 18 840 current and former smokers aged 55-74 scheduled to receive three annual lung screenings. Participants were randomized to low-dose computed tomography or single-view chest radiography in the American College of Radiology/National Lung Screening Trial. Outcome measures included point and sustained (6-month) abstinence and motivation to quit among smokers; and relapse among smokers who quit during follow-up, recent quitters (quit < 6 months), and long-term former smokers (quit ≥ 6 months). During five years of follow-up, annual point prevalence quit rates ranged from 11.6%-13.4%; 48% of current smokers reported a quit attempt and 7% of long-term former smokers relapsed. Any false positive screening result was associated with subsequent increased point (multivariable hazard ratio HR = 1.23, 95% CI = 1.13, 1.35) and sustained (HR = 1.28, 95% CI = 1.15, 1.43) abstinence among smokers. Recent quitters with ≥1 false positive screen were less likely to relapse (HR = 0.72, 95% CI = 0.54, 0.96). Screening result was not associated with relapse among long-term former smokers or among baseline smokers who quit during follow-up. A false positive screen was associated with increased smoking cessation and less relapse among recent quitters. Consistently negative screens were not associated with greater relapse among long-term former smokers. Given the Affordable Care Act requires most health plans to cover smoking cessation and lung screening, the impact and cost-effectiveness of lung screening could be further enhanced with the addition of smoking cessation interventions. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Usefulness of pulse-wave doppler tissue sampling and dobutamine stress echocardiography for identification of false positive inferior wall defects in SPECT

    International Nuclear Information System (INIS)

    Altinmakas, S.; Dagdeviren, B.; Turkmen, M.; Gursurer, M.; Say, B.; Tezel, T.; Ersek, B.

    2000-01-01

    False positive inferior wall perfusion defects restrict the accuracy of SPECT in diagnosis of coronary artery disease (CAD). Pulse-Wave Tissue Doppler (PWTD) has been recently proposed to assess regional wall motion velocities. The objectives of this study were to evaluate the presence of CAD by using PWTD during dobutamine stress echocardiography (DSE) in patients with an inferior perfusion defect detected by SPECT and compare PWTD parameters of normal cases with patients who had inferior perfusion defect and CAD. Sixty-five patients (mean age 58±8 years, 30 men) with a normal LV systolic function at rest according to echocardiographic evaluation with an inferior ischemia determined by SPECT and a control group (CG) of 34 normal cases (mean age 56±7 years, 16 men) were included in this study. All patients underwent a standard DSE (up to 40 μg/kg/min with additional atropine during sub-maximum heart rate responses). Pulse-wave Doppler tissue sampling of inferior wall was performed in the apical 2-chamber view at rest and stress. The coronary angiography was performed within 24 hours. The results were evaluated for the prediction of significant right coronary artery (RCA) and/or left circumflex coronary artery (CX) with narrowing (≥50% diameter stenosis, assessed by quantitative coronary angiography). It was observed that the peak stress mean E/A ratio was lower in patients with CAD when compared to patients without CAD (0.78±0.2 versus 1.29±0.11 p<0.0001). Also the peak stress E/A ratio of normal cases was significantly higher than patients who had CAD (1.19±0.3 versus 0.78±0.2 p<0.0001). When the cut off point for the E/A ratio was determined as 1, the sensitivity and specificity of dobutamine stress PWTD E/A were 89% and 86%, respectively. The peak stress E/A ratio was higher than 1 in all patients with a false positive perfusion defect. Systolic S velocity increase during DSE was significantly lower in patients with CAD (54%±17 versus 99%±24 p=0

  19. A Nested PCR Assay to Avoid False Positive Detection of the Microsporidian Enterocytozoon hepatopenaei (EHP) in Environmental Samples in Shrimp Farms

    Science.gov (United States)

    Jaroenlak, Pattana; Sanguanrut, Piyachat; Williams, Bryony A. P.; Stentiford, Grant D.; Flegel, Timothy W.; Sritunyalucksana, Kallaya

    2016-01-01

    Hepatopancreatic microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP) is an important disease of cultivated shrimp. Heavy infections may lead to retarded growth and unprofitable harvests. Existing PCR detection methods target the EHP small subunit ribosomal RNA (SSU rRNA) gene (SSU-PCR). However, we discovered that they can give false positive test results due to cross reactivity of the SSU-PCR primers with DNA from closely related microsporidia that infect other aquatic organisms. This is problematic for investigating and monitoring EHP infection pathways. To overcome this problem, a sensitive and specific nested PCR method was developed for detection of the spore wall protein (SWP) gene of EHP (SWP-PCR). The new SWP-PCR method did not produce false positive results from closely related microsporidia. The first PCR step of the SWP-PCR method was 100 times (104 plasmid copies per reaction vial) more sensitive than that of the existing SSU-PCR method (106 copies) but sensitivity was equal for both in the nested step (10 copies). Since the hepatopancreas of cultivated shrimp is not currently known to be infected with microsporidia other than EHP, the SSU-PCR methods are still valid for analyzing hepatopancreatic samples despite the lower sensitivity than the SWP-PCR method. However, due to its greater specificity and sensitivity, we recommend that the SWP-PCR method be used to screen for EHP in feces, feed and environmental samples for potential EHP carriers. PMID:27832178

  20. A Nested PCR Assay to Avoid False Positive Detection of the Microsporidian Enterocytozoon hepatopenaei (EHP) in Environmental Samples in Shrimp Farms.

    Science.gov (United States)

    Jaroenlak, Pattana; Sanguanrut, Piyachat; Williams, Bryony A P; Stentiford, Grant D; Flegel, Timothy W; Sritunyalucksana, Kallaya; Itsathitphaisarn, Ornchuma

    2016-01-01

    Hepatopancreatic microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP) is an important disease of cultivated shrimp. Heavy infections may lead to retarded growth and unprofitable harvests. Existing PCR detection methods target the EHP small subunit ribosomal RNA (SSU rRNA) gene (SSU-PCR). However, we discovered that they can give false positive test results due to cross reactivity of the SSU-PCR primers with DNA from closely related microsporidia that infect other aquatic organisms. This is problematic for investigating and monitoring EHP infection pathways. To overcome this problem, a sensitive and specific nested PCR method was developed for detection of the spore wall protein (SWP) gene of EHP (SWP-PCR). The new SWP-PCR method did not produce false positive results from closely related microsporidia. The first PCR step of the SWP-PCR method was 100 times (104 plasmid copies per reaction vial) more sensitive than that of the existing SSU-PCR method (106 copies) but sensitivity was equal for both in the nested step (10 copies). Since the hepatopancreas of cultivated shrimp is not currently known to be infected with microsporidia other than EHP, the SSU-PCR methods are still valid for analyzing hepatopancreatic samples despite the lower sensitivity than the SWP-PCR method. However, due to its greater specificity and sensitivity, we recommend that the SWP-PCR method be used to screen for EHP in feces, feed and environmental samples for potential EHP carriers.

  1. Use of the false discovery rate for evaluating clinical safety data.

    Science.gov (United States)

    Mehrotra, Devan V; Heyse, Joseph F

    2004-06-01

    Clinical adverse experience (AE) data are routinely evaluated using between group P values for every AE encountered within each of several body systems. If the P values are reported and interpreted without multiplicity considerations, there is a potential for an excess of false positive findings. Procedures based on confidence interval estimates of treatment effects have the same potential for false positive findings as P value methods. Excess false positive findings can needlessly complicate the safety profile of a safe drug or vaccine. Accordingly, we propose a novel method for addressing multiplicity in the evaluation of adverse experience data arising in clinical trial settings. The method involves a two-step application of adjusted P values based on the Benjamini and Hochberg false discovery rate (FDR). Data from three moderate to large vaccine trials are used to illustrate our proposed 'Double FDR' approach, and to reinforce the potential impact of failing to account for multiplicity. This work was in collaboration with the late Professor John W. Tukey who coined the term 'Double FDR'.

  2. Mood-congruent true and false memory: effects of depression.

    Science.gov (United States)

    Howe, Mark L; Malone, Catherine

    2011-02-01

    The Deese/Roediger-McDermott paradigm was used to investigate the effect of depression on true and false recognition. In this experiment true and false recognition was examined across positive, neutral, negative, and depression-relevant lists for individuals with and without a diagnosis of major depressive disorder. Results showed that participants with major depressive disorder falsely recognised significantly more depression-relevant words than non-depressed controls. These findings also parallel recent research using recall instead of recognition and show that there are clear mood congruence effects for depression on false memory performance. © 2011 Psychology Press, an imprint of the Taylor & Francis Group, an Informa business

  3. False recognition in behavioural variant frontotemporal dementia and Alzheimer’s disease – disinhibition or amnesia?

    Directory of Open Access Journals (Sweden)

    Emma C Flanagan

    2016-07-01

    Full Text Available Episodic memory recall processes in Alzheimer’s disease (AD and behavioural variant frontotemporal dementia (bvFTD can be similarly impaired, whereas recognition performance is more variable. A potential reason for this variability could be false-positive errors made on recognition trials and whether these errors are due to amnesia per se or a general over-endorsement of recognition items regardless of memory. The current study addressed this issue by analysing recognition performance on the Rey Auditory Verbal Learning Test (RAVLT in 39 bvFTD, 77 AD and 61 control participants from two centres (India, Australia, as well as disinhibition assessed using the Hayling test. Whereas both AD and bvFTD patients were comparably impaired on delayed recall, bvFTD patients showed intact recognition performance in terms of the number of correct hits. However, both patient groups endorsed significantly more false-positives than controls, and bvFTD and AD patients scored equally poorly on a sensitivity index (correct hits - false-positives. Furthermore, measures of disinhibition were significantly associated with false positives in both groups, with a stronger relationship with false-positives in bvFTD. Voxel-based morphometry analyses revealed similar neural correlates of false positive endorsement across bvFTD and AD, with both patient groups showing involvement of prefrontal and Papez circuitry regions, such as medial temporal and thalamic regions, and a DTI analysis detected an emerging but non-significant trend between false positives and decreased fornix integrity in bvFTD only. These findings suggest that false-positive errors on recognition tests relate to similar mechanisms in bvFTD and AD, reflecting deficits in episodic memory processes and disinhibition. These findings highlight that current memory tests are not sufficient to accurately distinguish between bvFTD and AD patients.

  4. Disfluent presentations lead to the creation of more false memories.

    Science.gov (United States)

    Sanchez, Christopher A; Naylor, Jamie S

    2018-01-01

    The creation of false memories within the Deese-Roediger-McDermott (DRM) paradigm has been shown to be sensitive to many factors such as task instructions, participant mood, or even presentation modality. However, do other simple perceptual differences also impact performance on the DRM and the creation of false memories? This study explores the potential impact of changes in perceptual disfluency on DRM performance. To test for a potential influence of disfluency on false memory creation, participants viewed lists under either perceptually disfluent conditions or not. Results indicated that disfluency did significantly impact performance in the DRM paradigm; more disfluent presentations significantly increased the recall and recognition of unpresented information, although they did not impact recall or recognition of presented information. Thus, although disfluency did impact performance, disfluency did not produce a positive benefit related to overall task performance. This finding instead suggests that more disfluent presentations can increase the likelihood that false memories are created, and provide little positive performance benefit.

  5. The Dutch Brucella abortus monitoring programme for cattle: the impact of false-positive serological reactions and comparison of serological tests.

    Science.gov (United States)

    Emmerzaal, A; de Wit, J J; Dijkstra, Th; Bakker, D; van Zijderveld, F G

    2002-02-01

    The Dutch national Brucella abortus eradication programme for cattle started in 1959. Sporadic cases occurred yearly until 1995; the last infected herd was culled in 1996. In August 1999 the Netherlands was declared officially free of bovine brucellosis by the European Union. Before 1999, the programme to monitor the official Brucella-free status of bovine herds was primarily based on periodical testing of dairy herds with the milk ring test (MRT) and serological testing of all animals older than 1 year of age from non-dairy herds, using the micro-agglutination test (MAT) as screening test. In addition, serum samples of cattle that aborted were tested with the MAT. The high number of false positive reactions in both tests and the serum agglutination test (SAT) and complement fixation test (CFT) used for confirmation seemed to result in unnecessary blockade of herds, subsequent testing and slaughter of animals. For this reason, a validation study was performed in which three indirect enzyme-linked immunosorbent assays (ELISAs), the CFT and the SAT were compared using a panel of sera from brucellosis-free cattle, sera from experimentally infected cattle, and sera from cattle experimentally infected with bacteria which are known to induce cross-reactive antibodies (Pasteurella, Salmonella, Yersinia, and Escherichia). Moreover, four ELISAs and the MRT were compared using a panel of 1000 bulk milk samples from Brucella-free herds and 12 milk samples from Brucella abortus- infected cattle. It is concluded that the ELISA obtained from ID-Lelystad is the most suitable test to monitor the brucelosis free status of herds because it gives rise to fewer false-positive reactions than the SAT.

  6. Particle drag history in a subcritical post-shock flow - data analysis method and uncertainty

    Science.gov (United States)

    Ding, Liuyang; Bordoloi, Ankur; Adrian, Ronald; Prestridge, Kathy; Arizona State University Team; Los Alamos National Laboratory Team

    2017-11-01

    A novel data analysis method for measuring particle drag in an 8-pulse particle tracking velocimetry-accelerometry (PTVA) experiment is described. We represented the particle drag history, CD(t) , using polynomials up to the third order. An analytical model for continuous particle position history was derived by integrating an equation relating CD(t) with particle velocity and acceleration. The coefficients of CD(t) were then calculated by fitting the position history model to eight measured particle locations in the sense of least squares. A preliminary test with experimental data showed that the new method yielded physically more reasonable particle velocity and acceleration history compared to conventionally adopted polynomial fitting. To fully assess and optimize the performance of the new method, we performed a PTVA simulation by assuming a ground truth of particle motion based on an ensemble of experimental data. The results indicated a significant reduction in the RMS error of CD. We also found that for particle locating noise between 0.1 and 3 pixels, a range encountered in our experiment, the lowest RMS error was achieved by using the quadratic CD(t) model. Furthermore, we will also discuss the optimization of the pulse timing configuration.

  7. Computer-aided mass detection in mammography: False positive reduction via gray-scale invariant ranklet texture features

    International Nuclear Information System (INIS)

    Masotti, Matteo; Lanconelli, Nico; Campanini, Renato

    2009-01-01

    In this work, gray-scale invariant ranklet texture features are proposed for false positive reduction (FPR) in computer-aided detection (CAD) of breast masses. Two main considerations are at the basis of this proposal. First, false positive (FP) marks surviving our previous CAD system seem to be characterized by specific texture properties that can be used to discriminate them from masses. Second, our previous CAD system achieves invariance to linear/nonlinear monotonic gray-scale transformations by encoding regions of interest into ranklet images through the ranklet transform, an image transformation similar to the wavelet transform, yet dealing with pixels' ranks rather than with their gray-scale values. Therefore, the new FPR approach proposed herein defines a set of texture features which are calculated directly from the ranklet images corresponding to the regions of interest surviving our previous CAD system, hence, ranklet texture features; then, a support vector machine (SVM) classifier is used for discrimination. As a result of this approach, texture-based information is used to discriminate FP marks surviving our previous CAD system; at the same time, invariance to linear/nonlinear monotonic gray-scale transformations of the new CAD system is guaranteed, as ranklet texture features are calculated from ranklet images that have this property themselves by construction. To emphasize the gray-scale invariance of both the previous and new CAD systems, training and testing are carried out without any in-between parameters' adjustment on mammograms having different gray-scale dynamics; in particular, training is carried out on analog digitized mammograms taken from a publicly available digital database, whereas testing is performed on full-field digital mammograms taken from an in-house database. Free-response receiver operating characteristic (FROC) curve analysis of the two CAD systems demonstrates that the new approach achieves a higher reduction of FP marks

  8. The effect of mood on false memory for emotional DRM word lists.

    Science.gov (United States)

    Zhang, Weiwei; Gross, Julien; Hayne, Harlene

    2017-04-01

    In the present study, we investigated the effect of participants' mood on true and false memories of emotional word lists in the Deese-Roediger-McDermott (DRM) paradigm. In Experiment 1, we constructed DRM word lists in which all the studied words and corresponding critical lures reflected a specified emotional valence. In Experiment 2, we used these lists to assess mood-congruent true and false memory. Participants were randomly assigned to one of three induced-mood conditions (positive, negative, or neutral) and were presented with word lists comprised of positive, negative, or neutral words. For both true and false memory, there was a mood-congruent effect in the negative mood condition; this effect was due to a decrease in true and false recognition of the positive and neutral words. These findings are consistent with both spreading-activation and fuzzy-trace theories of DRM performance and have practical implications for our understanding of the effect of mood on memory.

  9. Voting experiments: Bandwagon voting or false-consensus effect?

    OpenAIRE

    Ivo Bischoff; Henrik Egbert

    2008-01-01

    In an experiment designed to test for expressive voting, Tyran (JPubEc 2004) found a strong positive correlation between the participants' approval for a proposal to donate money for charity and their expected approval rate for fellow voters. This phenomenon can be due to bandwagon voting or a false consensus effect. The social science literature reports both effects for voting decisions. Replicating Tyran's experiment and adding new treatments, we provide evidence for a false consensus effec...

  10. Automated detection of masses on whole breast volume ultrasound scanner: false positive reduction using deep convolutional neural network

    Science.gov (United States)

    Hiramatsu, Yuya; Muramatsu, Chisako; Kobayashi, Hironobu; Hara, Takeshi; Fujita, Hiroshi

    2017-03-01

    Breast cancer screening with mammography and ultrasonography is expected to improve sensitivity compared with mammography alone, especially for women with dense breast. An automated breast volume scanner (ABVS) provides the operator-independent whole breast data which facilitate double reading and comparison with past exams, contralateral breast, and multimodality images. However, large volumetric data in screening practice increase radiologists' workload. Therefore, our goal is to develop a computer-aided detection scheme of breast masses in ABVS data for assisting radiologists' diagnosis and comparison with mammographic findings. In this study, false positive (FP) reduction scheme using deep convolutional neural network (DCNN) was investigated. For training DCNN, true positive and FP samples were obtained from the result of our initial mass detection scheme using the vector convergence filter. Regions of interest including the detected regions were extracted from the multiplanar reconstraction slices. We investigated methods to select effective FP samples for training the DCNN. Based on the free response receiver operating characteristic analysis, simple random sampling from the entire candidates was most effective in this study. Using DCNN, the number of FPs could be reduced by 60%, while retaining 90% of true masses. The result indicates the potential usefulness of DCNN for FP reduction in automated mass detection on ABVS images.

  11. Chemical applicability domain of the Local Lymph Node Assay (LLNA) for skin sensitisation potency. Part 3. Apparent discrepancies between LLNA and GPMT sensitisation potential: False positives or differences in sensitivity?

    Science.gov (United States)

    Roberts, David W; Schultz, Terry W; Api, Anne Marie

    2016-10-01

    The Local Lymph Node Assay (LLNA) is the gold standard regulatory toxicology test for skin sensitisation along with the guinea pig maximisation test (GPMT). Compared with the GPMT, LLNA uses fewer animals, it is quantitative, and it gives a numerical prediction of potency. However several concerns have been raised with this assay, mainly related to false positives and false negatives. Over the years, many authors, including the developers of the assay, have presented cases where there have been discrepancies between the GMPT and LLNA results. Several theories have been put forward for these discrepancies, the main one being the "over-sensitivity" of the GPMT. This paper analyses the data from a systematic study, published in three papers from 2008 to 2011, covering several classes of chemicals, in particular unsaturated fatty acids, sugar surfactants and ethoxylated alcohols, with many cases of chemicals testing positive in the LLNA being negative in the GPMT. Based on consideration of reaction chemistry and structural alerts, it is concluded that these discrepancies are not LLNA false positives, but can be rationalised in terms of the different protocols of the assays. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Mammography Clinical Image Quality and the False Positive Rate in a Canadian Breast Cancer Screening Program.

    Science.gov (United States)

    Guertin, Marie-Hélène; Théberge, Isabelle; Zomahoun, Hervé Tchala Vignon; Dufresne, Michel-Pierre; Pelletier, Éric; Brisson, Jacques

    2018-05-01

    The study sought to determine if mammography quality is associated with the false positive (FP) rate in the Quebec breast cancer screening program in 2004 and 2005. Mammography quality of a random sample of screen-film mammograms was evaluated by an expert radiologist following the criteria of the Canadian Association of Radiologists. For each screening examination, scores ranging from 1 (poor quality) to 5 (excellent quality) were attributed for positioning, compression, contrast, exposure level, sharpness, and artifacts. A final overall quality score (lower or higher) was also given. Poisson regression models with robust estimation of variance and adjusted for potential confounding factors were used to assess associations of mammography quality with the FP rate. Among 1,209 women without cancer, there were 104 (8.6%) FPs. Lower overall mammography quality is associated with an increase in the FP rate (risk ratio [RR], 1.4; 95% confidence interval [CI], 1.0-2.1; P = .07) but this increase was not statistically significant. Artifacts were associated with an increase in the FP rate (RR, 2.1; 95% CI, 1.3-3.3; P = .01) whereas lower quality of exposure level was related to a reduction of the FP rate (RR, 0.4; 95% CI, 0.1-1.0; P = .01). Lower quality scores for all other quality attributes were related to a nonstatistically significant increase in the FP rate of 10%-30%. Artifacts can have a substantial effect on the FP rate. The effect of overall mammography quality on the FP rate may also be substantial and needs to be clarified. Copyright © 2017 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

  13. Pluto behaving badly: false beliefs and their consequences.

    Science.gov (United States)

    Berkowitz, Shari R; Laney, Cara; Morris, Erin K; Garry, Maryanne; Loftus, Elizabeth F

    2008-01-01

    We exposed college students to suggestive materials in order to lead them to believe that, as children, they had a negative experience at Disneyland involving the Pluto character. A sizable minority of subjects developed a false belief or memory that Pluto had uncomfortably licked their ear. Suggestions about a positive experience with Pluto led to even greater acceptance of a lovable ear-licking episode. False beliefs and memories had repercussions; those seduced by the bad suggestions were not willing to pay as much for a Pluto souvenir. These findings are among the first to demonstrate that false beliefs can have repercussions for people, meaning that they can influence their later thoughts, beliefs, and behaviors.

  14. Antimicrobial Susceptibility and Genotypic Characteristic of Campylobacter spp. Isolates from Free-Living Birds in Poland.

    Science.gov (United States)

    Krawiec, Marta; Woźniak-Biel, Anna; Bednarski, Michał; Wieliczko, Alina

    2017-11-01

    Campylobacter spp. is the most commonly reported, bacterial cause of human foodborne infection worldwide. Commercial poultry and free-living birds are natural reservoirs of three particular species: Campylobacter jejuni, Campylobacter coli, and Campylobacter lari. The aim of this study was to determine the genotypic characteristics and antibiotic susceptibility of 43 Campylobacter strains, obtained from free-living birds, in Poland. In total, 700 birds were examined. The strains were isolated from 43 birds (6.14%) from the feces of 7 wild bird species: Mallard ducks Anas platyrhynchos (29 positive/121 tested), great cormorants Phalacrocorax carbo (5/77), velvet scoters Melanitta fusca (4/30), tawny owls Strix aluco (2/5), common buzzard Buteo buteo (1/3), rook Corvus frugilegus (1/6), and Eurasian tree sparrow Passer montanus (1/30). Thirty-eight (88.37%) of obtained strains belonged to C. jejuni and five (11.63%) to C. coli. Other 428 examined birds from different bird species were Campylobacter negative. The antimicrobial susceptibility to nine antimicrobials was also studied in investigated isolates of Campylobacter spp. Sixteen of the examined strains (37.21% of all positive samples) showed susceptibility to all of the nine antimicrobials. Moreover, the prevalence of selected virulence genes, such as flaA, cadF, ceuE, virB11, cdtA, cdtB, and cdtC were all analyzed. The virulence gene that was found most frequently in total number of Campylobacter strains was ceuE (72.10%) and other genes, such as flaA, cadF, cdtA, cdtB, and cdtC, were found in over 60% of all examined strains. Variable antimicrobial susceptibility and the presence of different virulence genes of examined strains, isolated from free-living birds, suggest that special attention should be given to wild birds and any potential approaches to the control of antibiotic-resistant Campylobacter should be discussed.

  15. Systematic hybrid LOH: a new method to reduce false positives and negatives during screening of yeast gene deletion libraries

    DEFF Research Database (Denmark)

    Alvaro, D.; Sunjevaric, I.; Reid, R. J.

    2006-01-01

    We have developed a new method, systematic hybrid loss of heterozygosity, to facilitate genomic screens utilizing the yeast gene deletion library. Screening is performed using hybrid diploid strains produced through mating the library haploids with strains from a different genetic background......, to minimize the contribution of unpredicted recessive genetic factors present in the individual library strains. We utilize a set of strains where each contains a conditional centromere construct on one of the 16 yeast chromosomes that allows the destabilization and selectable loss of that chromosome. After...... complementation of any spurious recessive mutations in the library strain, facilitating attribution of the observed phenotype to the documented gene deletion and dramatically reducing false positive results commonly obtained in library screens. The systematic hybrid LOH method can be applied to virtually any...

  16. False-positive 18F-fluorodeoxyglucose positron emission tomography/computed tomography in a patient with metallic implants following chondrosarcoma resection.

    Science.gov (United States)

    Zhou, P U; Tang, Jinliang; Zhang, Dong; Li, Guanghui

    2016-05-01

    Positron emission tomography (PET) with fluorine-18-labeled fluorodeoxyglucose ( 18 F-FDG) has been used for the staging and evaluation of recurrence in cancer patients. We herein report a false-positive result of 18 F-FDG PET/computed tomography (CT) scan in a patient following chondrosarcoma resection and metallic implanting. A 35-year-old male patient with chondrosarcoma of the left iliac bone underwent radical resection, metal brace implanting and radiotherapy. A high uptake of 18 F-FDG was observed in the metallic implants and adjacent tissue during PET/CT scanning in the 5th year of follow-up. Tissue biopsy and follow-up examination identified no tumor recurrence or infection at these sites, suggesting that the results of 18 F-FDG PET/CT must be interpreted with caution in cancer patients with metallic implants.

  17. Image findings of a false positive radioactive iodine-131 uptake mimicking metastasis in pulmonary aspergillosis identified on single photon emission computed tomography-computed tomography

    Directory of Open Access Journals (Sweden)

    Kamaleshwaran Koramadai Karuppusamy

    2015-01-01

    Full Text Available High doses of iodine-131 are commonly used in patients with differentiated thyroid cancer after total or subtotal thyroidectomy, in order to ablate the remaining cancer or normal thyroid tissue. Multiple different false-positive scans can occur in the absence of residual thyroid tissue or metastases. The authors present a case of abnormal uptake of radioactive iodine in the aspergilloma, potentially masquerading as pulmonary metastases.

  18. Detection of Yersinia enterocolitica serotype O:9 in the faeces of cattle with false positive reactions in serological tests for brucellosis in Ireland.

    Science.gov (United States)

    O'Grady, Don; Kenny, Kevin; Power, Seamus; Egan, John; Ryan, Fergus

    2016-10-01

    Intestinal infection by Yersinia enterocolitica serotype O:9 (YeO9) in cattle has been linked to false positive serological reactivity (FPSR) in diagnostic tests for brucellosis. Although eradicated in Ireland, brucellosis monitoring still identifies seropositive animals, usually one or two (termed singletons) per herd, which are classed as FPSR. To investigate a link between FPSR and YeO9, faeces and blood were collected from singleton FPSR cattle, and from companion animals, in eight selected herds with more than one FPSR animal, for YeO9 culture and Brucella serology. YeO9 was isolated from 76/474 (16%) FPSR singletons in 309 herds, but not from any of 621 animals in 122 control non-FPSR herds. In the FPSR herds 52/187 (27.8%) animals were culture positive, and 17% of the isolates were from seronegative animals. Seropositive animals were more likely to have a rising antibody titre when culture positive. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Sadder and less accurate? False memory for negative material in depression.

    Science.gov (United States)

    Joormann, Jutta; Teachman, Bethany A; Gotlib, Ian H

    2009-05-01

    Previous research has demonstrated that induced sad mood is associated with increased accuracy of recall in certain memory tasks; the effects of clinical depression, however, are likely to be quite different. The authors used the Deese-Roediger-McDermott paradigm to examine the impact of clinical depression on erroneous recall of neutral and/or emotional stimuli. Specifically, they presented Deese-Roediger-McDermott lists that were highly associated with negative, neutral, or positive lures and compared participants diagnosed with major depressive disorder and nondepressed control participants on the accuracy of their recall of presented material and their false recall of never-presented lures. Compared with control participants, major depressive disorder participants recalled fewer words that had been previously presented but were more likely to falsely recall negative lures; there were no differences between major depressive disorder and control participants in false recall of positive or neutral lures. These findings indicate that depression is associated with false memories of negative material.

  20. Significance of FDG-PET in Identification of Diseases of the Appendix – Based on Experience of Two Cases Falsely Positive for FDG Accumulation

    Directory of Open Access Journals (Sweden)

    Shimpei Ogawa

    2009-04-01

    Full Text Available A discussion of the significance of F-fluorodeoxyglucose positron emission tomography (FDG-PET in the identification of diseases of the appendix is presented based on two cases falsely positive for FDG accumulation. Both cases were palpable for a tumor in the lower right abdominal region and a prominently enlarged appendix was depicted by CT. Although the patients underwent ileocecal resection based on a strong suspicion of appendiceal cancer rather than appendicitis since abnormal accumulation exhibiting maximum standard uptake values (SUVs of 7.27 and 17.11, respectively, was observed at the same site in FDG-PET examination and since there no malignant findings observed histologically, the patients were diagnosed with appendicitis. Although FDG specifically accumulates not only in malignant tumors, but also in diseases such as acute or chronic inflammation, abscesses and lymphadenitis, and identification based on SUVs has been reported to be used as a method of identification, the two cases reported here were both false-positive cases exhibiting high maximum SUVs. At the present time, although the significance of FDG-PET in the identification of diseases of the appendix is somewhat low and there are limitations on its application, various research is currently being conducted with the aim of improving diagnostic accuracy, and it is hoped that additional studies will be conducted in the future.

  1. [Quantitative and qualitative analyses for characteristics of the clock drawing in Alzheimer's disease].

    Science.gov (United States)

    Konagaya, Yoko; Konagaya, Masaaki; Watanabe, Tomoyuki; Washimi, Yukihiko

    2014-01-01

    We analyzed the results of the clock drawing test (CDT) in patients with Alzheimer's disease (AD) by quantitative and qualitative methods to evaluate its significance for cognitive function screening. We administered the CDT and mini-mental state examination (MMSE) to a total of 156 AD patients, and CDT performance was scored quantitatively in accordance with the method by Freedman, while the CDT error types were qualitatively classified by Rouleau's method. We divided AD patients into three groups by their MMSE total score (A: 23 ≤, B: 18~22, C: ≤ 17). The mean total scores of CDT and MMSE in AD were 11.5 ± 3.4 and 19.8 ± 4.7, respectively, and the total CDT scores showed significant positive correlation with the total MMSE scores (r = 0.450). Fewer than 80% of subjects drew the clock correctly for 8 out of 15 sub-items, and fewer were able to correctly draw clock hands than could correctly draw numbers, contour or a center. In analysis of CDT qualitative error types, the most common error types were spatial and/or planning deficit (SPD) (28.2%), and conceptual deficit (CD) (23.7%), which suggested visuospatial impairments and semantic impairments play essential roles in AD patients' poor clock drawings. The frequency of CD and SPD error types significantly increased as severity of cognitive function worsened (p < 0.001, p < 0.05, respectively), and those of stimulus-bound response and perseveration had tendency to increase as severity of cognitive function. The present study suggests that CDT is a useful screening method not only for the impairment of cognitive function and the severity of cognitive dysfunction, but also for identification of specific cognitive function impairments in AD patients.

  2. Public health consequences of a false-positive laboratory test result for Brucella--Florida, Georgia, and Michigan, 2005.

    Science.gov (United States)

    2008-06-06

    Human brucellosis, a nationally notifiable disease, is uncommon in the United States. Most human cases have occurred in returned travelers or immigrants from regions where brucellosis is endemic, or were acquired domestically from eating illegally imported, unpasteurized fresh cheeses. In January 2005, a woman aged 35 years who lived in Nassau County, Florida, received a diagnosis of brucellosis, based on results of a Brucella immunoglobulin M (IgM) enzyme immunoassay (EIA) performed in a commercial laboratory using analyte specific reagents (ASRs); this diagnosis prompted an investigation of dairy products in two other states. Subsequent confirmatory antibody testing by Brucella microagglutination test (BMAT) performed at CDC on the patient's serum was negative. The case did not meet the CDC/Council of State and Territorial Epidemiologists' (CSTE) definition for a probable or confirmed brucellosis case, and the initial EIA result was determined to be a false positive. This report summarizes the case history, laboratory findings, and public health investigations. CDC recommends that Brucella serology testing only be performed using tests cleared or approved by the Food and Drug Administration (FDA) or validated under the Clinical Laboratory Improvement Amendments (CLIA) and shown to reliably detect the presence of Brucella infection. Results from these tests should be considered supportive evidence for recent infection only and interpreted in the context of a clinically compatible illness and exposure history. EIA is not considered a confirmatory Brucella antibody test; positive screening test results should be confirmed by Brucella-specific agglutination (i.e., BMAT or standard tube agglutination test) methods.

  3. False-positive radioactive iodine uptake mimicking miliary lung metastases in a patient affected by papillary thyroid cancer and IgA deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Demidowich, Andrew Paul; Reynolds, James C. [National Institutes of Health, Bethesda (United States); Kundu, Amartya [Dept. of MedicineUniversity of Massachusetts Medical School, Worcester (United States); Celi, Francesco S. [Div. of Endocrinology and MetabolismVirginia Commonwealth UniversityRichmond (United States)

    2016-09-15

    A 42-year-old female with immunoglobulin A deficiency and recurrent sinopulmonary infections underwent thyroidectomy for papillary thyroid cancer (PTC). Follow-up {sup 123}I scintigraphy demonstrated diffuse pulmonary uptake, suggesting metastatic disease. However, subsequent pathologic, biochemical and radiographic testing proved that she was in fact disease free, and the initial {sup 123}I pulmonary uptake was identified as a false positive. Inflammatory conditions may rarely cause iodine uptake in non-thyroidal tissues due to local retention, organification, and/or immunologic utilization. To avoid exposing patients to unnecessary treatments, it is critical for clinicians to recognize that comorbid pulmonary conditions may mimic metastatic PTC on radioiodine scintigraphy.

  4. Distance Sensitive Bloom Filters Without False Negatives

    DEFF Research Database (Denmark)

    Goswami, Mayank; Pagh, Rasmus; Silvestri, Francesco

    2017-01-01

    A Bloom filter is a widely used data-structure for representing a set S and answering queries of the form “Is x in S?”. By allowing some false positive answers (saying ‘yes’ when the answer is in fact ‘no’) Bloom filters use space significantly below what is required for storing S. In the distanc...

  5. False-negative diffusion-weighted imaging findings in acute stroke

    International Nuclear Information System (INIS)

    Ishikawa, Tatsuya; Yuasa, Naoki; Otomo, Takashi; Shiramizu, Hideki; Matsuda, Hiroshi; Kitagawa, Yasuhisa; Takagi, Shigeharu

    2006-01-01

    The utility of DWI (diffusion-weighted imaging) has been established in acute ischemic stroke. However, some patients with acute stroke show no abnormal signals on DWI, despite the presence of infarction (false-negative DWI). We analyzed the relationship between false-negative DWI and the clinical manifestations of acute ischemic stroke in 151 DWI-positive (89%) and 19 false-negative DWI (11%) patients. We performed MRI within 24 hours after onset at our hospital. Non-specific clinical manifestations, including vertigo and nausea, were frequently observed in false-negative DWI patients. As regards the vascular territory, false-negative DWI was noted in 15.3% of 59 patients with infarctions within the territory of the vertebrobasilar artery. Concerning the duration from onset to initial imaging, 73.7% of the patients with false-negative DWI findings underwent MRI examination within 6 hours after onset. Of the patients with false-negative DWI, 84.2% had lacunar infarction (χ 2 =16.4, P<0.001). In conclusion, false negative DWI is more frequently observed in lacunar infarction than in atherothrombotic infarction or cardiogenic embolism. It is important to examine carefully the neurological changes occurring in patients who present with acute stroke, but have negative DWI findings. (author)

  6. Benign oral pathology as a cause of false positive 131I uptake in thyroid carcinoma

    International Nuclear Information System (INIS)

    Mansberg, R.; Wadhwa, S.S.; Fernandes, V.B.

    1997-01-01

    Full text: We present three thyroidectomised patients with a history of thyroid carcinoma who had non-metastatic 131 I uptake due to benign oral pathology. A salivary gland study suggested impaired function but no obstruction was demonstrated on a sialogram. The symptoms resolved on antibiotic therapy and a subsequent 131 I study was normal. A subsequent thallium study demonstrated physiological tracer distribution. A 35-year-old female with papillary cell carcinoma of the thyroid demonstrated a focus of uptake on the right hemi-mandible following both a diagnostic and a therapeutic dose of 131 I. This area was tender and an OPG confirmed an area of liquefaction at this site. A 53-year-old female with medullary cell carcinoma of the thyroid demonstrated a focus of uptake in the right side of the maxilla following a diagnostic administration of 131 I. An OPG confirmed an area of liquefaction around the apex of the right upper centre. These three cases illustrate salivary gland and dental inflammation as causes of false positive 131 I uptake. It is important to differentiate non-metastatic 131 I uptake from that due to functioning metastatic thyroid carcinoma in order to avoid inappropriate treatment with large additional doses of 131 I. As in these patients, clinical assessment and the use of anatomical imaging or other isotopes such as thallium or technetium can be helpful in ruling out a mistaken diagnosis of metastasis

  7. False recollection of emotional pictures in Alzheimer's disease.

    Science.gov (United States)

    Gallo, David A; Foster, Katherine T; Wong, Jessica T; Bennett, David A

    2010-10-01

    Alzheimer's Disease (AD) can reduce the effects of emotional content on memory for studied pictures, but less is known about false memory. In healthy adults, emotionally arousing pictures can be more susceptible to false memory effects than neutral pictures, potentially because emotional pictures share conceptual similarities that cause memory confusions. We investigated these effects in AD patients and healthy controls. Participants studied pictures and their verbal labels, and then picture recollection was tested using verbal labels as retrieval cues. Some of the test labels had been associated with a picture at study, whereas other had not. On this picture recollection test, we found that both AD patients and controls incorrectly endorsed some of the test labels that had not been studied with pictures. These errors were associated with medium to high levels of confidence, indicating some degree of false recollection. Critically, these false recollection judgments were greater for emotional compared to neutral items, especially for positively valenced items, in both AD patients and controls. Dysfunction of the amygdala and hippocampus in early AD may impair recollection, but AD did not disrupt the effect of emotion on false recollection judgments. Copyright © 2010 Elsevier Ltd. All rights reserved.

  8. False memory and the associative network of happiness.

    Science.gov (United States)

    Koo, Minkyung; Oishi, Shigehiro

    2009-02-01

    This research examines the relationship between individuals' levels of life satisfaction and their associative networks of happiness. Study 1 measured European Americans' degree of false memory of happiness using the Deese-Roediger-McDermott paradigm. Scores on the Satisfaction With Life Scale predicted the likelihood of false memory of happiness but not of other lure words such as sleep . In Study 2, European American participants completed an association-judgment task in which they judged the extent to which happiness and each of 15 positive emotion terms were associated with each other. Consistent with Study 1's findings, chronically satisfied individuals exhibited stronger associations between happiness and other positive emotion terms than did unsatisfied individuals. However, Koreans and Asian Americans did not exhibit such a pattern regarding their chronic level of life satisfaction (Study 3). In combination, results suggest that there are important individual and cultural differences in the cognitive structure and associative network of happiness.

  9. Modeling Kepler Transit Light Curves as False Positives: Rejection of Blend Scenarios for Kepler-9, and Validation of Kepler-9 d, a Super-Earth-Size Planet in a Multiple System

    Science.gov (United States)

    Torres, Guillermo; Fressin, Francois; Batalha, Natalie M.; Borucki, William J.; Brown, Timothy M.; Bryson, Stephen T.; Buchhave, Lars A.; Charbonneau, David; Ciardi, David R.; Dunham, Edward W.; hide

    2011-01-01

    Light curves from the Kepler Mission contain valuable information on the nature of the phenomena producing the transit-like signals. To assist in exploring the possibility that they are due to an astrophysical false positive we describe a procedure (BLENDER) to model the photometry in terms of a blend rather than a planet orbiting a star. A blend may consist of a background or foreground eclipsing binary (or star-planet pair) whose eclipses are attenuated by the light of the candidate and possibly other stars within the photometric aperture. We apply BLENDER to the case of Kepler-9 (KIC 3323887), a target harboring two previously confirmed Saturn-size planets (Kepler-9 b and Kepler-9 c) showing transit timing variations, and an additional shallower signal with a 1.59 day period suggesting the presence of a super-Earth-size planet. Using BLENDER together with constraints from other follow-up observations we are able to rule out all blends for the two deeper signals and provide independent validation of their planetary nature. For the shallower signal, we rule out a large fraction of the false positives that might mimic the transits. The false alarm rate for remaining blends depends in part (and inversely) on the unknown frequency of small-size planets. Based on several realistic estimates of this frequency, we conclude with very high confidence that this small signal is due to a super-Earth-size planet (Kepler-9 d) in a multiple system, rather than a false positive. The radius is determined to be 1.64(exp)(sub-14),R, and current spectroscopic observations are as yet insufficient to establish its mass.

  10. Too Good to be False: Nonsignificant Results Revisited

    Directory of Open Access Journals (Sweden)

    Chris H. J. Hartgerink

    2017-03-01

    Full Text Available Due to its probabilistic nature, Null Hypothesis Significance Testing (NHST is subject to decision errors. The concern for false positives has overshadowed the concern for false negatives in the recent debates in psychology. This might be unwarranted, since reported statistically nonsignificant findings may just be ‘too good to be false’. We examined evidence for false negatives in nonsignificant results in three different ways. We adapted the Fisher test to detect the presence of at least one false negative in a set of statistically nonsignificant results. Simulations show that the adapted Fisher method generally is a powerful method to detect false negatives. We examined evidence for false negatives in the psychology literature in three applications of the adapted Fisher method. These applications indicate that (i the observed effect size distribution of nonsignificant effects exceeds the expected distribution assuming a null-effect, and approximately two out of three (66.7% psychology articles reporting nonsignificant results contain evidence for at least one false negative, (ii nonsignificant results on gender effects contain evidence of true nonzero effects, and (iii the statistically nonsignificant replications from the Reproducibility Project Psychology (RPP do not warrant strong conclusions about the absence or presence of true zero effects underlying these nonsignificant results. We conclude that false negatives deserve more attention in the current debate on statistical practices in psychology. Potentially neglecting effects due to a lack of statistical power can lead to a waste of research resources and stifle the scientific discovery process.

  11. The mechanism of Jurkat cells apoptosis induced by Aggregatibacter actinomycetemcomitans cytolethal distending toxin.

    Science.gov (United States)

    Chen, Hui-Ping; Li, Lu; Chen, Xu; Yang, Mi-Fang; Ye, Yu; Wang, Xiao-Qian; Xu, Yan

    2017-06-01

    Cytolethal distending toxin (CDT) which is produced by Aggregatibacter actinomycetemcomitans causes apoptosis in lymphocytes. But the specific mechanism is not clear. The aim of our research was to investigate the effect and mechanism during this process. The wild-type CdtA, CdtB, CdtC (CdtA W , CdtB W , CdtC W ) and mutant CdtB (CdtB M ) were expressed and purified respectively and the purity of each subunit was examined by BandScan software. And the type I deoxyribonuclease and PI-3,4,5-triphosphate (PI-3,4,5-P3, PIP3) phosphatase activity were detected by DNA agarose gel electrophoresis and enzyme-linked immunosorbent assay respectively. The cell apoptosis rates were analyzed by flow cytometry. The morphological changes of apoptosis cells were observed by confocal laser scanning microscopy. The protein expression of Bax and Bcl-2 was examined by western blot. Differentially expressed apoptosis-related proteins were identified based on isobaric tags for relative and absolute quantitation technology. In the present study we found that: (i) recombinant wild-type CdtA, CdtB and CdtC (CdtA W , CdtB W , CdtC W ) and mutant CdtB (CdtB M ) were correctly expressed and the purity of each protein was higher than 80%, (ii) the average apoptosis rate in wild-type CDT (CDT W ) treated groups was 50.54%, which was significantly higher than the controls (4.71%) and mutant CDT (CDT M ) treated groups (5.58%) (p apoptosis were observed in CDT W treated cells, (iv) the expression of Bax protein was significantly increased in CDT W treated cells, while Bcl-2 protein expression was significantly decreased, (v) 17 apoptosis-related proteins were expressed differentially, among which 10 proteins (SMNDC1, TNFRSF10B, UBE2I, ITM2A, CASP3, P53, EIF1, TCF3, HMGN5, CASP8) were up-regulated and 7 proteins (RRM2, TPX2, KIF11, NUCKS1, TOP2A, XRCC1, PTPLAD1, RRM2) were down-regulated, (vi) one possible apoptotic pathway [Ubc9 (UBE2I)/P53/DR5 (TNFRSF10B)/Caspase-8 (CASP8)/ Caspase-3 (CASP3

  12. False memories and memory confidence in borderline patients.

    Science.gov (United States)

    Schilling, Lisa; Wingenfeld, Katja; Spitzer, Carsten; Nagel, Matthias; Moritz, Steffen

    2013-12-01

    Mixed results have been obtained regarding memory in patients with borderline personality disorder (BPD). Prior reports and anecdotal evidence suggests that patients with BPD are prone to false memories but this assumption has to been put to firm empirical test, yet. Memory accuracy and confidence was assessed in 20 BPD patients and 22 healthy controls using a visual variant of the false memory (Deese-Roediger-McDermott) paradigm which involved a negative and a positive-valenced picture. Groups did not differ regarding veridical item recognition. Importantly, patients did not display more false memories than controls. At trend level, borderline patients rated more items as new with high confidence compared to healthy controls. The results tentatively suggest that borderline patients show uncompromised visual memory functions and display no increased susceptibility for distorted memories. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Sample Size Calculation for Controlling False Discovery Proportion

    Directory of Open Access Journals (Sweden)

    Shulian Shang

    2012-01-01

    Full Text Available The false discovery proportion (FDP, the proportion of incorrect rejections among all rejections, is a direct measure of abundance of false positive findings in multiple testing. Many methods have been proposed to control FDP, but they are too conservative to be useful for power analysis. Study designs for controlling the mean of FDP, which is false discovery rate, have been commonly used. However, there has been little attempt to design study with direct FDP control to achieve certain level of efficiency. We provide a sample size calculation method using the variance formula of the FDP under weak-dependence assumptions to achieve the desired overall power. The relationship between design parameters and sample size is explored. The adequacy of the procedure is assessed by simulation. We illustrate the method using estimated correlations from a prostate cancer dataset.

  14. Upward creep of the heart: A frequent source of false-positive reversible defects during thallium-201 stress-redistribution SPECT

    International Nuclear Information System (INIS)

    Friedman, J.; Van Train, K.; Maddahi, J.; Rozanski, A.; Prigent, F.; Bietendorf, J.; Waxman, A.; Berman, D.S.

    1989-01-01

    A new cause of artifactual 201 Tl defects on single photon emission computed tomography (SPECT) termed upward creep of the heart is described. In 102 consecutive patients undergoing 201 Tl SPECT, 30 (29%) demonstrated upward creep defined by an upward movement of the heart of greater than or equal to 2 pixels during acquisition. In 45 consecutive patients with a less than 5% likelihood of coronary artery disease, 17 (38%) had upward creep. Of these nine had reversible 201 Tl defects localized to the inferior and basal inferoseptal walls, while none of the 28 without upward creep had defects. The 17 low likelihood patients with upward creep had longer exercise duration and higher peak heart rate than those without upward creep. In five additional low likelihood patients with upward creep in whom imaging was immediately repeated, the upward creep pattern disappeared on the repeated images. After we changed our test protocol to begin imaging 15 min postexercise, only five (14%) of 36 low likelihood patients tested demonstrated upward creep. Upward creep is probably related to a transient increase in mean total lung volume early following exhaustive exercise, resulting in a mean lower position of the diaphragm (and thus the heart) at the beginning of imaging. The frequency of this source of false-positive 201 Tl studies can be reduced by delaying SPECT acquisition until 15 min postexercise

  15. Confabulation versus experimentally induced false memories in Korsakoff patients.

    Science.gov (United States)

    Van Damme, Ilse; d'Ydewalle, Géry

    2010-09-01

    The present study focuses on both the clinical symptom of confabulation and experimentally induced false memories in patients suffering from Korsakoff's syndrome. Despite the vast amount of case studies of confabulating patients and studies investigating false memories in the Deese-Roediger-McDermott (DRM) paradigm, the nature of Korsakoff patients' confabulatory behaviour and its association with DRM false memories have been rarely examined. Hence, the first aim of the present study was to evaluate confabulatory responses in a large sample of chronic Korsakoff patients and matched controls by means of the Dalla Barba Confabulation Battery. Second, the association between (provoked) confabulation and the patients' DRM false recognition performance was investigated. Korsakoff patients mainly confabulated in response to questions about episodic memory and questions to which the answer was unknown. A positive association was obtained between confabulation and the tendency to accept unstudied distractor words as being old in the DRM paradigm. On the other hand, there was a negative association between confabulation and false recognition of critical lures. The latter could be attributed to the importance of strategic retrieval at delayed memory testing.

  16. A critical reappraisal of false negative sentinel lymph node biopsy in melanoma

    International Nuclear Information System (INIS)

    Manca, G.; Mazzarri, S.; Boni, G.; Chiacchio, S.; Tredici, M.; Duce, V.; Tardelli, E.; Volterrani, D.; Mariani, G.; Romanini, A.; Rubello, D.

    2014-01-01

    Lymphatic mapping and sentinel lymph node biopsy (SLNB) have completely changed the clinical management of cutaneous melanoma. This procedure has been accepted worldwide as a recognized method for nodal staging. SLNB is able to accurately determine nodal basin status, providing the most useful prognostic information. However, SLNB is not a perfect diagnostic test. Several large-scale studies have reported a relatively high false-negative rate (5.6-21%), correctly defined as the proportion of false-negative results with respect to the total number of “actual” positive lymph nodes. The main purpose of this review is to address the technical issues that nuclear physicians, surgeons, and pathologists should carefully consider to improve the accuracy of SLNB by minimizing its false-negative rate. In particular, SPECT/CT imaging has demonstrated to be able to identify a greater number of sentinel lymph nodes (SLNs) than those found by planar lymphoscintigraphy. Furthermore, a unique definition in the international guidelines is missing for the operational identification of SLNs, which may be partly responsible for this relatively high false-negative rate of SLNB. Therefore, it is recommended for the scientific community to agree on the radioactive counting rate threshold so that the surgeon can be better radioguided to detect all the lymph nodes which are most likely to harbor metastases. Another possible source of error may be linked to the examination of the harvested SLNs by conventional histopathological methods. A more careful and extensive SLN analysis (e.g. molecular analysis by RT-PCR) is able to find more positive nodes, so that the false-negative rate is reduced. Older age at diagnosis, deeper lesions, histologic ulceration, head-neck anatomical location of primary lesions are the clinical factors associated with false-negative SLNBs in melanoma patients. There is still much controversy about the clinical significance of a false-negative SLNB on the

  17. Emotion and false memory: How goal-irrelevance can be relevant for what people remember.

    Science.gov (United States)

    Van Damme, Ilse; Kaplan, Robin L; Levine, Linda J; Loftus, Elizabeth F

    2017-02-01

    Elaborating on misleading information concerning emotional events can lead people to form false memories. The present experiment compared participants' susceptibility to false memories when they elaborated on information associated with positive versus negative emotion and pregoal versus postgoal emotion. Pregoal emotion reflects appraisals that goal attainment or failure is anticipated but has not yet occurred (e.g., hope and fear). Postgoal emotion reflects appraisals that goal attainment or failure has already occurred (e.g., happiness and devastation). Participants watched a slideshow depicting an interaction between a couple and were asked to empathise with the protagonist's feelings of hope (positive pregoal), happiness (positive postgoal), fear (negative pregoal), or devastation (negative postgoal); in control conditions, no emotion was mentioned. Participants were then asked to reflect on details of the interaction that had occurred (true) or had not occurred (false), and that were relevant or irrelevant to the protagonist's goal. Irrespective of emotional valence, participants in the pregoal conditions were more susceptible to false memories concerning goal-irrelevant details than were participants in the other conditions. These findings support the view that pregoal emotions narrow attention to information relevant to goal pursuit, increasing susceptibility to false memories for irrelevant information.

  18. Feature-guided analysis for reduction of false positives in CAD of polyps for computed tomographic colonography

    International Nuclear Information System (INIS)

    Naeppi, Janne; Yoshida, Hiroyuki

    2003-01-01

    We evaluated the effect of our novel technique of feature-guided analysis of polyps on the reduction of false-positive (FP) findings generated by our computer-aided diagnosis (CAD) scheme for the detection of polyps from computed tomography colonographic data sets. The detection performance obtained by use of feature-guided analysis in the segmentation and feature analysis of polyp candidates was compared with that obtained by use of our previously employed fuzzy clustering technique. We also evaluated the effect of a feature called modified gradient concentration (MGC) on the detection performance. A total of 144 data sets, representing prone and supine views of 72 patients that included 14 patients with 21 colorectal polyps 5-25 mm in diameter, were used in the evaluation. At a 100% by-patient (95% by-polyp) detection sensitivity, the FP rate of our CAD scheme with feature-guided analysis based on round-robin evaluation was 1.3 (1.5) FP detections per patient. This corresponds to a 70-75 % reduction in the number of FPs obtained by use of fuzzy clustering at the same sensitivity levels. Application of the MGC feature instead of our previously used gradient concentration feature did not improve the detection result. The results indicate that feature-guided analysis is useful for achieving high sensitivity and a low FP rate in our CAD scheme

  19. First report of Clostridium difficile NAP1/027 in a Mexican hospital.

    Directory of Open Access Journals (Sweden)

    Adrián Camacho-Ortiz

    Full Text Available Clostridium difficile NAP1/ribotype 027 is associated with severe disease and high mortality rates. Our aim was to determine the prevalence of NAP1/ribotype 027 among C. difficile isolates in a tertiary care hospital, and review the main clinical data.We included 106 stool samples from 106 patients. Samples were tested for A&B toxins and were cultured on CCFA agar. The genes tcdA, tcdB, tcdC, cdtA, and cdtB were amplified using PCR in clinical isolates. The tcdA 3'-end deletion analysis, PCR-ribotyping, and pulsed-field gel electrophoresis (PFGE were also performed. Stool samples that were positive for culture were tested by the GeneXpert C. difficile assay. Clinical data were collected.Thirty-six patients tested positive for A&B toxins; and 22 patients had positive culture for C. difficile, 14 of which tested positive for the A&B toxins and all 22 patients tested positive by the GeneXpert C. difficile assay. Risk factors included an average hospital stay of 16.1 days prior to toxin detection, average antibiotic use for 16.2 days, and a median of 3 antibiotics used. The 30-day crude mortality rate was 8.4%. Six of the 22 patients died, and 3 of those deaths were directly attributed to C. difficile infection. The majority of isolates, 90.9% (20/22, carried genes tcdB, tcdA, cdtA, and cdtB; and these strains carried the corresponding downregulator gene tcdC, with an 18-bp deletion. PFGE was performed on 17 isolates, and one main pattern was observed. Analysis of the ribotyping data showed similar results.The above findings represent the clonal spread of C. difficile in our institution, which mainly includes the NAP1/027 strain. This is the first report of C. difficile ribotype NAP1/027 in Mexico.

  20. Enhancing the Statistical Filtering Scheme to Detect False Negative Attacks in Sensor Networks

    Directory of Open Access Journals (Sweden)

    Muhammad Akram

    2017-06-01

    Full Text Available In this paper, we present a technique that detects both false positive and false negative attacks in statistical filtering-based wireless sensor networks. In statistical filtering scheme, legitimate reports are repeatedly verified en route before they reach the base station, which causes heavy energy consumption. While the original statistical filtering scheme detects only false reports, our proposed method promises to detect both attacks.

  1. Veridical and false recall in adults who stutter.

    Science.gov (United States)

    Byrd, Courtney T; Sheng, Li; Ratner, Nan Bernstein; Gkalitsiou, Zoi

    2015-02-01

    This study used a false memory paradigm to explore the veridical and false recall of adults who stutter. Twelve adults who stutter and 12 age-matched typically fluent peers listened to and then verbally recalled lists of words that consisted of either semantic or phonological associates or an equal number of semantic and phonological associates (i.e., hybrid condition) of a single, unpresented critical "lure" word. Three parameters of recall performance were measured across these 3 conditions: (a) number of accurately recalled words, (b) order of recall (primacy vs. recency effect), and (c) number of critical lures produced (i.e., false memories). Significant group differences were noted in recall accuracy specific to list type and also list position as well as relative to critical lure productions. Results suggest that certain basic memory processes (i.e., recency effect) and the processing of gist semantic information are largely intact in adults who stutter, but recall of verbatim phonological information and subvocal rehearsal may be deficient.

  2. False memory in aging: effects of emotional valence on word recognition accuracy.

    Science.gov (United States)

    Piguet, Olivier; Connally, Emily; Krendl, Anne C; Huot, Jessica R; Corkin, Suzanne

    2008-06-01

    Memory is susceptible to distortions. Valence and increasing age are variables known to affect memory accuracy and may increase false alarm production. Interaction between these variables and their impact on false memory was investigated in 36 young (18-28 years) and 36 older (61-83 years) healthy adults. At study, participants viewed lists of neutral words orthographically related to negative, neutral, or positive critical lures (not presented). Memory for these words was subsequently tested with a remember-know procedure. At test, items included the words seen at study and their associated critical lures, as well as sets of orthographically related neutral words not seen at study and their associated unstudied lures. Positive valence was shown to have two opposite effects on older adults' discrimination of the lures: It improved correct rejection of unstudied lures but increased false memory for critical lures (i.e., lures associated with words studied previously). Thus, increased salience triggered by positive valence may disrupt memory accuracy in older adults when discriminating among similar events. These findings likely reflect a source memory deficit due to decreased efficiency in cognitive control processes with aging.

  3. Teacher Education and the Enduring Significance of "False Empathy"

    Science.gov (United States)

    Warren, Chezare A.; Hotchkins, Bryan K.

    2015-01-01

    The concept "False Empathy" posited by critical race theory luminary Richard Delgado ("Calif Law Rev" 84(1):61-100, 1996) easily obscures White teacher's good intentions to be effective educators of racially, culturally, and linguistically diverse students. It is argued here that critical race theory is useful for isolating and…

  4. Massive-training artificial neural network (MTANN) for reduction of false positives in computer-aided detection of polyps: Suppression of rectal tubes

    International Nuclear Information System (INIS)

    Suzuki, Kenji; Yoshida, Hiroyuki; Naeppi, Janne; Dachman, Abraham H.

    2006-01-01

    One of the limitations of the current computer-aided detection (CAD) of polyps in CT colonography (CTC) is a relatively large number of false-positive (FP) detections. Rectal tubes (RTs) are one of the typical sources of FPs because a portion of a RT, especially a portion of a bulbous tip, often exhibits a cap-like shape that closely mimics the appearance of a small polyp. Radiologists can easily recognize and dismiss RT-induced FPs; thus, they may lose their confidence in CAD as an effective tool if the CAD scheme generates such ''obvious'' FPs due to RTs consistently. In addition, RT-induced FPs may distract radiologists from less common true positives in the rectum. Therefore, removal RT-induced FPs as well as other types of FPs is desirable while maintaining a high sensitivity in the detection of polyps. We developed a three-dimensional (3D) massive-training artificial neural network (MTANN) for distinction between polyps and RTs in 3D CTC volumetric data. The 3D MTANN is a supervised volume-processing technique which is trained with input CTC volumes and the corresponding ''teaching'' volumes. The teaching volume for a polyp contains a 3D Gaussian distribution, and that for a RT contains zeros for enhancement of polyps and suppression of RTs, respectively. For distinction between polyps and nonpolyps including RTs, a 3D scoring method based on a 3D Gaussian weighting function is applied to the output of the trained 3D MTANN. Our database consisted of CTC examinations of 73 patients, scanned in both supine and prone positions (146 CTC data sets in total), with optical colonoscopy as a reference standard for the presence of polyps. Fifteen patients had 28 polyps, 15 of which were 5-9 mm and 13 were 10-25 mm in size. These CTC cases were subjected to our previously reported CAD scheme that included centerline-based segmentation of the colon, shape-based detection of polyps, and reduction of FPs by use of a Bayesian neural network based on geometric and texture

  5. Mouse obesity network reconstruction with a variational Bayes algorithm to employ aggressive false positive control

    Directory of Open Access Journals (Sweden)

    Logsdon Benjamin A

    2012-04-01

    Full Text Available Abstract Background We propose a novel variational Bayes network reconstruction algorithm to extract the most relevant disease factors from high-throughput genomic data-sets. Our algorithm is the only scalable method for regularized network recovery that employs Bayesian model averaging and that can internally estimate an appropriate level of sparsity to ensure few false positives enter the model without the need for cross-validation or a model selection criterion. We use our algorithm to characterize the effect of genetic markers and liver gene expression traits on mouse obesity related phenotypes, including weight, cholesterol, glucose, and free fatty acid levels, in an experiment previously used for discovery and validation of network connections: an F2 intercross between the C57BL/6 J and C3H/HeJ mouse strains, where apolipoprotein E is null on the background. Results We identified eleven genes, Gch1, Zfp69, Dlgap1, Gna14, Yy1, Gabarapl1, Folr2, Fdft1, Cnr2, Slc24a3, and Ccl19, and a quantitative trait locus directly connected to weight, glucose, cholesterol, or free fatty acid levels in our network. None of these genes were identified by other network analyses of this mouse intercross data-set, but all have been previously associated with obesity or related pathologies in independent studies. In addition, through both simulations and data analysis we demonstrate that our algorithm achieves superior performance in terms of power and type I error control than other network recovery algorithms that use the lasso and have bounds on type I error control. Conclusions Our final network contains 118 previously associated and novel genes affecting weight, cholesterol, glucose, and free fatty acid levels that are excellent obesity risk candidates.

  6. Discrete emotion-congruent false memories in the DRM paradigm.

    Science.gov (United States)

    Bland, Cassandra E; Howe, Mark L; Knott, Lauren

    2016-08-01

    Research has shown that false-memory production is enhanced for material that is emotionally congruent with the mood of the participant at the time of encoding. So far this research has only been conducted to examine the influence of generic negative affective mood states and generic negative stimuli on false-memory production. In addition, much of the research is limited as it focuses on valence and arousal dimensions, and fails to take into account the more comprehensive nature of emotions. The current study demonstrates that this effect goes beyond general negative or positive moods and acts at a more discrete emotional level. Participants underwent a standard emotion-induction procedure before listening to negative emotional or neutral associative word lists. The emotions induced, negative word lists, and associated nonpresented critical lures, were related to either fear or anger, 2 negative valence emotions that are also both high in arousal. Results showed that when valence and arousal are controlled for, false memories are more likely to be produced for discrete emotionally congruent compared with incongruent materials. These results support spreading activation theories of false remembering and add to our understanding of the adaptive nature of false-memory production. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  7. False Positive Stress Testing: Does Endothelial Vascular Dysfunction Contribute to ST-Segment Depression in Women? A Pilot Study.

    Science.gov (United States)

    Sharma, Shilpa; Mehta, Puja K; Arsanjani, Reza; Sedlak, Tara; Hobel, Zachary; Shufelt, Chrisandra; Jones, Erika; Kligfield, Paul; Mortara, David; Laks, Michael; Diniz, Marcio; Bairey Merz, C Noel

    2018-06-19

    The utility of exercise-induced ST-segment depression for diagnosing ischemic heart disease (IHD) in women is unclear. Based on evidence that IHD pathophysiology in women involves coronary vascular dysfunction, we hypothesized that coronary vascular dysfunction contributes to exercise electrocardiography (Ex-ECG) ST-depression in the absence of obstructive CAD, so-called "false positive" results. We tested our hypothesis in a pilot study evaluating the relationship between peripheral vascular endothelial function and Ex-ECG. Twenty-nine asymptomatic women without cardiac risk factors underwent maximal Bruce protocol exercise treadmill testing and peripheral endothelial function assessment using peripheral arterial tonometry (Itamar EndoPAT 2000) to measure reactive hyperemia index (RHI). The relationship between RHI and Ex-ECG ST-segment depression was evaluated using logistic regression and differences in subgroups using two-tailed t-tests. Mean age was 54 ± 7 years, body mass index 25 ± 4 kg/m 2 , and RHI 2.51 ± 0.66. Three women (10%) had RHI less than 1.68, consistent with abnormal peripheral endothelial function, while 18 women (62%) met criteria for a positive Ex-ECG based on ST-segment depression in contiguous leads. Women with and without ST-segment depression had similar baseline and exercise vital signs, metabolic equivalents (METS) achieved, and RHI (all p>0.05). RHI did not predict ST-segment depression. Our pilot study demonstrates a high prevalence of exercise-induced ST-segment depression in asymptomatic, middle-aged, overweight women. Peripheral vascular endothelial dysfunction did not predict Ex-ECG ST-segment depression. Further work is needed to investigate the utility of vascular endothelial testing and Ex-ECG for IHD diagnostic and management purposes in women. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  8. [Neuropsychological study of false memory in patients with amnesia mild cognitive impairment].

    Science.gov (United States)

    Xie, Dan-dan; Cheng, Huai-dong; Yin, Chang-lin; Lü, Xin-yi; Wang, Kai

    2011-01-18

    To explore the profile of false memory in aMCI (amnesia mild cognitive impairment) and to elucidate the neuropsychological mechanism of false memory. False memory provoked by pictures and feeling-of-knowing (FOK) test in episodic memory (EM) were conducted in 25 aMCI patients at our hospital from October 2009 to May 2010. And 25 age and education level-matched healthy patients were recruited into the healthy control (HC) group. As compared with HC group, the rate of false memory was higher in the aMCI group. The rate of false memory in recall stage was 26% ± 7% and that of questionnaire stage 28% ± 12%. And the difference between two group was significant (t = 14.437, 7.597, P false recognition in the aMCI group (41% ± 10%) was higher than the HC group. And the difference was significant (t = 4.207, P false memory in recall and questionnaire stages were positively correlated with FOK-EM in aMCI group (r = 0.563, 0.705, P false memory provoked by pictures. The deficit of memory monitoring in aMCI may be the foundation of false memory.

  9. Siblings, Language, and False Belief in Low-Income Children

    Science.gov (United States)

    Tompkins, Virginia; Farrar, M. Jeffrey; Guo, Ying

    2013-01-01

    The authors examined the relationship between number of siblings and false belief understanding (FBU) in 94 low-income 4-5-year-olds. Previous research with middle-income children has shown a positive association between number of siblings and FBU. However, it is unclear whether having multiple siblings in low-income families is related to better…

  10. Avian metapneumovirus RT-nested-PCR: a novel false positive reducing inactivated control virus with potential applications to other RNA viruses and real time methods.

    Science.gov (United States)

    Falchieri, Marco; Brown, Paul A; Catelli, Elena; Naylor, Clive J

    2012-12-01

    Using reverse genetics, an avian metapneumovirus (AMPV) was modified for use as a positive control for validating all stages of a popular established RT-nested PCR, used in the detection of the two major AMPV subtypes (A and B). Resultant amplicons were of increased size and clearly distinguishable from those arising from unmodified virus, thus allowing false positive bands, due to control virus contamination of test samples, to be identified readily. Absorption of the control virus onto filter paper and subsequent microwave irradiation removed all infectivity while its function as an efficient RT-nested-PCR template was unaffected. Identical amplicons were produced after storage for one year. The modified virus is likely to have application as an internal standard as well as in real time methods. Additions to AMPV of RNA from other RNA viruses, including hazardous examples such HIV and influenza, are likely to yield similar safe RT-PCR controls. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. How Fuzzy-Trace Theory Predicts True and False Memories for Words, Sentences, and Narratives

    OpenAIRE

    Reyna, Valerie F.; Corbin, Jonathan C.; Weldon, Rebecca B.; Brainerd, Charles J.

    2016-01-01

    Fuzzy-trace theory posits independent verbatim and gist memory processes, a distinction that has implications for such applied topics as eyewitness testimony. This distinction between precise, literal verbatim memory and meaning-based, intuitive gist accounts for memory paradoxes including dissociations between true and false memory, false memories outlasting true memories, and developmental increases in false memory. We provide an overview of fuzzy-trace theory, and, using mathematical model...

  12. False-positive uptake on 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) positron-emission tomography/computed tomography (PET/CT) in oncological imaging

    International Nuclear Information System (INIS)

    Culverwell, A.D.; Scarsbrook, A.F.; Chowdhury, F.U.

    2011-01-01

    With the increasing utilization of integrated positron-emission tomography/computed tomography (PET/CT) using the glucose analogue 2-[ 18 F]-fluoro-2-deoxy-D-glucose (FDG) in oncological imaging, it is important for radiologists and nuclear medicine physicians to be aware that FDG uptake is not specific for malignancy, as many different physiological variants and benign pathological conditions can also exhibit increased glucose metabolism. Such false-positive FDG uptake often arises outside the area of primary interest and may mimic malignant disease, thereby confounding accurate interpretation of PET/CT studies. With the use of illustrative clinical cases, this article will provide a systematic overview of potential interpretative pitfalls and illustrate how such unexpected findings can be appropriately evaluated.

  13. Interference Helps to Equalize the Read Range and Reduce False Positives of Passive RFID Tags

    DEFF Research Database (Denmark)

    Krigslund, Rasmus; Popovski, Petar; Pedersen, Gert Frølund

    2012-01-01

    In various applications of RFID systems a reader should reliably get the ID of the tags that are within a bounded proximity region, termed the interrogation zone. This gives rise to two types of errors 1) False Negative Detections (FNDs), when tags within the intended interrogation zone cannot...... interference enables design of well-defined interrogation zones for passive RFID systems....

  14. Toward the breast screening balance sheet: cumulative risk of false positives for annual versus biennial mammograms commencing at age 40 or 50.

    Science.gov (United States)

    Winch, Caleb J; Sherman, Kerry A; Boyages, John

    2015-01-01

    This study aimed to: (1) Estimate cumulative risk of recall from breast screening where no cancer is detected (a harm) in Australia; (2) Compare women screened annually versus biennially, commencing age 40 versus 50; and (3) Compare with international findings. At the no-cost metropolitan program studied, women attended biennial screening, but were offered annual screening if regarded at elevated risk for breast cancer. The cumulative risk of at least one recall was estimated using discrete-time survival analysis. Cancer detection statistics were computed. In total, 801,636 mammograms were undertaken in 231,824 women. Over 10 years, cumulative risk of recall was 13.3 % (95 % CI 12.7-13.8) for those screened biennially, and 19.9 % (CI 16.6-23.2) for those screened annually from age 50-51. Cumulative risk of complex false positive involving a biopsy was 3.1 % (CI 2.9-3.4) and 5.0 % (CI 3.4-6.6), respectively. From age 40-41, the risk of recall was 15.1 % (CI 14.3-16.0) and 22.5 % (CI 17.9-27.1) for biennial and annual screening, respectively. Corresponding rates of complex false positive were 3.3 % (CI 2.9-3.8) and 6.3 % (CI 3.4-9.1). Over 10 mammograms, invasive cancer was detected in 3.4 % (CI 3.3-3.5) and ductal carcinoma in situ in 0.7 % (CI 0.6-0.7) of women, with a non-significant trend toward a larger proportion of Tis and T1N0 cancers in women screened annually (74.5 %) versus biennially (70.1 %), χ (2) = 2.77, p = 0.10. Cancer detection was comparable to international findings. Recall risk was equal to European estimates for women screening from 50 and lower for screening from 40. Recall risk was half of United States' rates across start age and rescreening interval categories. Future benefit/harm balance sheets may be useful for communicating these findings to women.

  15. Cytolethal distending toxin in isolates of Aggregatibacter actinomycetemcomitans from Ghanaian adolescents and association with serotype and disease progression.

    Science.gov (United States)

    Höglund Åberg, Carola; Antonoglou, Georgios; Haubek, Dorte; Kwamin, Francis; Claesson, Rolf; Johansson, Anders

    2013-01-01

    The cytolethal distending toxin (Cdt) is a highly conserved exotoxin that are produced by a number of Gram negative bacteria, including Aggregatibacter actinomycetemcomitans, and affects mammalian cells by inhibiting cell division and causing apoptosis. A complete cdt-operon is present in the majority of A. actinomycetemcomitans, but the proportion of isolates that lack cdt-encoding genes (A, B and C) varies according to the population studied. The objectives of this study were to examine serotype, Cdt-genotype, and Cdt-activity in isolates of A. actinomycetemcomitans collected from an adolescent West African population and to examine the association between the carrier status of A. actinomycetemcomitans and the progression of attachment loss (AL). A total of 249 A. actinomycetemcomitans isolates from 200 Ghanaian adolescents were examined for serotype and cdt-genotype by PCR. The activity of the Cdt-toxin was examined by DNA-staining of exposed cultured cells and documented with flow cytometry. The periodontal status of the participants was examined at baseline and at a two-year follow-up. Presence of all three cdt-encoding genes was detected in 79% of the examined A. actinomycetemcomitans isolates. All these isolates showed a substantial Cdt-activity. The two different cdt-genotypes (with and without presence of all three cdt-encoding genes) showed a serotype-dependent distribution pattern. Presence of A. actinomycetemcomitans was significantly associated with progression of AL (OR = 5.126; 95% CI = [2.994-8.779], padolescents showed a distribution of serotype and cdt-genotype in line with results based on other previously studied populations. Presence of A. actinomycetemcomitans was significantly associated with disease progression, in particular the b serotype, whereas the association with disease progression was not particularly related to cdt-genotype, and Cdt-activity.

  16. Magnetic resonance imaging of lumbar spine disc diseases. Frequency of false negatives

    International Nuclear Information System (INIS)

    Berthelot, J.M.; Maugars, Y.; Delecrin, Y.; Caillon, F.; Prost, A.

    1995-01-01

    Magnetic resonance imaging (MRI) has had an impressive impact on evaluation of degenerative diseases of the spine. Nevertheless, false negatives can occur on images involving lumbar discs. Degenerative disc diseases documented on discography and/or pathology examination of the discs can go unrecognized. Likewise sensitivity for the detection of protruding disc hernias is not totally satisfactory (20% false negatives). Finally, a magnetic resonance image visualizing displacement of the disc is not specific (10 to 15% false positives); images showing protrusion or hernia can be seen in 30% of asymptomatic patients. Although MRI gives slightly more information than other imaging techniques, false images do exist. Moreover, the usefulness of MRI to demonstrate disc disease in case of a negative CT-scan remains to be demonstrated. (authors). 26 refs

  17. Cytolethal Distending Toxin Enhances Radiosensitivity in Prostate Cancer Cells by Regulating Autophagy

    Directory of Open Access Journals (Sweden)

    Hwai-Jeng Lin

    2017-06-01

    Full Text Available Cytolethal distending toxin (CDT produced by Campylobacter jejuni contains three subunits: CdtA, CdtB, and CdtC. Among these three toxin subunits, CdtB is the toxic moiety of CDT with DNase I activity, resulting in DNA double-strand breaks (DSB and, consequently, cell cycle arrest at the G2/M stage and apoptosis. Radiation therapy is an effective modality for the treatment of localized prostate cancer (PCa. However, patients often develop radioresistance. Owing to its particular biochemical properties, we previously employed CdtB as a therapeutic agent for sensitizing radioresistant PCa cells to ionizing radiation (IR. In this study, we further demonstrated that CDT suppresses the IR-induced autophagy pathway in PCa cells by attenuating c-Myc expression and therefore sensitizes PCa cells to radiation. We further showed that CDT prevents the formation of autophagosomes via decreased high-mobility group box 1 (HMGB1 expression and the inhibition of acidic vesicular organelle (AVO formation, which are associated with enhanced radiosensitivity in PCa cells. The results of this study reveal the detailed mechanism of CDT for the treatment of radioresistant PCa.

  18. The Clock Drawing Test A review of its accuracy in screening for dementia

    Directory of Open Access Journals (Sweden)

    Ivan Aprahamian

    Full Text Available Abstract The Clock Drawing Test (CDT is a simple neuropsychometric instrument that can be easily applied to assess several cognitive functions. Over the past 20 years, the CDT has aroused considerable interest in its role for the early screening of cognitive impairment, especially in dementia. Although the CDT is considered an accurate test for dementia screening, recent studies including comparisons with structured batteries such as the CAMCOG have shown mixed results. Objectives: To investigate the importance of the CDT compared to other commonly used tests, in the diagnosis of dementia in the elderly; (2 to evaluate the reliability and correlation between available CDT scoring scales from recent studies. Methods: A systematic search in the literature was conducted in September 2008 for studies comparing CDT scoring systems and comparing the CDT with neuropsychiatric batteries. Results: Twelve studies were selected for analyses. Seven of these studies compared CDT scoring scales while five compared the CDT against the CAMCOG and the MMSE. Eight studies found good correlation and reliability between the scales and the other tests. Conclusion: Despite the mixed results in these studies, the CDT appears to be a good screening test for dementia.

  19. SU-G-BRB-03: Assessing the Sensitivity and False Positive Rate of the Integrated Quality Monitor (IQM) Large Area Ion Chamber to MLC Positioning Errors

    Energy Technology Data Exchange (ETDEWEB)

    Boehnke, E McKenzie; DeMarco, J; Steers, J; Fraass, B [Cedars-Sinai Medical Center, Los Angeles, CA (United States)

    2016-06-15

    Purpose: To examine both the IQM’s sensitivity and false positive rate to varying MLC errors. By balancing these two characteristics, an optimal tolerance value can be derived. Methods: An un-modified SBRT Liver IMRT plan containing 7 fields was randomly selected as a representative clinical case. The active MLC positions for all fields were perturbed randomly from a square distribution of varying width (±1mm to ±5mm). These unmodified and modified plans were measured multiple times each by the IQM (a large area ion chamber mounted to a TrueBeam linac head). Measurements were analyzed relative to the initial, unmodified measurement. IQM readings are analyzed as a function of control points. In order to examine sensitivity to errors along a field’s delivery, each measured field was divided into 5 groups of control points, and the maximum error in each group was recorded. Since the plans have known errors, we compared how well the IQM is able to differentiate between unmodified and error plans. ROC curves and logistic regression were used to analyze this, independent of thresholds. Results: A likelihood-ratio Chi-square test showed that the IQM could significantly predict whether a plan had MLC errors, with the exception of the beginning and ending control points. Upon further examination, we determined there was ramp-up occurring at the beginning of delivery. Once the linac AFC was tuned, the subsequent measurements (relative to a new baseline) showed significant (p <0.005) abilities to predict MLC errors. Using the area under the curve, we show the IQM’s ability to detect errors increases with increasing MLC error (Spearman’s Rho=0.8056, p<0.0001). The optimal IQM count thresholds from the ROC curves are ±3%, ±2%, and ±7% for the beginning, middle 3, and end segments, respectively. Conclusion: The IQM has proven to be able to detect not only MLC errors, but also differences in beam tuning (ramp-up). Partially supported by the Susan Scott Foundation.

  20. Unusual False Positive Radioiodine Uptake on 131I Whole Body Scintigraphy in Three Unrelated Organs with Different Pathologies in Patients of Differentiated Thyroid Carcinoma: A Case Series

    International Nuclear Information System (INIS)

    Ranade, Rohit; Pawar, Shwetal; Mahajan, Abhishek; Basu, Sandip

    2016-01-01

    Three cases with unusual false positive radioiodine uptake in three different organs and pathologies (infective old fibrotic lesion in the lung, simple liver cyst, and benign breast lesion) on iodine-131 ( 131 I) whole body scintigraphy. Clinicoradiological correlation was undertaken in all three cases and the pathologies were ascertained. In all the three cases, single-photon emission computerized tomography-computed tomography (SPECT-CT) and ancillary imaging modalities were employed and were helpful in arriving at the final diagnosis

  1. Studies for the application of Boron neutron capture therapy (BNCT) to the treatment of differentiated thyroid cancer (CDT)

    International Nuclear Information System (INIS)

    Carpano, Marina; Thomasz, Lisa; Perona, Marina; Juvenal, Guillermo J.; Pisarev, Mario; Dagrosa, Maria A.; Nievas, Susana I.; Pozzi, Emiliano; Thorp, Silvia

    2009-01-01

    Boron neutron capture therapy (BNCT) is a high linear energy transfer (LET) radiotherapy for cancer, which it is based on the nuclear reaction that occurs when boron-10 that it is a non radioactive isotope of the natural elemental boron, is irradiated with low energy thermal neutrons to produce an alpha particle and a nucleus of lithium-7. Both particles have a range smaller than the diameter of a cell causing cell tumor death without significant damage to the surrounding normal tissues. In previous studies we have shown that BNCT can be a possibility for the treatment of undifferentiated thyroid cancer (UTC). However, more than 80 % of patients with thyroid neoplasm present differentiated carcinoma (CDT). These carcinomas are treated by surgery followed by therapy with 131 I and mostly these forms are well controlled. But in some patients recurrence of the tumor is observed. BNCT can be an alternative for these patients in who the tumor lost the capacity to concentrate iodide. The aim of these studies was to evaluate the possibility of treating differentiated thyroid cancer by BNCT. Materials and Methods: The human cell lines of follicular (WRO) and papillary carcinomas (TPC-1) were grown in RPMI and modified DMEM medium respectively. Both supplemented with 10 % of SFB. The cell line of thyroid rat, FRTL-5, used as control normal, was cultured in DMEM/F12. The uptakes of 125 I and p-borophenylalanine BPA (6.93mM) were studied. The intracellular boron concentration was measured by inductively coupled plasma optical emission spectroscopy (ICP-OES) at 2 hr post incubation. The NIH strain of male nude mice, aged 6 to 8 weeks and weighing 20 to 25 g were implanted (s.c) in the back right flank with different concentrations of tumor cells. The size of the tumors was measured with a caliper twice or three times a week and the volume was calculated according the following formulae: A 2 x B/2 (were A is the width and B is the length). To evaluate the BPA uptake, animals

  2. Filing false vice reports: Distinguishing true from false allegations of rape

    NARCIS (Netherlands)

    de Zutter, A.; Horselenberg, R.; van Koppen, P.J.

    2017-01-01

    False allegations constitute a problem since they may cause harm. To study the difference between true and false allegations we used a quasi-experimental approach. In the control condition likely true allegations were retrieved from criminal files. The victims, all female, were between the ages of

  3. Psychosomatic disorders of gravida status: false and denied pregnancies.

    Science.gov (United States)

    Kenner, William D; Nicolson, Stephen E

    2015-01-01

    The authors review the literature on two dramatic psychosomatic disorders of reproduction and offer a potential classification of pregnancy denial. Information on false and denied pregnancies is summarized by comparing the descriptions, differential diagnoses, epidemiology, patient characteristics, psychological factors, abdominal tone, and neuroendocrinology. Pregnancy denial's association with neonaticide is reviewed. False and denied pregnancies have fooled women, families, and doctors for centuries as the body obscures her true condition. Improvements in pregnancy testing have decreased reports of false pregnancy. However, recent data suggests 1/475 pregnancies are denied to 20 weeks, and 1/2455 may go undiagnosed to delivery. Factors that may contribute to the unconscious deception include abdominal muscle tone, persistent corpus luteum function, and reduced availability of biogenic amines in false pregnancy, and posture, fetal position, and corpus luteum insufficiency in denied pregnancy. For each condition, there are multiple reports in which the body reveals her true pregnancy status as soon as the woman is convinced of her diagnosis. Forensic literature on denied pregnancy focused on the woman's rejection of motherhood, while psychiatric studies have revealed that trauma and dissociation drive her denial. False pregnancy has firm grounding as a classic psychosomatic disorder. Pregnancy denial's association with neonaticide has led to misleading forensic data, which obscures the central role of trauma and dissociation. A reappraisal of pregnancy denial confirms it as the somatic inverse of false pregnancy. With that perspective, clinicians can help women understand their pregnancy status to avoid unexpected deliveries with tragic outcomes. Copyright © 2015 The Academy of Psychosomatic Medicine. Published by Elsevier Inc. All rights reserved.

  4. False memories for aggressive acts.

    Science.gov (United States)

    Laney, Cara; Takarangi, Melanie K T

    2013-06-01

    Can people develop false memories for committing aggressive acts? How does this process compare to developing false memories for victimhood? In the current research we used a simple false feedback procedure to implant false memories for committing aggressive acts (causing a black eye or spreading malicious gossip) or for victimhood (receiving a black eye). We then compared these false memories to other subjects' true memories for equivalent events. False aggressive memories were all too easy to implant, particularly in the minds of individuals with a proclivity towards aggression. Once implanted, the false memories were indistinguishable from true memories for the same events, on several dimensions, including emotional content. Implications for aggression-related memory more generally as well as false confessions are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. The Alcohol Use Disorders Identification Test and carbohydrate-deficient transferrin in alcohol-related sickness absence.

    Science.gov (United States)

    Hermansson, Ulric; Helander, Anders; Brandt, Lena; Huss, Anders; Rönnberg, Sten

    2002-01-01

    Previous studies have shown that elevated, risky levels of alcohol consumption may lead to higher rates of sickness absence. However, no studies have examined the Alcohol Use Disorders Identification Test (AUDIT) or serum carbohydrate-deficient transferrin (CDT) in relation to sickness absence in the workplace. The purpose of this study was to examine the relationship between sick-days, 12 months before screening, and the AUDIT and CDT (CDTect kit). Serum gamma-glutamyltransferase also was used for comparison. The study was carried out over 36 months in a large workplace and formed part of an ongoing controlled study. In conjunction with a routine health examination, employees were offered the opportunity to undergo an alcohol screening. Absence data were obtained from the company payroll system, and sickness absence was analyzed by using a three-ordinal level cumulative logistic model on the number of sick-days. Odds ratios (OR) and 95% confidence intervals (CI) are reported. Of the 989 subjects who participated in the study, 193 (19.5%) screened positive in relation to either the AUDIT (>or=8 points) or CDT (women), or both. Employees who screened positive with the AUDIT had a significantly higher proportion of sick-days (p = 0.047) compared with those who screened negative (OR = 1.4, CI 1.0-1.9). Neither long, continuous periods of sickness absence nor absence on Mondays or Fridays gave a clear indication of individuals who screened positive on the AUDIT or CDT test. Our data indicate that individuals with moderately elevated or risky levels of alcohol consumption show an increase in sick-days. Accordingly, workplaces have a good reason for using a more systematic approach to alcohol screening in routine workplace health examinations.

  6. Stress and emotional valence effects on children's versus adolescents' true and false memory.

    Science.gov (United States)

    Quas, Jodi A; Rush, Elizabeth B; Yim, Ilona S; Edelstein, Robin S; Otgaar, Henry; Smeets, Tom

    2016-01-01

    Despite considerable interest in understanding how stress influences memory accuracy and errors, particularly in children, methodological limitations have made it difficult to examine the effects of stress independent of the effects of the emotional valence of to-be-remembered information in developmental populations. In this study, we manipulated stress levels in 7-8- and 12-14-year-olds and then exposed them to negative, neutral, and positive word lists. Shortly afterward, we tested their recognition memory for the words and false memory for non-presented but related words. Adolescents in the high-stress condition were more accurate than those in the low-stress condition, while children's accuracy did not differ across stress conditions. Also, among adolescents, accuracy and errors were higher for the negative than positive words, while in children, word valence was unrelated to accuracy. Finally, increases in children's and adolescents' cortisol responses, especially in the high-stress condition, were related to greater accuracy but not false memories and only for positive emotional words. Findings suggest that stress at encoding, as well as the emotional content of to-be-remembered information, may influence memory in different ways across development, highlighting the need for greater complexity in existing models of true and false memory formation.

  7. Specificity of antibodies directed against the cytolethal distending toxin of Haemophilus ducreyi in patients with chancroid.

    Science.gov (United States)

    Mbwana, Judica; Ahmed, Hinda J; Ahlman, Karin; Sundaeus, Vivian; Dahlén, Gunnar; Lyamuya, Eligius; Lagergård, Teresa

    2003-09-01

    Antibodies specific for the cytolethal-distending toxin of Haemophilus ducreyi (HdCDT) complex and for the CdtA, CdtB, and CdtC components were measured by ELISA in the sera of 50 patients with culture and/or PCR proven chancroid, 42 patients with periodontitis, 50 blood donors from Tanzania, 50 blood donors from Sweden. In addition, the biological activity e.g. neutralization capacity of the sera were tested. Our results demonstrate that majority of chancroid patients and healthy individuals had detectable levels of serum antibodies to HdCDT complex and to separate toxin components. However, high levels (> or =100 units) of antibodies to HdCDT complex were significantly more prevalent in the sera of patients with both chancroid and periodontitis than in the sera of the corresponding controls (P=0.001 and P=0.04, respectively). In the sera of the 50 patients with chancroid, antibodies to CdtA, CdtB, and CdtC were detected in 50, 35, and 34 individuals, respectively. Antibodies to CdtC, being less frequently detected than the antibodies to other components, show a good correlation with the neutralizing capacity of sera. High levels of neutralizing antibodies (> or =160) were detected in only 22 and 2% of the patients with chancroid and periodontitis, respectively. The data suggest that the low levels of anti-HdCDT antibodies, which include neutralizing antibodies, may contribute to limited protection in chancroid and since anti-HdCDT antibodies, may be detected in healthy individuals and in patients with certain disease conditions (e.g. periodontitis), they may not be specific markers for chancroid infection.

  8. Social influence and mental routes to the production of authentic false memories and inauthentic false memories.

    Science.gov (United States)

    Wagner, Michael F; Skowronski, John J

    2017-05-01

    Two studies assessed the extent to which people incorporated false facts provided by bogus others into their own recognition memory reports, and how these false memory reports were affected by: (a) truth of the information in others' summaries supporting the false facts, (b) motivation to process stories and summaries, (c) source credibility, and (d) ease of remembering original facts. False memory report frequency increased when false facts in a summary were supported by true information and varied inversely with the ease with which original facts could be remembered. Results from a measure probing participants' memory perceptions suggest that some false memories are authentic: People sometimes lack awareness of both the incorporation of false facts into their memory reports and where the false facts came from. However, many false memories are inauthentic: Despite reporting a false memory, people sometimes retain knowledge of the original stimulus and/or the origin of false facts. Copyright © 2017. Published by Elsevier Inc.

  9. Pregnancy and variations of carbohydrate-deficient transferrin levels measured by the candidate reference HPLC method.

    Science.gov (United States)

    Bianchi, Vincenza; Ivaldi, Alessandra; Raspagni, Alessia; Arfini, Carlo; Vidali, Matteo

    2011-01-01

    Contrasting data are available on the diagnostic accuracy of carbohydrate-deficient transferrin (CDT) during pregnancy. These differences may depend in part on how CDT was evaluated and expressed. Here, we report on variations of CDT levels in pregnant women using the high performance liquid chromatography (HPLC) candidate reference method. Alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase, mean corpuscular volume, serum transferrin, urine and serum ethyl glucuronide and CDT were measured in 64 women, self-reporting as non-alcohol abusers (age: median 34, IQR: 28-38), at different stages of normal pregnancy (gestational weeks: median 28, IQR: 8-33). CDT was expressed as percentage of disialotransferrin to total transferrin (%CDT). Transferrin was associated with both %CDT (r = 0.66; P pregnancy trimester (first trimester: mean 1.01% (SD 0.19); second trimester: 1.30% (SD 0.14); third trimester: 1.53% (SD 0.22); ANOVA P pregnancy trimesters (P pregnancy and CDT could be more complex. The diagnostic accuracy of CDT for detecting alcohol abuse in a legal context may be limited in pregnant women and the effect of gestational age should be considered.

  10. Adaptive false memory: Imagining future scenarios increases false memories in the DRM paradigm.

    Science.gov (United States)

    Dewhurst, Stephen A; Anderson, Rachel J; Grace, Lydia; van Esch, Lotte

    2016-10-01

    Previous research has shown that rating words for their relevance to a future scenario enhances memory for those words. The current study investigated the effect of future thinking on false memory using the Deese/Roediger-McDermott (DRM) procedure. In Experiment 1, participants rated words from 6 DRM lists for relevance to a past or future event (with or without planning) or in terms of pleasantness. In a surprise recall test, levels of correct recall did not vary between the rating tasks, but the future rating conditions led to significantly higher levels of false recall than the past and pleasantness conditions did. Experiment 2 found that future rating led to higher levels of false recognition than did past and pleasantness ratings but did not affect correct recognition. The effect in false recognition was, however, eliminated when DRM items were presented in random order. Participants in Experiment 3 were presented with both DRM lists and lists of unrelated words. Future rating increased levels of false recognition for DRM lures but did not affect correct recognition for DRM or unrelated lists. The findings are discussed in terms of the view that false memories can be associated with adaptive memory functions.

  11. True and false recall and dissociation among maltreated children: the role of self-schema.

    Science.gov (United States)

    Valentino, Kristin; Cicchetti, Dante; Rogosch, Fred A; Toth, Sheree L

    2008-01-01

    The current investigation addresses the manner through which trauma affects basic memory and self-system processes. True and false recall for self-referent stimuli were assessed in conjunction with dissociative symptomatology among abused (N=76), neglected (N=92), and nonmaltreated (N=116) school-aged children. Abused, neglected, and nonmaltreated children did not differ in the level of processing self-schema effect or in the occurrence and frequency of false recall. Rather, differences in the affective valence of false recall emerged as a function of maltreatment subtype and age. Regarding dissociation, the abused children displayed higher levels of dissociative symptomatology than did the nonmaltreated children. Although abused, neglected, and nonmaltreated children did not exhibit differences in the valence of their self-schemas, positive and negative self-schemas were related to self-integration differently among the subgroups of maltreatment. Negative self-schemas were associated with increased dissociation among the abused children, whereas positive self-schemas were related to increased dissociation for the neglected children. Thus, positive self-schemas displayed by the younger neglected children were related to higher dissociation, suggestive of defensive self-processing. Implications for clinical intervention are underscored.

  12. A cause of false positive of the whole body scanning with iodine 131: obstructive hydronephrosis; Une cause de faux-positif du balayage corps entier a l'iode 131: l'hydronephrose obstructive

    Energy Technology Data Exchange (ETDEWEB)

    Sellem, A.; Elbez, I.; Rejeb, O.; Elkadri, N.; Hammami, H. [Service de medecine nucleaire, hopital Militaire, Tunis, (Tunisia)

    2009-05-15

    The objective is to report the case of a differentiated carcinoma of the thyroid with a false positive aspect to the whole-body scanning with iodine 131 in relation with an accumulation of the tracer at the level of an obstructive appearance hydronephrosis. (N.C.)

  13. Amphetamine Positive Urine Toxicology Screen Secondary to Atomoxetine

    Directory of Open Access Journals (Sweden)

    Joshua L. Fenderson

    2013-01-01

    Full Text Available The aim of this paper is to report the first case of atomoxetine leading to false-positive urine drug screen. An otherwise healthy 27-year-old female with a history of attention deficit hyperactivity disorder (ADHD treated with atomoxetine had an acute onset tonic-clonic seizure. On arrival to the hospital, a urine toxicological drug screen with immunochemical cloned enzyme donor immunoassay (CEDIA was performed. Results were positive for amphetamines; however, the presence of these substances could not be confirmed with urine gas chromatography-mass spectrometry (GC-MS. She denied any illicit drug use, herbal medications, or supplements, and her other prescription medications have not been previously known to cause a false-positive result for amphetamines. While stimulant treatments for ADHD could certainly result in a positive result on urine screen for amphetamines, there have been no reports of false-positive results for amphetamines secondary to patients using atomoxetine. We implicate atomoxetine, and/or its metabolites, as a compound or compounds which may interfere with urine drug immunoassays leading to false-positive results for amphetamines CEDIA assays.

  14. Arousal?But Not Valence?Reduces False Memories at Retrieval

    OpenAIRE

    Mirandola, Chiara; Toffalini, Enrico

    2016-01-01

    Mood affects both memory accuracy and memory distortions. However, some aspects of this relation are still poorly understood: (1) whether valence and arousal equally affect false memory production, and (2) whether retrieval-related processes matter; the extant literature typically shows that mood influences memory performance when it is induced before encoding, leaving unsolved whether mood induced before retrieval also impacts memory. We examined how negative, positive, and neutral mood indu...

  15. Detecting dementia in patients with normal neuropsychological screening by Short Smell Test and Palmo-Mental Reflex Test: an observational study.

    Science.gov (United States)

    Streit, Sven; Limacher, Andreas; Zeller, Andreas; Bürge, Markus

    2015-07-25

    General practitioners (GPs) are in best position to suspect dementia. Mini-Mental State Examination (MMSE) and Clock Drawing Test (CDT) are widely used. Additional neurological tests may increase the accuracy of diagnosis. We aimed to evaluate diagnostic ability to detect dementia with a Short Smell Test (SST) and Palmo-Mental Reflex (PMR) in patients whose MMSE and CDT are normal, but who show signs of cognitive dysfunction. This was a 3.5-year cross-sectional observational study in the Memory Clinic of the University Department of Geriatrics in Bern, Switzerland. Participating patients with normal MMSE (>26 points) and CDT (>5 points) were referred by GPs because they suspected dementia. All were examined according to a standardized protocol. Diagnosis of dementia was based on DSM-IV TR criteria. We used SST and PMR to determine if they accurately detected dementia. In our cohort, 154 patients suspected of dementia had normal MMSE and CDT test results. Of these, 17 (11%) were demented. If SST or PMR were abnormal, sensitivity was 71% (95% CI 44-90%), and specificity 64% (95% CI 55-72%) for detecting dementia. If both tests were abnormal, sensitivity was 24% (95% CI 7-50%), but specificity increased to 93% (95% CI 88-97%). Patients suspected of dementia, but with normal MMSE and CDT results, may benefit if SST and PMR are added as diagnostic tools. If both SST and PMR are abnormal, this is a red flag to investigate these patients further, even though their negative neuropsychological screening results.

  16. False feedback and beliefs influence name recall in younger and older adults.

    Science.gov (United States)

    Strickland-Hughes, Carla M; West, Robin Lea; Smith, Kimberly A; Ebner, Natalie C

    2017-09-01

    Feedback is an important self-regulatory process that affects task effort and subsequent performance. Benefits of positive feedback for list recall have been explored in research on goals and feedback, but the effect of negative feedback on memory has rarely been studied. The current research extends knowledge of memory and feedback effects by investigating face-name association memory and by examining the potential mediation of feedback effects, in younger and older adults, through self-evaluative beliefs. Beliefs were assessed before and after name recognition and name recall testing. Repeated presentation of false positive feedback was compared to false negative feedback and a no feedback condition. Results showed that memory self-efficacy declined over time for participants in the negative and no feedback conditions but was sustained for those receiving positive feedback. Furthermore, participants who received negative feedback felt older after testing than before testing. For name recall, the positive feedback group outperformed the negative feedback and no feedback groups combined, with no age interactions. The observed feedback-related effects on memory were fully mediated by changes in memory self-efficacy. These findings advance our understanding of how beliefs are related to feedback in memory and inform future studies examining the importance of self-regulation in memory.

  17. Negative affect promotes encoding of and memory for details at the expense of the gist: affect, encoding, and false memories.

    Science.gov (United States)

    Storbeck, Justin

    2013-01-01

    I investigated whether negative affective states enhance encoding of and memory for item-specific information reducing false memories. Positive, negative, and neutral moods were induced, and participants then completed a Deese-Roediger-McDermott (DRM) false-memory task. List items were presented in unique spatial locations or unique fonts to serve as measures for item-specific encoding. The negative mood conditions had more accurate memories for item-specific information, and they also had fewer false memories. The final experiment used a manipulation that drew attention to distinctive information, which aided learning for DRM words, but also promoted item-specific encoding. For the condition that promoted item-specific encoding, false memories were reduced for positive and neutral mood conditions to a rate similar to that of the negative mood condition. These experiments demonstrated that negative affective cues promote item-specific processing reducing false memories. People in positive and negative moods encode events differently creating different memories for the same event.

  18. Emotional content enhances true but not false memory for categorized stimuli.

    Science.gov (United States)

    Choi, Hae-Yoon; Kensinger, Elizabeth A; Rajaram, Suparna

    2013-04-01

    Past research has shown that emotion enhances true memory, but that emotion can either increase or decrease false memory. Two theoretical possibilities-the distinctiveness of emotional stimuli and the conceptual relatedness of emotional content-have been implicated as being responsible for influencing both true and false memory for emotional content. In the present study, we sought to identify the mechanisms that underlie these mixed findings by equating the thematic relatedness of the study materials across each type of valence used (negative, positive, or neutral). In three experiments, categorically bound stimuli (e.g., funeral, pets, and office items) were used for this purpose. When the encoding task required the processing of thematic relatedness, a significant true-memory enhancement for emotional content emerged in recognition memory, but no emotional boost to false memory (exp. 1). This pattern persisted for true memory with a longer retention interval between study and test (24 h), and false recognition was reduced for emotional items (exp. 2). Finally, better recognition memory for emotional items once again emerged when the encoding task (arousal ratings) required the processing of the emotional aspect of the study items, with no emotional boost to false recognition (EXP. 3). Together, these findings suggest that when emotional and neutral stimuli are equivalently high in thematic relatedness, emotion continues to improve true memory, but it does not override other types of grouping to increase false memory.

  19. Coinfection of hepatitis A virus genotype IA and IIIA complicated with autoimmune hemolytic anemia, prolonged cholestasis, and false-positive immunoglobulin M anti-hepatitis E virus: a case report.

    Science.gov (United States)

    Kim, Hee Sup; Jeong, Sook Hyang; Jang, Je Hyuck; Myung, Hyung Joon; Kim, Jin Wook; Bang, Soo Mee; Song, Sang Hoon; Kim, Haeryoung; Yun, Hae Sun

    2011-12-01

    A 37-year-old male presented with fever and jaundice was diagnosed as hepatitis A complicated with progressive cholestasis and severe autoimmune hemolytic anemia. He was treated with high-dose prednisolone (1.5 mg/kg), and eventually recovered. His initial serum contained genotype IA hepatitis A virus (HAV), which was subsequently replaced by genotype IIIA HAV. Moreover, at the time of development of hemolytic anemia, he became positive for immunoglobulin M (IgM) anti-hepatitis E virus (HEV). We detected HAV antigens in the liver biopsy specimen, while we detected neither HEV antigen in the liver nor HEV RNA in his serum. This is the first report of hepatitis A coinfected with two different genotypes manifesting with autoimmune hemolytic anemia, prolonged cholestasis, and false-positive IgM anti-HEV.

  20. False-negative type-specific glycoprotein G antibody responses in STI clinic patients with recurrent HSV-1 or HSV-2 DNA positive genital herpes, The Netherlands.

    Science.gov (United States)

    van Rooijen, Martijn S; Roest, Wim; Hansen, Gino; Kwa, David; de Vries, Henry J C

    2016-06-01

    Herpes simplex virus (HSV) type-discriminating antibody tests (glycoprotein G (gG) directed) are used to identify naïve persons and differentiate acute infections from recurrences. We studied test characteristics of three commercially available antibody tests in patients with recurrent (established by viral PCR tests) herpes simplex virus type 1 (HSV-1) or herpes simplex virus type 2 (HSV-2) genital herpes episodes. Serum samples (at minimum 3 months after t=0) were examined for the presence of gG-1-specific or gG-2-specific antibodies using the HerpeSelect 1 and 2 Immunoblot IgG, the HerpeSelect 1 and 2 enzyme linked immunoassays IgG and the LIAISON HSV-1 and HSV-2 IgG indirect chemiluminescence immunoassays. The immunoblot was HSV-1 positive in 70.6% (95% CI 44.0% to 89.7%), the LIAISON in 88.2% (95% CI 63.5% to 98.5%) and the ELISA in 82.4% (95% CI 56.6% to 96.2%) of the 17 patients with a recurrent HSV-1 episode. From 33 patients with a recurrent HSV-2 episode, the immunoblot was HSV-2 positive in 84.8% (95% CI 68.1% to 94.9%), the LIAISON in 69.7% (95% CI 51.3% to 84.4%) and the ELISA in 84.8% (95% CI 68.1% to 94.9%). Among 15/17 (88.2%; 95% CI 63.5% to 98.5%) patients with HSV-1 and 30/33 (90.1%; 95% CI 75.7% to 98.1%) patients with HSV-2, HSV-1 or HSV-2 antibodies, respectively, were detected in at least one of the three antibody tests. Commercial type-specific gG HSV-1 or HSV-2 antibody assays were false negative in 12-30% of patients with recurrent HSV-1 or HSV-2 DNA positive genital lesions. The clinical and epidemiological use of type-specific HSV serology can be hampered by false-negative results, especially if based on a single test. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. False Positive 18F-FDG Uptake in Mediastinal Lymph Nodes Detected with Positron Emission Tomography in Breast Cancer: A Case Report

    Directory of Open Access Journals (Sweden)

    Gamze Uğurluer

    2013-01-01

    Full Text Available Breast cancer is the most frequently diagnosed cancer among females. It is accepted that lymph node involvement with metastatic tumor and the presence of distant metastasis are the most important prognostic factors. Accurate staging is important in determining prognosis and appropriate treatment. Positron emission tomography with computed tomography detects malignancies using 2-[18F]-fluoro-2-deoxy-d-glucose (18F-FDG PET CT with high accuracy and they contribute to decisions regarding diagnosis, staging, recurrence, and treatment response. Here, we report a case of false positive metastatic mediastinal lymph nodes that were diagnosed by 18F-FDG PET CT in a 40-year-old breast cancer patient who had undergone preoperative evaluation. Right paratracheal, prevascular, aorticopulmonary, precarinal, subcarinal, hilar, and subhilar multiple conglomerated mediastinal lymph nodes were revealed in addition to left breast mass and axillary lymph nodes. Mediastinoscopy was performed with biopsy and pathology was reported as granulomatous lymphadenitis. In conclusion, any abnormal FDG accumulation in unusual lymph nodes must be evaluated carefully and confirmed histopathologically.

  2. The false sero-negativity of brucella standard agglutination test: Prozone phenomenon

    Directory of Open Access Journals (Sweden)

    İrfan Binici

    2011-12-01

    Full Text Available Objectives: We aimed to assess prozone phenomenon that is quite rare and causes false negativity in serological diagnosisof brucellosis with standard dilution titers.Materials and methods: In this study the tests of four cases that have false negative serological results were evaluated.Blood cultures were obtained from all cases while cerebrospinal fluid cultures were studied in the two cases. Standardagglutination test (SAT and Coombs test were performed to all patients.Results: SAT and Coombs test was negative in titers up to 1/640 in all cases. The SAT and Coombs tests in cerebrospinalfluid (CSF of the two cases with neurobrucellosis diagnosis were negative, as well. Since the clinical and laboratoryfindings suggested the brucellosis, the serums were restudied by diluting up to 1/10240 titer and we saw that the first3 cases became positive at a titer of 1/1280. The fourth case remained negative and therefore, we applied high dilutionCoombs test. This time the test gave a positive result at 1/10240 titer beginning from 1/2560 titer. B.melitensis wasisolated from two cases.Conclusion: SAT and Coombs’ test must be diluted to titers 1/2560 or more in order to exclude false sero-negativity incases with clinical and laboratory findings suggesting brucellosis. J Microbiol Infect Dis 2011; 1(3:110-113

  3. A Case of False-Positive Mycobacterium tuberculosis Caused by Mycobacterium celatum

    Directory of Open Access Journals (Sweden)

    Edward Gildeh

    2016-01-01

    Full Text Available Mycobacterium celatum is a nontuberculous mycobacterium shown to cause symptoms similar to pulmonary M. tuberculosis. Certain strains have been shown to cross-react with the probes used to detect M. tuberculosis, making this a diagnostic challenge. We present a 56-year-old gentleman who developed signs and symptoms of lung infection with computed tomography scan of the chest showing right lung apex cavitation. Serial sputum samples were positive for acid-fast bacilli and nucleic acid amplification testing identified M. tuberculosis ribosomal RNA, resulting in treatment initiation. Further testing with high performance liquid chromatography showed a pattern consistent with M. celatum. This case illustrates the potential for M. celatum to mimic M. tuberculosis in both its clinical history and laboratory testing due to the identical oligonucleotide sequence contained in both. An increasing number of case reports suggest that early reliable differentiation could reduce unnecessary treatment and public health intervention associated with misdiagnosed tuberculosis.

  4. Effects of hydrocortisone on false memory recognition in healthy men and women.

    Science.gov (United States)

    Duesenberg, Moritz; Weber, Juliane; Schaeuffele, Carmen; Fleischer, Juliane; Hellmann-Regen, Julian; Roepke, Stefan; Moritz, Steffen; Otte, Christian; Wingenfeld, Katja

    2016-12-01

    Most of the studies focusing on the effect of stress on false memories by using psychosocial and physiological stressors yielded diverse results. In the present study, we systematically tested the effect of exogenous hydrocortisone using a false memory paradigm. In this placebo-controlled study, 37 healthy men and 38 healthy women (mean age 24.59 years) received either 10 mg of hydrocortisone or placebo 75 min before using the false memory, that is, Deese-Roediger-McDermott (DRM), paradigm. We used emotionally charged and neutral DRM-based word lists to look for false recognition rates in comparison to true recognition rates. Overall, we expected an increase in false memory after hydrocortisone compared to placebo. No differences between the cortisol and the placebo group were revealed for false and for true recognition performance. In general, false recognition rates were lower compared to true recognition rates. Furthermore, we found a valence effect (neutral, positive, negative, disgust word stimuli), indicating higher rates of true and false recognition for emotional compared to neutral words. We further found an interaction effect between sex and recognition. Post hoc t tests showed that for true recognition women showed a significantly better memory performance than men, independent of treatment. This study does not support the hypothesis that cortisol decreases the ability to distinguish between old versus novel words in young healthy individuals. However, sex and emotional valence of word stimuli appear to be important moderators. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  5. Shedding of Clostridium difficile PCR ribotype 078 by zoo animals, and report of an unstable metronidazole-resistant isolate from a zebra foal (Equus quagga burchellii).

    Science.gov (United States)

    Álvarez-Pérez, Sergio; Blanco, José L; Martínez-Nevado, Eva; Peláez, Teresa; Harmanus, Celine; Kuijper, Ed; García, Marta E

    2014-03-14

    Clostridium difficile is an emerging and potentially zoonotic pathogen, but its prevalence in most animal species, including exhibition animals, is currently unknown. In this study we assessed the prevalence of faecal shedding of C. difficile by zoo animals, and determined the ribotype, toxin profile and antimicrobial susceptibility of recovered isolates. A total of 200 samples from 40 animal species (36.5% of which came from plains zebra, Equus quagga burchellii) were analysed. C. difficile was isolated from 7 samples (3.5% of total), which came from the following animal species: chimpanzee (Pan troglodytes troglodytes), dwarf goat (Capra hircus), and Iberian ibex (Capra pyrenaica hispanica), with one positive sample each; and plains zebra, with 4 positive samples from 3 different individuals. Most recovered isolates (4/7, 57.1%) belonged to the epidemic PCR ribotype 078, produced toxins A and B, and had the genes encoding binary toxin (i.e. A(+)B(+)CDT(+) isolates). The remaining three isolates belonged to PCR ribotypes 039 (A(-)B(-)CDT(-)), 042 (A(+)B(+)CDT(-)) and 110 (A(-)B(+)CDT(-)). Regardless of their ribotype, all isolates displayed high-level resistance to the fluoroquinolones ciprofloxacin, enrofloxacin and levofloxacin. Some isolates were also resistant to meropenem and/or ertapenem. A ribotype 078 isolate recovered from a male zebra foal initially showed in vitro resistance to metronidazole (MIC ≥ 256 μg/ml), but lost that trait after subculturing on non-selective media. We conclude that zoo animals belonging to different species can carry ribotype 078 and other toxigenic strains of C. difficile showing resistance to antimicrobial compounds commonly used in veterinary and/or human medicine. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Emotion and false memory: How goal-irrelevance can be relevant for what people remember

    OpenAIRE

    Van Damme, I; Kaplan, RL; Levine, LJ; Loftus, EF

    2017-01-01

    Elaborating on misleading information concerning emotional events can lead people to form false memories. The present experiment compared participants' susceptibility to false memories when they elaborated on information associated with positive versus negative emotion and pregoal versus postgoal emotion. Pregoal emotion reflects appraisals that goal attainment or failure is anticipated but has not yet occurred (e.g., hope and fear). Postgoal emotion reflects appraisals that goal attainment o...

  7. Il nuovo reato di false comunicazioni sociali

    Directory of Open Access Journals (Sweden)

    Lorenzo Maria Corvucci

    2015-12-01

    Full Text Available The author examines the new offence of false social communication introduced by the Italian law dated 27 may 2015 n.69 in force from 14 June 2015. Considering the modifications added to the new offence of false accounting- basically explained to highlight the novum - the attention is paid on a specific major issue, previously discussed by the fifth section of the Italian Supreme Court competent in this matter after a few months from the moment the new law came in force. The questions applies to the fact whether the fraudulent evidence should remain to be punishable as the new discipline has limited the object of the criminal conduct only to “material relevant facts which are untrue” or to the omission of material relevant facts whose communication is imposed by the law regulating the economic situation, the assets and financial position of the company or of the group to which the company belongs. In this way any reference to the evaluations contained in the text previously in force is eliminated. Omissive conduct is the new definition recalling the two previous rules (art. 2621 and 2622 of the Italian civil code.

  8. Cytolethal distending toxin: a conserved bacterial genotoxin that blocks cell cycle progression, leading to apoptosis of a broad range of mammalian cell lineages.

    Science.gov (United States)

    Jinadasa, Rasika N; Bloom, Stephen E; Weiss, Robert S; Duhamel, Gerald E

    2011-07-01

    Cytolethal distending toxin (CDT) is a heterotrimeric AB-type genotoxin produced by several clinically important Gram-negative mucocutaneous bacterial pathogens. Irrespective of the bacterial species of origin, CDT causes characteristic and irreversible cell cycle arrest and apoptosis in a broad range of cultured mammalian cell lineages. The active subunit CdtB has structural homology with the phosphodiesterase family of enzymes including mammalian DNase I, and alone is necessary and sufficient to account for cellular toxicity. Indeed, mammalian cells treated with CDT initiate a DNA damage response similar to that elicited by ionizing radiation-induced DNA double strand breaks resulting in cell cycle arrest and apoptosis. The mechanism of CDT-induced apoptosis remains incompletely understood, but appears to involve both p53-dependent and -independent pathways. While epithelial, endothelial and fibroblast cell lines respond to CDT by undergoing arrest of cell cycle progression resulting in nuclear and cytoplasmic distension that precedes apoptotic cell death, cells of haematopoietic origin display rapid apoptosis following a brief period of cell cycle arrest. In this review, the ecology of pathogens producing CDT, the molecular biology of bacterial CDT and the molecular mechanisms of CDT-induced cytotoxicity are critically appraised. Understanding the contribution of a broadly conserved bacterial genotoxin that blocks progression of the mammalian cell cycle, ultimately causing cell death, should assist with elucidating disease mechanisms for these important pathogens.

  9. The utility of the clock drawing test in detection of delirium in elderly hospitalised patients.

    Science.gov (United States)

    Adamis, Dimitrios; Meagher, David; O'Neill, Donagh; McCarthy, Geraldine

    2016-09-01

    Delirium is common neuropsychiatric condition among elderly inpatients. The clock drawing test (CDT) has been used widely as bedside screening tool in assessing cognitive impairment in elderly people. Previous studies which evaluate its usefulness in delirium reported conflicting results. The objective of this study was to evaluate the utility of CDT to detect delirium in elderly medical patients. Prospective, observational, longitudinal study. All acute medical admissions 70 years of age and above were approached within 72 hours of admission for recruitment. Patients eligible for inclusion were assessed four times, twice weekly during admission. Assessment included Confusion Assessment Method (CAM), Delirium Rating Scale (DRS-98R), Montreal Cognitive Assessment (MoCA), Acute Physiology and Chronic Health Evaluation II (APACHE) II, and CDT. Data was analysed using a linear mixed effect model. Three hundred and twenty-three assessments with the CDT were performed on 200 subjects (50% male, mean age 81.13; standard deviation: 6.45). The overall rate of delirium (CAM+) during hospitalisation was 23%. There was a significant negative correlation between the CDT and DRS-R98 scores (Pearson correlation r = -0.618, p < 0.001), CDT and CAM (Spearman's rho = -0.402, p < 0.001) and CDT and total MoCA score (Pearson's r = 0.767, p < 0.001). However, when the data were analysed longitudinally controlling for all the factors, we found that cognitive function and age were significant factors associated with CDT scores (p < .0001): neither the presence nor the severity of delirium had an additional significant effect on the CDT. CDT score reflects cognitive impairment, independently of the presence or severity of delirium. The CDT is not a suitable test for delirium in hospitalised elderly patients.

  10. Faecal excretion of brush border membrane enzymes in patients with clostridium difficile diarrhoea

    Directory of Open Access Journals (Sweden)

    Katyal R

    2002-01-01

    Full Text Available PURPOSE: To look for the presence of intestinal brush border membrane (BBM enzymes in the faecal samples of patients with Clostridium difficile association. METHODS: One hundred faecal samples were investigated for C.difficile toxin (CDT. Simultaneous assays for faecal excretion of intestinal BBM enzymes viz., disaccharidases, alkaline phosphatase (AP and leucine aminopeptidase (LAP were also done. RESULTS: C.difficile toxin was detected in 25 (25% of the samples with a titre ranging from 10 to 160. No significant difference (p>0.05 was seen between the CDT positive and negative groups with any of the disaccharidases studied. However, significant increase (pC.difficile diarrhoea.

  11. A Brighter Side to Memory Illusions: False Memories Prime Children's and Adults' Insight-Based Problem Solving

    Science.gov (United States)

    Howe, Mark L.; Garner, Sarah R.; Charlesworth, Monica; Knott, Lauren

    2011-01-01

    Can false memories have a positive consequence on human cognition? In two experiments, we investigated whether false memories could prime insight problem-solving tasks. Children and adults were asked to solve compound remote associate task (CRAT) problems, half of which had been primed by the presentation of Deese/Roediger-McDermott (DRM) lists…

  12. Increased Diagnostic Accuracy of Digital vs. Conventional Clock Drawing Test for Discrimination of Patients in the Early Course of Alzheimer's Disease from Cognitively Healthy Individuals.

    Science.gov (United States)

    Müller, Stephan; Preische, Oliver; Heymann, Petra; Elbing, Ulrich; Laske, Christoph

    2017-01-01

    The conventional Clock Drawing Test (cCDT) is a rapid and inexpensive screening tool for detection of moderate and severe dementia. However, its usage is limited due to poor diagnostic accuracy especially in patients with mild cognitive impairment (MCI). The diagnostic value of a newly developed digital Clock Drawing Test (dCDT) was evaluated and compared with the cCDT in 20 patients with early dementia due to AD (eDAT), 30 patients with amnestic MCI (aMCI) and 20 cognitively healthy controls (HCs). Parameters assessed by dCDT were time while transitioning the stylus from one stroke to the next above the surface (i.e., time-in-air), time the stylus produced a visible stroke (i.e., time-on-surface) and total-time during clock drawing. Receiver-operating characteristic (ROC) curves were calculated and logistic regression analyses have been conducted for statistical analysis. Using dCDT, time-in-air was significantly increased in eDAT (70965.8 ms) compared to aMCI (54073.7 ms; p = 0.027) and HC (32315.6 ms; p < 0.001). In addition, time-in-air was significantly longer in patients with aMCI compared to HC ( p = 0.003), even in the aMCI group with normal cCDT score (54141.8 ms; p < 0.001). Time-in-air using dCDT allowed discrimination of patients with aMCI from HCs with a sensitivity of 81.3% and a specificity of 72.2% while cCDT scoring revealed a sensitivity of 62.5% and a specificity of 83.3%. Most interestingly, time-in-air allowed even discrimination of aMCI patients with normal cCDT scores (80% from all aMCI patients) from HCs with a clinically relevant sensitivity of 80.8% and a specificity of 77.8%. A combination of dCDT variables and cCDT scores did not improve the discrimination of patients with aMCI from HC. In conclusion, assessment of time-in-air using dCDT yielded a higher diagnostic accuracy for discrimination of aMCI patients from HCs than the use of cCDT even in those aMCI patients with normal cCDT scores. Modern digitizing devices offer the opportunity

  13. Increased Diagnostic Accuracy of Digital vs. Conventional Clock Drawing Test for Discrimination of Patients in the Early Course of Alzheimer’s Disease from Cognitively Healthy Individuals

    Science.gov (United States)

    Müller, Stephan; Preische, Oliver; Heymann, Petra; Elbing, Ulrich; Laske, Christoph

    2017-01-01

    The conventional Clock Drawing Test (cCDT) is a rapid and inexpensive screening tool for detection of moderate and severe dementia. However, its usage is limited due to poor diagnostic accuracy especially in patients with mild cognitive impairment (MCI). The diagnostic value of a newly developed digital Clock Drawing Test (dCDT) was evaluated and compared with the cCDT in 20 patients with early dementia due to AD (eDAT), 30 patients with amnestic MCI (aMCI) and 20 cognitively healthy controls (HCs). Parameters assessed by dCDT were time while transitioning the stylus from one stroke to the next above the surface (i.e., time-in-air), time the stylus produced a visible stroke (i.e., time-on-surface) and total-time during clock drawing. Receiver-operating characteristic (ROC) curves were calculated and logistic regression analyses have been conducted for statistical analysis. Using dCDT, time-in-air was significantly increased in eDAT (70965.8 ms) compared to aMCI (54073.7 ms; p = 0.027) and HC (32315.6 ms; p < 0.001). In addition, time-in-air was significantly longer in patients with aMCI compared to HC (p = 0.003), even in the aMCI group with normal cCDT score (54141.8 ms; p < 0.001). Time-in-air using dCDT allowed discrimination of patients with aMCI from HCs with a sensitivity of 81.3% and a specificity of 72.2% while cCDT scoring revealed a sensitivity of 62.5% and a specificity of 83.3%. Most interestingly, time-in-air allowed even discrimination of aMCI patients with normal cCDT scores (80% from all aMCI patients) from HCs with a clinically relevant sensitivity of 80.8% and a specificity of 77.8%. A combination of dCDT variables and cCDT scores did not improve the discrimination of patients with aMCI from HC. In conclusion, assessment of time-in-air using dCDT yielded a higher diagnostic accuracy for discrimination of aMCI patients from HCs than the use of cCDT even in those aMCI patients with normal cCDT scores. Modern digitizing devices offer the opportunity

  14. Individual differences in susceptibility to false memories: The effect of memory specificity.

    Science.gov (United States)

    Dewhurst, Stephen A; Anderson, Rachel J; Berry, Donna M; Garner, Sarah R

    2017-06-25

    Previous research has highlighted the wide individual variability in susceptibility to the false memories produced by the Deese/Roediger-McDermott (DRM) procedure [Deese, J. (1959). On the prediction of occurrence of particular verbal intrusions in immediate recall. Journal of Experimental Psychology, 58, 17-22; Roediger, H. L., III, & McDermott, K. B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, & Cognition, 21, 803-814]. The current study investigated whether susceptibility to false memories is influenced by individual differences in the specificity of autobiographical memory retrieval. Memory specificity was measured using the Sentence Completion for Events from the Past Test (SCEPT) [Raes, F., Hermans, D., Williams, J. M. G., & Eelen, P. (2007). A sentence completion procedure as an alternative to the Autobiographical Memory Test for assessing overgeneral memory in non-clinical populations. Memory, 15, 495-507]. Memory specificity did not correlate with correct recognition, but a specific retrieval style was positively correlated with levels of false recognition. It is proposed that the contextual details that frequently accompany false memories of nonstudied lures are more accessible in individuals with specific retrieval styles.

  15. Selective activation around the left occipito-temporal sulcus for words relative to pictures: individual variability or false positives?

    Science.gov (United States)

    Wright, Nicholas D; Mechelli, Andrea; Noppeney, Uta; Veltman, Dick J; Rombouts, Serge A R B; Glensman, Janice; Haynes, John-Dylan; Price, Cathy J

    2008-08-01

    We used high-resolution fMRI to investigate claims that learning to read results in greater left occipito-temporal (OT) activation for written words relative to pictures of objects. In the first experiment, 9/16 subjects performing a one-back task showed activation in > or =1 left OT voxel for words relative to pictures (P or =1 left OT voxel for words relative to pictures. However, at this low statistical threshold false positives need to be excluded. The semantic decision paradigm was therefore repeated, within subject, in two different scanners (1.5 and 3 T). Both scanners consistently localised left OT activation for words relative to fixation and pictures relative to words, but there were no consistent effects for words relative to pictures. Finally, in a third experiment, we minimised the voxel size (1.5 x 1.5 x 1.5 mm(3)) and demonstrated a striking concordance between the voxels activated for words and pictures, irrespective of task (naming vs. one-back) or script (English vs. Hebrew). In summary, although we detected differential activation for words relative to pictures, these effects: (i) do not withstand statistical rigour; (ii) do not replicate within or between subjects; and (iii) are observed in voxels that also respond to pictures of objects. Our findings have implications for the role of left OT activation during reading. More generally, they show that studies using low statistical thresholds in single subject analyses should correct the statistical threshold for the number of comparisons made or replicate effects within subject. (c) 2007 Wiley-Liss, Inc.

  16. False memory production :effects of self-consistent false information and motivated cognition

    OpenAIRE

    Brown, Martha

    1996-01-01

    Remembrance of one's personal past and the development of false memories have recently received intense public scrutiny. Based upon self-schema (Markus, 1977) and selfverification (Swann, 1987) theories, two studies were conducted to investigate the hypothesis that a self-schema guides cognitive processing of self-relevant information and thereby influences the construction of a memory that includes false information, particularly more so if this information is self-schema consistent than ...

  17. False alarms and incorrect rejections in an information security center: correlation with the frequency of incidents.

    Science.gov (United States)

    Bruno, Thiers; Abrahão, Julia

    2012-01-01

    This study examines the actions taken by operators aimed at preventing and combating information security incidents at a banking organization. The work utilizes the theoretical framework of ergonomics and cognitive psychology. The method is workplace ergonomic analysis. Its focus is directed towards examining the cognitive dimension of the work environment with special attention to the occurrence of correlations between variability in incident frequency and the results of sign detection actions. It categorizes 45,142 operator decisions according to the theory of signal detection (Sternberg, 2000). It analyzes the correlation between incident proportions (indirectly associated with the cognitive efforts demanded from the operator) and operator decisions. The study demonstrated the existence of a positive correlation between incident proportions and false positive decisions (false alarms). However, this correlation could not be observed in relation to decisions of the false-negative type (incorrect rejection).

  18. False memory and level of processing effect: an event-related potential study.

    Science.gov (United States)

    Beato, Maria Soledad; Boldini, Angela; Cadavid, Sara

    2012-09-12

    Event-related potentials (ERPs) were used to determine the effects of level of processing on true and false memory, using the Deese-Roediger-McDermott (DRM) paradigm. In the DRM paradigm, lists of words highly associated to a single nonpresented word (the 'critical lure') are studied and, in a subsequent memory test, critical lures are often falsely remembered. Lists with three critical lures per list were auditorily presented here to participants who studied them with either a shallow (saying whether the word contained the letter 'o') or a deep (creating a mental image of the word) processing task. Visual presentation modality was used on a final recognition test. True recognition of studied words was significantly higher after deep encoding, whereas false recognition of nonpresented critical lures was similar in both experimental groups. At the ERP level, true and false recognition showed similar patterns: no FN400 effect was found, whereas comparable left parietal and late right frontal old/new effects were found for true and false recognition in both experimental conditions. Items studied under shallow encoding conditions elicited more positive ERP than items studied under deep encoding conditions at a 1000-1500 ms interval. These ERP results suggest that true and false recognition share some common underlying processes. Differential effects of level of processing on true and false memory were found only at the behavioral level but not at the ERP level.

  19. High confidence in falsely recognizing prototypical faces.

    Science.gov (United States)

    Sampaio, Cristina; Reinke, Victoria; Mathews, Jeffrey; Swart, Alexandra; Wallinger, Stephen

    2018-06-01

    We applied a metacognitive approach to investigate confidence in recognition of prototypical faces. Participants were presented with sets of faces constructed digitally as deviations from prototype/base faces. Participants were then tested with a simple recognition task (Experiment 1) or a multiple-choice task (Experiment 2) for old and new items plus new prototypes, and they showed a high rate of confident false alarms to the prototypes. Confidence and accuracy relationship in this face recognition paradigm was found to be positive for standard items but negative for the prototypes; thus, it was contingent on the nature of the items used. The data have implications for lineups that employ match-to-suspect strategies.

  20. 19 CFR 111.32 - False information.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false False information. 111.32 Section 111.32 Customs... CUSTOMS BROKERS Duties and Responsibilities of Customs Brokers § 111.32 False information. A broker must... procure the giving of, any false or misleading information or testimony in any matter pending before the...

  1. Bandwagon voting or false-consensus effect in voting experiments? First results and methodological limits

    OpenAIRE

    Bischoff, Ivo; Egbert, Henrik

    2008-01-01

    In an experiment designed to test for expressive voting, Tyran (JPubEc 2004) found a strong positive correlation between the participants' approval to a proposal to donate money for charity and their expected approval rate for fellow voters. This phenomenon can be due to a bandwagon effect or a false consensus effect. Both effects have been reported for voting decisions in the social science literature. Redoing Tyran's experiment and adding new treatments, we provide evidence for a false cons...

  2. PET Study with false positive {sup 68}Ga-Dotatate caused by the presence of an accessory spleen; Estudio PET con {sup 68}Ga-Dotatate falso positivo causado por la presencia de un bazo accesorio

    Energy Technology Data Exchange (ETDEWEB)

    Massardo, Teresa [Centro PET de Imagenes Moleculares, Hospital Militar de Santiago / Seccion Medicina Nuclear, Departamento Medicina, Hospital Clinico Universidad de Chile. Santiago (Chile); Jofre, Josefina; Sierralta, M. Paulina; Canessa, Jose [Centro PET de Imagenes Moleculares, Hospital Militar de Santiago. Santiago (Chile)

    2013-05-31

    Neuroendocrine tumors with somatostatin receptor expression are suitable for imaging with somatostatin analogues. {sup 68}Ga-labeled peptides are useful for the diagnosis, staging and assessment of therapeutic response of these tumors. However, for a correct interpretation it is necessary to know the normal biodistribution of somatostatin receptors in the body. Asymmetric adrenal uptake may be a normal variant to cause confusion, or an accessory or ectopic spleen can lead to a false positive result. We report a case of asymmetric adrenal uptake which was correctly considered as a normal variant, but an accessory spleen caused the false impression of being a metastasis from a previously resected primary carcinoid tumor.

  3. Raising Awareness of False Positive Newborn Screening Results Arising from Pivalate-Containing Creams and Antibiotics in Europe When Screening for Isovaleric Acidaemia

    Directory of Open Access Journals (Sweden)

    James R. Bonham

    2018-02-01

    Full Text Available While the early and asymptomatic recognition of treatable conditions offered by newborn screening confers clear health benefits for the affected child, the clinical referral of patients with screen positive results can cause significant harm for some families. The use of pivalate-containing antibiotics and more recently the inclusion of neopentanoate as a component within moisturising creams used as nipple balms by nursing mothers can result in a significant number of false positive results when screening for isovaleric acidaemia (IVA by measuring C5 acylcarnitine. A recent survey conducted within centres from nine countries indicated that this form of contamination had been or was a significant confounding factor in the detection of IVA in seven of the nine who responded. In three of these seven the prominent cause was believed to derive from the use of moisturising creams and in another three from antibiotics containing pivalate; one country reported that the cause was mixed. As a result, four of these seven centres routinely perform second tier testing to resolve C5 isobars when an initial C5 result is elevated, and a fifth is considering making this change within their national programme. The use of creams containing neopentanoate by nursing mothers and evolving patterns in the prescription of pivalate-containing antibiotics during pregnancy require those involved in the design and operation of newborn screening programmes used to detect IVA and the doctors who receive clinical referrals from these programmes to maintain an awareness of the potential impact of this form of interference on patient results.

  4. Word type effects in false recall: concrete, abstract, and emotion word critical lures.

    Science.gov (United States)

    Bauer, Lisa M; Olheiser, Erik L; Altarriba, Jeanette; Landi, Nicole

    2009-01-01

    Previous research has demonstrated that definable qualities of verbal stimuli have implications for memory. For example, the distinction between concrete and abstract words has led to the finding that concrete words have an advantage in memory tasks (i.e., the concreteness effect). However, other word types, such as words that label specific human emotions, may also affect memory processes. This study examined the effects of word type on the production of false memories by using a list-learning false memory paradigm. Participants heard lists of words that were highly associated to nonpresented concrete, abstract, or emotion words (i.e., the critical lures) and then engaged in list recall. Emotion word critical lures were falsely recalled at a significantly higher rate (with the effect carried by the positively valenced critical lures) than concrete and abstract critical lures. These findings suggest that the word type variable has implications for our understanding of the mechanisms that underlie recall and false recall.

  5. Development of a prototype chest digital tomosynthesis (CDT) R/F system with fast image reconstruction using graphics processing unit (GPU) programming

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sunghoon, E-mail: choi.sh@yonsei.ac.kr [Department of Radiological Science, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of); Lee, Seungwan [Department of Radiological Science, College of Medical Science, Konyang University, 158 Gwanjeodong-ro, Daejeon, 308-812 (Korea, Republic of); Lee, Haenghwa [Department of Radiological Science, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of); Lee, Donghoon; Choi, Seungyeon [Department of Radiation Convergence Engineering, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of); Shin, Jungwook [LISTEM Corporation, 94 Donghwagongdan-ro, Munmak-eup, Wonju (Korea, Republic of); Seo, Chang-Woo [Department of Radiological Science, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of); Kim, Hee-Joung, E-mail: hjk1@yonsei.ac.kr [Department of Radiological Science, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of); Department of Radiation Convergence Engineering, College of Health Science, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 220-710 (Korea, Republic of)

    2017-03-11

    Digital tomosynthesis offers the advantage of low radiation doses compared to conventional computed tomography (CT) by utilizing small numbers of projections (~80) acquired over a limited angular range. It produces 3D volumetric data, although there are artifacts due to incomplete sampling. Based upon these characteristics, we developed a prototype digital tomosynthesis R/F system for applications in chest imaging. Our prototype chest digital tomosynthesis (CDT) R/F system contains an X-ray tube with high power R/F pulse generator, flat-panel detector, R/F table, electromechanical radiographic subsystems including a precise motor controller, and a reconstruction server. For image reconstruction, users select between analytic and iterative reconstruction methods. Our reconstructed images of Catphan700 and LUNGMAN phantoms clearly and rapidly described the internal structures of phantoms using graphics processing unit (GPU) programming. Contrast-to-noise ratio (CNR) values of the CTP682 module of Catphan700 were higher in images using a simultaneous algebraic reconstruction technique (SART) than in those using filtered back-projection (FBP) for all materials by factors of 2.60, 3.78, 5.50, 2.30, 3.70, and 2.52 for air, lung foam, low density polyethylene (LDPE), Delrin{sup ®} (acetal homopolymer resin), bone 50% (hydroxyapatite), and Teflon, respectively. Total elapsed times for producing 3D volume were 2.92 s and 86.29 s on average for FBP and SART (20 iterations), respectively. The times required for reconstruction were clinically feasible. Moreover, the total radiation dose from our system (5.68 mGy) was lower than that of conventional chest CT scan. Consequently, our prototype tomosynthesis R/F system represents an important advance in digital tomosynthesis applications.

  6. 28 CFR 345.20 - Position classification.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Position classification. 345.20 Section... INDUSTRIES (FPI) INMATE WORK PROGRAMS Position Classification § 345.20 Position classification. (a) Inmate... the objectives and principles of pay classification as a part of the routine orientation of new FPI...

  7. The role of Campylobacter jejuni cytolethal distending toxin in gastroenteritis

    DEFF Research Database (Denmark)

    Mortensen, Ninell P; Schiellerup, Peter; Boisen, Nadia

    2011-01-01

    The role of Campylobacter jejuni cytolethal distending toxin (CDT) on clinical outcome after gastroenteritis was investigated. Clinical data, blood serum samples, and Campylobacter spp. isolated, from each of 30 patients were collected over a period of 6 months. The CDT encoding genes, cdt...

  8. Catheter-directed thrombolysis and pharmacomechanical thrombectomy improve midterm outcome in acute iliofemoral deep vein thrombosis

    Directory of Open Access Journals (Sweden)

    Tzu-Ting Kuo

    2017-02-01

    Conclusion: CDT and PMT have similar venous outcomes in patients with acute iliofemoral DVT, although PTS is less severe following PMT than after CDT. We propose that early and thorough removal of thrombus, using either CDT or PMT, is beneficial to prevent PTS.

  9. False memories to emotional stimuli are not equally affected in right- and left-brain-damaged stroke patients.

    Science.gov (United States)

    Buratto, Luciano Grüdtner; Zimmermann, Nicolle; Ferré, Perrine; Joanette, Yves; Fonseca, Rochele Paz; Stein, Lilian Milnitsky

    2014-10-01

    Previous research has attributed to the right hemisphere (RH) a key role in eliciting false memories to visual emotional stimuli. These results have been explained in terms of two right-hemisphere properties: (i) that emotional stimuli are preferentially processed in the RH and (ii) that visual stimuli are represented more coarsely in the RH. According to this account, false emotional memories are preferentially produced in the RH because emotional stimuli are both more strongly and more diffusely activated during encoding, leaving a memory trace that can be erroneously reactivated by similar but unstudied emotional items at test. If this right-hemisphere hypothesis is correct, then RH damage should result in a reduction in false memories to emotional stimuli relative to left-hemisphere lesions. To investigate this possibility, groups of right-brain-damaged (RBD, N=15), left-brain-damaged (LBD, N=15) and healthy (HC, N=30) participants took part in a recognition memory experiment with emotional (negative and positive) and non-emotional pictures. False memories were operationalized as incorrect responses to unstudied pictures that were similar to studied ones. Both RBD and LBD participants showed similar reductions in false memories for negative pictures relative to controls. For positive pictures, however, false memories were reduced only in RBD patients. The results provide only partial support for the right-hemisphere hypothesis and suggest that inter-hemispheric cooperation models may be necessary to fully account for false emotional memories. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Are the memories of older adults positively biased?

    Science.gov (United States)

    Fernandes, Myra; Ross, Michael; Wiegand, Melanie; Schryer, Emily

    2008-06-01

    There is disagreement in the literature about whether a "positivity effect" in memory performance exists in older adults. To assess the generalizability of the effect, the authors examined memory for autobiographical, picture, and word information in a group of younger (17-29 years old) and older (60-84 years old) adults. For the autobiographical memory task, the authors asked participants to produce 4 positive, 4 negative, and 4 neutral recent autobiographical memories and to recall these a week later. For the picture and word tasks, participants studied photos or words of different valences (positive, negative, neutral) and later remembered them on a free-recall test. The authors found significant correlations in memory performance, across task material, for recall of both positive and neutral valence autobiographical events, pictures, and words. When the authors examined accurate memories, they failed to find consistent evidence, across the different types of material, of a positivity effect in either age group. However, the false memory findings offer more consistent support for a positivity effect in older adults. During recall of all 3 types of material, older participants recalled more false positive than false negative memories.

  11. 21 CFR 868.6820 - Patient position support.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Miscellaneous § 868.6820 Patient position support. (a) Identification. A patient position support is a device intended to maintain the position of an anesthetized... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Patient position support. 868.6820 Section 868...

  12. The cytolethal distending toxin contributes to microbial virulence and disease pathogenesis by acting as a tri-perditious toxin

    Directory of Open Access Journals (Sweden)

    Monika D Scuron

    2016-12-01

    Full Text Available This review summarizes the current status and recent advances in our understanding of the role that the cytolethal distending toxin (Cdt plays as a virulence factor in promoting disease by toxin-producing pathogens. A major focus of this review is on the relationship between structure and function of the individual subunits that comprise the AB2 Cdt holotoxin. In particular, we concentrate on the molecular mechanisms that characterize this toxin and which account for the ability of Cdt to intoxicate multiple cell types by utilizing a ubiquitous binding partner on the cell membrane. Furthermore, we propose a paradigm shift for the molecular mode of action by which the active Cdt subunit, CdtB, is able to block a key signaling cascade and thereby lead to outcomes based upon programming and the role of the phosphatidylinositol 3-kinase (PI-3K in a variety of cells. Based upon the collective Cdt literature, we now propose that Cdt is a unique and potent virulence factor capable of acting as a tri-perditious toxin that impairs host defenses by: 1 disrupting epithelial barriers; 2 suppressing acquired immunity; 3 promoting pro-inflammatory responses. Thus Cdt plays a key role in facilitating the early stages of infection and the later stages of disease progression by contributing to persistence and impairing host elimination.

  13. Specific algorithm method of scoring the Clock Drawing Test applied in cognitively normal elderly

    Directory of Open Access Journals (Sweden)

    Liana Chaves Mendes-Santos

    Full Text Available The Clock Drawing Test (CDT is an inexpensive, fast and easily administered measure of cognitive function, especially in the elderly. This instrument is a popular clinical tool widely used in screening for cognitive disorders and dementia. The CDT can be applied in different ways and scoring procedures also vary. OBJECTIVE: The aims of this study were to analyze the performance of elderly on the CDT and evaluate inter-rater reliability of the CDT scored by using a specific algorithm method adapted from Sunderland et al. (1989. METHODS: We analyzed the CDT of 100 cognitively normal elderly aged 60 years or older. The CDT ("free-drawn" and Mini-Mental State Examination (MMSE were administered to all participants. Six independent examiners scored the CDT of 30 participants to evaluate inter-rater reliability. RESULTS AND CONCLUSION: A score of 5 on the proposed algorithm ("Numbers in reverse order or concentrated", equivalent to 5 points on the original Sunderland scale, was the most frequent (53.5%. The CDT specific algorithm method used had high inter-rater reliability (p<0.01, and mean score ranged from 5.06 to 5.96. The high frequency of an overall score of 5 points may suggest the need to create more nuanced evaluation criteria, which are sensitive to differences in levels of impairment in visuoconstructive and executive abilities during aging.

  14. 30 CFR 56.7052 - Drilling positions.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Drilling positions. 56.7052 Section 56.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7052 Drilling positions. Persons shall not drill from— (a) Positions which hinder...

  15. E-commerce Review System to Detect False Reviews.

    Science.gov (United States)

    Kolhar, Manjur

    2017-08-15

    E-commerce sites have been doing profitable business since their induction in high-speed and secured networks. Moreover, they continue to influence consumers through various methods. One of the most effective methods is the e-commerce review rating system, in which consumers provide review ratings for the products used. However, almost all e-commerce review rating systems are unable to provide cumulative review ratings. Furthermore, review ratings are influenced by positive and negative malicious feedback ratings, collectively called false reviews. In this paper, we proposed an e-commerce review system framework developed using the cumulative sum method to detect and remove malicious review ratings.

  16. Quality of life of older adults in Canada and Norway: examining the Iowa model.

    Science.gov (United States)

    Low, Gail; Molzahn, Anita E; Kalfoss, Mary

    2008-06-01

    In this study, Glick and Tripp-Reimer's (1996) Iowa model for gerontological nursing serves as a guiding framework for a descriptive exploratory study of quality of life (QOL) of older adults. Using secondary data, the authors explored whether the effects of health appraisal, morbidities, social support transitions (SST), and the environment on QOL would be partly mediated by cognitive developmental transitions (CDT). Data sets were available from studies with random samples of community-dwelling older adults from Canada (n = 202) and Norway (n = 490). The partly and fully mediated effects found suggest positive CDT in older age might be significantly enhanced by the presence of intimate ties, positive perceptions of one's health limitations, and residence in a healthy, safe, and resource-rich physical environment. These findings represent a novel attempt at testing complex linkages between aspects of elder, environment, and nursing concepts within the Iowa model warranting further research.

  17. The use of the Clock Drawing Test in bipolar disorder with or without dementia of Alzheimer’s type

    Directory of Open Access Journals (Sweden)

    Ivan Aprahamian

    2014-12-01

    Full Text Available There is limited data regarding the cognitive profile from screening tests of older adults with bipolar disorder (BD with dementia. Objective To investigate the Clock Drawing Test (CDT among older adults with BD with and without Alzheimer’s disease (AD. Method 209 older adults (79 with BD without dementia and 70 controls; 60 with AD, being 27 with BD were included to evaluate the performance of three CDT scoring scales, beyond the Mini-Mental State Examination (MMSE and verbal fluency (VFT. Results Patients with BD without dementia presented with lower scores in MMSE, VF and one CDT scoring scale than controls. Patients with BD and AD presented with lower scores in VF and CDT scoring scales than patients with only AD. All CDT scales presented similar sensitivity and specificity for BD and non-BD groups. Conclusion Elderly subjects with BD showed greater impairment in CDT in both groups of normal cognition and AD.

  18. A model for emergence of space and time

    Energy Technology Data Exchange (ETDEWEB)

    Ambjørn, J., E-mail: ambjorn@nbi.dk [The Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, DK-2100 Copenhagen Ø (Denmark); Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radbaud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen (Netherlands); Watabiki, Y., E-mail: watabiki@th.phys.titech.ac.jp [Tokyo Institute of Technology, Dept. of Physics, High Energy Theory Group, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2015-10-07

    We study string field theory (third quantization) of the two-dimensional model of quantum geometry called generalized CDT (“causal dynamical triangulations”). Like in standard non-critical string theory the so-called string field Hamiltonian of generalized CDT can be associated with W-algebra generators through the string mode expansion. This allows us to define an “absolute” vacuum. “Physical” vacua appear as coherent states created by vertex operators acting on the absolute vacuum. Each coherent state corresponds to specific values of the coupling constants of generalized CDT. The cosmological “time” only exists relatively to a given “physical” vacuum and comes into existence before space, which is created because the “physical” vacuum is unstable. Thus each CDT “universe” is created as a “Big Bang” from the absolute vacuum, its time evolution is governed by the CDT string field Hamiltonian with given coupling constants, and one can imagine interactions between CDT universes with different coupling constants (“fourth quantization”)

  19. A model for emergence of space and time

    Directory of Open Access Journals (Sweden)

    J. Ambjørn

    2015-10-01

    Full Text Available We study string field theory (third quantization of the two-dimensional model of quantum geometry called generalized CDT (“causal dynamical triangulations”. Like in standard non-critical string theory the so-called string field Hamiltonian of generalized CDT can be associated with W-algebra generators through the string mode expansion. This allows us to define an “absolute” vacuum. “Physical” vacua appear as coherent states created by vertex operators acting on the absolute vacuum. Each coherent state corresponds to specific values of the coupling constants of generalized CDT. The cosmological “time” only exists relatively to a given “physical” vacuum and comes into existence before space, which is created because the “physical” vacuum is unstable. Thus each CDT “universe” is created as a “Big Bang” from the absolute vacuum, its time evolution is governed by the CDT string field Hamiltonian with given coupling constants, and one can imagine interactions between CDT universes with different coupling constants (“fourth quantization”

  20. Gene Amplification on Demand Accelerates Cellobiose Utilization in Engineered Saccharomyces cerevisiae.

    Science.gov (United States)

    Oh, Eun Joong; Skerker, Jeffrey M; Kim, Soo Rin; Wei, Na; Turner, Timothy L; Maurer, Matthew J; Arkin, Adam P; Jin, Yong-Su

    2016-06-15

    efficient strategy for yeast metabolic engineering. In order to enable rapid and efficient fermentation of cellulosic hydrolysates by engineered yeast, we delve into the limiting factors of cellobiose fermentation by engineered yeast expressing a cellobiose transporter (encoded by cdt-1) and an intracellular β-glucosidase (encoded by gh1-1). Through laboratory evolution, we isolated mutant strains capable of fermenting cellobiose much faster than a parental strain. Genome sequencing of the fast cellobiose-fermenting mutant reveals that there are massive amplifications of cdt-1 and gh1-1 in the yeast genome. We also found positive and quantitative relationships between the rates of cellobiose consumption and the copy numbers of cdt-1 and gh1-1 in the evolved strains. Our results suggest that the cellobiose assimilation pathway (transport and hydrolysis) might be a rate-limiting step for efficient cellobiose fermentation. We demonstrate the feasibility of optimizing not only heterologous metabolic pathways in yeast through laboratory evolution but also on-demand gene amplification in yeast, which can be broadly applicable for metabolic engineering. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  1. Is the truth in the details? Extended narratives help distinguishing false "memories" from false "reports".

    Science.gov (United States)

    Sjödén, Björn; Granhag, Pär Anders; Ost, James; Roos Af Hjelmsäter, Emma

    2009-06-01

    The present study examined the effects of fantasy proneness on false "reports" and false "memories", of existent and non-existent footage of a public event. We predicted that highly fantasy prone individuals would be more likely to stand by their initial claim of having seen a film of the event than low fantasy prone participants when prompted for more details about their experiences. Eighty creative arts students and 80 other students were asked whether they had seen CCTV footage preceding the attack on Swedish foreign minister Anna Lindh up to, and including, non-existent footage of the actual moment of the attack. If affirmative, they were probed for extended narratives of what they claimed to have seen. Overall, 64% of participants provided a false "report" by answering yes to the initial question. Of these, 30% provided no explicit details of the attack, and a further 15% retracted their initial answer in their narratives. This left 19% of the sample who appeared to have false "memories" because they provided explicit details of the actual moment of the attack. Women scored higher than men and art students scored higher than other students on fantasy proneness, but there was no effect on levels of false reporting or false "memory". Memories were rated more vivid and clear for existent compared to non-existent aspects of the event. In sum, these data suggest a more complex relationship between memory distortions and fantasy proneness than previously observed.

  2. The impact of sleep on true and false memory across long delays.

    Science.gov (United States)

    Pardilla-Delgado, Enmanuelle; Payne, Jessica D

    2017-01-01

    While the influence of sleep on memory has a long history, sleep's role in the formation of false memories is less clear. Moreover, virtually nothing is known about the development of false memories beyond delays of about 12h. Here, for the first time, we assess post-sleep development of true and false memories across longer delay intervals of 24 and 48h. Although technically a false memory, remembering information that is related to the theme, or gist, of an experience can be considered an adaptive process. Some evidence suggests that sleep, compared to a wake period, increases both true and gist-based false memories in the Deese-Roediger-McDermott (DRM) task, but not all studies have returned this result, and most studies cannot rule out the possibility that sleep is merely protecting the information from interference, as opposed to actively aiding its consolidation. Here, to equate amount of time spent awake and asleep across groups, we assess how the positioning of sleep relative to memory encoding impacts retention across longer delays of 24 and 48h. Participants encoded 16 DRM lists in the morning (WAKE 1st Groups) or evening (SLEEP 1st Groups), and were tested either 24 or 48h later at the same time of day. Results demonstrate that true memory is better when participants sleep soon after learning. Sleeping first also increased false memory, but only in low performers. Importantly, and similar to previous studies, we found a negative correlation between slow-wave sleep (SWS) and false memory, suggesting that SWS may be detrimental for semantic/gist processing. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Laboratory diagnosis of Clostridium difficile infection: Comparison of Techlab C. diff Quik Chek Complete, Xpert C. difficile, and multistep algorithmic approach.

    Science.gov (United States)

    Seo, Ja Young; Jeong, Ji Hun; Kim, Kyung Hee; Ahn, Jeong-Yeal; Park, Pil-Whan; Seo, Yiel-Hea

    2017-11-01

    Clostridium difficile is a major pathogen responsible for nosocomial infectious diarrhea. We explored optimal laboratory strategies for diagnosis of C. difficile infection (CDI) in our clinical settings, a 1400-bed tertiary care hospital. Using 191 fresh stool samples from adult patients, we evaluated the performance of Xpert C. difficile (Xpert CD), C. diff Quik Chek Complete (which simultaneously detects glutamate dehydrogenase [GDH] and C. difficile toxins [CDT]), toxigenic culture, and a two-step algorithm composed of GDH/CDT as a screening test and Xpert CD as a confirmatory test. Clostridium difficile was detected in 35 samples (18.3%), and all isolates were toxigenic strains. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value of each assay for detecting CDI were as follows: Quik Chek Complete CDT (45.7%, 100%, 100%, 89.1%), Quik Chek Complete GDH (97.1%, 99.4%, 97.1%, 99.4%), Xpert CD (94.3%, 100%, 100%, 98.7%), and toxigenic culture (91.4%, 100%, 100%, 98.1%). A two-step algorithm performed identically with Xpert CD assay. Our data showed that most C. difficile isolates from adult patients were toxigenic. We demonstrated that a two-step algorithm based on GDH/CDT assay followed by Xpert CD assay as a confirmatory test was rapid, reliable, and cost effective for diagnosis of CDI in an adult patient setting with high prevalence of toxigenic C. difficile. © 2017 Wiley Periodicals, Inc.

  4. Early Detection of Alzheimer's Disease Based on the Patient's Creative Drawing Process: First Results with a Novel Neuropsychological Testing Method.

    Science.gov (United States)

    Heymann, Petra; Gienger, Regine; Hett, Andreas; Müller, Stephan; Laske, Christoph; Robens, Sibylle; Ostermann, Thomas; Elbing, Ulrich

    2018-01-01

    Based on the knowledge of art therapy, we developed a new neuropsychological drawing test in order to identify individuals with mild cognitive impairment (MCI) as well as dementia patients and healthy controls (HC). By observing a variety of drawing characteristics of 92 participants with a mean age of 67.7, art therapy and dementia experts discriminate HC from MCI, early dementia of the Alzheimer-type (eDAT), and moderate dementia of the Alzheimer-type (mDAT) by the process analysis of tree drawings on a digitizing tablet. The art therapist's average categorical rating of healthy and MCI or demented individuals matched the clinical diagnosis by 88%. In a first small study, we analyzed interrater reliability, sensitivity, specificity, negative and positive predicted values of our tree drawing test (TDT) in comparison with the clock drawing test (CDT). Similar values of moderate interrater reliability were found for the TDT (0.56) as well as for the CDT (0.54). A significant high sensitivity of 0.9 within this binary impairment scale (HC versus impaired or demented) can be demonstrated. Substantial values for the specificity (0.67) could be obtained that however remain under a perfect value of the CDT (1.0). Considering 31 individuals that received the clinical diagnosis "impaired or demented" the TDT shows a higher recognition rate for the MCI group than the CDT. Furthermore in 8 of 12 borderline cases of clinical diagnosis, the outcome of the TDT diagnosis was consistent with the final clinical result.

  5. Comparison of Low-Dose Catheter-Directed Thrombolysis with and without Pharmacomechanical Thrombectomy for Acute Lower Extremity Ischemia.

    Science.gov (United States)

    Gandhi, Sagar S; Ewing, Joseph A; Cooper, Emily; Chaves, Jose Mauro; Gray, Bruce H

    2018-01-01

    Catheter-directed thrombolysis (CDT) and/or pharmacomechanical thrombectomy (PMT) can dissolve/remove thrombus; PMT alone, however, may require the adjunctive use of CDT. The aim of this study was to compare the use of CDT with and without PMT for the treatment of acute lower extremity ischemia (ALI). We retrospectively reviewed all patients with ALI who underwent CDT with or without PMT between January 2008 and April 2014 (n = 99). Patients with incomplete medical charts were excluded (n = 16). Remaining patients were divided into 2 cohorts: group 1 included patients who underwent PMT + CDT (n = 54); group 2 included those who underwent CDT alone (n = 29). Lesions were further characterized by anatomic location: iliac disease (n = 14), femoropopliteal disease (n = 53), tibial disease (n = 2), and multilevel disease (n = 14). Data collection included patient and limb characteristics, duration of treatment, complications, clinical outcomes, adjunctive interventions, and follow-up. No significant differences were seen between treatment groups in terms of patient characteristics, occlusion length and location, Rutherford class, median duration of ischemia time (P = 0.22), or mean lysis time (P = 0.58). Treatment groups were also similar with regard to outcomes, including periprocedure complications, patency, reintervention, limb salvage, and amputation-free survival. There was no different between PMT + CDT and CDT alone in terms of periprocedural complications or outcomes. In the quest to resolve ALI, initial thrombus extraction with PMT may not reduce the need, duration, or efficacy of CDT. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Blind sequential lineup administration reduces both false identifications and confidence in those false identifications.

    Science.gov (United States)

    Charman, Steve D; Quiroz, Vanessa

    2016-10-01

    One of the most recommended procedures proposed by eyewitness experts is the use of double-blind lineups, in which the administrator does not know the identity of the suspect in the lineup. But despite the near universality of this recommendation, there is surprisingly little empirical research to support the claim that nonblind administration inflates false identifications. What little research has been conducted has shown conflicting findings with regard to the conditions under which nonblind administration affects false identifications, as well as its effects on witness confidence. The current study attempts to elucidate this effect. Student-participants (n = 312) were randomly assigned to play the role of either a lineup administrator (who were either told the identity of the suspect in the lineup or not) or a mock crime witness. Following unbiased instructions, administrators presented either a target-present or target-absent sequential lineup to the witness while being surreptitiously videorecorded. Nonblind administration significantly inflated false, but not correct, identifications, and significantly inflated witness confidence in those false identifications. Video recordings indicated that nonblind administrators were significantly more likely than blind administrators to smile (a) while the witness was viewing a photograph of the suspect, and (b) after a suspect identification. Results provide stronger support for the use of blind lineup administration by broadening the conditions under which nonblind administration is shown to inflate false identifications. Possible reconciliations for conflicting findings in the literature are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  7. Case of false positive scanning observed after radiation therapy for orbital tumor

    Energy Technology Data Exchange (ETDEWEB)

    Ohara, H [Gifu Prefectural Tajimi Hospital (Japan); Nakamura, K; Maeda, S; Watanabe, R; Miyajima, T

    1978-12-01

    A report was made of 56-year-old female patient of abducensparesis. In the early stage the cause remained undetermined with nothing abnormal noted in scintigraphy. Diplopia disappeared once, but right, exophalmus relapsed. In gammaencepharography, a hot spot was noted in the orbita, sinus ethmoidalis and sirus sphenoidalis. In an operation, squamous cell carcinoma was removed and radiation therapy was performed (total dose of 3520 r) and, three months later a scintigraphy disclosed a high spot of /sup 203/Hg uptake ratio in the right orbita and its lower portions. The biopsy of these portions disclosed a necrotic tissue instead of a tumor. In scintigraphy after radiation therapy against the tumor, it was reported that a positive scintigraphy was present because of the vascular trouble of said portions, although the tumor had disappeared. Attention should be given as well as an opinion of high density together with the examination by CT, especially as to enhancement.

  8. How Fuzzy-Trace Theory Predicts True and False Memories for Words, Sentences, and Narratives

    Science.gov (United States)

    Reyna, Valerie F.; Corbin, Jonathan C.; Weldon, Rebecca B.; Brainerd, Charles J.

    2016-01-01

    Fuzzy-trace theory posits independent verbatim and gist memory processes, a distinction that has implications for such applied topics as eyewitness testimony. This distinction between precise, literal verbatim memory and meaning-based, intuitive gist accounts for memory paradoxes including dissociations between true and false memory, false memories outlasting true memories, and developmental increases in false memory. We provide an overview of fuzzy-trace theory, and, using mathematical modeling, also present results demonstrating verbatim and gist memory in true and false recognition of narrative sentences and inferences. Results supported fuzzy-trace theory's dual-process view of memory: verbatim memory was relied on to reject meaning-consistent, but unpresented, sentences (via recollection rejection). However, verbatim memory was often not retrieved, and gist memory supported acceptance of these sentences (via similarity judgment and phantom recollection). Thus, mathematical models of words can be extended to explain memory for complex stimuli, such as narratives, the kind of memory interrogated in law. PMID:27042402

  9. False-negative results of breast core needle biopsies - retrospective analysis of 988 biopsies

    International Nuclear Information System (INIS)

    Boba, M.; Koltun, U.; Bobek-Billewicz, B.; Eksner, B.; Olejnik, T.; Chmielik, E.

    2011-01-01

    Background: Breast cancer is the most common malignant neoplasm and the most common cause of death among women. The core needle biopsy is becoming a universal practice in diagnosing breast lesions suspected of malignancy. Unfortunately, breast core needle biopsies also bear the risk of having false-negative results. Material/Methods: 988 core needle breast biopsies were performed at the Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, between 01 March 2006 and 29 February 2008. Malignant lesions were diagnosed in 426/988 (43.12%) cases, atypical hyperplasia in 69/988 (6.98%), and benign lesions in 493/988 (49.90%) cases. Results: Twenty-two out of 988 biopsies (2.23%) were found to be false negative. Histopathological assessment of tissue specimens was repeated in these cases. In 14/22 (64%) cases, the previous diagnosis of a benign lesion was changed. In 8/22 (36%) cases, the diagnosis of a benign lesion was confirmed. False-negative rate was calculated at 2.2%. The rate of false-negative diagnoses resulting from a radiological mistake was estimated at 36%. The rate of false-negative diagnoses, resulting from histopathological assessment, was 64%. False-negative results caused by a radiological error comprised 1.5% of all histopathologically diagnosed cancers and atypias (sensitivity of 98.5%). There were no false-positive results in our material - the specificity of the method was 100%. Conclusions: Histopathological interpretation is a substantial cause of false-negative results of breast core needle biopsy. Thus, in case of a radiological-histopathological divergence, histopathological analysis of biopsy specimens should be repeated. The main radiological causes of false-negative results of breast core needle biopsy are as follows: sampling from an inappropriate site and histopathological non-homogeneity of cancer infiltration. (authors)

  10. False memory for context and true memory for context similarly activate the parahippocampal cortex.

    Science.gov (United States)

    Karanian, Jessica M; Slotnick, Scott D

    2017-06-01

    The role of the parahippocampal cortex is currently a topic of debate. One view posits that the parahippocampal cortex specifically processes spatial layouts and sensory details (i.e., the visual-spatial processing view). In contrast, the other view posits that the parahippocampal cortex more generally processes spatial and non-spatial contexts (i.e., the general contextual processing view). A large number of studies have found that true memories activate the parahippocampal cortex to a greater degree than false memories, which would appear to support the visual-spatial processing view as true memories are typically associated with greater visual-spatial detail than false memories. However, in previous studies, contextual details were also greater for true memories than false memories. Thus, such differential activity in the parahippocampal cortex may have reflected differences in contextual processing, which would challenge the visual-spatial processing view. In the present functional magnetic resonance imaging (fMRI) study, we employed a source memory paradigm to investigate the functional role of the parahippocampal cortex during true memory and false memory for contextual information to distinguish between the visual-spatial processing view and the general contextual processing view. During encoding, abstract shapes were presented to the left or right of fixation. During retrieval, old shapes were presented at fixation and participants indicated whether each shape was previously on the "left" or "right" followed by an "unsure", "sure", or "very sure" confidence rating. The conjunction of confident true memories for context and confident false memories for context produced activity in the parahippocampal cortex, which indicates that this region is associated with contextual processing. Furthermore, the direct contrast of true memory and false memory produced activity in the visual cortex but did not produce activity in the parahippocampal cortex. The present

  11. Neural Global Pattern Similarity Underlies True and False Memories.

    Science.gov (United States)

    Ye, Zhifang; Zhu, Bi; Zhuang, Liping; Lu, Zhonglin; Chen, Chuansheng; Xue, Gui

    2016-06-22

    The neural processes giving rise to human memory strength signals remain poorly understood. Inspired by formal computational models that posit a central role of global matching in memory strength, we tested a novel hypothesis that the strengths of both true and false memories arise from the global similarity of an item's neural activation pattern during retrieval to that of all the studied items during encoding (i.e., the encoding-retrieval neural global pattern similarity [ER-nGPS]). We revealed multiple ER-nGPS signals that carried distinct information and contributed differentially to true and false memories: Whereas the ER-nGPS in the parietal regions reflected semantic similarity and was scaled with the recognition strengths of both true and false memories, ER-nGPS in the visual cortex contributed solely to true memory. Moreover, ER-nGPS differences between the parietal and visual cortices were correlated with frontal monitoring processes. By combining computational and neuroimaging approaches, our results advance a mechanistic understanding of memory strength in recognition. What neural processes give rise to memory strength signals, and lead to our conscious feelings of familiarity? Using fMRI, we found that the memory strength of a given item depends not only on how it was encoded during learning, but also on the similarity of its neural representation with other studied items. The global neural matching signal, mainly in the parietal lobule, could account for the memory strengths of both studied and unstudied items. Interestingly, a different global matching signal, originated from the visual cortex, could distinguish true from false memories. The findings reveal multiple neural mechanisms underlying the memory strengths of events registered in the brain. Copyright © 2016 the authors 0270-6474/16/366792-11$15.00/0.

  12. Way forward in case of a false positive in vitro genotoxicity result for a cosmetic substance?

    Science.gov (United States)

    Doktorova, Tatyana Y; Ates, Gamze; Vinken, Mathieu; Vanhaecke, Tamara; Rogiers, Vera

    2014-02-01

    The currently used regulatory in vitro mutagenicity/genotoxicity test battery has a high sensitivity for detecting genotoxicants, but it suffers from a large number of irrelevant positive results (i.e. low specificity) thereby imposing the need for additional follow-up by in vitro and/or in vivo genotoxicity tests. This could have a major impact on the cosmetic industry in Europe, seen the imposed animal testing and marketing bans on cosmetics and their ingredients. Afflicted, but safe substances could therefore be lost. Using the example of triclosan, a cosmetic preservative, we describe here the potential applicability of a human toxicogenomics-based in vitro assay as a potential mechanistically based follow-up test for positive in vitro genotoxicity results. Triclosan shows a positive in vitro chromosomal aberration test, but is negative during in vivo follow-up tests. Toxicogenomics analysis unequivocally shows that triclosan is identified as a compound acting through non-DNA reactive mechanisms. This proof-of-principle study illustrates the potential of genome-wide transcriptomics data in combination with in vitro experimentation as a possible weight-of-evidence follow-up approach for de-risking a positive outcome in a standard mutagenicity/genotoxicity battery. As such a substantial number of cosmetic compounds wrongly identified as genotoxicants could be saved for the future. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Reduced False Memory after Sleep

    Science.gov (United States)

    Fenn, Kimberly M.; Gallo, David A.; Margoliash, Daniel; Roediger, Henry L., III; Nusbaum, Howard C.

    2009-01-01

    Several studies have shown that sleep contributes to the successful maintenance of previously encoded information. This research has focused exclusively on memory for studied events, as opposed to false memories. Here we report three experiments showing that sleep reduces false memories in the Deese-Roediger-McDermott (DRM) memory illusion. False…

  14. 5 CFR 214.402 - Career reserved positions.

    Science.gov (United States)

    2010-01-01

    ... collection of taxes and the preparation or review of interpretative opinions. (2) Career reserved positions... review agency designations of general and career reserved positions. If the Office finds that an agency... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Career reserved positions. 214.402...

  15. 20 CFR 655.154 - Additional positive recruitment.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Additional positive recruitment. 655.154... recruitment. (a) Where to conduct additional positive recruitment. The employer must conduct positive recruitment within a multistate region of traditional or expected labor supply where the CO finds that there...

  16. Synthesis of Cyclododecatriene from 1,3-Butadiene by Trimerization over Amine-Titanium Complex Catalyst

    International Nuclear Information System (INIS)

    Park, Da Min; Kim, Gye Ryung; Lee, Ju Hyun; Kim, Geon-Joong; Cho, Deuk Hee

    2013-01-01

    The new complex catalysts were synthesized by the reaction of titanium compounds (titanium chloride or titanium butoxide) and diamines in this work, and they showed very high catalytic activities for the cyclododecatriene (CDT) synthesis from 1,3-butadiene through trimerization. CDT synthetic reaction was performed in an autoclave reactor, and the effects of reaction temperature, type of catalyst, catalyst amount added into the system, the mole ratio of Al/Ti and immobilization method were investigated on the yield of product CDT. The titanium complex catalyst combined to diamine with 1:1 ratio showed high selectivity to CDT more than 90%. The ratio of TTT-CDT/TTC-CDT isomers in the product revealed as different values, depending on the type of diamine combined to titanium and Ti/diamine ratios. Those homogeneous complexes could be used as a heterogenized catalyst after anchoring on the supports, and the immobilized titanium catalyst retained the catalytic activities for several times in the recycled reactions without leaching. The carbon support containing titanium has exhibited superior activity to the silica support. Especially, when the titanium complex was anchored on the support which was fabricated by the hydrolysis of tripropylaminosilane itself, the resulting titanium catalyst showed the highest BD conversion and CDT selectivity

  17. False-Belief Understanding and Language Ability Mediate the Relationship between Emotion Comprehension and Prosocial Orientation in Preschoolers.

    Science.gov (United States)

    Ornaghi, Veronica; Pepe, Alessandro; Grazzani, Ilaria

    2016-01-01

    Emotion comprehension (EC) is known to be a key correlate and predictor of prosociality from early childhood. In the present study, we examined this relationship within the broad theoretical construct of social understanding which includes a number of socio-emotional skills, as well as cognitive and linguistic abilities. Theory of mind, especially false-belief understanding, has been found to be positively correlated with both EC and prosocial orientation. Similarly, language ability is known to play a key role in children's socio-emotional development. The combined contribution of false-belief understanding and language to explaining the relationship between EC and prosociality has yet to be investigated. Thus, in the current study, we conducted an in-depth exploration of how preschoolers' false-belief understanding and language ability each contribute to modeling the relationship between children's comprehension of emotion and their disposition to act prosocially toward others, after controlling for age and gender. Participants were 101 4- to 6-year-old children (54% boys), who were administered measures of language ability, false-belief understanding, EC and prosocial orientation. Multiple mediation analysis of the data suggested that false-belief understanding and language ability jointly and fully mediated the effect of preschoolers' EC on their prosocial orientation. Analysis of covariates revealed that gender exerted no statistically significant effect, while age had a trivial positive effect. Theoretical and practical implications of the findings are discussed.

  18. Cytolethal Distending Toxin From Campylobacter jejuni Requires the Cytoskeleton for Toxic Activity

    Science.gov (United States)

    Méndez-Olvera, Estela T.; Bustos-Martínez, Jaime A.; López-Vidal, Yolanda; Verdugo-Rodríguez, Antonio; Martínez-Gómez, Daniel

    2016-01-01

    Background Campylobacter jejuni is one of the major causes of infectious diarrhea worldwide. The distending cytolethal toxin (CDT) of Campylobacter spp. interferes with normal cell cycle progression. This toxic effect is considered a result of DNase activity that produces chromosomal DNA damage. To perform this event, the toxin must be endocytosed and translocated to the nucleus. Objectives The aim of this study was to evaluate the role of the cytoskeleton in the translocation of CDT to the nucleus. Methods Campylobacter jejuni ATCC 33291 and seven isolates donated from Instituto de Biotecnologia were used in this study. The presence of CDT genes in C. jejuni strains was determined by PCR. To evaluate the effect of CDT, HeLa cells were treated with bacterial lysate, and the damage and morphological changes were analyzed by microscopy, immunofluorescence staining, and flow cytometry. To evaluate the role of the cytoskeleton, HeLa cells were treated with either latrunculin A or by nocodazole and analyzed by microscopy, flow cytometry, and immunoquantification (ELISA). Results The results obtained showed that the eight strains of C. jejuni, including the reference strain, had the ability to produce the toxin. Usage of latrunculin A and nocodazole, two cytoskeletal inhibitors, blocked the toxic effect in cells treated with the toxin. This phenomenon was evident in flow cytometry analysis and immunoquantification of Cdc2-phosphorylated. Conclusions This work showed that the cytotoxic activity of the C. jejuni CDT is dependent on its endocytosis. The alteration in the microtubules and actin filaments caused a blockage transit of the toxin, preventing it from reaching the nucleus of the cell, as well as preventing DNA fragmentation and alteration of the cell cycle. The CDT toxin appears to be an important element for the pathogenesis of campylobacteriosis, since all clinical isolates showed the presence of cdtA, cdtB and cdtC genes. PMID:27942359

  19. Cytolethal Distending Toxin From Campylobacter jejuni Requires the Cytoskeleton for Toxic Activity.

    Science.gov (United States)

    Méndez-Olvera, Estela T; Bustos-Martínez, Jaime A; López-Vidal, Yolanda; Verdugo-Rodríguez, Antonio; Martínez-Gómez, Daniel

    2016-10-01

    Campylobacter jejuni is one of the major causes of infectious diarrhea worldwide. The distending cytolethal toxin (CDT) of Campylobacter spp. interferes with normal cell cycle progression. This toxic effect is considered a result of DNase activity that produces chromosomal DNA damage. To perform this event, the toxin must be endocytosed and translocated to the nucleus. The aim of this study was to evaluate the role of the cytoskeleton in the translocation of CDT to the nucleus. Campylobacter jejuni ATCC 33291 and seven isolates donated from Instituto de Biotecnologia were used in this study. The presence of CDT genes in C. jejuni strains was determined by PCR. To evaluate the effect of CDT, HeLa cells were treated with bacterial lysate, and the damage and morphological changes were analyzed by microscopy, immunofluorescence staining, and flow cytometry. To evaluate the role of the cytoskeleton, HeLa cells were treated with either latrunculin A or by nocodazole and analyzed by microscopy, flow cytometry, and immunoquantification (ELISA). The results obtained showed that the eight strains of C. jejuni , including the reference strain, had the ability to produce the toxin. Usage of latrunculin A and nocodazole, two cytoskeletal inhibitors, blocked the toxic effect in cells treated with the toxin. This phenomenon was evident in flow cytometry analysis and immunoquantification of Cdc2-phosphorylated. This work showed that the cytotoxic activity of the C. jejuni CDT is dependent on its endocytosis. The alteration in the microtubules and actin filaments caused a blockage transit of the toxin, preventing it from reaching the nucleus of the cell, as well as preventing DNA fragmentation and alteration of the cell cycle. The CDT toxin appears to be an important element for the pathogenesis of campylobacteriosis, since all clinical isolates showed the presence of cdtA , cdtB and cdtC genes.

  20. Cadmium and cadmium-tolerant soil bacteria in cacao crops from northeastern Colombia.

    Science.gov (United States)

    Bravo, D; Pardo-Díaz, S; Benavides-Erazo, J; Rengifo-Estrada, G; Braissant, O; Leon-Moreno, C

    2018-05-01

    This research aims to assess total-cadmium soil content and microbiological aspects to understand the dynamics of culturable cadmium-tolerant bacteria (CdtB) in cacao soils from northeastern Colombia. An integration of inverted dish plating, Cd determination and a microcalorimetry assay (IMC) was carried out. A farm in Boyacá showed the highest level of total soil Cd (3·74 mg kg -1 ) followed by farms in Santander and Arauca (2·76 and 1·16 mg kg -1 , respectively). Coefficient of determination between total soil Cd and CFU of CdtB was high (R 2  = 0·83) for the farm in Boyacá. Moreover, a pool of 129 CdtB was isolated, and phylogeny of 21 CdtB was discussed. Among CdtB strains isolated, Enterobacter sp. CdDB41 showed major Cd immobilization capacity (Q max of 2·21 and 2·32 J at 6 and 24 mg l -1 of CdCl 2 ), with an immobilization rate of 0·220 mg kg -1  h -1 . Among CdtB strains isolated, Enterobacter sp. CdDB41 showed major Cd immobilization capacity (Q max of 2·21 and 2·32 J at 6 and 24 mg l -1 of CdCl 2 ), with an immobilization rate of 0·220 mg kg -1  h -1 . Nothing is known about soil CdtB in cacao. Our data showed that CdtB such as Enterobacter sp. has high immobilization capacity. Furthermore, the otavite found in situ might be mineralized due to the bacterial metabolic activity of CdtB. © 2018 The Society for Applied Microbiology.

  1. Priming analogical reasoning with false memories.

    Science.gov (United States)

    Howe, Mark L; Garner, Sarah R; Threadgold, Emma; Ball, Linden J

    2015-08-01

    Like true memories, false memories are capable of priming answers to insight-based problems. Recent research has attempted to extend this paradigm to more advanced problem-solving tasks, including those involving verbal analogical reasoning. However, these experiments are constrained inasmuch as problem solutions could be generated via spreading activation mechanisms (much like false memories themselves) rather than using complex reasoning processes. In three experiments we examined false memory priming of complex analogical reasoning tasks in the absence of simple semantic associations. In Experiment 1, we demonstrated the robustness of false memory priming in analogical reasoning when backward associative strength among the problem terms was eliminated. In Experiments 2a and 2b, we extended these findings by demonstrating priming on newly created homonym analogies that can only be solved by inhibiting semantic associations within the analogy. Overall, the findings of the present experiments provide evidence that the efficacy of false memory priming extends to complex analogical reasoning problems.

  2. 38 CFR 1.892 - Review of positions.

    Science.gov (United States)

    2010-07-01

    ... PROVISIONS Part-Time Career Employment Program § 1.892 Review of positions. Positions becoming vacant, unless... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Review of positions. 1...-time. Among the criteria which may be used when conducting this review are: (a) Mission requirements...

  3. The Times They Are a-Changin': Clock Drawing and Prediction of Dementia.

    Science.gov (United States)

    Amodeo, Sean; Mainland, Brian J; Herrmann, Nathan; Shulman, Kenneth I

    2015-06-01

    Identification of individuals who will eventually develop dementia is critical for early intervention, treatment, and care planning. The clock drawing test (CDT) is a widely used cognitive screening tool that has been well accepted among clinicians and patients for its ease of use and short administration time. This review explores the value of the CDT for predicting the later development of dementia in cognitively intact older adults and patients with mild cognitive impairment (MCI). Additionally, we reviewed studies that examined the ability of the CDT to monitor declines in cognitive functioning over time. A PubMed literature search for articles that included a longitudinal analysis of the CDT was conducted. The search included articles published up to June 2013 and manual cross-referencing of bibliographies. Relevant studies were categorized, summarized, and critiqued. The consensus from the studies reviewed suggests that the CDT is a useful measure of cognitive decline over time. Conceptual clock drawing errors (eg, misrepresentation of time) detected this decline most effectively. In addition, the CDT appears to differentiate at baseline between cognitively intact older adults who will develop dementia up to 2 years postbaseline. Finally, the CDT has been found to differentiate between patients with MCI who will progress to dementia up to 6 years postbaseline. The CDT appears useful for the longitudinal assessment of cognitive impairment and together with other validated measures may be helpful for predicting conversion to dementia. Cost-effective and practical ways of predicting risk of dementia will become increasingly critical as we develop disease-modifying treatments. © The Author(s) 2014.

  4. The Mini-Cog versus the Mini-Mental State Examination and the Clock Drawing Test in daily clinical practice: screening value in a German Memory Clinic.

    Science.gov (United States)

    Milian, Monika; Leiherr, Anna-Maria; Straten, Guido; Müller, Stephan; Leyhe, Thomas; Eschweiler, Gerhard W

    2012-05-01

    The aim of this study was to compare the screening value of the Mini-Cog, Clock Drawing Test (CDT), Mini-Mental State Examination (MMSE) and the algorithm MMSE and/or CDT to separate elderly people with dementia from healthy depending on test time, type and severity of dementia, and demographic variables in a German Memory Clinic. Data from a heterogeneous patient sample and healthy participants (n = 502) were retrospectively analyzed. Of the 438 patients with dementia, 49.1% of the dementia diagnoses were Alzheimer's dementia and 50.9% were non-Alzheimer's dementia. Sixty-four participants were classified as cognitively unimpaired. The CDT and an extraction of the 3-item recall of the MMSE were used to constitute the Mini-Cog algorithm. Overall, the Mini-Cog showed significantly higher discriminatory power (86.8%) than the MMSE (72.6% at a cut-off ≤ 24 and 79.2% at ≤ 25, respectively) and CDT (78.1%) (each p 0.05). The specificity of the Mini-Cog (100.0%) was similar to that of the MMSE (100.0% for both cut-offs) and CDT (96.9%) (p = 0.154). For all age and educational groups the Mini-Cog outmatched the CDT and MMSE, and was less affected by education than MMSE and less susceptible for the dementia stage than the CDT. The Mini-Cog proved to have superior discriminatory power than either CDT or MMSE and is demonstrated to be a valid "short" screening instrument taking 3 to 4 minutes to administer in the geriatric setting.

  5. False memory ≠ false memory: DRM errors are unrelated to the misinformation effect.

    Directory of Open Access Journals (Sweden)

    James Ost

    Full Text Available The DRM method has proved to be a popular and powerful, if controversial, way to study 'false memories'. One reason for the controversy is that the extent to which the DRM effect generalises to other kinds of memory error has been neither satisfactorily established nor subject to much empirical attention. In the present paper we contribute data to this ongoing debate. One hundred and twenty participants took part in a standard misinformation effect experiment, in which they watched some CCTV footage, were exposed to misleading post-event information about events depicted in the footage, and then completed free recall and recognition tests. Participants also completed a DRM test as an ostensibly unrelated filler task. Despite obtaining robust misinformation and DRM effects, there were no correlations between a broad range of misinformation and DRM effect measures (mean r  = -.01. This was not due to reliability issues with our measures or a lack of power. Thus DRM 'false memories' and misinformation effect 'false memories' do not appear to be equivalent.

  6. Is it wise to protect false targets?

    International Nuclear Information System (INIS)

    Levitin, Gregory; Hausken, Kjell

    2011-01-01

    The paper considers a system consisting of genuine elements and false targets that cannot be distinguished by the attacker's observation. The false targets can be destroyed with much less effort than the genuine elements. We show that even when an attacker cannot distinguish between the genuine elements and the false targets, in many cases it can enhance the attack efficiency using a double attack strategy in which it tries first to eliminate with minimal effort as many false targets as possible in the first attack and then distributes its entire remaining resource among all surviving targets in the second attack. The model for evaluating the system vulnerability in the double attack is suggested for a single genuine element, and multiple genuine elements configured in parallel or in series. This model assumes that in both attacks the attacking resource is distributed evenly among the attacked targets. The defender can optimize its limited resource distribution between deploying more false targets and protecting them better. The attacker can optimize its limited resource distribution between two attacks. The defense strategy is analyzed based on a two period minmax game. A numerical procedure is suggested that allows the defender to find the optimal resource distribution between deploying and protecting the false targets. The methodology of optimal attack and defense strategies analysis is demonstrated. It is shown that protecting the false targets may reduce the efficiency of the double attack strategy and make this strategy ineffective in situations with low contest intensity and few false targets. - Highlights: ► The efficiency of the double attack tactics against using false targets is analyzed. ► The role of the false target protection in system survivability enhancement is shown. ► The resource distribution between deploying more false targets and protecting them better is optimized. ► Both series and parallel systems are considered.

  7. 14 CFR 99.15 - Position reports.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Position reports. 99.15 Section 99.15 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SECURITY CONTROL OF AIR TRAFFIC General § 99.15 Position reports. (a) The...

  8. 30 CFR 57.7052 - Drilling positions.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Drilling positions. 57.7052 Section 57.7052... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface and Underground § 57.7052 Drilling positions. Persons shall not drill...

  9. False-positive pregnancy test after transfusion of solvent/detergent-treated plasma.

    Science.gov (United States)

    Jilma-Stohlawetz, Petra; Wreford-Bush, Tim; Mills, Francesca; Davidson, Fiona; Kursten, Friedrich W; Jilma, Bernd; Birchall, Janet

    2017-12-01

    The transmission of pathogens, antibodies, and proteins is a possible consequence of blood product transfusion. A female patient had an unexpected positive serum β-human chorionic gonadotropin result, indicative of pregnancy, after she had received a transfusion with 1 unit of platelet concentrate, 4 units of red blood cells, and 4 units of pooled solvent/detergent-treated plasma (Octaplas). To investigate the possibility of passive transfusion of β-human chorionic gonadotropin from the plasma transfusion, one additional unit from the same batch was thawed and analyzed. To validate the β-human chorionic gonadotropin assay for use in solvent/detergent-treated plasma and to investigate any interference in the assay, dilution experiments were performed using the implicated plasma batch diluted with male and non-pregnant female sera. Also, plasma from a known pregnant woman was diluted with Octaplas (tested negative for β-human chorionic gonadotropin) and with a male serum to validate the assay for use in solvent/detergent-treated plasma. The implicated solvent/detergent-treated plasma had a mean β-human chorionic gonadotropin level of 91.5 mIU/mL. Results from the dilution experiments revealed an excellent correlation (r > 0.99) between β-human chorionic gonadotropin measurement in solvent/detergent-treated plasma and male serum and no over or under recovery of the expected results. Further measurements of β-human chorionic gonadotropin levels in the female recipient revealed an estimated half-life of 6 hours. This case demonstrates the importance of considering the possibility of passive transmission of analytes to a patient from the transfusion of blood products. Furthermore, the measurement of β-human chorionic gonadotropin is valid in solvent/detergent-treated plasma using a Roche Cobas analyzer. © 2017 AABB.

  10. Catheter-directed Thrombolysis with Argatroban and tPA for Massive Iliac and Femoropopliteal Vein Thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Sharifi, Mohsen, E-mail: seyedmohsensharifi@yahoo.com [Arizona Cardiovascular Consultants (United States); Bay, Curt [A. T. Still University (United States); Nowroozi, Sasan; Bentz, Suzanne; Valeros, Gayle; Memari, Sara [Arizona Cardiovascular Consultants (United States)

    2013-12-15

    Purpose: Catheter-directed thrombolysis (CDT) is a highly effective approach in the treatment of deep venous thrombosis (DVT). There are no data on the primary use of CDT with argatroban and tissue plasminogen activator (tPA) in patients without heparin-induced thrombocytopenia (HIT). The aim of this study was to evaluate the efficacy and safety of the combined administration of argatroban and tPA during CDT for massive DVT in patients without HIT. Methods: Thirty-three patients with massive symptomatic iliac and femoropopliteal DVT underwent CDT with tPA and argatroban within 28 {+-} 6 h of presentation. The dose of tPA was 0.75-1 mg/h through the infusion port and that of argatroban at 0.3-1 {mu}g/kg/min through the side port of the sheath. The patients were evaluated for the efficacy and safety of CDT and recurrent symptomatic venous thromboembolism (VTE) at a mean follow-up of 22 months. Results: There was no bleeding or iatrogenic pulmonary embolism with the CDT regimen we used. Grade III lysis (complete resolution of thrombus on venography) was achieved in 30 patients (91 %). In 3 patients with additional inferior vena cava filter thrombosis, further thrombectomy of the filter was required. No patient developed recurrent VTE. Conclusion: Concomitant administration of argatroban and tPA is a highly safe and effective regimen for CDT for massive DVT.

  11. Pro- and Anti-Inflammatory Cytokines Release in Mice Injected with Crotalus durissus terrificus Venom

    Directory of Open Access Journals (Sweden)

    A. Hernández Cruz

    2008-01-01

    Full Text Available The effects of Crotalus durissus terrificus venom (Cdt were analyzed with respect to the susceptibility and the inflammatory mediators in an experimental model of severe envenomation. BALB/c female mice injected intraperitoneally presented sensibility to Cdt, with changes in specific signs, blood biochemical and inflammatory mediators. The venom induced reduction of glucose and urea levels and an increment of creatinine levels in serum from mice. Significant differences were observed in the time-course of mediator levels in sera from mice injected with Cdt. The maximum levels of IL-6, NO, IL-5, TNF, IL-4 and IL-10 were observed 15 min, 30 min, 1, 2 and 4 hours post-injection, respectively. No difference was observed for levels of IFN-γ. Taken together, these data indicate that the envenomation by Cdt is regulated both pro- and anti-inflammatory cytokine responses at time-dependent manner. In serum from mice injected with Cdt at the two first hours revealed of pro-inflammatory dominance. However, with an increment of time an increase of anti-inflammatory cytokines was observed and the balance toward to anti-inflammatory dominance. In conclusion, the observation that Cdt affects the production of pro- and anti-inflammatory cytokines provides further evidence for the role played by Cdt in modulating pro/anti-inflammatory cytokine balance.

  12. Retroperitoneal Endometriosis: A Possible Cause of False Positive Finding at 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

    International Nuclear Information System (INIS)

    Maffione, Anna Margherita; Panzavolta, Riccardo; Lisato, Laura Camilla; Ballotta, Maria; D'Isanto, Mariangela Zanforlini; Rubello, Domenico

    2015-01-01

    Endometriosis is a frequent and clinically relevant problem in young women. Laparoscopy is still the gold standard for the diagnosis of endometriosis, but frequently both morphologic and functional imaging techniques are involved in the diagnostic course before achieving a conclusive diagnosis. We present a case of a patient affected by infiltrating retroperitoneal endometriosis falsely interpreted as a malignant mass by contrast-enhanced magnetic resonance imaging and 18 F-fluorodeoxyglucose positron emission tomography/computed tomography

  13. True photographs and false memories.

    Science.gov (United States)

    Lindsay, D Stephen; Hagen, Lisa; Read, J Don; Wade, Kimberley A; Garry, Maryanne

    2004-03-01

    Some trauma-memory-oriented psychotherapists advise clients to review old family photo albums to cue suspected "repressed" memories of childhood sexual abuse. Old photos might cue long-forgotten memories, but when combined with other suggestive influences they might also contribute to false memories. We asked 45 undergraduates to work at remembering three school-related childhood events (two true events provided by parents and one pseudoevent). By random assignment, 23 subjects were also given their school classes' group photos from the years of the to-be-recalled events as memory cues. As predicted, the rate of false-memory reports was dramatically higher in the photo condition than in the no-photo condition. Indeed, the rate of false-memory reports in the photo condition was substantially higher than the rate in any previously published study.

  14. False-belief understanding and language ability mediate the relationship between emotion comprehension and prosocial orientation in preschoolers

    Directory of Open Access Journals (Sweden)

    Veronica Ornaghi

    2016-10-01

    Full Text Available Emotion comprehension is known to be a key correlate and predictor of prosociality from early childhood. The present study look at their relation within the wide theoretical construct of social understanding which includes a number of socio-emotional skills, as well as cognitive and linguistic abilities. Theory of mind, especially false-belief understanding, has been found to have positive correlations with both emotion comprehension and prosocial orientation. Similarly, language ability is known to play a key role in children’s socio-emotional development. The combined contribution of both false-belief understanding and language in explaining the relation between emotion comprehension and prosociality has yet to be investigated. Thus, in the current study, we conducted an in-depth exploration of how preschoolers’ false-belief understanding and language ability each contribute to modeling the relationship between their comprehension of emotion and their disposition to act prosocially towards others, after controlling for age and gender. Participants were 101 4-to-6 year old children (54% boys, who were administered measures of language ability, false-belief understanding, emotion comprehension and prosocial orientation. Multiple mediation analysis of the data suggested that false-belief understanding and language ability jointly and fully mediated the effect of preschoolers’ emotion comprehension on their prosocial orientation. Analysis of covariates revealed that gender exerted no statistically significant effect, while age had a trivial positive effect. Theoretical and practical implications of the findings are discussed.

  15. Systemic True False

    African Journals Online (AJOL)

    Preferred Customer

    ):. (a). (b). (c). (d). Answer: True systemics are (b & c); False Systemics (a & d). For more examples, see (10 and 11). Na2O2. NaCl. Na. HCl heat /excess. (O). 300°C electrolysis. (molten). NaOH. NaCl. Na. HCl. H2O electrolysis. (solution). NaCl.

  16. High false-negative rate of anti-HCV among Egyptian patients on regular hemodialysis.

    Science.gov (United States)

    El-Sherif, Assem; Elbahrawy, Ashraf; Aboelfotoh, Atef; Abdelkarim, Magdy; Saied Mohammad, Abdel-Gawad; Abdallah, Abdallah Mahmoud; Mostafa, Sadek; Elmestikawy, Amr; Elwassief, Ahmed; Salah, Mohamed; Abdelbaseer, Mohamed Ali; Abdelwahab, Kouka Saadeldin

    2012-07-01

    Routine serological testing for hepatitis C virus (HCV) infection among hemodialysis (HD) patients is currently recommended. A dilemma existed on the value of serology because some investigators reported a high rate of false-negative serologic testing. In this study, we aimed to detect the false-negative rate of anti-HCV among Egyptian HD patients. Seventy-eight HD patients, negative for anti-HCV, anti-HIV, and hepatitis B surface antigen, were tested for HCV RNA by reverse transcriptase polymerase chain reaction (RT-PCR). In the next step, the viral load was quantified by real-time PCR in RT-PCR-positive patients. Risk factors for HCV infection, as well as clinical and biochemical indicators of liver disease, were compared between false-negative and true-negative anti-HCV HD patients. The frequency of false-negative anti-HCV was 17.9%. Frequency of blood transfusion, duration of HD, dialysis at multiple centers, and diabetes mellitus were not identified as risk factors for HCV infection. The frequency of false-negative results had a linear relation to the prevalence of HCV infection in the HD units. Timely identification of HCV within dialysis units is needed in order to lower the risk of HCV spread within the HD units. The high false-negative rate of anti-HCV among HD patients in our study justifies testing of a large scale of patients for precious assessment of effectiveness of nucleic acid amplification technology testing in screening HD patient. © 2012 The Authors. Hemodialysis International © 2012 International Society for Hemodialysis.

  17. The False Memory and the Mirror Effects: The Role of Familiarity and Backward Association in Creating False Recollections

    Science.gov (United States)

    Anaki, D.; Faran, Y.; Ben-Shalom, D.; Henik, A.

    2005-01-01

    The mirror effect refers to a phenomenon where the hit rate is higher for low frequency words while the false alarm rate is higher for high frequency distractors. Using a false memory paradigm (Roediger & McDermott, 1995), we examined whether false memory for non-presented lures would be influenced by the lure's familiarity. The results revealed…

  18. False-negative results of breast core needle biopsies – retrospective analysis of 988 biopsies

    International Nuclear Information System (INIS)

    Boba, Marek; Kołtun, Urszula; Bobek-Billewicz, Barbara; Chmielik, Ewa; Eksner, Bartosz; Olejnik, Tomasz

    2011-01-01

    Breast cancer is the most common malignant neoplasm and the most common cause of death among women. The core needle biopsy is becoming a universal practice in diagnosing breast lesions suspected of malignancy. Unfortunately, breast core needle biopsies also bear the risk of having false-negative results. 988 core needle breast biopsies were performed at the Maria Skłodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, between 01 March 2006 and 29 February 2008. Malignant lesions were diagnosed in 426/988 (43.12%) cases, atypical hyperplasia in 69/988 (6.98%), and benign lesions in 493/988 (49.90%) cases. Twenty-two out of 988 biopsies (2.23%) were found to be false negative. Histopathological assessment of tissue specimens was repeated in these cases. In 14/22 (64%) cases, the previous diagnosis of a benign lesion was changed. In 8/22 (36%) cases, the diagnosis of a benign lesion was confirmed. False-negative rate was calculated at 2.2%. The rate of false-negative diagnoses resulting from a radiological mistake was estimated at 36%. The rate of false-negative diagnoses, resulting from histopathological assessment, was 64%. False-negative results caused by a radiological error comprised 1.5% of all histopathologically diagnosed cancers and atypias (sensitivity of 98.5%). There were no false-positive results in our material - the specificity of the method was 100%. Histopathological interpretation is a substantial cause of false-negative results of breast core needle biopsy. Thus, in case of a radiological-histopathological divergence, histopathological analysis of biopsy specimens should be repeated. The main radiological causes of false-negative results of breast core needle biopsy are as follows: sampling from an inappropriate site and histopathological non-homogeneity of cancer infiltration

  19. False belief understanding in Cantonese-speaking children.

    Science.gov (United States)

    Tardif, Twila; Wellman, Henry M; Cheung, Kar Man

    2004-11-01

    The present study investigates the performance of 96 Cantonese-speaking three- to five-year-old preschoolers on three false belief tasks - a deceptive object, a change of location, and an unexpected contents task encompassing a variety of task factors. Most importantly, the research examines the possibility that false belief performance depends on specific linguistic factors such as the type of verb used in the test question--an explicitly false vs. a neutral belief verb. Cantonese was chosen as particularly useful for examining this question because it explicitly codes belief status as either neutral (nam5) or false (ji5wai4), and because it offers additional linguistic and cultural contrasts to research conducted on false belief with children learning English and other Indo-European languages. As expected, a strong age effect was found, as well as a significant advantage for children who received the explicit false belief (ji5wai4) wording and for those who were asked to explain rather than predict the protagonist's actions. Interestingly, there was also a strong task difference with children performing better on the deceptive object task than on the other two false belief tasks. We argue that these results point both to universal trajectories in theory of mind development and to interesting, but localized, effects of language and culture on children's false belief understanding.

  20. Sleep loss produces false memories.

    Directory of Open Access Journals (Sweden)

    Susanne Diekelmann

    Full Text Available People sometimes claim with high confidence to remember events that in fact never happened, typically due to strong semantic associations with actually encoded events. Sleep is known to provide optimal neurobiological conditions for consolidation of memories for long-term storage, whereas sleep deprivation acutely impairs retrieval of stored memories. Here, focusing on the role of sleep-related memory processes, we tested whether false memories can be created (a as enduring memory representations due to a consolidation-associated reorganization of new memory representations during post-learning sleep and/or (b as an acute retrieval-related phenomenon induced by sleep deprivation at memory testing. According to the Deese, Roediger, McDermott (DRM false memory paradigm, subjects learned lists of semantically associated words (e.g., "night", "dark", "coal",..., lacking the strongest common associate or theme word (here: "black". Subjects either slept or stayed awake immediately after learning, and they were either sleep deprived or not at recognition testing 9, 33, or 44 hours after learning. Sleep deprivation at retrieval, but not sleep following learning, critically enhanced false memories of theme words. This effect was abolished by caffeine administration prior to retrieval, indicating that adenosinergic mechanisms can contribute to the generation of false memories associated with sleep loss.

  1. Quantitative evaluation of anatomical noise in chest digital tomosynthesis, digital radiography, and computed tomography

    International Nuclear Information System (INIS)

    Lee, D.; Kim, D.; Choi, S.; Kim, H.-J.; Choi, S.; Lee, H.

    2017-01-01

    Lung cancer is currently the worldwide leading cause of death from cancer. Thus, detection of lung cancer at its early stages is critical for improving the survival rate of patients. Chest digital tomosynthesis (CDT) is a recently developed imaging modality, combining many advantages of digital radiography (DR) and computed tomography (CT). This method has the potential to be widely used in the clinical setting. In this study, we introduce a developed CDT R/F system and compare its image quality with those of DR and CT, especially with respect to anatomical noise and lung nodule conspicuity, for LUNGMAN phantoms. The developed CDT R/F system consists of a CsI scintillator flat panel detector, X-ray tube, and tomosynthesis data acquisition geometry. For CDT R/F imaging, 41 projections were acquired at different angles, over the ± 20° angular range, in a linear translation geometry. To evaluate the clinical effectiveness of the CDT R/F system, the acquired images were compared with CT (Philips brilliance CT 64, Philips healthcare, U.S.) and DR (ADR-M, LISTEM, Korea) phantom images in terms of the anatomical noise power spectrum (aNPS). DR images exhibited low conspicuity for a small-size lung nodule, while CDT R/F and CT exhibited relatively high sensitivity for all lung nodule sizes. The aNPS of the CDT R/F system was better than that of DR, by resolving anatomical overlapping problems. In conclusion, the developed CDT R/F system is likely to contribute to early diagnosis of lung cancer, while requiring a relatively low patient dose, compared with CT.

  2. Quantitative evaluation of anatomical noise in chest digital tomosynthesis, digital radiography, and computed tomography

    Science.gov (United States)

    Lee, D.; Choi, S.; Lee, H.; Kim, D.; Choi, S.; Kim, H.-J.

    2017-04-01

    Lung cancer is currently the worldwide leading cause of death from cancer. Thus, detection of lung cancer at its early stages is critical for improving the survival rate of patients. Chest digital tomosynthesis (CDT) is a recently developed imaging modality, combining many advantages of digital radiography (DR) and computed tomography (CT). This method has the potential to be widely used in the clinical setting. In this study, we introduce a developed CDT R/F system and compare its image quality with those of DR and CT, especially with respect to anatomical noise and lung nodule conspicuity, for LUNGMAN phantoms. The developed CDT R/F system consists of a CsI scintillator flat panel detector, X-ray tube, and tomosynthesis data acquisition geometry. For CDT R/F imaging, 41 projections were acquired at different angles, over the ± 20° angular range, in a linear translation geometry. To evaluate the clinical effectiveness of the CDT R/F system, the acquired images were compared with CT (Philips brilliance CT 64, Philips healthcare, U.S.) and DR (ADR-M, LISTEM, Korea) phantom images in terms of the anatomical noise power spectrum (aNPS). DR images exhibited low conspicuity for a small-size lung nodule, while CDT R/F and CT exhibited relatively high sensitivity for all lung nodule sizes. The aNPS of the CDT R/F system was better than that of DR, by resolving anatomical overlapping problems. In conclusion, the developed CDT R/F system is likely to contribute to early diagnosis of lung cancer, while requiring a relatively low patient dose, compared with CT.

  3. Comparison study of noise reduction algorithms in dual energy chest digital tomosynthesis

    Science.gov (United States)

    Lee, D.; Kim, Y.-S.; Choi, S.; Lee, H.; Choi, S.; Kim, H.-J.

    2018-04-01

    Dual energy chest digital tomosynthesis (CDT) is a recently developed medical technique that takes advantage of both tomosynthesis and dual energy X-ray images. However, quantum noise, which occurs in dual energy X-ray images, strongly interferes with diagnosis in various clinical situations. Therefore, noise reduction is necessary in dual energy CDT. In this study, noise-compensating algorithms, including a simple smoothing of high-energy images (SSH) and anti-correlated noise reduction (ACNR), were evaluated in a CDT system. We used a newly developed prototype CDT system and anthropomorphic chest phantom for experimental studies. The resulting images demonstrated that dual energy CDT can selectively image anatomical structures, such as bone and soft tissue. Among the resulting images, those acquired with ACNR showed the best image quality. Both coefficient of variation and contrast to noise ratio (CNR) were the highest in ACNR among the three different dual energy techniques, and the CNR of bone was significantly improved compared to the reconstructed images acquired at a single energy. This study demonstrated the clinical value of dual energy CDT and quantitatively showed that ACNR is the most suitable among the three developed dual energy techniques, including standard log subtraction, SSH, and ACNR.

  4. Improvement of color and physiological properties of tuna-processing by-product by gamma irradiation

    International Nuclear Information System (INIS)

    Choi, Jong-il; Kim, Hyun-Joo; Kim, Jae-Hun; Song, Beom-Seok; Chun, Byeong-Soo; Ahn, Dong-Hyun; Byun, Myung-Woo; Lee, Ju-Woon

    2009-01-01

    Although the by-products from fishery industry had many nutrients, it is being wasted or only used as bacteria media. In this study, the effect of a gamma irradiation on the cooking drips of Thunnus thynnus (CDT) was investigated to examine the possible use of the cooking drips as a functional material for food and cosmetic composition. Total aerobic bacteria, and yeasts/molds from CDT were detected at the level of 2.79 and 2.58 Log CFU/mL, respectively. But, CDT was efficiently sterilized by a gamma irradiation at a low dose of 1 kGy. The Hunter L* value of the gamma-irradiated ethanol extract of CDT was increased, and the a* and b* values were decreased compared to the non-irradiated extract, showing color improvement. Antioxidant activity of the ethanol extract of CDT was increased by a gamma irradiation depending on the irradiation dose. The increased contents of polyphenolic compounds and proteins in CDT extract by gamma irradiation may be the reason of the increased biological activity. These results suggested that the wasted cooking drips can be successfully used as functional components with gamma irradiation treatment.

  5. Catheter-Directed Thrombolysis via Small Saphenous Veins for Treating Acute Deep Venous Thrombosis.

    Science.gov (United States)

    Yang, Bin; Xu, Xiao-Dong; Gao, Peng; Yu, Ji-Xiang; Li, Yu; Zhu, Ai-Dong; Meng, Ran-Ran

    2016-08-23

    BACKGROUND There is little data comparing catheter-directed thrombolysis (CDT) via small saphenous veins vs. systematic thrombolysis on complications and efficacy in acute deep venous thrombosis patients. The aim of our study was to compare the efficacy and safety of CDT via the small saphenous veins with systematic thrombolysis for patients with acute deep venous thrombosis (DVT). MATERIAL AND METHODS Sixty-six patients with acute DVT admitted from June 2012 to December 2013 were divided into 2 groups: 27 patients received systemic thrombolysis (ST group) and 39 patients received CDT via the small saphenous veins (CDT group). The thrombolysis efficiency, limb circumference differences, and complications such as post-thrombotic syndrome (PTS) in the 2 groups were recorded. RESULTS The angiograms demonstrated that all or part of the fresh thrombus was dissolved. There was a significant difference regarding thrombolysis efficiency between the CDT group and ST group (71.26% vs. 48.26%, P=0.001). In both groups the postoperative limb circumference changes were higher compared to the preoperative values. The differences between postoperative limb circumferences on postoperative days 7 and 14 were significantly higher in the CDT group than in the ST group (all Pdeep venous thrombosis.

  6. False memories in social anxiety disorder

    Directory of Open Access Journals (Sweden)

    PRISCILA DE CAMARGO PALMA

    Full Text Available Abstract Background False memories are memories of events that never occurred or that occurred, but not exactly as we recall. Events with emotional content are subject to false memories production similar to neutral events. However, individual differences, such as the level of maladjustment and emotional instability characteristics of Social Anxiety Disorder (SAD, may interfere in the production of false memories. Objectives This study aimed to assess the effect of emotion in memory performance for an event witnessed by participants with and without SAD. Methods Participants were 61 young adults with SAD and 76 without any symptoms of SAD who were randomly assigned to watch a story with or without emotional arousal. Participants answered a subjective scale of emotion about the story and a recognition memory test. Results Participants with SAD recovered more true memories and more false memories for the non-emotional version compared to the emotional version of the story. Overall, participants with SAD produced fewer false memories compared to those without SAD. Discussion This finding suggests that social anxiety may have a significant impact on emotional memory accuracy, which may assist in the development and improvement of techniques for therapeutic intervention.

  7. Attitude Importance and the False Consensus Effect.

    Science.gov (United States)

    Fabrigar, Leandre R.; Krosnick, Jon A.

    1995-01-01

    Explores the possibility that importance may regulate the magnitude of the false consensus effect. Analysis revealed a strong false consensus effect but no reliable relation between its magnitude and attitude importance. Results contradict assumptions that the false consensus effect arises from attitudes that directly or indirectly influence…

  8. Falsely elevated troponin: rare occurrence or future problem

    Directory of Open Access Journals (Sweden)

    James Nguyen

    2016-12-01

    Full Text Available Introduction: Troponins are known to be released in response to cardiac damage and therefore are the biomarkers of choice for the early diagnosis of acute myocardial infarction (AMI, improving outcome in patients presenting with chest pain. However, false results can occur due to interference from other substances in the blood. Case: A 52-year-old male with a past medical history of alcohol abuse, hypertension, and coronary artery bypass graft at age 34 with normal stress test 2 years before presented to the emergency department (ED complaining of 1 day of non-exertional chest pain with radiation to the neck and left arm. His troponin was elevated to 5 ng/mL in two samples drawn 12 h apart, with normal CK-MB. Renal function was normal. Electrocardiogram (ECG showed normal sinus rhythm with no ST elevations or depressions. He underwent cardiac catheterization which showed no obstructive lesions. Five years later, he returned to the ED with abdominal pain and shortness of breath. Troponin was elevated and showed no signs of downtrend on repeat every 6 h. ECG was unchanged from 5 years before. He was discharged with a follow-up cardiac computed tomography (CT. Troponin was measured on the day of his scan and remained elevated; he was asymptomatic. Cardiac CT showed unremarkable coronaries and bypass grafts. Given persistently positive troponin in the setting of minimal to no symptoms, he was thought to have falsely elevated troponins. Centrifugation and 2:1 dilution of the sample resulted in the same general value, respectively. Rheumatoid factor and heterophile antibodies were negative. When his blood sample was sent to a different hospital utilizing a three-site immunoassay method, the value was found zero. Discussion: Cardiac troponins (cTn are structural proteins unique to the heart, not expressed outside of cardiac tissue and have high sensitivity and specificity for myocardial damage. Therefore, it is the test of choice for the diagnosis of

  9. Current management of inguinal false aneurysms

    DEFF Research Database (Denmark)

    Houlind, Kim; Jepsen, Jørn M; Saicu, Cristian

    2017-01-01

    False aneurysms are formed as a result of bleeding causing a hematoma to compress the surrounding tissue. The majority of false aneurysms presenting to the vascular surgeon are caused by iatrogenic injury to an artery. Although anastomotic failure occurs, a much higher number is caused by bleeding...... vessels. endovascular treatment with coils or covered stent grafts have proven useful in infected ilio-femoral false aneurysms. Open surgical repair may be the best treatment in the setting of imminent rupture, massive haematoma and skin necrosis. We present three patient cases treated with open surgery...

  10. False-Negative Rate of Gram-Stain Microscopy for Diagnosis of Septic Arthritis: Suggestions for Improvement

    Directory of Open Access Journals (Sweden)

    Paul Stirling

    2014-01-01

    Full Text Available We quantify the false-negative diagnostic rate of septic arthritis using Gram-stain microscopy of synovial fluid and compare this to values reported in the peer-reviewed literature. We propose a method of improving the diagnostic value of Gram-stain microscopy using Lithium Heparin containers that prevent synovial fluid coagulation. Retrospective study of the Manchester Royal Infirmary microbiology database of patients undergoing synovial fluid Gram-stain and culture between December 2003 and March 2012 was undertaken. The initial cohort of 1896 synovial fluid analyses for suspected septic arthritis was reduced to 143 after exclusion criteria were applied. Analysis of our Gram-stain microscopy yielded 111 false-negative results from a cohort size of 143 positive synovial fluid cultures, giving a false-negative rate of 78%. We report a false-negative rate of Gram-stain microscopy for septic arthritis of 78%. Clinicians should therefore avoid the investigation until a statistically significant data set confirms its efficacy. The investigation's value could be improved by using Lithium Heparin containers to collect homogenous synovial fluid samples. Ongoing research aims to establish how much this could reduce the false-negative rate.

  11. Semantic processes leading to true and false memory formation in schizophrenia.

    Science.gov (United States)

    Paz-Alonso, Pedro M; Ghetti, Simona; Ramsay, Ian; Solomon, Marjorie; Yoon, Jong; Carter, Cameron S; Ragland, J Daniel

    2013-07-01

    Encoding semantic relationships between items on word lists (semantic processing) enhances true memories, but also increases memory distortions. Episodic memory impairments in schizophrenia (SZ) are strongly driven by failures to process semantic relations, but the exact nature of these relational semantic processing deficits is not well understood. Here, we used a false memory paradigm to investigate the impact of implicit and explicit semantic processing manipulations on episodic memory in SZ. Thirty SZ and 30 demographically matched healthy controls (HC) studied Deese/Roediger-McDermott (DRM) lists of semantically associated words. Half of the lists had strong implicit semantic associations and the remainder had low strength associations. Similarly, half of the lists were presented under "standard" instructions and the other half under explicit "relational processing" instructions. After study, participants performed recall and old/new recognition tests composed of targets, critical lures, and unrelated lures. HC exhibited higher true memories and better discriminability between true and false memory compared to SZ. High, versus low, associative strength increased false memory rates in both groups. However, explicit "relational processing" instructions positively improved true memory rates only in HC. Finally, true and false memory rates were associated with severity of disorganized and negative symptoms in SZ. These results suggest that reduced processing of semantic relationships during encoding in SZ may stem from an inability to implement explicit relational processing strategies rather than a fundamental deficit in the implicit activation and retrieval of word meanings from patients' semantic lexicon. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Explaining the Development of False Memories.

    Science.gov (United States)

    Reyna, Valerie F.; Holliday, Robyn; Marche, Tammy

    2002-01-01

    Reviews explanatory dimensions of children's false memory relevant to forensic practice: measurement, development, social factors, individual differences, varieties of memories and memory judgments, and varieties of procedures inducing false memories. Asserts that recent studies fail to use techniques that separate acquiescence from memory…

  13. Mental Rotation in False Belief Understanding.

    Science.gov (United States)

    Xie, Jiushu; Cheung, Him; Shen, Manqiong; Wang, Ruiming

    2018-05-01

    This study examines the spontaneous use of embodied egocentric transformation (EET) in understanding false beliefs in the minds of others. EET involves the participants mentally transforming or rotating themselves into the orientation of an agent when trying to adopt his or her visuospatial perspective. We argue that psychological perspective taking such as false belief reasoning may also involve EET because of what has been widely reported in the embodied cognition literature, showing that our processing of abstract, propositional information is often grounded in concrete bodily sensations which are not apparently linked to higher cognition. In Experiment 1, an agent placed a ball into one of two boxes and left. The ball then rolled out and moved either into the other box (new box) or back into the original one (old box). The participants were to decide from which box they themselves or the agent would try to recover the ball. Results showed that false belief performance was affected by increased orientation disparity between the participants and the agent, suggesting involvement of embodied transformation. In Experiment 2, false belief was similarly induced and the participants were to decide if the agent would try to recover the ball in one specific box. Orientation disparity was again found to affect false belief performance. The present results extend previous findings on EET in visuospatial perspective taking and suggest that false belief reasoning, which is a kind of psychological perspective taking, can also involve embodied rotation, consistent with the embodied cognition view. Copyright © 2018 Cognitive Science Society, Inc.

  14. When representations conflict with reality: the preschooler's problem with false beliefs and "false" photographs.

    Science.gov (United States)

    Zaitchik, D

    1990-04-01

    It has been argued that young preschoolers cannot correctly attribute a false belief to a deceived actor (Wimmer & Perner, 1983). Some researchers claim that the problem lies in the child's inadequate epistemology (Chandler & Boyes, 1982; Wellman, 1988); as such, it is specific to the child's theory of mind and no such problem should appear in reasoning about nonmental representations. This prediction is tested below in the "false photograph" task: here an actor takes a photograph of an object in location X; the object is then moved to location Y. Preschool subjects are asked: "In the picture, where is the object?" Results indicate that photographs are no easier to reason about than are beliefs. Manipulations to boost performance on the photograph task proved ineffective. Further, an explanation of the failure as a processing limitation having nothing to do with the representational nature of beliefs or photographs was ruled out. It is argued that young children's failure on the false belief task is not due to an inadequate epistemology (though they may have one) and is symptomatic of a larger problem with representations.

  15. Remedies by competitors for false advertising.

    Science.gov (United States)

    Hirsch, B D; Wilcox, D P

    1990-05-01

    Patients who are victimized as a consequence of false medical advertising are not the only ones who can sue for damages. Under section 43(a) of the Lanham Act, effective November 17, 1989, anyone "who believes that he or she is or is likely to be damaged" by deceptive advertising may bring a civil action for damages (1). Competing physicians may sue other physicians who falsely advertise that they possess unique skills and achieve better results than other physicians because they employ exclusive methods of treatment or claim that certain surgical procedures they perform in the office are absolutely safe and without risk or who advertise false professional credentials to lure patients. Voluntary informed consent excludes the use of deceit. Misrepresentation through advertising deprives a patient of the right to exercise an informed consent (2). A patient who relies on a doctor's false advertising in agreeing to a procedure that causes the patient injury may sue for malpractice even if the procedure was performed without negligence. False medical advertising also exposes the advertiser to litigation by competitors for unfair competition. This article is concerned with the remedy that may be available for instituting private litigation against physicians and other health care providers who engage in untruthful advertising.

  16. Proposal for the award of an industrial support contract for paintwork, false ceilings, plasterwork and false floors at CERN

    CERN Document Server

    2006-01-01

    This document concerns the award of a contract for paintwork, false ceilings, plasterwork and false floors at CERN. The Finance Committee is invited to agree to the negotiation of a contract with the firm PREZIOSO (FR), the lowest bidder, for the provision of paintwork, false ceilings, plasterwork and false floors at CERN for a period of three years for a total amount not exceeding 538 419 euros (830 381 Swiss francs), not subject to revision for the first two years. The contract will include options for two one-year extensions beyond the initial threeyear period.

  17. Effects of Instructions on False Recognition.

    Science.gov (United States)

    Mueller, John H.; And Others

    Four experiments were conducted to examine the effects of various processing instructions on the rate of false recognition. The continuous single-item procedure was used, and false recognitions of four types were examined: synonyms, antonyms, nonsemantic associates, and homonyms. The instructions encouraged subjects to think of associates, usages…

  18. 46 CFR 28.260 - Electronic position fixing devices.

    Science.gov (United States)

    2010-10-01

    ... Trade § 28.260 Electronic position fixing devices. Each vessel 79 feet (24 meters) or more in length must be equipped with an electronic position fixing device capable of providing accurate fixes for the... 46 Shipping 1 2010-10-01 2010-10-01 false Electronic position fixing devices. 28.260 Section 28...

  19. Can False Memories Prime Problem Solutions?

    Science.gov (United States)

    Howe, Mark L.; Garner, Sarah R.; Dewhurst, Stephen A.; Ball, Linden J.

    2010-01-01

    Previous research has suggested that false memories can prime performance on related implicit and explicit memory tasks. The present research examined whether false memories can also be used to prime higher order cognitive processes, namely, insight-based problem solving. Participants were asked to solve a number of compound remote associate task…

  20. Rapid induction of false memory for pictures.

    Science.gov (United States)

    Weinstein, Yana; Shanks, David R

    2010-07-01

    Recognition of pictures is typically extremely accurate, and it is thus unclear whether the reconstructive nature of memory can yield substantial false recognition of highly individuated stimuli. A procedure for the rapid induction of false memories for distinctive colour photographs is proposed. Participants studied a set of object pictures followed by a list of words naming those objects, but embedded in the list were names of unseen objects. When subsequently shown full colour pictures of these unseen objects, participants consistently claimed that they had seen them, while discriminating with high accuracy between studied pictures and new pictures whose names did not appear in the misleading word list. These false memories can be reported with high confidence as well as the feeling of recollection. This new procedure allows the investigation of factors that influence false memory reports with ecologically valid stimuli and of the similarities and differences between true and false memories.

  1. False-negative reactions to the comparative intradermal tuberculin test for bovine tuberculosis

    Directory of Open Access Journals (Sweden)

    Rudielle A. Rodrigues

    Full Text Available ABSTRACT: According to the Brazilian National Program for the Control and Eradication of Animal Brucellosis and Tuberculosis (PNCEBT, the routine tests for the diagnosis of bovine tuberculosis in the country are the simple intradermal tuberculin test (SITT of the Ministry of Agriculture, Livestock and Food Supply (MAPA, the caudal fold test and the comparative intradermal tuberculin test (CITT. The latter is also used as a confirmatory test. A group of 53 animals from three dairy herds in a focal area for bovine tuberculosis, that were submitted to depopulation in the state of Rio Grande do Sul, were submitted to the CITT. Tissues were cultured and the resulting colonies were confirmed by PCR and DNA sequencing. Among the 53 animals analyzed using the CITT, 32 (60.4% were negative, 14 (26.4% were positive and seven (13.2% results were inconclusive. The CITT detected 11 of the 39 animals with culture-confirmed M. bovis infection as positive. Among the total of 14 uninfected animals based on cultures, the CBT detected eight as negative. Thus, the CITT demonstrated sensitivity of 28.2% and specificity of 57.1% for the population sampled. A total of 24/32 (75.0% of the animals with negative CITT results were culture positive (confirmed by PCR and were considered false negatives based on the CITT. The maintenance of these false-negative animals in herds has serious implications for the control of the disease, since they can be a source of infection. The addition of complementary tests could help identify such animals and increase the odds of diagnostic success.

  2. The role of backward associative strength in false recognition of DRM lists with multiple critical words.

    Science.gov (United States)

    Beato, María S; Arndt, Jason

    2017-08-01

    Memory is a reconstruction of the past and is prone to errors. One of the most widely-used paradigms to examine false memory is the Deese/Roediger-McDermott (DRM) paradigm. In this paradigm, participants studied words associatively related to a non-presented critical word. In a subsequent memory test critical words are often falsely recalled and/or recognized. In the present study, we examined the influence of backward associative strength (BAS) on false recognition using DRM lists with multiple critical words. In forty-eight English DRM lists, we manipulated BAS while controlling forward associative strength (FAS). Lists included four words (e.g., prison, convict, suspect, fugitive) simultaneously associated with two critical words (e.g., CRIMINAL, JAIL). The results indicated that true recognition was similar in high-BAS and low-BAS lists, while false recognition was greater in high-BAS lists than in low-BAS lists. Furthermore, there was a positive correlation between false recognition and the probability of a resonant connection between the studied words and their associates. These findings suggest that BAS and resonant connections influence false recognition, and extend prior research using DRM lists associated with a single critical word to studies of DRM lists associated with multiple critical words.

  3. The Biology of the Cytolethal Distending Toxins

    Directory of Open Access Journals (Sweden)

    Teresa Frisan

    2011-03-01

    Full Text Available The cytolethal distending toxins (CDTs, produced by a variety of Gram-negative pathogenic bacteria, are the first bacterial genotoxins described, since they cause DNA damage in the target cells. CDT is an A-B2 toxin, where the CdtA and CdtC subunits are required to mediate the binding on the surface of the target cells, allowing internalization of the active CdtB subunit, which is functionally homologous to the mammalian deoxyribonuclease I. The nature of the surface receptor is still poorly characterized, however binding of CDT requires intact lipid rafts, and its internalization occurs via dynamin-dependent endocytosis. The toxin is retrograde transported through the Golgi complex and the endoplasmic reticulum, and subsequently translocated into the nuclear compartment, where it exerts the toxic activity. Cellular intoxication induces DNA damage and activation of the DNA damage responses, which results in arrest of the target cells in the G1 and/or G2 phases of the cell cycle and activation of DNA repair mechanisms. Cells that fail to repair the damage will senesce or undergo apoptosis. This review will focus on the well-characterized aspects of the CDT biology and discuss the questions that still remain unanswered.

  4. Memory Distortion and Its Avoidance: An Event-Related Potentials Study on False Recognition and Correct Rejection.

    Science.gov (United States)

    Cadavid, Sara; Beato, Maria Soledad

    2016-01-01

    Memory researchers have long been captivated by the nature of memory distortions and have made efforts to identify the neural correlates of true and false memories. However, the underlying mechanisms of avoiding false memories by correctly rejecting related lures remains underexplored. In this study, we employed a variant of the Deese/Roediger-McDermott paradigm to explore neural signatures of committing and avoiding false memories. ERP were obtained for True recognition, False recognition, Correct rejection of new items, and, more importantly, Correct rejection of related lures. With these ERP data, early-frontal, left-parietal, and late right-frontal old/new effects (associated with familiarity, recollection, and monitoring processes, respectively) were analysed. Results indicated that there were similar patterns for True and False recognition in all three old/new effects analysed in our study. Also, False recognition and Correct rejection of related lures activities seemed to share common underlying familiarity-based processes. The ERP similarities between False recognition and Correct rejection of related lures disappeared when recollection processes were examined because only False recognition presented a parietal old/new effect. This finding supported the view that actual false recollections underlie false memories, providing evidence consistent with previous behavioural research and with most ERP and neuroimaging studies. Later, with the onset of monitoring processes, False recognition and Correct rejection of related lures waveforms presented, again, clearly dissociated patterns. Specifically, False recognition and True recognition showed more positive going patterns than Correct rejection of related lures signal and Correct rejection of new items signature. Since False recognition and Correct rejection of related lures triggered familiarity-recognition processes, our results suggest that deciding which items are studied is based more on recollection

  5. Memory Distortion and Its Avoidance: An Event-Related Potentials Study on False Recognition and Correct Rejection.

    Directory of Open Access Journals (Sweden)

    Sara Cadavid

    Full Text Available Memory researchers have long been captivated by the nature of memory distortions and have made efforts to identify the neural correlates of true and false memories. However, the underlying mechanisms of avoiding false memories by correctly rejecting related lures remains underexplored. In this study, we employed a variant of the Deese/Roediger-McDermott paradigm to explore neural signatures of committing and avoiding false memories. ERP were obtained for True recognition, False recognition, Correct rejection of new items, and, more importantly, Correct rejection of related lures. With these ERP data, early-frontal, left-parietal, and late right-frontal old/new effects (associated with familiarity, recollection, and monitoring processes, respectively were analysed. Results indicated that there were similar patterns for True and False recognition in all three old/new effects analysed in our study. Also, False recognition and Correct rejection of related lures activities seemed to share common underlying familiarity-based processes. The ERP similarities between False recognition and Correct rejection of related lures disappeared when recollection processes were examined because only False recognition presented a parietal old/new effect. This finding supported the view that actual false recollections underlie false memories, providing evidence consistent with previous behavioural research and with most ERP and neuroimaging studies. Later, with the onset of monitoring processes, False recognition and Correct rejection of related lures waveforms presented, again, clearly dissociated patterns. Specifically, False recognition and True recognition showed more positive going patterns than Correct rejection of related lures signal and Correct rejection of new items signature. Since False recognition and Correct rejection of related lures triggered familiarity-recognition processes, our results suggest that deciding which items are studied is based more on

  6. Identification of and Screening for Human Helicobacter cinaedi Infections and Carriers via Nested PCR

    Science.gov (United States)

    Oyama, Kohta; Khan, Shahzada; Okamoto, Tatsuya; Fujii, Shigemoto; Ono, Katsuhiko; Matsunaga, Tetsuro; Yoshitake, Jun; Sawa, Tomohiro; Tomida, Junko; Kawamura, Yoshiaki

    2012-01-01

    Helicobacter cinaedi is the most frequently reported enterohepatic Helicobacter species isolated from humans. Earlier research suggested that certain patients with H. cinaedi infection may remain undiagnosed or incorrectly diagnosed because of difficulties in detecting the bacteria by conventional culture methods. Here, we report a nested PCR assay that rapidly detects the cytolethal distending toxin gene (cdt) of H. cinaedi with high specificity and sensitivity. Specificity of the assay was validated by using different species of Helicobacter and Campylobacter, as well as known H. cinaedi-positive and -negative samples. The sensitivity of detection for the cdt gene in the assay was 102 CFU/ml urine or 102 CFU/105 infected RAW 264.7 cells. In an H. cinaedi-infected mouse model, the cdt gene of H. cinaedi was effectively detected via the assay with urine (6/7), stool (2/3), and blood (2/6) samples. Importantly, it detected H. cinaedi in blood, urine, and stool samples from one patient with a suspected H. cinaedi infection and three patients with known infections. The assay was further used clinically to follow up two H. cinaedi-infected patients after antibiotic treatment. Stool samples from these two patients evaluated by nested PCR after antibiotic therapy showed clearance of bacterial DNA. Finally, analysis of stool specimens from healthy volunteers showed occasional positive reactions (4/30) to H. cinaedi DNA, which suggests intestinal colonization by H. cinaedi in healthy subjects. In conclusion, this nested PCR assay may be useful for the rapid diagnosis, antimicrobial treatment evaluation, and epidemiological study of H. cinaedi infection. PMID:23015666

  7. Combined roentgenoultrasonic diagnosis of false pancreatic cysts

    International Nuclear Information System (INIS)

    Dubrov, Eh.Ya.; Beresneva, Eh.A.; Chervonenkis, A.V.; Morozova, N.A.

    1986-01-01

    X-ray and ultrasound semiotics of false pancreatic cysts in 21 patients have been described. Such a study proves to be highly informative permitting early detection of false pancreatic cysts and observation of the stages of their formation and development of complications. The ultrasound method has advantages for the investigation of patients in early time of false cyst formation and provides an opportunity to detect formations of minimum sizes

  8. 30 CFR 71.208 - Bimonthly sampling; designated work positions.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bimonthly sampling; designated work positions... UNDERGROUND COAL MINES Sampling Procedures § 71.208 Bimonthly sampling; designated work positions. (a) Each... standard when quartz is present), respirable dust sampling of designated work positions shall begin on the...

  9. 28 CFR 17.42 - Positions requiring financial disclosure.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Positions requiring financial disclosure... INFORMATION AND ACCESS TO CLASSIFIED INFORMATION Access to Classified Information § 17.42 Positions requiring financial disclosure. (a) The Assistant Attorney General for Administration, in consultation with the...

  10. Automated detection of pulmonary nodules in PET/CT images: Ensemble false-positive reduction using a convolutional neural network technique

    Energy Technology Data Exchange (ETDEWEB)

    Teramoto, Atsushi, E-mail: teramoto@fujita-hu.ac.jp [Faculty of Radiological Technology, School of Health Sciences, Fujita Health University, 1-98 Dengakugakubo, Kutsukake, Toyoake, Aichi 470-1192 (Japan); Fujita, Hiroshi [Department of Intelligent Image Information, Division of Regeneration and Advanced Medical Sciences, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1194 (Japan); Yamamuro, Osamu; Tamaki, Tsuneo [East Nagoya Imaging Diagnosis Center, 3-4-26 Jiyugaoka, Chikusa-ku, Nagoya, Aichi 464-0044 (Japan)

    2016-06-15

    Purpose: Automated detection of solitary pulmonary nodules using positron emission tomography (PET) and computed tomography (CT) images shows good sensitivity; however, it is difficult to detect nodules in contact with normal organs, and additional efforts are needed so that the number of false positives (FPs) can be further reduced. In this paper, the authors propose an improved FP-reduction method for the detection of pulmonary nodules in PET/CT images by means of convolutional neural networks (CNNs). Methods: The overall scheme detects pulmonary nodules using both CT and PET images. In the CT images, a massive region is first detected using an active contour filter, which is a type of contrast enhancement filter that has a deformable kernel shape. Subsequently, high-uptake regions detected by the PET images are merged with the regions detected by the CT images. FP candidates are eliminated using an ensemble method; it consists of two feature extractions, one by shape/metabolic feature analysis and the other by a CNN, followed by a two-step classifier, one step being rule based and the other being based on support vector machines. Results: The authors evaluated the detection performance using 104 PET/CT images collected by a cancer-screening program. The sensitivity in detecting candidates at an initial stage was 97.2%, with 72.8 FPs/case. After performing the proposed FP-reduction method, the sensitivity of detection was 90.1%, with 4.9 FPs/case; the proposed method eliminated approximately half the FPs existing in the previous study. Conclusions: An improved FP-reduction scheme using CNN technique has been developed for the detection of pulmonary nodules in PET/CT images. The authors’ ensemble FP-reduction method eliminated 93% of the FPs; their proposed method using CNN technique eliminates approximately half the FPs existing in the previous study. These results indicate that their method may be useful in the computer-aided detection of pulmonary nodules

  11. Automated detection of pulmonary nodules in PET/CT images: Ensemble false-positive reduction using a convolutional neural network technique

    International Nuclear Information System (INIS)

    Teramoto, Atsushi; Fujita, Hiroshi; Yamamuro, Osamu; Tamaki, Tsuneo

    2016-01-01

    Purpose: Automated detection of solitary pulmonary nodules using positron emission tomography (PET) and computed tomography (CT) images shows good sensitivity; however, it is difficult to detect nodules in contact with normal organs, and additional efforts are needed so that the number of false positives (FPs) can be further reduced. In this paper, the authors propose an improved FP-reduction method for the detection of pulmonary nodules in PET/CT images by means of convolutional neural networks (CNNs). Methods: The overall scheme detects pulmonary nodules using both CT and PET images. In the CT images, a massive region is first detected using an active contour filter, which is a type of contrast enhancement filter that has a deformable kernel shape. Subsequently, high-uptake regions detected by the PET images are merged with the regions detected by the CT images. FP candidates are eliminated using an ensemble method; it consists of two feature extractions, one by shape/metabolic feature analysis and the other by a CNN, followed by a two-step classifier, one step being rule based and the other being based on support vector machines. Results: The authors evaluated the detection performance using 104 PET/CT images collected by a cancer-screening program. The sensitivity in detecting candidates at an initial stage was 97.2%, with 72.8 FPs/case. After performing the proposed FP-reduction method, the sensitivity of detection was 90.1%, with 4.9 FPs/case; the proposed method eliminated approximately half the FPs existing in the previous study. Conclusions: An improved FP-reduction scheme using CNN technique has been developed for the detection of pulmonary nodules in PET/CT images. The authors’ ensemble FP-reduction method eliminated 93% of the FPs; their proposed method using CNN technique eliminates approximately half the FPs existing in the previous study. These results indicate that their method may be useful in the computer-aided detection of pulmonary nodules

  12. Caprine and ovine Greek dairy products: The official German method generates false-positive results due to κ-casein gene polymorphism.

    Science.gov (United States)

    Tsartsianidou, V; Triantafillidou, D; Karaiskou, N; Tarantili, P; Triantafillidis, G; Georgakis, E; Triantafyllidis, A

    2017-05-01

    Caseins are widely used for species identification of dairy products. Isoelectric focusing (IEF) of para-κ-casein peptide is used as the official German method for the differentiation between caprine (isoform A) and ovine (isoform B) dairy products, based on their different isoelectric points. The discrimination between Greek goat and ewe dairy products using IEF has, however, been shown to be problematic because of the existence of the ewe isoform in milk from Greek indigenous dairy goats. This could be due to nucleotide polymorphisms within the goat κ-casein gene of Greek indigenous breeds, which alter the isoelectric point of the para-κ-casein peptide and lead to false positive results. Previous DNA analysis of the goat κ-casein gene has shown high levels of polymorphism; however, no such information is available for Greek indigenous dairy goats. Therefore, 87 indigenous dairy goats were sequenced at exon IV of κ-casein gene. In total, 9 polymorphic sites were detected. Three nonsynonymous point mutations were identified, which change the isoelectric point of the goat para-κ-casein peptide so that it appears identical to that of the ewe peptide. Ten composite genotypes were reconstructed and 6 of them included the problematic point mutations. For the verification of genetic results, IEF was carried out. Both goat and ewe patterns appeared in the problematic genotypes. The frequency of these genotypes could be characterized as moderate (0.23) to high (0.60) within Greek indigenous breeds. However, this is not an issue restricted to Greece, as such genotypes have been detected in various non-Greek goat breeds. In conclusion, IEF based on the official German method is certainly inappropriate for ovine and caprine discrimination concerning Greek dairy goat products, and consequently a new method should be established. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. A designated centre for people with disabilities operated by St Michael's House, Co. Dublin

    LENUS (Irish Health Repository)

    Cobbe, Sinead

    2017-12-05

    Complex decongestive therapy (CDT) is a regimen of physical treatment for lymphedema. Its effectiveness is unknown in advanced cancer patients. This study evaluates effectiveness of CDT in this population.

  14. Pilot Study: The Effectiveness of Complex Decongestive Therapy for Lymphedema in Palliative Care Patients with Advanced Cancer.

    LENUS (Irish Health Repository)

    Cobbe, Sinead

    2017-12-05

    Complex decongestive therapy (CDT) is a regimen of physical treatment for lymphedema. Its effectiveness is unknown in advanced cancer patients. This study evaluates effectiveness of CDT in this population.

  15. 29 CFR 2200.39 - Statement of position.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Statement of position. 2200.39 Section 2200.39 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH REVIEW COMMISSION RULES OF PROCEDURE... intervene, may file a statement of position with respect to any or all issues to be heard. The Judge may...

  16. 33 CFR 161.20 - Position Report (PR).

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Position Report (PR). 161.20 Section 161.20 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... Report (PR). A vessel must report its name and position: (a) Upon point of entry into a VMRS area; (b) At...

  17. The spread of true and false news online.

    Science.gov (United States)

    Vosoughi, Soroush; Roy, Deb; Aral, Sinan

    2018-03-09

    We investigated the differential diffusion of all of the verified true and false news stories distributed on Twitter from 2006 to 2017. The data comprise ~126,000 stories tweeted by ~3 million people more than 4.5 million times. We classified news as true or false using information from six independent fact-checking organizations that exhibited 95 to 98% agreement on the classifications. Falsehood diffused significantly farther, faster, deeper, and more broadly than the truth in all categories of information, and the effects were more pronounced for false political news than for false news about terrorism, natural disasters, science, urban legends, or financial information. We found that false news was more novel than true news, which suggests that people were more likely to share novel information. Whereas false stories inspired fear, disgust, and surprise in replies, true stories inspired anticipation, sadness, joy, and trust. Contrary to conventional wisdom, robots accelerated the spread of true and false news at the same rate, implying that false news spreads more than the truth because humans, not robots, are more likely to spread it. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  18. Massive venlafaxine overdose resulted in a false positive Abbott AxSYM (R) urine immunoassay for phencyclidine

    NARCIS (Netherlands)

    Bond, GR; Steele, PE; Uges, DRA

    2003-01-01

    Case report: A 13-yr-old girl overdosed on 48 x 150 mg venlafaxine (Effexor XR(R)). She was taking venlafaxine regularly for depression. Her only other medications included topical Benzamycin and pyridoxine 50 mg daily for acne. The Abbott AxSYM(R) assay was positive only for phencyclidine, but

  19. A false single nucleotide polymorphism generated by gene duplication compromises meat traceability.

    Science.gov (United States)

    Sanz, Arianne; Ordovás, Laura; Zaragoza, Pilar; Sanz, Albina; de Blas, Ignacio; Rodellar, Clementina

    2012-07-01

    Controlling meat traceability using SNPs is an effective method of ensuring food safety. We have analyzed several SNPs to create a panel for bovine genetic identification and traceability studies. One of these was the transversion g.329C>T (Genbank accession no. AJ496781) on the cytochrome P450 17A1 gene, which has been included in previously published panels. Using minisequencing reactions, we have tested 701 samples belonging to eight Spanish cattle breeds. Surprisingly, an excess of heterozygotes was detected, implying an extreme departure from Hardy-Weinberg equilibrium (PT SNP is a false positive polymorphism, which allows us to explain the inflated heterozygotic value. We recommend that this ambiguous SNP, as well as other polymorphisms located in this region, should not be used in identification, traceability or disease association studies. Annotation of these false SNPs should improve association studies and avoid misinterpretations. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Cytolethal Distending Toxin Demonstrates Genotoxic Activity in a Yeast Model

    OpenAIRE

    Hassane, Duane C.; Lee, Robert B.; Mendenhall, Michael D.; Pickett, Carol L.

    2001-01-01

    Cytolethal distending toxins (CDTs) are multisubunit proteins produced by a variety of bacterial pathogens that cause enlargement, cell cycle arrest, and apoptosis in mammalian cells. While their function remains uncertain, recent studies suggest that they can act as intracellular DNases in mammalian cells. Here we establish a novel yeast model for understanding CDT-associated disease. Expression of the CdtB subunit in yeast causes a G2/M arrest, as seen in mammalian cells. CdtB toxicity is n...