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Sample records for false positive aortic

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

    Science.gov (United States)

    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.

  2. The Kepler False Positive Table

    Science.gov (United States)

    Bryson, Steve; Kepler False Positive Working Group

    2015-01-01

    The Kepler Space Telescope has detected thousands of candidate exoplanets by observing transit signals in a sample of more than 190,000 stars. Many of these transit signals are false positives, defined as a transit-like signal that is not due to a planet orbiting the target star (or a bound companion if the target is a multiple-star system). Astrophysical causes of false positives include background eclipsing binaries, planetary transits not associated with the target star, and non-planetary eclipses of the target star by stellar companions. The fraction of Kepler planet candidates that are false positives ranges from about 10% at high Galactic latitudes to 40% at low Galactic latitudes. Creating a high-reliability planet candidate catalog for statistical studies such as occurrence rate calculations requires removing clearly identified false positives.The Kepler Object of Interest (KOI) catalog at the NExScI NASA Exoplanet Archive flags false positives, and will soon provide a high-level classification of false positives, but lacks detailed description of why a KOI was determined to be a false positive. The Kepler False Positive Working Group (FPWG) examines each false positive in detail to certify that it is correctly identified as a false positive, and determines the primary reason(s) a KOI is classified as a false positive. The work of the FPWG will be published as the Kepler False Positive Table, hosted at the NExScI NASA Exoplanet Archive.The Kepler False Positive Table provides detailed information on the evidence for background binaries, transits caused by stellar companions, and false alarms. In addition to providing insight into the Kepler false positive population, the false positive table gives information about the background binary population and other areas of astrophysical interest. Because a planet around a star not associated with the target star is considered a false positive, the false positive table likely contains further planet candidates

  3. False positives in cancer epidemiology.

    Science.gov (United States)

    McLaughlin, Joseph K; Tarone, Robert E

    2013-01-01

    A recent attempt to estimate the false-positive rate for cancer epidemiology studies is based on agents in International Agency for Research on Cancer (IARC) category 3 (agent not classifiable as to its carcinogenicity to humans) in the IARC Monographs Program. The estimation method is critiqued regarding biases caused by its reliance on the IARC classification criteria for assessing carcinogenic potential. The privileged position given to epidemiologic studies by the IARC criteria ensures that the percentage of positive epidemiologic studies for an agent will depend strongly on the IARC category to which the agent is assigned. Because IARC category 3 is composed of agents with the lowest-assessed carcinogenic potential to which the estimation approach in question could be applied, a spuriously low estimated false-positive rate was necessarily the outcome of this approach. Tendentious estimation approaches like that employed will by necessity produce spuriously low and misleading false positive rates. The recently reported estimates of the false-positive rate in cancer epidemiology are seriously biased and contribute nothing substantive to the literature on the very real problems related to false-positive findings in epidemiology.

  4. False positives in imaging genetics.

    Science.gov (United States)

    Meyer-Lindenberg, Andreas; Nicodemus, Kristin K; Egan, Michael F; Callicott, Joseph H; Mattay, Venkata; Weinberger, Daniel R

    2008-04-01

    Imaging genetics provides an enormous amount of functional-structural data on gene effects in living brain, but the sheer quantity of potential phenotypes raises concerns about false discovery. Here, we provide the first empirical results on false positive rates in imaging genetics. We analyzed 720 frequent coding SNPs without significant association with schizophrenia and a subset of 492 of these without association with cognitive function. Effects on brain structure (using voxel-based morphometry, VBM) and brain function, using two archival imaging tasks, the n-back working memory task and an emotional face matching task, were studied in whole brain and regions of interest and corrected for multiple comparisons using standard neuroimaging procedures. Since these variants are unlikely to impact relevant brain function, positives obtained provide an upper empirical estimate of the false positive association rate. In a separate analysis, we randomly permuted genotype labels across subjects, removing any true genotype-phenotype association in the data, to derive a lower empirical estimate. At a set correction level of 0.05, in each region of interest and data set used, the rate of positive findings was well below 5% (0.2-4.1%). There was no relationship between the region of interest and the false positive rate. Permutation results were in the same range as empirically derived rates. The observed low rates of positives provide empirical evidence that the type I error rate is well controlled by current commonly used correction procedures in imaging genetics, at least in the context of the imaging paradigms we have used. In fact, our observations indicate that these statistical thresholds are conservative.

  5. Postsurgical aortic false aneurysm: pathogenesis, clinical presentation and surgical strategy.

    Science.gov (United States)

    Raffa, Giuseppe M; Malvindi, Pietro G; Ornaghi, Diego; Basciu, Alessio; Barbone, Alessandro; Tarelli, Giuseppe; Settepani, Fabrizio

    2013-08-01

    Postsurgical aortic false aneurysm occurs in less than 0.5% of all cardiac surgical cases and its management is a challenge in terms of preoperative evaluation and surgical approach. Although infections are well recognized as risk factors, technical aspects of a previous operation may have a role in pseudoaneurysm formation. The risk factors and clinical presentation of pseudoaneurysms and the surgical strategy are revisited in this article.

  6. Traumatic aortic arch false aneurysm after blunt chest trauma in a motocross rider.

    Science.gov (United States)

    Bizzarri, Federico; Mattia, Consalvo; Ricci, Massimo; Chirichilli, Ilaria; Santo, Chiara; Rose, David; Muzzi, Luigi; Pugliese, Giuseppe; Frati, Giacomo; Sartini, Patrizio; Ferrari, Riccardo; Della Rocca, Carlo; Laghi, Andrea

    2008-05-01

    This article details a case report of a traumatic aortic arch false aneurysm after blunt chest trauma. Thoracic aorta false aneurysms are a rare and life-threatening complication of aortic surgery, infection, genetic disorders and trauma.

  7. Controlling False Positives in Association Rule Mining

    CERN Document Server

    Liu, Guimei; Wong, Limsoon

    2011-01-01

    Association rule mining is an important problem in the data mining area. It enumerates and tests a large number of rules on a dataset and outputs rules that satisfy user-specified constraints. Due to the large number of rules being tested, rules that do not represent real systematic effect in the data can satisfy the given constraints purely by random chance. Hence association rule mining often suffers from a high risk of false positive errors. There is a lack of comprehensive study on controlling false positives in association rule mining. In this paper, we adopt three multiple testing correction approaches---the direct adjustment approach, the permutation-based approach and the holdout approach---to control false positives in association rule mining, and conduct extensive experiments to study their performance. Our results show that (1) Numerous spurious rules are generated if no correction is made. (2) The three approaches can control false positives effectively. Among the three approaches, the permutation...

  8. Traumatic aortic arch false aneurysm after blunt chest trauma in a motocross rider

    Directory of Open Access Journals (Sweden)

    Sartini Patrizio

    2008-05-01

    Full Text Available Abstract This article details a case report of a traumatic aortic arch false aneurysm after blunt chest trauma. Thoracic aorta false aneurysms are a rare and life-threatening complication of aortic surgery, infection, genetic disorders and trauma.

  9. Predictors of patent false lumen of the aortic arch after hemiarch replacement.

    Science.gov (United States)

    Uchino, Gaku; Ohashi, Takeki; Iida, Hiroshi; Tadakoshi, Masao; Kageyama, Souichirou; Furui, Masato; Kodani, Noriko

    2016-12-01

    Hemiarch replacement for acute type A aortic dissection is less invasive than total arch replacement but involves increased risk of late aortic arch dilation because of patent false lumen of the aortic arch. If we can predict this risk, it may be a valuable prognostic indicator for selecting surgical procedures for acute type A aortic dissection. We reviewed our surgical experience to predict patent false lumen. From January 2009 to November 2014, we performed 108 hemiarch replacement procedures for acute type A aortic dissection that had patent false lumen of the ascending aortic arch. We identified 56 patients who had preoperative and postoperative contrast-enhanced computed tomography. Patients' preoperative characteristics, preoperative and postoperative contrast-enhanced computed tomography findings, intraoperative findings and postoperative course were investigated. Of the 56 patients, 32 (57.1 %) were men and their mean age at surgery was 63.7 ± 11.8 years. Overall in-hospital mortality rate was 7.1 % (4 patients). According to postoperative imaging findings, 56 patients were classified into two groups: group A (39 patients), with patent false lumen, and group B (17 patients), with thrombosed false lumen. Logistic regression analysis revealed that brachiocephalic artery dissection and no tear resection contributed to postoperative patent false lumen of the aortic arch more strongly than did other factors. Brachiocephalic artery dissection and no tear resection are potential predictors of patent false lumen of the aortic arch after hemiarch replacement.

  10. False positive reduction for lung nodule CAD

    Science.gov (United States)

    Zhao, Luyin; Boroczky, Lilla; Drysdale, Jeremy; Agnihotri, Lalitha; Lee, Michael C.

    2007-03-01

    Computer-aided detection (CAD) algorithms 'automatically' identify lung nodules on thoracic multi-slice CT scans (MSCT) thereby providing physicians with a computer-generated 'second opinion'. While CAD systems can achieve high sensitivity, their limited specificity has hindered clinical acceptance. To overcome this problem, we propose a false positive reduction (FPR) system based on image processing and machine learning to reduce the number of false positive lung nodules identified by CAD algorithms and thereby improve system specificity. To discriminate between true and false nodules, twenty-three 3D features were calculated from each candidate nodule's volume of interest (VOI). A genetic algorithm (GA) and support vector machine (SVM) were then used to select an optimal subset of features from this pool of candidate features. Using this feature subset, we trained an SVM classifier to eliminate as many false positives as possible while retaining all the true nodules. To overcome the imbalanced nature of typical datasets (significantly more false positives than true positives), an intelligent data selection algorithm was designed and integrated into the machine learning framework, thus further improving the FPR rate. Three independent datasets were used to train and validate the system. Using two datasets for training and the third for validation, we achieved a 59.4% FPR rate while removing one true nodule on the validation datasets. In a second experiment, 75% of the cases were randomly selected from each of the three datasets and the remaining cases were used for validation. A similar FPR rate and true positive retention rate was achieved. Additional experiments showed that the GA feature selection process integrated with the proposed data selection algorithm outperforms the one without it by 5%-10% FPR rate. The methods proposed can be also applied to other application areas, such as computer-aided diagnosis of lung nodules.

  11. A closer look at self-reported suicide attempts: false positives and false negatives.

    Science.gov (United States)

    Plöderl, Martin; Kralovec, Karl; Yazdi, Kurosch; Fartacek, Reinhold

    2011-02-01

    The validity of self-reported suicide attempt information is undermined by false positives (e.g., incidences without intent to die), or by unreported suicide attempts, referred to as false negatives. In a sample of 1,385 Austrian adults, we explored the occurrence of false positives and false negatives with detailed, probing questions. Removing false positives decreased the rate of suicide attempters from 4.3% to 2.7%. Probing questions also revealed 0.8% false negatives. We recommend using probing questions with both those who report a suicide attempt and those who do not report a suicide attempt to increase the validity of self-reported suicide-related information.

  12. Consequences of a false-positive mammography result

    DEFF Research Database (Denmark)

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

    2016-01-01

    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 of ...

  13. False positive test results for pheochromocytoma from 2000 to 2008.

    Science.gov (United States)

    Yu, R; Wei, M

    2010-10-01

    Testing for pheochromocytoma becomes more frequent in clinical practice. False positive test results may cause patient anxiety and unnecessary imaging studies. The data on false positive results for pheochromocytoma in routine clinical practice are lacking. To examine the prevalence of false positive results and to reveal the clinical features and laboratory tests of patients with markedly elevated but false positive test results, a database of tests for pheochromocytoma at a large general hospital between 2000 and 2008 was reviewed. Of 1,896 patients tested, 417 (22.0%) had at least one abnormal test result and 66 (3.5%) had markedly elevated results. 24 patients with markedly elevated but false positive results received 65 imaging studies and 1 adrenalectomy. The causes of the misleading results included physiological variations (33%), laboratory errors (29%), and drug interference with measurement (21%). The false positive rate of a markedly elevated result was lowest for vanillylmandelic acid (9%) and highest for urine metanephrines (50%) (p = 0.03). Nearly half of all test results were normal and 79% of patients had at least one normal result. Therefore false positive test results for pheochromocytoma are rather common. Markedly elevated but false positive test results can potentially be avoided by judicious selection of patients and tests. Pretest risk, physiological variations of catecholamine levels, laboratory errors, and drug interference should be considered in interpreting abnormal test results. © J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.

  14. Improving retouched Bloom filter for trading off selected false positives against false negatives

    OpenAIRE

    Donnet, Benoît; Baynat, Bruno; Friedman, Timur

    2010-01-01

    Where distributed agents must share voluminous set membership information, Bloom fil- ters provide a compact, though lossy, way for them to do so. Numerous recent networking papers have examined the trade-offs between the bandwidth consumed by the transmis- sion of Bloom filters, and the error rate, which takes the form of false positives. This paper is about the retouched Bloom filter (RBF). An RBF is an extension that makes the Bloom fil- ter more flexible by permitting the removal of false...

  15. Characterisation of false-positive observations in botanical surveys

    Directory of Open Access Journals (Sweden)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Jung Min; Lee, Hyun Ju; Goo, Jin Mo; Lee, Ho Young; Lee, Jong Jin; Chung, June Key; Im, Jung Gi [Seoul National University Hospital, Seoul (Korea, Republic of)

    2006-03-15

    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.

  17. Escitalopram-Induced Amenorrhea and False Positive Urine Pregnancy Test

    Science.gov (United States)

    Hour, Siv; Gunasekar, Palanikumar; Gray, Caron; Smith, James F.

    2017-01-01

    Escitalopram is a selective serotonin reuptake inhibitor antidepressant approved by the Food and Drug Administration for the treatment of major depressive disorder and generalized anxiety disorder. A 34-year-old female patient with major depressive disorder developed amenorrhea and had a false-positive urine pregnancy test after initiation of escitalopram treatment. To our knowledge, no published case report of amenorrhea and false-positive urine pregnancy tests in women taking escitalopram exists. This case report suggests that women of child-bearing age should be carefully monitored for amenorrhea while they are on an antidepressant treatment regimen. PMID:28197332

  18. Retouched Bloom Filters: Allowing Networked Applications to Flexibly Trade Off False Positives Against False Negatives

    OpenAIRE

    Donnet, Benoît; Baynat, Bruno; Friedman, Timur

    2006-01-01

    Where distributed agents must share voluminous set mem- bership information, Bloom filters provide a compact, though lossy, way for them to do so. Numerous recent networking papers have examined the trade-offs between the bandwidth consumed by the transmission of Bloom filters, and the er- ror rate, which takes the form of false positives, and which rises the more the filters are compressed. In this paper, we introduce the retouched Bloom filter (RBF), an extension that makes the Bloom filter...

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...... between those of women withnormal mammography and those of women determined to have breast cancer. CONCLUSIONS: We found no evidence that use of more invasive diagnosticswas associated with worse psychosocial consequences. It is therefore reasonableto pool subgroups of women with false...

  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. High false positive rates in common sensory threshold tests.

    Science.gov (United States)

    Running, Cordelia A

    2015-02-01

    Large variability in thresholds to sensory stimuli is observed frequently even in healthy populations. Much of this variability is attributed to genetics and day-to-day fluctuation in sensitivity. However, false positives are also contributing to the variability seen in these tests. In this study, random number generation was used to simulate responses in threshold methods using different "stopping rules": ascending 2-alternative forced choice (AFC) with 5 correct responses; ascending 3-AFC with 3 or 4 correct responses; staircase 2-AFC with 1 incorrect up and 2 incorrect down, as well as 1 up 4 down and 5 or 7 reversals; staircase 3-AFC with 1 up 2 down and 5 or 7 reversals. Formulas are presented for rates of false positives in the ascending methods, and curves were generated for the staircase methods. Overall, the staircase methods generally had lower false positive rates, but these methods were influenced even more by number of presentations than ascending methods. Generally, the high rates of error in all these methods should encourage researchers to conduct multiple tests per individual and/or select a method that can correct for false positives, such as fitting a logistic curve to a range of responses.

  2. 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…

  3. 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…

  4. Reducing False Positives in Runtime Analysis of Deadlocks

    Science.gov (United States)

    Bensalem, Saddek; Havelund, Klaus; Clancy, Daniel (Technical Monitor)

    2002-01-01

    This paper presents an improvement of a standard algorithm for detecting dead-lock potentials in multi-threaded programs, in that it reduces the number of false positives. The standard algorithm works as follows. The multi-threaded program under observation is executed, while lock and unlock events are observed. A graph of locks is built, with edges between locks symbolizing locking orders. Any cycle in the graph signifies a potential for a deadlock. The typical standard example is the group of dining philosophers sharing forks. The algorithm is interesting because it can catch deadlock potentials even though no deadlocks occur in the examined trace, and at the same time it scales very well in contrast t o more formal approaches to deadlock detection. The algorithm, however, can yield false positives (as well as false negatives). The extension of the algorithm described in this paper reduces the amount of false positives for three particular cases: when a gate lock protects a cycle, when a single thread introduces a cycle, and when the code segments in different threads that cause the cycle can actually not execute in parallel. The paper formalizes a theory for dynamic deadlock detection and compares it to model checking and static analysis techniques. It furthermore describes an implementation for analyzing Java programs and its application to two case studies: a planetary rover and a space craft altitude control system.

  5. False positive and false negative radon measurement results due to uncertainties in seasonal correction factors

    Energy Technology Data Exchange (ETDEWEB)

    Cliff, K.D.; Miles, J.C.H.; Naismith, S.P. [National Radiological Protection Board, Chilton (United Kingdom)

    1994-12-31

    Data from the UK national survey of radon in 2300 homes has been re-analysed to determine the uncertainty in seasonal correction factors applied to measurements of less than 1 year. The required correction factor for each six-month result was calculated from the known annual average for the appropriate home. The seasonal correction factors derived for each month were found to be approximately log-normally distributed, with an average geometric standard deviation of 1.36. Following this initial survey, radon measurements have been made in more than 80,000 homes in southwest England to determine whether they are above the UK radon Action Level of 2000 Bq.m{sup -3}. The measurements were carried out over three months in each case using etched track detectors in two locations in each home, and the results were corrected for the average seasonal variation found in the original UK study of radon in homes. Because of the uncertainty in the seasonal correction factors, households with between 130 and 300 Bq.m{sup -3} were advised to have a second three-month measurement in a different season before deciding whether or not to take remedial action. More than 7000 homes were remonitored for this purpose. The results are analysed to show the number of false positive and false negative results that would have been reported if advice had been based solely on the initial measurement. It is shown that the present scheme results in extremely small numbers of false positive and false negative results. (author).

  6. False positives to confusable objects predict medial temporal lobe atrophy.

    Science.gov (United States)

    Kivisaari, Sasa L; Monsch, Andreas U; Taylor, Kirsten I

    2013-09-01

    Animal models agree that the perirhinal cortex plays a critical role in object recognition memory, but qualitative aspects of this mnemonic function are still debated. A recent model claims that the perirhinal cortex is required to recognize the novelty of confusable distractor stimuli, and that damage here results in an increased propensity to judge confusable novel objects as familiar (i.e., false positives). We tested this model in healthy participants and patients with varying degrees of perirhinal cortex damage, i.e., amnestic mild cognitive impairment and very early Alzheimer's disease (AD), with a recognition memory task with confusable and less confusable realistic object pictures, and from whom we acquired high-resolution anatomic MRI scans. Logistic mixed-model behavioral analyses revealed that both patient groups committed more false positives with confusable than less confusable distractors, whereas healthy participants performed comparably in both conditions. A voxel-based morphometry analysis demonstrated that this effect was associated with atrophy of the anteromedial temporal lobe, including the perirhinal cortex. These findings suggest that also the human perirhinal cortex recognizes the novelty of confusable objects, consistent with its border position between the hierarchical visual object processing and medial temporal lobe memory systems, and explains why AD patients exhibit a heightened propensity to commit false positive responses with inherently confusable stimuli.

  7. Gallbladder tuberculosis: False-positive PET diagnosis of gallbladder cancer

    Institute of Scientific and Technical Information of China (English)

    JM Ramia; K Muffak; A Fernández; J Villar; D Garrote; JA Ferron

    2006-01-01

    Gallbladder tuberculosis (GT) is an extremely rare disease, and very few cases have been reported in the literature. The first case of GT was described in 1870 by Gaucher. A correct preoperative diagnosis of GT is unusual, and it is frequently confused with various gallbladder diseases. We present a new case of a patient who underwent surgery with the preoperative diagnosis of gallbladder cancer after a false positive positron emission tomography scan in the diagnostic work-up.

  8. False-positive colorimetric capnometry after ingestion of carbonated beverages.

    Science.gov (United States)

    Keller, William Ryan; Biehler, Jefrey; Linares, Marc Yves-Rene; Garcia-Pena, Barbara M

    2009-02-01

    To investigate the potential for false-positive colorimetric capnometric readings during esophageal intubation after ingestion of carbonated beverages. The study was conducted in the human patient simulation laboratory of a tertiary care pediatric hospital. The sole outcome measurement was the capnometric indicator membrane color after expiration for 10 breaths. Readings were recorded for scenarios simulating 8 different models. For all carbonated beverage trials with a cuffed endotracheal tube (ETT) and those with 2 and 6 oz of beverage in the gastric sac with an uncuffed ETT, a false-positive result was observed on the capnometer's indicator for breaths 1 through 10. The sensitivity of the capnometer for the detection of CO2 after full exhalation of breath 6 for these trials was 100%. For trials containing 12 oz in the gastric sac and an uncuffed ETT, yellow was observed on the capnometer indicator for breaths 1 through 3, tan for breaths 4 through 6, and purple for breath 7. The sensitivity of the capnometer for the detection of adequate CO2 after full exhalation of breath 6 for these trials was 0%. The overall sensitivity of the capnometer for the carbonated beverage models with a cuffed ETT was 100%, whereas the combined sensitivity for the trials with an uncuffed ETT was 67%. Under proper circumstances, a significant potential exists for false-positive colorimetric capnometric results in the presence of even small amounts of carbonated beverages.

  9. "False Positive" Claims of Near-Death Experiences and "False Negative" Denials of Near-Death Experiences

    Science.gov (United States)

    Greyson, Bruce

    2005-01-01

    Some persons who claim to have had near-death experiences (NDEs) fail research criteria for having had NDEs ("false positives"); others who deny having had NDEs do meet research criteria for having had NDEs ("false negatives"). The author evaluated false positive claims and false negative denials in an organization that promotes near-death…

  10. The false-positive to false-negative ratio in epidemiologic studies.

    Science.gov (United States)

    Ioannidis, John P A; Tarone, Robert; McLaughlin, Joseph K

    2011-07-01

    The ratio of false-positive to false-negative findings (FP:FN ratio) is an informative metric that warrants further evaluation. The FP:FN ratio varies greatly across different epidemiologic areas. In genetic epidemiology, it has varied from very high values (possibly even >100:1) for associations reported in candidate-gene studies to very low values (1:100 or lower) for associations with genome-wide significance. The substantial reduction over time in the FP:FN ratio in human genome epidemiology has corresponded to the routine adoption of stringent inferential criteria and comprehensive, agnostic reporting of all analyses. Most traditional fields of epidemiologic research more closely follow the practices of past candidate gene epidemiology, and thus have high FP:FN ratios. Further, FP and FN results do not necessarily entail the same consequences, and their relative importance may vary in different settings. This ultimately has implications for what is the acceptable FP:FN ratio and for how the results of published epidemiologic studies should be presented and interpreted.

  11. Abort Trigger False Positive and False Negative Analysis Methodology for Threshold-Based Abort Detection

    Science.gov (United States)

    Melcher, Kevin J.; Cruz, Jose A.; Johnson Stephen B.; Lo, Yunnhon

    2015-01-01

    This paper describes a quantitative methodology for bounding the false positive (FP) and false negative (FN) probabilities associated with a human-rated launch vehicle abort trigger (AT) that includes sensor data qualification (SDQ). In this context, an AT is a hardware and software mechanism designed to detect the existence of a specific abort condition. Also, SDQ is an algorithmic approach used to identify sensor data suspected of being corrupt so that suspect data does not adversely affect an AT's detection capability. The FP and FN methodologies presented here were developed to support estimation of the probabilities of loss of crew and loss of mission for the Space Launch System (SLS) which is being developed by the National Aeronautics and Space Administration (NASA). The paper provides a brief overview of system health management as being an extension of control theory; and describes how ATs and the calculation of FP and FN probabilities relate to this theory. The discussion leads to a detailed presentation of the FP and FN methodology and an example showing how the FP and FN calculations are performed. This detailed presentation includes a methodology for calculating the change in FP and FN probabilities that result from including SDQ in the AT architecture. To avoid proprietary and sensitive data issues, the example incorporates a mixture of open literature and fictitious reliability data. Results presented in the paper demonstrate the effectiveness of the approach in providing quantitative estimates that bound the probability of a FP or FN abort determination.

  12. A "false positive" octreoscan in ileal Crohn's disease

    Institute of Scientific and Technical Information of China (English)

    Alberto Fernandez; Olga Tabuenca; Angeles Peteiro

    2008-01-01

    We present a case report of a patient with a suspicious ileal carcinoid turnout.Clinical examination as well as computer tomograghy (CT) scan suggested a tumour.Octeotride scan showed uptake in the same bowel loop reported as pathological in CT.The patient underwent surgery and biopsy which reported Crohn's disease (CD).The interest in the case is due to the fact that this is,to the best of our knowledge,the second report of Crohn's disease as a cause of false positive octeotride scan.Unfortunately,no somatostatin recptors could be found in the sample,so further studies should be performed.

  13. On the Low False Positive Probabilities of Kepler Planet Candidates

    CERN Document Server

    Morton, Timothy D

    2011-01-01

    We present a framework to conservatively estimate the probability that any particular planet-like transit signal observed by the Kepler mission is in fact a planet, prior to any ground-based follow-up efforts. We use Monte Carlo methods based on stellar population synthesis and Galactic structure models, and we provide empirical analytic fits to our results that may be applied to the as-yet-unconfirmed Kepler candidates. We find that the false positive probability for candidates that pass preliminary Kepler vetting procedures is generally 20% to < 2%, assuming a continuous power law for the planet mass function with index alpha = -1.5. Since Kepler will detect many more planetary signals than can be positively confirmed with ground-based follow-up efforts in the near term, these calculations will be crucial to using the ensemble of Kepler data to determine population characteristic s of planetary systems.

  14. 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.

  15. False positivity of gamma-glutamyl transpeptidase measurement in urine.

    Science.gov (United States)

    Crivellenti, Leandro Zuccolotto; Mesa, Javier Sousa; Meirelles, Adriana Érica Wilkes Burton; Borin Crivellenti, Sofia; Mireya, Edna Gomes; Canola, Julio Carlos; Hatayde, Mário Roberto; Santana, Aureo Evangelista; Dantas, Márcio; Silva, Gyl Eanes Barros

    2014-05-01

    Although enzymuria tends to be associated to renal injury, there are no studies that have evaluated the presence of the enzyme gamma-glutamyl transpeptidase (GGT) spectrophotometry in the urine using a non-nephrotoxic agent (Nerium oleander) in order to evaluate the possibility of false positive results. The urinary GGT/urinary creatinine concentration ratio (uGGT/uCr) of 10 healthy dogs was calculated and posteriorly confronted with data from clinical evaluation, hematological and serum biochemical profiles, creatinine clearance (CrC), urinalysis, urine protein/creatinine ratio (UPC), electrocardiogram, systemic blood pressure (SBP) and light and electron microscopy. The results for kidney histology, SBP, UPC and CrC were not significantly different in any of the time-points analyzed. However, uGGT/uCr was significantly higher when measured 4 hours and 24 hours after administration of N. oleander. The measurement of the urinary GGT enzyme, as performed in many studies, yielded false positive results in dogs poisoned by a non-nephrotoxic agent.

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

    Science.gov (United States)

    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

    2013-11-15

    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 related to differences in FIT sensitivity and specificity or to differences in prior CRC risk. Randomly selected, asymptomatic individuals were invited to undergo colonoscopy. Participants were asked to undergo one sample FIT and to complete a risk questionnaire. We identified patient characteristics associated with a false negative and false positive FIT results using logistic regression. We focused on statistically significant differences as well as on variables influencing the false positive or negative risk for which the odds ratio exceeded 1.25. Of the 1,426 screening participants, 1,112 (78%) completed FIT and the questionnaire; 101 (9.1%) had advanced neoplasia. 102 Individuals were FIT positive, 65 (64%) had a false negative FIT result and 66 (65%) a false positive FIT result. Participants at higher age and smokers had a significantly higher risk of a false negative FIT result. Males were at increased risk of a false positive result, so were smokers and regular NSAID users. FIT sensitivity was lower in females. Specificity was lower for males, smokers and regular NSAID users. FIT sensitivity was lower in women. FIT specificity was lower in males, smokers and regular NSAID users. Our results can be used for further evidence based individualization of screening strategies.

  17. 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.

  18. Pre-Spectroscopic False Positive Elimination of Kepler Planet Candidates

    CERN Document Server

    Batalha, N M; Gilliland, R L; Jenkins, J J; Caldwell, D A; Borucki, W J; Koch, D G; Lissauer, J J; Dunham, E W; Gautier, T N; Howell, S B; Latham, D W; Marcy, G W; Prsa, A

    2010-01-01

    Ten days of commissioning data (Quarter 0) and thirty-three days of science data (Quarter 1) yield instrumental flux timeseries of ~150,000 stars that were combed for transit events, termed Threshold Crossing Events (TCE), each having a total detection statistic above 7.1-sigma. TCE light curves are modeled as star+planet systems. Those returning a companion radius smaller than 2R_J are assigned a KOI (Kepler Object of Interest) 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 a being a planetary companion. This vetting using Kepler data is referred to as data validation. Herein, we describe the data validation metrics and graphics used to identify viable planet candidates amongst the KOIs. Light curve modeling tests for a) the difference in depth of the odd- versus even-numbered transits, b) evidence of ellipsoidal variations, and c) evidence of a secondary eclipse event at pha...

  19. Stanford type A aortic dissection with closed false lumen: Analysis of prognostic factors at initial CT or MRI

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Yohjiro; Sakamoto, Ichiro; Ogawa, Yohji; Sueyoshi, Eijun; Hayashi, Kuniaki; Takagi, Masatake [Nagasaki Univ. (Japan). School of Medicine; Narimatsu, Motoharu

    1997-08-01

    Nineteen patients with Stanford type A acute aortic dissection with closed false lumen were reviewed. In the follow-up examinations, ulcerlike projection (ULP) in the ascending aorta (AA) or aortic arch (AR) was identified in 8 of 19 patients. In 5 of these 8 patients, acute cardiac tamponade occurred and 3 of them died. In the other 11 patients, there was no mortality, and only one patient underwent elective surgery. The appearance of ULP in the AA/AR is considered an indication for urgent surgery because it is regarded as a precursor of lethal complications such as cardiac tamponade. The purpose of this study was to investigate predictors of the appearance of ULP in the AA/AR with early imagings (CT or MRI) before the appearance of ULP. The patients were divided into two groups: patients with ULP in the AA/AR (8 patients) and others (11 patients). Initial CT or MRI findings of the thoracic aorta were retrospectively statistically analyzed in each group. Three predictive factors were statistically significant for the appearance of ULP in the AA/AR (diameter of the AA{>=}5 cm, thickness of the false lumen of the AA{>=}1 cm, thickness of the false lumen of the AA{>=} that of the descending aorta). Close attention should be paid, if any of these 3 factors is observed at initial CT or MRI. (author)

  20. 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 is un...

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

    Science.gov (United States)

    Di, Li; Li, Yan

    2017-06-08

    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; PTB tended to induce false-positive results (OR 30.297; 95%CI 7.069-129.849; PTB (exclude tuberculous meningitis) (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.

  2. Right circumflex retro-oesophageal aortic arch with coarctation of a high-positioned right arch

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Kyung-Sik; Yong, Hwan Seok; Woo, Ok Hee; Kang, Eun-Young [Korea University Guro Hospital, Department of Radiology, Seoul (Korea); Lee, Joo-Won [Korea University Guro Hospital, Department of Paediatrics, Seoul (Korea)

    2007-06-15

    We present a rare case of right circumflex retro-oesophageal aortic arch with coarctation of a high-positioned right arch. A 7-month-old boy presented with a cardiac murmur. Cardiac situs was normal and there was no evidence of an intracardiac shunt or patent ductus arteriosus. MR aortography revealed a right aortic arch that was high-positioned, tortuous and narrowed. This right aortic arch crossed the midline behind the oesophagus and continued as a left-sided descending aorta. The left common carotid and subclavian arteries arose from a large branching vascular structure that derived from the top of the left-sided descending aorta. The right common carotid artery arose from the ascending aorta. The proximal portion of the right common carotid artery showed very severe stenosis and poststenotic dilatation. The right subclavian artery originated distal to the narrowed and tortuous segment of the aortic arch. (orig.)

  3. Astrophysical false positives in exoplanet transit surveys: why do we need bright stars ?

    CERN Document Server

    Santerne, A; Almenara, J -M; Lethuillier, A; Deleuil, M; Moutou, C

    2013-01-01

    Astrophysical false positives that mimic planetary transit are one of the main limitation to exoplanet transit surveys. In this proceeding, we review the issue of the false positive in transit survey and the possible complementary observations to constrain their presence. We also review the false-positive rate of both Kepler and CoRoT missions and present the basics of the planet-validation technique. Finally, we discuss the interest of observing bright stars, as PLATO 2.0 and TESS will do, in the context of the false positives. According to simulations with the Besan\\c{c}on galactic model, we find that PLATO 2.0 is expected to have less background false positives than Kepler, and thus an even lower false-positive rate.

  4. 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

    INTRODUCTION: There is an ongoing debate concerning possible disadvantages of mammography screening, one being the consequence of receiving a false positive test-result. It is argued that receiving a false positive answer may have short- and/or long-term adverse psychological effects on women, bu...

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

    DEFF Research Database (Denmark)

    Roman, Marta; Castells, Xavier; Hofvind, Solveig

    2016-01-01

    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 ...

  6. 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

    INTRODUCTION: Studies have shown that women with a false-positive result from mammography screening have an excess risk for breast cancer compared with women who only have negative results. We aimed to assess the excess risk of cancer after a false-positive result excluding cases of misclassifica...

  7. CT colonography with computer-aided detection: recognizing the causes of false-positive reader results.

    Science.gov (United States)

    Trilisky, Igor; Wroblewski, Kristen; Vannier, Michael W; Horne, John M; Dachman, Abraham H

    2014-01-01

    Computed tomography (CT) colonography is a screening modality used to detect colonic polyps before they progress to colorectal cancer. Computer-aided detection (CAD) is designed to decrease errors of detection by finding and displaying polyp candidates for evaluation by the reader. CT colonography CAD false-positive results are common and have numerous causes. The relative frequency of CAD false-positive results and their effect on reader performance on the basis of a 19-reader, 100-case trial shows that the vast majority of CAD false-positive results were dismissed by readers. Many CAD false-positive results are easily disregarded, including those that result from coarse mucosa, reconstruction, peristalsis, motion, streak artifacts, diverticulum, rectal tubes, and lipomas. CAD false-positive results caused by haustral folds, extracolonic candidates, diminutive lesions (reader false-positive results. Nondismissable CAD soft-tissue polyp candidates larger than 6 mm are another common cause of reader false-positive results that may lead to further evaluation with follow-up CT colonography or optical colonoscopy. Strategies for correctly evaluating CAD polyp candidates are important to avoid pitfalls from common sources of CAD false-positive results. ©RSNA, 2014.

  8. Endovascular treatment of false-aneurysm ten years after dacron patch aortoplasty for coarctation of the aortic isthmus. Report of a case.

    Science.gov (United States)

    Illuminati, Giulio; Pacilè, Maria Antonietta; Palumbo, Piergaspare; Salvatori, Filippo Maria; Vietri, Francesco

    2013-01-01

    False aneurysm degeneration is a known complication of patch aortoplasty for coarctation of the aortic isthmus. Open surgical treatment consists of prosthetic graft repair of the involved aorta, often requires circulatory arrest to achieve a safe proximal aortic control and perform proximal anastomosis, and finally is associated with substantial perioperative morbidity. Endografting of the diseased aorta is a valuable alternative to open repair, when feasible, with good short and long term results. We now report one more case of false aneurysm ten years after Dacron patch aortoplasty for isthmic coarctation in a 26-year-old woman, successfully treated by endovascular repair via the left common iliac artery, and a complete exclusion of the aneurysm at two year follow-up.

  9. A Case of Systemic Lupus Erythematosus Associated with False Positive VDRL and TPHA

    Directory of Open Access Journals (Sweden)

    Muzeyyen Gonul

    2008-09-01

    Full Text Available Systemic lupus erythematosus (SLE is a connective tissue disease characterized by vasculitis, which may involve multiple organs as well as the skin. Serologic tests for syphilis may be false positive in SLE. Although the false positivity of VDRL (Venereal Disease Research Laboratory is commonly seen, false positivity of TPHA (Treponema pallidum haemagglutination is a rare condition. We present a case of SLE with false positive VDRL and TPHA. A 26-year-old woman was admitted to our clinic with violaceous papules and plaques with whitish desquamation and erosions, and crusts on the face, arms and back. The histopathological examination of the skin biopsy supported the diagnosis of discoid lupus erythematosus. The diagnosis of SLE was based on the presence of photosensitivity and the detection of leukopenia, anemia and positivities of antinuclear antibody, anti DNA, and VDRL. In addition to these findings, TPHA was found to be positive, but the ELISA test for syphilis and FTA ABS Ig M were negative. The positivity of VDRL and TPHA were accepted as false positives. We would like to point out that the false positivity of TPHA, although more rarely encountered, as well as that of VDRL, may be observed in SLE patients.

  10. Consequences of a false-positive mammography result: drug consumption before and after screening.

    Science.gov (United States)

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

    2016-05-01

    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 of drug use for women with false-positive versus women with normal mammograms, before and after the event, using population-based registers, 1997-2006. The ratio of the ratios (RRR) assessed the impact. Results Before the test, 40.3% of women from the false-positive group versus 36.2% from the normal 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 mammograms already before the screening event, while the changes from before to after screening were similar for both groups. The results point to the importance of control for potential selection in studies of screening effects.

  11. 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...... 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...

  12. Experimental investigation of false positive errors in auditory species occurrence surveys

    Science.gov (United States)

    Miller, David A.W.; Weir, Linda A.; McClintock, Brett T.; Grant, Evan H. Campbell; Bailey, Larissa L.; Simons, Theodore R.

    2012-01-01

    False positive errors are a significant component of many ecological data sets, which in combination with false negative errors, can lead to severe biases in conclusions about ecological systems. We present results of a field experiment where observers recorded observations for known combinations of electronically broadcast calling anurans under conditions mimicking field surveys to determine species occurrence. Our objectives were to characterize false positive error probabilities for auditory methods based on a large number of observers, to determine if targeted instruction could be used to reduce false positive error rates, and to establish useful predictors of among-observer and among-species differences in error rates. We recruited 31 observers, ranging in abilities from novice to expert, that recorded detections for 12 species during 180 calling trials (66,960 total observations). All observers made multiple false positive errors and on average 8.1% of recorded detections in the experiment were false positive errors. Additional instruction had only minor effects on error rates. After instruction, false positive error probabilities decreased by 16% for treatment individuals compared to controls with broad confidence interval overlap of 0 (95% CI: -46 to 30%). This coincided with an increase in false negative errors due to the treatment (26%; -3 to 61%). Differences among observers in false positive and in false negative error rates were best predicted by scores from an online test and a self-assessment of observer ability completed prior to the field experiment. In contrast, years of experience conducting call surveys was a weak predictor of error rates. False positive errors were also more common for species that were played more frequently, but were not related to the dominant spectral frequency of the call. Our results corroborate other work that demonstrates false positives are a significant component of species occurrence data collected by auditory

  13. Evaluation of flow volume and flow patterns in the patent false lumen of chronic aortic dissections using velocity-encoded cine magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Toshihisa; Watanabe, Shigeru; Sakurada, Hideki; Ono, Katsuhiro; Urano, Miharu; Hijikata, Yasuyoshi; Saito, Isao; Masuda, Yoshiaki [Chiba Univ. (Japan). School of Medicine

    2000-10-01

    In 21 patients with chronic aortic dissections and proven patent false lumens, the flow volume and flow patterns in the patent false lumens was evaluated using velocity-encoded cine magnetic resonance imaging (VENC-MRI) and the relationship between the flow characteristics and aortic enlargement was retrospectively examined. Flow patterns in the false lumen were divided into 3 groups: pattern A with primarily antegrade flow (n=6), pattern R with primarily retrograde flow (n=3), and pattern B with bidirectional flow (n=12). In group A, the rate of flow volume in the false lumen compared to the total flow volume in true and false lumens (%TFV) and the average rate of enlargement of the maximum diameter of the dissected aorta per year ({delta}D) were significantly greater than in groups R and B (%TFV: 74.1{+-}0.07 vs 15.2{+-}0.03 vs 11.8{+-}0.04, p<0.01; {delta}D: 3.62{+-}0.82 vs 0 vs 0.58{+-}0.15 mm/year, p<0.05, respectively). There was a significant correlation between %TFV and {delta}D (r=0.79, p<0.0001). Evaluation of flow volume and flow patterns in the patent false lumen using VENC-MRI may be useful for predicting enlargement of the dissected aorta. (author)

  14. False-positive interferences of common urine drug screen immunoassays: a review.

    Science.gov (United States)

    Saitman, Alec; Park, Hyung-Doo; Fitzgerald, Robert L

    2014-09-01

    Urine drug screen (UDS) immunoassays are a quick and inexpensive method for determining the presence of drugs of abuse. Many cross-reactivities exist with other analytes, potentially causing a false-positive result in an initial drug screen. Knowledge of these potential interferents is important in determining a course of action for patient care. We present an inclusive review of analytes causing false-positive interferences with drugs-of-abuse UDS immunoassays, which covers the literature from the year 2000 to present. English language articles were searched via the SciFinder platform with the strings 'false positive [drug] urine' yielding 173 articles. These articles were then carefully analyzed and condensed to 62 that included data on causes of false-positive results. The discussion is separated into six sections by drug class with a corresponding table of cross-reacting compounds for quick reference. False-positive results were described for amphetamines, opiates, benzodiazepines, cannabinoids, tricyclic antidepressants, phencyclidine, lysergic acid diethylamide and barbiturates. These false-positive results support the generally accepted practice that immunoassay positive results are considered presumptive until confirmed by a second independent chemical technique.

  15. Frequency of False Positive Amphetamine Screens due to Bupropion Using the Syva Emit II Immunoassay

    OpenAIRE

    Casey, Erica R; Scott, Mitchell G.; Tang, Schirin; Mullins, Michael E.

    2010-01-01

    Bupropion is a commonly prescribed, monocyclic antidepressant often used as an aid for smoking cessation. Several case reports have described false positive amphetamine urine drug screens (UDS) associated with bupropion. We sought to determine whether false positive amphetamine UDS due to the use of bupropion would be a frequent occurrence. We conducted an IRB-approved, retrospective chart review of all emergency department patients who underwent UDS between 1 January 2006 and 31 July 2007. A...

  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. 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.

  18. GeneWaltz--A new method for reducing the false positives of gene finding

    Directory of Open Access Journals (Sweden)

    Misawa Kazuharu

    2010-09-01

    Full Text Available Abstract Background Identifying protein-coding regions in genomic sequences is an essential step in genome analysis. It is well known that the proportion of false positives among genes predicted by current methods is high, especially when the exons are short. These false positives are problematic because they waste time and resources of experimental studies. Methods We developed GeneWaltz, a new filtering method that reduces the risk of false positives in gene finding. GeneWaltz utilizes a codon-to-codon substitution matrix that was constructed by comparing protein-coding regions from orthologous gene pairs between mouse and human genomes. Using this matrix, a scoring scheme was developed; it assigned higher scores to coding regions and lower scores to non-coding regions. The regions with high scores were considered candidate coding regions. One-dimensional Karlin-Altschul statistics was used to test the significance of the coding regions identified by GeneWaltz. Results The proportion of false positives among genes predicted by GENSCAN and Twinscan were high, especially when the exons were short. GeneWaltz significantly reduced the ratio of false positives to all positives predicted by GENSCAN and Twinscan, especially when the exons were short. Conclusions GeneWaltz will be helpful in experimental genomic studies. GeneWaltz binaries and the matrix are available online at http://en.sourceforge.jp/projects/genewaltz/.

  19. False Positive Results of Carpal tunnel syndrome in Electro Diagnosis Tests

    Directory of Open Access Journals (Sweden)

    MR Emad

    2010-07-01

    Full Text Available Introduction & Objective: Carpal tunnel syndrome is identified due to compression of median nerve at wrist and develops symptoms such as wrist pain, paresthesia, numbness and the dysfunction of the hands. The gold standard to diagnose, determining prognosis and planning treatment process based on the severity of nerve involvement are electro-diagnosis tests. The purpose of this study was to specify the least and the most false positive results in common electro-diagnosis tests. Materials & Methods: This descriptive study was conducted at Shiraz University of Medical Sciences in 2009. Twelve different electro-diagnosis tests on fifty-five normal cases (110 available hands, which never had experienced the symptoms of this syndrome, were carried out. The data was statistically analyzed by SPSS software, using T test and Cochran's `Q. Results: There were false positive results in many of the performed tests. The most false-positive result was in- difference between median and ulnar motor distal latencies- test with the rate of 15.5% and the lowest false positive result was in- difference between median and ulnar sensory distal latencies of digit 4- test with the rate of 0%. Conclusion: This study revealed that tests which evaluate the differences between median and ulnar or radial nerves sensory distal latency (in the finger 4 and or 1, respectively, had less false positive results, and are more reliable in suspected cases of this syndrome. Also by using several different electro-diagnostic tests, rapid and efficient diagnosis can be achieved.

  20. Receipt of a false positive test result during routine screening for ovarian cancer: a teachable moment?

    Science.gov (United States)

    Floyd, Andrea; Steffens, Rachel F; Pavlik, Edward; Andrykowski, Michael A

    2011-03-01

    The term "teachable moment" (TM) has been used to describe a life transition or event which motivates an individual to change a behavior or presents an opportunity to intervene to prompt behavior change. We examined whether receipt of a false positive ovarian cancer (OC) screening result may represent a TM. 403 women participating in an OC screening program completed questionnaires assessing demographic, clinical, behavioral, and psychosocial information. The TM was operationalized as expressed interest in receiving health-related information. We hypothesized that among women receiving a false positive screening test result, those women who had experienced greater personal perceived risk for OC as well as distress would be more interested in receiving health-related information than women receiving a normal result. Analyses revealed that women receiving a false positive screening result were less interested in receiving health-related information than women receiving a normal screening result. For women receiving a false positive result, expressed interest in receipt of health-related information was only modestly related to distress and related even less to perceptions of OC risk. Our data do not support viewing a false positive OC screening result as a TM. Potential explanations for the current findings as well as recommendations for future research investigating the TM are discussed.

  1. 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.

  2. 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.

  3. False positive malaria rapid diagnostic test in returning traveler with typhoid fever.

    Science.gov (United States)

    Meatherall, Bonnie; Preston, Keith; Pillai, Dylan R

    2014-07-09

    Rapid diagnostic tests play a pivotal role in the early diagnosis of malaria where microscopy or polymerase chain reaction are not immediately available. We report the case of a 39 year old traveler to Canada who presented with fever, headache, and abdominal pain after visiting friends and relatives in India. While in India, the individual was not ill and had no signs or symptoms of malaria. Laboratory testing upon his return to Canada identified a false positive malaria rapid diagnostic (BinaxNOW® malaria) result for P. falciparum with coincident Salmonella Typhi bacteraemia without rheumatoid or autoimmune factors. Rapid diagnostic test false positivity for malaria coincided with the presence or absence of Salmonella Typhi in the blood. Clinicians should be aware that Salmonella Typhi infection may result in a false positive malaria rapid diagnostic test. The mechanism of this cross-reactivity is not clear.

  4. Case Reports of Aripiprazole Causing False-Positive Urine Amphetamine Drug Screens in Children.

    Science.gov (United States)

    Kaplan, Justin; Shah, Pooja; Faley, Brian; Siegel, Mark E

    2015-12-01

    Urine drug screens (UDSs) are used to identify the presence of certain medications. One limitation of UDSs is the potential for false-positive results caused by cross-reactivity with other substances. Amphetamines have an extensive list of cross-reacting medications. The literature contains reports of false-positive amphetamine UDSs with multiple antidepressants and antipsychotics. We present 2 cases of presumed false-positive UDSs for amphetamines after ingestion of aripiprazole. Case 1 was a 16-month-old girl who accidently ingested 15 to 45 mg of aripiprazole. She was lethargic and ataxic at home with 1 episode of vomiting containing no identifiable tablets. She remained sluggish with periods of irritability and was admitted for observation. UDS on 2 consecutive days came back positive for amphetamines. Case 2 was of a 20-month-old girl who was brought into the hospital after accidental ingestion of an unknown quantity of her father's medications which included aripiprazole. UDS on the first day of admission came back positive only for amphetamines. Confirmatory testing with gas chromatography-mass spectrometry (GC-MS) on the blood and urine samples were also performed for both patients on presentation to detect amphetamines and were subsequently negative. Both patients returned to baseline and were discharged from the hospital. To our knowledge, these cases represent the first reports of false-positive amphetamine urine drug tests with aripiprazole. In both cases, aripiprazole was the drug with the highest likelihood of causing the positive amphetamine screen. The implications of these false-positives include the possibility of unnecessary treatment and monitoring of patients.

  5. Research: Association of Low-Amplitude QRSs with False-Positive Asystole Alarms.

    Science.gov (United States)

    Pelter, Michele M; Fidler, Richard; Hu, Xiao

    2016-01-01

    Although electrocardiographic monitoring is valuable for continuous surveillance of intensive care unit (ICU) patients, false alarms are common and have been cited as a cause of alarm fatigue. ANSI/AAMI EC12:2002 states that electrocardiograms (ECGs) should not detect a QRS if the waveform is less than 0.15 mV (1.5 mm) for adult patients, in order to avoid mislabeling P waves or baseline noise as QRSs during complete heart block or asystole. However, ECG software algorithms often use more conservative QRS thresholds, which may result in false-positive asystole alarms in patients with low-amplitude QRS complexes. To 1) assess the frequency of low QRS amplitude in a group of ICU patients with one or more false-positive asystole alarms and 2) determine whether low-amplitude QRSs are associated with false-positive asystole alarms during continuous ECG monitoring. Hospital-acquired standard 12-lead ECGs were examined in a group of 82 ICU patients who had one or more false-positive asystole alarms. Low QRS amplitude was defined as a unidirectional (only positive or negative) QRS of less than 5 mm in two of four leads (I, II, III, and V1). Low-amplitude QRSs were present in 45 of 82 (55%) patients. The presence of low-amplitude QRSs did not differ according to age, sex, or race. Patients treated in the cardiac ICU had the highest proportion of low-amplitude QRSs. An equivalent proportion of patients had false-positive asystole alarms by group (no low-amplitude QRSs 95% vs. low-amplitude QRSs 87%; P = 0.229). Eight patients (10%) had both true- and false-positive asystole alarms (two [5%] with no low-amplitude QRSs and six [13%] with low-amplitude QRSs; P = 0.229). Low-amplitude QRS, as assessed from hospital 12-lead ECGs, occurs frequently and is more common in cardiac ICU patients. However, this ECG feature did not identify patients with false-positive asystole alarms during continuous ECG monitoring.

  6. False positive diagnosis on (131)iodine whole-body scintigraphy of differentiated thyroid cancers.

    Science.gov (United States)

    Triggiani, Vincenzo; Giagulli, Vito Angelo; Iovino, Michele; De Pergola, Giovanni; Licchelli, Brunella; Varraso, Antonio; Dicembrino, Franca; Valle, Guido; Guastamacchia, Edoardo

    2016-09-01

    (131)Iodine is used both to ablate any residual thyroid tissue or metastatic disease and to obtain whole-body diagnostic images after total thyroidectomy for differentiated thyroid cancer (DTC). Even though whole-body scan is highly accurate in showing thyroid residues as well as metastases of DTC, false positive results can be found, possibly leading to diagnostic errors and unnecessary treatments. This paper reviews the physiological and pathological processes involved as well as the strategy to recognize and rule out false positive radioiodine images.

  7. 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...

  8. The rapid plasma reagin (circle) card test in biological false positive and leprosy sera

    Science.gov (United States)

    Garner, M. F.; Backhouse, J. L.

    1972-01-01

    The rapid plasma reagin (RPR) circle card and the Venereal Disease Reference Laboratory (VDRL) slide test results were compared on a group of sera known to show biological false positive (BFP) reactions to reagin detection tests for syphilis. The RPR test was more specific than the VDRL test on the sera selected, ie, it gave fewer false positive results than the VDRL test. However, in a group of presumed normal sera, the RPR test gave BFP reactions while the VDRL test gave none. The RPR test gave fewer BFP reactions than the VDRL test in 269 sera from patients with lepromatous leprosy. PMID:5086221

  9. 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.

  10. Does replication groups scoring reduce false positive rate in SNP interaction discovery?

    Directory of Open Access Journals (Sweden)

    Demsar Janez

    2010-01-01

    Full Text Available Abstract Background Computational methods that infer single nucleotide polymorphism (SNP interactions from phenotype data may uncover new biological mechanisms in non-Mendelian diseases. However, practical aspects of such analysis face many problems. Present experimental studies typically use SNP arrays with hundreds of thousands of SNPs but record only hundreds of samples. Candidate SNP pairs inferred by interaction analysis may include a high proportion of false positives. Recently, Gayan et al. (2008 proposed to reduce the number of false positives by combining results of interaction analysis performed on subsets of data (replication groups, rather than analyzing the entire data set directly. If performing as hypothesized, replication groups scoring could improve interaction analysis and also any type of feature ranking and selection procedure in systems biology. Because Gayan et al. do not compare their approach to the standard interaction analysis techniques, we here investigate if replication groups indeed reduce the number of reported false positive interactions. Results A set of simulated and false interaction-imputed experimental SNP data sets were used to compare the inference of SNP-SNP interactions by means of replication groups to the standard approach where the entire data set was directly used to score all candidate SNP pairs. In all our experiments, the inference of interactions from the entire data set (e.g. without using the replication groups reported fewer false positives. Conclusions With respect to the direct scoring approach the utility of replication groups does not reduce false positive rates, and may, depending on the data set, often perform worse.

  11. False memory for positive and negative life events. The role of mental imagery

    Directory of Open Access Journals (Sweden)

    Mairean, C.

    2015-07-01

    Full Text Available A false memory appears when a person recalls memories of events that did not actually happen to him or her. The present study focused on situational and personal determinants of spontaneous false memories. Specifically, we aimed to investigate the role of emotional valence of an event, as well as the individual differences in mental imagery in evocation false memory. Three videos in which related details were not shown but were presented during a recognition task were used to induce spontaneous false memories. The three videos are different in terms of valence, reflecting positive, negative and neutral events. A scale for measuring mental imagery was also used. A sample of 132 participants completed the study. The results showed that the positive event lead to a higher level of false memory than the negative event. Moreover, the participants differ in their susceptibility to false memories based on the level of imagery, but the interaction between the emotional valence of the event and mental imagery is not significant. The results are discussed from the perspective of their legal and clinical implications.

  12. 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

  13. Ruptured aortic aneurysm due to Mycobacterium bovis BCG with a delayed bacteriological diagnosis due to false negative result of the MPB 64 immunochromatographic assay.

    Science.gov (United States)

    Simar, J; Belkhir, L; Tombal, B; André, E

    2017-01-26

    Adjuvant therapy with bacillus Calmette-Guerin (BCG), a live attenuated strain of Mycobacterium bovis, has become the treatment of choice for low-risk superficial bladder carcinoma following transurethral resection of the bladder. Complications following vesical BCG instillations are uncommon but, in some cases, severe side-effects can occur such as sepsis or mycotic aneurysm. Besides usual laboratory techniques used for the diagnosis of Mycobacterium tuberculosis complex (MTBC) infections (smear microscopy and cultures), commercial immunochromatographic assays detecting MBP64, a 24 kDa M. tuberculosis complex-specific secretory protein, can rapidly distinguish MTBC and non-tuberculosis mycobacteria (NTM). MPB64 is found in M. tuberculosis, M. bovis and some but not all substrains of M.bovis BCG. Therefore, these immunochromatographic tests can lead to false negative results and delayed bacteriological diagnosis depending on the presence or absence of MPB64 protein in BCG substrains used for intravesical therapy. We report the case of a 78-year-old male patient who was admitted to the hospital because of a 1-month history of unexplained fever, thrill, weight-loss and general malaise. His past medical history was marked by a non-muscle-invasive bladder carcinoma treated by transurethral resection followed by BCG instillations (Oncotice, Merck, USA). The patient was initially treated for a urinary tract infection but as fever persists after 72 h of antibiotherapy, urinary tract ultrasound was performed and revealed a large abdominal aortic aneurysm confirmed by computed tomography. Surgery was performed after multidisciplinary discussion. Direct smear of perioperative samples revealed acid-fast bacilli and both solid and liquid cultures were massively positive. Rapid identification of the positive mycobacterial culture was performed using an immunochromatographic assay based on the detection of the Mycobacterium tuberculosis MPB 64 antigen. The result was negative

  14. EMPLOYING TOPOGRAPHICAL HEIGHT MAP IN COLONIC POLYP MEASUREMENT AND FALSE POSITIVE REDUCTION.

    Science.gov (United States)

    Yao, Jianhua; Li, Jiang; Summers, Ronald M

    2009-01-01

    CT Colonography (CTC) is an emerging minimally invasive technique for screening and diagnosing colon cancers. Computer Aided Detection (CAD) techniques can increase sensitivity and reduce false positives. Inspired by the way radiologists detect polyps via 3D virtual fly-through in CTC, we borrowed the idea from geographic information systems to employ topographical height map in colonic polyp measurement and false positive reduction. After a curvature based filtering and a 3D CT feature classifier, a height map is computed for each detection using a ray-casting algorithm. We design a concentric index to characterize the concentric pattern in polyp height map based on the fact that polyps are protrusions from the colon wall and round in shape. The height map is optimized through a multi-scale spiral spherical search to maximize the concentric index. We derive several topographic features from the map and compute texture features based on wavelet decomposition. We then send the features to a committee of support vector machines for classification. We have trained our method on 394 patients (71 polyps) and tested it on 792 patients (226 polyps). Results showed that we can achieve 95% sensitivity at 2.4 false positives per patient and the height map features can reduce false positives by more than 50%. We compute the polyp height and width measurements and correlate them with manual measurements. The Pearson correlations are 0.74 (p=0.11) and 0.75 (p=0.17) for height and width, respectively.

  15. 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 limited...

  16. Predicting the risk of a false-positive test for women following a mammography screening programme

    DEFF Research Database (Denmark)

    Njor, Sisse Helle; Olsen, Anne Helene; Schwartz, Walter

    2007-01-01

    OBJECTIVES: The objectives of this study was to provide a simple estimate of the cumulative risk of a false-positive test for women participating in mammography screening. To test the method, we used data from two well-established, organized mammography screening programmes offering biennial...... be calculated in a simple way relatively early after the start of a mammography screening programme....

  17. Factors Associated With False-Positive Emergency Medical Services Triage for Percutaneous Coronary Intervention

    Directory of Open Access Journals (Sweden)

    Yamamoto Swan, Pamela

    2009-11-01

    Full Text Available Background: In 2005, Orange County California Emergency Medical Services (EMS initiated a field 12-lead program to minimize time to emergency percutaneous coronary intervention (PCI for field-identified acute myocardial infarction (MI. As the program matured, “false-positive” (defined as no PCI or coronary artery occlusion upon PCI field MI activations have been identified as a problem for the program.Objectives: To identify potentially correctable factors associated with false-positive EMS triage to PCI centers.Methods: This was a retrospective, outcome study of EMS 12-lead cases from February 2006 to June 2007. The study system exclusively used cardiac monitor internal interpretation algorithms indicating an acute myocardial infarction as the basis for triage. Indicators and variables were defined prior to the study. Data, including outcome, was from the Orange County EMS database, which included copies of 12-lead ECGs used for field triage. Negative odds ratios (OR of less than 1.0 for positive PCI were the statistical measure of interest.Results: Five hundred forty-eight patients were triaged from the field for PCI. We excluded 19 cases from the study because of death prior to PCI, refusal of PCI, and co-morbid illness (sepsis, altered consciousness that precluded PCI. Three hundred ninety-three (74.3% patients had PCI with significant coronary lesions found. False-positive field triages were associated with underlying cardiac rhythm of sinus tachycardia [OR = 0.38 (95% CI 0.23, 0.62]; atrial fibrillation [OR = 0.43 (95% CI = 0.20, 0.94]; an ECG lead not recorded [OR = 0.39 (95% CI = 0.20, 0.76]; poor ECG baseline [OR = 0.59 (95% CI = 0.25, 1.37]; One of three brands of monitors used in the field [OR = 0.35 (95% CI = 0.21, 0.59]; and female gender [OR = 0.50 (95% CI = 0.34, 0.75]. Age was not associated with false-positive triage as determined by ordinal regression (p=1.00.Conclusion: For the urban-suburban EMS field 12-lead program

  18. Copy-number variation and false positive prenatal aneuploidy screening results.

    Science.gov (United States)

    Snyder, Matthew W; Simmons, LaVone E; Kitzman, Jacob O; Coe, Bradley P; Henson, Jessica M; Daza, Riza M; Eichler, Evan E; Shendure, Jay; Gammill, Hilary S

    2015-04-23

    Investigations of noninvasive prenatal screening for aneuploidy by analysis of circulating cell-free DNA (cfDNA) have shown high sensitivity and specificity in both high-risk and low-risk cohorts. However, the overall low incidence of aneuploidy limits the positive predictive value of these tests. Currently, the causes of false positive results are poorly understood. We investigated four pregnancies with discordant prenatal test results and found in two cases that maternal duplications on chromosome 18 were the likely cause of the discordant results. Modeling based on population-level copy-number variation supports the possibility that some false positive results of noninvasive prenatal screening may be attributable to large maternal copy-number variants. (Funded by the National Institutes of Health and others.).

  19. Risk of Breast Cancer in Women with False-Positive Results according to Mammographic Features.

    Science.gov (United States)

    Castells, Xavier; Torá-Rocamora, Isabel; Posso, Margarita; Román, Marta; Vernet-Tomas, Maria; Rodríguez-Arana, Ana; Domingo, Laia; Vidal, Carmen; Baré, Marisa; Ferrer, Joana; Quintana, María Jesús; Sánchez, Mar; Natal, Carmen; Espinàs, Josep A; Saladié, Francina; Sala, María

    2016-08-01

    Purpose To assess the risk of breast cancer in women with false-positive screening results according to radiologic classification of mammographic features. Materials and Methods Review board approval was obtained, with waiver of informed consent. This retrospective cohort study included 521 200 women aged 50-69 years who underwent screening as part of the Spanish Breast Cancer Screening Program between 1994 and 2010 and who were observed until December 2012. Cox proportional hazards regression analysis was used to estimate the age-adjusted hazard ratio (HR) of breast cancer and the 95% confidence interval (CI) in women with false-positive mammograms as compared with women with negative mammograms. Separate models were adjusted for screen-detected and interval cancers and for screen-film and digital mammography. Time without a breast cancer diagnosis was plotted by using Kaplan-Meier curves. Results When compared with women with negative mammograms, the age-adjusted HR of cancer in women with false-positive results was 1.84 (95% CI: 1.73, 1.95; P < .001). The risk was higher in women who had calcifications, whether they were (HR, 2.73; 95% CI: 2.28, 3.28; P < .001) or were not (HR, 2.24; 95% CI: 2.02, 2.48; P < .001) associated with masses. Women in whom mammographic features showed changes in subsequent false-positive results were those who had the highest risk (HR, 9.13; 95% CI: 8.28, 10.07; P < .001). Conclusion Women with false-positive results had an increased risk of breast cancer, particularly women who had calcifications at mammography. Women who had more than one examination with false-positive findings and in whom the mammographic features changed over time had a highly increased risk of breast cancer. Previous mammographic features might yield useful information for further risk-prediction models and personalized follow-up screening protocols. (©) RSNA, 2016 Online supplemental material is available for this article.

  20. Herbal medicine and false-positive results on lymphocyte transformation test.

    Science.gov (United States)

    Mantani, Naoki; Sakai, Shinya; Kogure, Toshiaki; Goto, Hirozo; Shibahara, Naotoshi; Kita, Toshiaki; Shimada, Yutaka; Terasawa, Katsutoshi

    2002-06-01

    In vitro mitogenic activity of 16 herbs and 3 Kampo (herbal medicine) formulae have been reported in experimental studies. It is not known how many herbs and Kampo formulae in total have mitogenic activity. Lymphocyte transformation test (LTT) is generally utilized to diagnose drug-induced liver injury. In LTT, mitogenic activity is assessed by measuring 3H-thymidine incorporation. The objective of the present study was to determine which herbs and which Kampo formulae caused false-positivity on LTT. We examined 2496 summaries of all admission records from 1979 to 1999 in our department. We selected patients in whom liver injuries were diagnosed as definitely unrelated to Kampo medication. In these patients, LTT was performed for some herbs contained in the suspect Kampo medicines, resulting in positive LTT for 17 herbs: Evodiae Fructus (Goshuyu), Zizyphi Fructus (Taiso), Ginseng Radix (Ninjin), Zingiberis Rhizoma (Shokyo), Hoelen (Bukuryo), Aconiti Tuber (Bushi), Angelicae Radix (Toki), Cnidii Rhizoma (Senkyu), Rehmanniae Radix (Jio), Ephedrae Herba (Mao), Anemarrhenae Rhizoma (Chimo), Cinnamomi Cortex (Keihi), Bupleuri Radix (Saiko), Artemisiae Capillari Spica (Inchinko), Persicae Semen (Tonin), Moutan Cortex (Botanpi) and Paeoniae Radix (Shakuyaku). These results were considered false-positive, because the results were observed in the "definitely unrelated" patients. Mitogenic activity inherent to some herbs and Kampo formulae may sometimes cause false-positivity on LTT in clinical situations. These examples suggest that LTT for Kampo formulae may be unreliable as a diagnostic method for drug-induced liver injury.

  1. 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

  2. High false-positive rate of questionnaire-based restless legs syndrome diagnosis in multiple sclerosis.

    Science.gov (United States)

    Mery, V; Kimoff, R J; Suarez, I; Benedetti, A; Kaminska, M; Robinson, A; Lapierre, Y; Bar-Or, A; Trojan, D A

    2015-07-01

    Restless legs syndrome (RLS) is diagnosed by self-reported symptoms. Multiple sclerosis (MS) patients have disease-related symptoms which could mimic RLS. This study assessed the: (1) false-positive rate for questionnaire-based RLS diagnosis in MS patients and (2) utility of periodic leg movements during wakefulness (PLMW) on overnight polysomnography (PSG) in identifying true-positive RLS patients. Ambulatory MS patients without known sleep disorders were recruited. Subjects completed the International RLS Study Group (IRLSG) diagnostic questionnaire (IRLDQ) and underwent full overnight PSG. IRLDQ-positive patients underwent clinical evaluation to confirm the diagnosis and completed the RLS severity scale (IRLS). Seventy-one MS patients (mean age 46.8 ± 10.4 years) were evaluated. Thirty-eight had a positive IRLDQ. RLS diagnosis was confirmed in 22, yielding a false-positive rate of 42% [95% confidence interval (CI) 26-59%], predominantly attributable to paresthesiae (n = 7), and cramps and/or muscle spasms (n = 4). IRLS scores were not significantly different between subjects with confirmed and nonconfirmed RLS. The PLMW index was significantly higher in patients with confirmed RLS (55.4 ± 41.9 vs. 29.7 ± 18.8, p = 0.03). The sensitivity of a PLMW index >70/h for true-positive IRLDQ was 8/22 = 36%, 95% CI: 17.2-59.3, and the specificity was 16/16 = 100%, 95% CI: 79.4-100. MS patients have a high false-positive rate of RLS diagnosis using a standardized questionnaire largely attributable to MS-related sensorimotor symptoms. While detailed clinical evaluation is essential for confirming RLS diagnosis, the PLMW index may provide useful adjunctive information. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. False Positives and Referral Bias: Content for a Quantitative Literacy Course

    Directory of Open Access Journals (Sweden)

    Stuart Boersma

    2008-07-01

    Full Text Available An extended study of accuracy in medical screening is presented as a useful application to increase students’ quantitative reasoning skills. Two detailed examples are presented. The first explores the frequency of obtaining false positive results from a medical screening tool while the second examines the issue of referral bias and its effect on the apparent sensitivity and specificity of the screening tool. Results from student assessments indicate that the activity increases one’s ability to define terms such as “false positive” and “false negative” and increases one’s ability to read and compute with information obtained from a two-way table. Teacher assessment results indicate that the activity is challenging and could be used in existing high school or college classrooms. Additionally, links to a student activity, instructor notes, and Excel calculation tool are provided.

  4. Doxylamine toxicity: seizure, rhabdomyolysis and false positive urine drug screen for methadone.

    Science.gov (United States)

    Syed, Husnain; Som, Sumit; Khan, Nazia; Faltas, Wael

    2009-01-01

    The present report highlights the possible adverse effects of doxylamine, a common over the counter sleep aid. Doxylamine is an antihistamine that at toxic doses can cause anticholinergic effects, including seizures, rhabdomyolysis and death. The following case describes a patient with doxylamine toxicity who presented with seizure and confusion. Our patient was managed symptomatically, and remained otherwise stable throughout his hospitalisation. This case is atypical in terms of a delayed rhabdomyolysis and a false positive urine drug screen test for methadone. There is evidence that doxylamine at toxic levels can lead to false positives for methadone and phencyclidine testing using immunoassay-based urine drug screen kits. Urine drug screen testing on patients who are hospitalised is typically performed using immunoassays. However, in certain cases confirmatory secondary testing may be required. Doxylamine is prone to abuse and knowledge of the clinical presentation of its toxicity and the management of acute overdose can be life-saving.

  5. Chromosomes Emission of Planet Candidate Host Stars: A Way to Identify False Positives

    Science.gov (United States)

    Karoff, Christoffer; Albrecht, Simon; Bonanno, Alfio; Faurschou Knudsen, Mads

    2016-10-01

    It has been hypothesized that the presence of closely orbiting giant planets is associated with enhanced chromospheric emission of their host stars. The main cause for such a relation would likely be enhanced dynamo action induced by the planet. We present measurements of chromospheric emission in 234 planet candidate systems from the Kepler mission. This ensemble includes 37 systems with giant-planet candidates, which show a clear emission enhancement. The enhancement, however, disappears when systems that are also identified as eclipsing binary candidates are removed from the ensemble. This suggests that a large fraction of the giant-planet candidate systems with chromospheric emission stronger than the Sun are not giant-planet systems, but false positives. Such false-positive systems could be tidally interacting binaries with strong chromospheric emission. This hypothesis is supported by an analysis of 188 eclipsing binary candidates that show increasing chromospheric emission as function of decreasing orbital period.

  6. Chromospheric emission of planet candidate systems - a way to identify false positives

    CERN Document Server

    Karoff, Christoffer; Boxano, Alfio; Knudsen, Mads Faurschou

    2016-01-01

    It has been hypothesized that the presence of closely orbiting giant planets is associated with enhanced chromospheric emission of their host stars. The main cause for such a relation would likely be enhanced dynamo action induced by the planet. We present measurements of chromospheric emission in 234 planet candidate systems from the Kepler mission. This ensemble includes 37 systems with giant planet candidates, which show a clear emission enhancement. The enhancement, however, disappears when systems which are also identified as eclipsing binary candidates are removed from the ensemble. This suggests that a large fraction of the giant planet candidate systems with chromospheric emission stronger than the Sun are not giant planet system, but false positives. Such false-positive systems could be tidally interacting binaries with strong chromospheric emission. This hypotesis is supported by an analysis of 188 eclipsing binary candidates that show increasing chromospheric emission as function of decreasing orbi...

  7. 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

    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...... is only recognized (1) by a negative muscle tissue control that does not harbor the protein to be examined (fx. from knockout mouse) or (2) by use of a nonsense rabbit antibody that has been prepared in the same way as the antibody of interest. However, many muscle immuno(cyto/histo)chemical studies only...... 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...

  8. Frequency of false positive amphetamine screens due to bupropion using the Syva EMIT II immunoassay.

    Science.gov (United States)

    Casey, Erica R; Scott, Mitchell G; Tang, Schirin; Mullins, Michael E

    2011-06-01

    Bupropion is a commonly prescribed, monocyclic antidepressant often used as an aid for smoking cessation. Several case reports have described false positive amphetamine urine drug screens (UDS) associated with bupropion. We sought to determine whether false positive amphetamine UDS due to the use of bupropion would be a frequent occurrence. We conducted an IRB-approved, retrospective chart review of all emergency department patients who underwent UDS between 1 January 2006 and 31 July 2007. All urine samples were screened using Syva EMIT II Plus immunoassay reagents. All positive screens underwent confirmation by gas chromatography (GC). We reviewed the records of patients with positive amphetamine UDS. We documented prescription use of bupropion, other antidepressants, stimulants, antipsychotics, and anti-hypertensives. We recorded evidence of polysubstance abuse (PSA) as patients who had had a documented diagnosis or laboratory evidence of abuse of at least two substances (drugs or ethanol). Of 10,011 urine drug screens, 362 (3.6%) were positive for amphetamine. GC confirmed amphetamines in 234 (65%), but failed to confirm in 128 (35%). Among the 234 confirmed, records reflected use of bupropion in three (1.3%), other antidepressants in 38 (16%), antipsychotics in 17 (8%), and amphetamine in 50 (21%). Records indicated evidence of PSA in 55 (24%). Among the 128 which failed to confirm, records reflected prescription use of bupropion in 53 (41%). None whose drug screen failed to confirm had evidence of PSA. Therapeutic use of bupropion appears to be the most frequent cause of false positive urine drug screens for amphetamines in our population.

  9. "Does replication groups scoring reduce false positive rate in SNP interaction discovery?: Response"

    Directory of Open Access Journals (Sweden)

    González-Pérez Antonio

    2010-06-01

    Full Text Available Abstract A response to Toplak et al: Does replication groups scoring reduce false positive rate in SNP interaction discovery? BMC Genomics 2010, 11:58. Background The genomewide evaluation of genetic epistasis is a computationally demanding task, and a current challenge in Genetics. HFCC (Hypothesis-Free Clinical Cloning is one of the methods that have been suggested for genomewide epistasis analysis. In order to perform an exhaustive search of epistasis, HFCC has implemented several tools and data filters, such as the use of multiple replication groups, and direction of effect and control filters. A recent article has claimed that the use of multiple replication groups (as implemented in HFCC does not reduce the false positive rate, and we hereby try to clarify these issues. Results/Discussion HFCC uses, as an analysis strategy, the possibility of replicating findings in multiple replication groups, in order to select a liberal subset of preliminary results that are above a statistical criterion and consistent in direction of effect. We show that the use of replication groups and the direction filter reduces the false positive rate of a study, although at the expense of lowering the overall power of the study. A post-hoc analysis of these selected signals in the combined sample could then be performed to select the most promising results. Conclusion Replication of results in independent samples is generally used in scientific studies to establish credibility in a finding. Nonetheless, the combined analysis of several datasets is known to be a preferable and more powerful strategy for the selection of top signals. HFCC is a flexible and complete analysis tool, and one of its analysis options combines these two strategies: A preliminary multiple replication group analysis to eliminate inconsistent false positive results, and a post-hoc combined-group analysis to select the top signals.

  10. "Does replication groups scoring reduce false positive rate in SNP interaction discovery?: Response"

    Science.gov (United States)

    2010-01-01

    A response to Toplak et al: Does replication groups scoring reduce false positive rate in SNP interaction discovery? BMC Genomics 2010, 11:58. Background The genomewide evaluation of genetic epistasis is a computationally demanding task, and a current challenge in Genetics. HFCC (Hypothesis-Free Clinical Cloning) is one of the methods that have been suggested for genomewide epistasis analysis. In order to perform an exhaustive search of epistasis, HFCC has implemented several tools and data filters, such as the use of multiple replication groups, and direction of effect and control filters. A recent article has claimed that the use of multiple replication groups (as implemented in HFCC) does not reduce the false positive rate, and we hereby try to clarify these issues. Results/Discussion HFCC uses, as an analysis strategy, the possibility of replicating findings in multiple replication groups, in order to select a liberal subset of preliminary results that are above a statistical criterion and consistent in direction of effect. We show that the use of replication groups and the direction filter reduces the false positive rate of a study, although at the expense of lowering the overall power of the study. A post-hoc analysis of these selected signals in the combined sample could then be performed to select the most promising results. Conclusion Replication of results in independent samples is generally used in scientific studies to establish credibility in a finding. Nonetheless, the combined analysis of several datasets is known to be a preferable and more powerful strategy for the selection of top signals. HFCC is a flexible and complete analysis tool, and one of its analysis options combines these two strategies: A preliminary multiple replication group analysis to eliminate inconsistent false positive results, and a post-hoc combined-group analysis to select the top signals. PMID:20576100

  11. "Does replication groups scoring reduce false positive rate in SNP interaction discovery?: Response"

    OpenAIRE

    González-Pérez Antonio; Gayán Javier; Ruiz Agustín

    2010-01-01

    Abstract A response to Toplak et al: Does replication groups scoring reduce false positive rate in SNP interaction discovery? BMC Genomics 2010, 11:58. Background The genomewide evaluation of genetic epistasis is a computationally demanding task, and a current challenge in Genetics. HFCC (Hypothesis-Free Clinical Cloning) is one of the methods that have been suggested for genomewide epistasis analysis. In order to perform an exhaustive search of epistasis, HFCC has implemented several tools ...

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

    Directory of Open Access Journals (Sweden)

    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.

  13. 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.

  14. The trazodone metabolite meta-chlorophenylpiperazine can cause false-positive urine amphetamine immunoassay results.

    Science.gov (United States)

    Baron, Jason M; Griggs, David A; Nixon, Andrea L; Long, William H; Flood, James G

    2011-07-01

    Amphetamines and methamphetamines are part of an important class of drugs included in most urine drugs of abuse screening panels, and a common assay to detect these drugs is the Amphetamines II immunoassay (Roche Diagnostics). To demonstrate that meta-chlorophenylpiperazine (m-CPP), a trazodone metabolite, cross-reacts in the Amphetamines II assay, we tested reference standards of m-CPP at various concentrations (200 to 20,000 g/L). We also tested real patient urine samples containing m-CPP (detected and quantified by HPLC) with no detectable amphetamine, methamphetamine, or MDMA (demonstrated by GC MS). In both the m-CPP standards and the patient urine samples, we found a strong association between m-CPP concentration and Amphetamines II immunoreactivity (r = 0.990 for the urine samples). Further, we found that patients taking trazodone can produce urine with sufficient m-CPP to result in false-positive Amphetamines II results. At our institution, false-positive amphetamine results occur not infrequently in patients taking trazodone with at least 8 trazodone-associated false-positive results during a single 26-day period. Laboratories should remain cognizant of this interference when interpreting results of this assay.

  15. False positivity of ETV6/RUNX1 detected by FISH in healthy newborns and adults

    DEFF Research Database (Denmark)

    Kusk, Maria Schioldan; Lausten-Thomsen, Ulrik; Andersen, Mette Klarskov

    2014-01-01

    The leukemia-associated ETV6-RUNX1-translocation frequently emerges prenatally. Reverse-transcriptase PCR screening may indicate presence of ETV6-RUNX1 transcripts in random cord blood samples. Subsequent cell enrichment validation finds significantly lower levels than validation applying...... fluorescence in situ hybridization (FISH) (RUNX1-positive dilution series, healthy adults and random cord blood samples. The t(12;21) single fusion extra signal translocation probe and the ETV6 break apart probe...... gave false positive results mimicking ETV6-RUNX1-positive cell levels of 10(-3). This questions the paradigm that 1% of newborns have ETV6-RUNX1-positive cells at levels of 10(-3) to 10(-4)....

  16. THE FALSE POSITIVE RATE OF KEPLER AND THE OCCURRENCE OF PLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Fressin, Francois; Torres, Guillermo; Charbonneau, David; Dressing, Courtney D. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Bryson, Stephen T.; Christiansen, Jessie; Jenkins, Jon M.; Batalha, Natalie M. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Walkowicz, Lucianne M., E-mail: ffressin@cfa.harvard.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2013-04-01

    The Kepler mission is uniquely suited to study the frequencies of extrasolar planets. This goal requires knowledge of the incidence of false positives such as eclipsing binaries in the background of the targets, or physically bound to them, which can mimic the photometric signal of a transiting planet. We perform numerical simulations of the Kepler targets and of physical companions or stars in the background to predict the occurrence of astrophysical false positives detectable by the mission. Using real noise level estimates, we compute the number and characteristics of detectable eclipsing pairs involving main-sequence stars and non-main-sequence stars or planets, and we quantify the fraction of those that would pass the Kepler candidate vetting procedure. By comparing their distribution with that of the Kepler Objects of Interest (KOIs) detected during the first six quarters of operation of the spacecraft, we infer the false positive rate of Kepler and study its dependence on spectral type, candidate planet size, and orbital period. We find that the global false positive rate of Kepler is 9.4%, peaking for giant planets (6-22 R{sub Circled-Plus }) at 17.7%, reaching a low of 6.7% for small Neptunes (2-4 R{sub Circled-Plus }), and increasing again for Earth-size planets (0.8-1.25 R{sub Circled-Plus }) to 12.3%. Most importantly, we also quantify and characterize the distribution and rate of occurrence of planets down to Earth size with no prior assumptions on their frequency, by subtracting from the population of actual Kepler candidates our simulated population of astrophysical false positives. We find that 16.5% {+-} 3.6% of main-sequence FGK stars have at least one planet between 0.8 and 1.25 R{sub Circled-Plus} with orbital periods up to 85 days. This result is a significant step toward the determination of eta-earth, the occurrence of Earth-like planets in the habitable zone of their parent stars. There is no significant dependence of the rates of planet

  17. Serial changes of hemodynamic performance with Medtronic Hall valve in aortic position.

    Science.gov (United States)

    Cho, Yang Hyun; Jeong, Dong Seop; Park, Pyo Won; Park, Kay-Hyun; Sung, Kiick; Kim, Wook Sung; Lee, Young Tak

    2011-02-01

    The aim of this study was to evaluate the long-term hemodynamic performance of the Medtronic Hall valve by analyzing serial changes in echocardiographic outcomes in aortic position. One hundred seventeen patients who underwent aortic valve replacement (AVR) using the Medtronic Hall valve between August 1997 and January 2004 were retrospectively studied. Fifty-five patients underwent isolated AVR (AVR group), and 62 patients underwent AVR and mitral valve replacement (double valve replacement group). Mean age was 51.2 ± 10.4 years (range, 26 to 67 years), and mean follow-up duration was 93.7 ± 25.6 months (913.6 patient-years; range, 17 to 140 months). Serial echocardiographic data were analyzed. Overall mortality was 12.8% (15 of 117), but no early mortality occurred. A greater than 15 mm Hg increment of aortic transprosthetic mean pressure gradient at last follow-up occurred in 13 patients (11.1%). Redo AVR was performed in 7 patients, 6 of whom had subaortic pannus ingrowths. Group cumulative survival rates at 10 years were similar (90.4%, AVR group versus 88.4%, double valve replacement group; p = 0.580), but the AVR group showed better adverse cardiac event-free survival at 10 years (80.1% versus 53.8%; p = 0.025). Multivariate analysis showed that double valve replacement and a small-sized valve (20 mm) significantly predicted the increment of aortic transprosthetic mean pressure gradient at last follow up greater than 15 mm Hg (p = 0.013; odds ratio, 13.9; p = 0.019; odds ratio, 4.2, respectively). The transprosthetic mean pressure gradient of the Medtronic Hall valve in the aortic position frequently increased as a function of time, and this increase was more common in patients who had undergone double valve replacement, especially in those implanted with a small valve. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  18. Octogenarian with an untreated femoral neck fracture: upright position during the postoperative course after aortic valve replacement

    Directory of Open Access Journals (Sweden)

    M. Polastri

    2015-06-01

    Full Text Available We describe a patient with a femoral neck fracture undergoing an aortic valve replacement. The study design was a case report. An 82-year-old female with an untreated right femoral neck fracture, and a severe aortic valve stenosis was admitted to a cardiac surgery department for surgical treatment of the valve disease. She underwent aortic valve replacement with a sutureless biological valve prosthesis through a partial sternotomy. At an early stage, the patient was instructed to make postural changes in the standing position. As a result, she was able to perform body movements associated with either a sitting or standing position. This case shows that appropriate early mobilization of a patient with a femoral neck fracture is feasible after aortic valve replacement, even though this does not necessarily mean that the patient needs to walk.

  19. PET-CT in presurgical lymph node staging in non-small cell lung cancer: the importance of false-negative and false-positive findings.

    Science.gov (United States)

    García de Castro, A Bustos; Domínguez, J Ferreirós; Bolton, R Delgado; Pérez, C Fernández; Martínez, B Cabeza; García-Esquinas, M García; Carreras Delgado, J L

    To assess the importance of false-negative and false-positive findings in computed tomography (CT) and (18)F-FDG positron emission tomography (PET) in mediastinal lymph node staging in patients undergoing surgery for non-small cell lung cancer (NSCLC). This retrospective study included 113 consecutive patients and 120 resected NSCLCs; 22 patients received neoadjuvant treatment. We compared the findings on preoperative (18)F-FDG PET-CT studies with the postoperative pathology findings. Lymph node size and primary tumor size were measured with CT, and lymph nodes and primary tumors were evaluated qualitatively and semiquantitatively (using standardized uptake values (SUVmax)) with PET. Metastatic lymph nodes were found in 26 (21.7%) of the 120 tumors and in 41 (7.7%) of the 528 lymph node stations analyzed. (18)F-FDG PET-CT yielded 53.8% sensitivity, 76.6% specificity, 38.9% positive predictive value, 85.7% negative predictive value, and 71.7% diagnostic accuracy. The false-negative rate was 14.2%. Multivariable analysis found that the factors associated with false-negative findings were a moderate degree of differentiation in the primary tumor (p = 0.005) and an SUVmax of the primary tumor >4 (p = 0.027). The false-positive rate was 61.1%, and the multivariable analysis found that lymph node size >1cm was associated with false-positive findings (p < 0.001). In mediastinal lymph node staging in patients with NSCLC, (18)F-FDG PET-CT improves the specificity and negative predictive value and helps clinicians to select the patients that will benefit from surgery. Given the high rate of false positives, histological confirmation of positive cases is recommendable. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

  20. Estimating False Positive Contamination in Crater Annotations from Citizen Science Data

    Science.gov (United States)

    Tar, P. D.; Bugiolacchi, R.; Thacker, N. A.; Gilmour, J. D.

    2017-01-01

    Web-based citizen science often involves the classification of image features by large numbers of minimally trained volunteers, such as the identification of lunar impact craters under the Moon Zoo project. Whilst such approaches facilitate the analysis of large image data sets, the inexperience of users and ambiguity in image content can lead to contamination from false positive identifications. We give an approach, using Linear Poisson Models and image template matching, that can quantify levels of false positive contamination in citizen science Moon Zoo crater annotations. Linear Poisson Models are a form of machine learning which supports predictive error modelling and goodness-of-fits, unlike most alternative machine learning methods. The proposed supervised learning system can reduce the variability in crater counts whilst providing predictive error assessments of estimated quantities of remaining true verses false annotations. In an area of research influenced by human subjectivity, the proposed method provides a level of objectivity through the utilisation of image evidence, guided by candidate crater identifications.

  1. Estimating False Positive Contamination in Crater Annotations from Citizen Science Data

    Science.gov (United States)

    Tar, P. D.; Bugiolacchi, R.; Thacker, N. A.; Gilmour, J. D.

    2016-11-01

    Web-based citizen science often involves the classification of image features by large numbers of minimally trained volunteers, such as the identification of lunar impact craters under the Moon Zoo project. Whilst such approaches facilitate the analysis of large image data sets, the inexperience of users and ambiguity in image content can lead to contamination from false positive identifications. We give an approach, using Linear Poisson Models and image template matching, that can quantify levels of false positive contamination in citizen science Moon Zoo crater annotations. Linear Poisson Models are a form of machine learning which supports predictive error modelling and goodness-of-fits, unlike most alternative machine learning methods. The proposed supervised learning system can reduce the variability in crater counts whilst providing predictive error assessments of estimated quantities of remaining true verses false annotations. In an area of research influenced by human subjectivity, the proposed method provides a level of objectivity through the utilisation of image evidence, guided by candidate crater identifications.

  2. 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 BACKGROUND: 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. METHODOLOGY AND PRINCIPAL FINDINGS: 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. CONCLUSION: 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.

  3. Parathyroid incidentalomas detected during thyroid ultrasonography and effect of chronic thyroiditis on false positive parathyroid lesions.

    Science.gov (United States)

    Ozdemir, Didem; Arpaci, Dilek; Ucler, Rifki; Cuhaci, Neslihan; Ersoy, Reyhan; Cakir, Bekir

    2012-12-01

    We aimed to determine the prevalence of parathyroid incidentalomas in patients referred for thyroid ultrasonography (US) and investigate the role of chronic thyroiditis on false positive lesions. Patients suspected to have parathyroid lesions during thyroid US were recorded prospectively between August 2009 and January 2010. Patients referred for parathyroid US and patients with known high serum calcium or parathyroid hormone (PTH) levels were excluded. Suspected parathyroid lesions were defined as hypoechoic, homogeneous, solid lesions with regular margins located outside the thyroid lobe, most commonly inferior to the thyroid gland. Thyroid US was performed in 6,528 patients. There were 78 patients (1.19 %) (73 female and 5 male) with suspected parathyroid lesion. The diagnosis of a true parathyroid adenoma was confirmed in 6 (7.69 %) patients. In patients with true adenoma, mean serum calcium, phosphorus, and PTH levels were 10.57 ± 0.48 mg/dl, 3.03 ± 0.52 mg/dl, and 182.91 ± 46.62 pg/ml, respectively. Among 72 patients with false positive parathyroid lesion, antithyroid peroxidase antibody was positive in 50 (69.4 %), antithyroglobulin antibody was positive in 46 (63.9 %), and one of these antibodies were positive in 59 (81.9 %) patients. Also, 46 (63.9 %) of these patients had thyroid dysfunctions (43 hypothyroidism and 3 hyperthyroidism) and 59 (81.9 %) had chronic thyroiditis ultrasonographically. Parathyroid incidentaloma was detected in 0.09 % of patients referred for thyroid US. The presence of clinically or ultrasonographically chronic thyroiditis might cause inadvertent interpretation of a hypoechoic lesion as a parathyroid pathology during thyroid US.

  4. 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......, and statistical methods, can explain the reported differences. METHODS: We included all screens from women first screened at age 50-69 years in the US Breast Cancer Surveillance Consortium (BCSC) (n=99,455) between 1996-2010, and from two population-based mammography screening programs in Denmark (n=230,452 and n...

  5. Xanthogranulomatous cholecystitis mimicking gallbladder carcinoma with a false-positive result on fluorodeoxyglucose PET

    Institute of Scientific and Technical Information of China (English)

    Isamu Makino; Takahiro Yamaguchi; Nariatsu Sato; Toshiaki Yasui; Ichiro Kita

    2009-01-01

    Recently, several reports have demonstrated that fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) is useful in differentiating between benign and mal ignant lesions in the gallbladder. However, there is a limitation in the ability of FDG-PET to differentiate between inflammatory and malignant lesions. We herein present a case of xanthogranulomatous cholecystitis misdiagnosed as gallbladder carcinoma by ultrasonography and computed tomography. FDG-PET also showed increased activity. In this case, FDG-PET findings resulted in a false-positive for the diagnosis of gallbladder carcinoma.

  6. 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.

  7. False-Positive Clostridium difficile in Negative-Control Reactions Peak and Then Decrease with Repetitive Refrigeration of Immunoassay.

    Science.gov (United States)

    Rodriguez-Palacios, Alexander; Stämpfli, Henry R; Chang, Yung-Fu

    2014-01-01

    Aberrant false-positive reactions in negative-controls during ELISA testing for Clostridium difficile indicated the potential for false-diagnoses. Experiments with 96-well products showed a maximum peak of false-positive immunoassay reactions with the provided negative-control reagents after 5 refrigeration-to-room temperature cycles (P refrigeration cycles. Because repetitive refrigeration causes a peak of false-positives, the use of single negative-controls per ELISA run might be insufficient to monitor aberrant preanalytical false-positives if immunoassays are subject to repetitive refrigeration.

  8. False positive RNA binding activities after Ni-affinity purification from Escherichia coli.

    Science.gov (United States)

    Milojevic, Tetyana; Sonnleitner, Elisabeth; Romeo, Alessandra; Djinović-Carugo, Kristina; Bläsi, Udo

    2013-06-01

    A His-tag is often added by means of recombinant DNA technology to a heterologous protein of interest, which is then over-produced in Escherchia coli and purified by one-step immobilized metal-affinity chromatography (IMAC). Owing to the presence of 24 histidines at the C-termini of the hexameric E. coli RNA chaperone Hfq, the protein co-purifies with His-tagged proteins of interest. As Hfq can bind to distinct RNA substrates with high affinity, its presence can obscure studies performed with (putative) RNA binding activities purified by IMAC. Here, we present results for a seemingly positive RNA-binding activity, exemplifying that false-positive results can be avoided if the protein of interest is either subjected to further purification step(s) or produced in an E. coli hfq- strain.

  9. 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.

  10. False-positive rates associated with the use of multiple performance and symptom validity tests.

    Science.gov (United States)

    Larrabee, Glenn J

    2014-06-01

    Performance validity test (PVT) error rates using Monte Carlo simulation reported by Berthelson and colleagues (in False positive diagnosis of malingering due to the use of multiple effort tests. Brain Injury, 27, 909-916, 2013) were compared with PVT and symptom validity test (SVT) failure rates in two nonmalingering clinical samples. At a per-test false-positive rate of 10%, Monte Carlo simulation overestimated error rates for: (i) failure of ≥2 out of 5 PVTs/SVT for Larrabee (in Detection of malingering using atypical performance patterns on standard neuropsychological tests. The Clinical Neuropsychologist, 17, 410-425, 2003) and ACS (Pearson, Advanced clinical solutions for use with WAIS-IV and WMS-IV. San Antonio: Pearson Education, 2009) and (ii) failure of ≥2 out of 7 PVTs/SVT for Larrabee (Detection of malingering using atypical performance patterns on standard neuropsychological tests. The Clinical Neuropsychologist, 17, 410-425, 2003; Malingering scales for the Continuous Recognition Memory Test and Continuous Visual Memory Test. The Clinical Neuropsychologist, 23, 167-180, 2009 combined). Monte Carlo overestimation is likely because PVT performances are atypical in pattern or degree for what occurs in actual neurologic, psychiatric, or developmental disorders. Consequently, PVT scores form skewed distributions with performance at ceiling and restricted range, rather than forming a standard normal distribution with mean of 0 and standard deviation of 1.0. These results support the practice of using ≥2 PVT/SVT failures as representing probable invalid clinical presentation.

  11. Astrophysical false positives in direct imaging for exoplanets: a white dwarf close to a rejuvenated star

    CERN Document Server

    Zurlo, A; Hagelberg, J; Desidera, S; Chauvin, G; Almenara, J M; Biazzo, K; Bonnefoy, M; Carson, J C; Covino, E; Delorme, P; D'Orazi, V; Gratton, R; Mesa, D; Messina, S; Moutou, C; Segransan, D; Turatto, M; Udry, S; Wildi, F

    2013-01-01

    As is the case for all techniques involved in the research for exoplanets, direct imaging has to take into account the probability of so-called astrophysical false positives, which are phenomena that mimic the signature of objects we are seeking. In this work we aim to present a case of a false positive found during a direct imaging survey conducted with VLT/NACO. A promising exoplanet candidate was detected around the K2-type star HD\\,8049 in July 2010.Its contrast of $\\Delta H$=7.05 at 1.57 arcsec allowed us to guess the presence of a 35 \\MJup companion at 50 projected AU, for the nominal system age and heliocentric distance.To check whether it was gravitationally bound to the host star, as opposed to an unrelated background object, we re-observed the system one year later and concluded a high probability of a bound system. We also used radial velocity measurements of the host star, spanning a time range of $\\sim$ 30 yr, to constrain the companion's mass and orbital properties, as well as to probe the host ...

  12. Pulmonary Nodule Detection in CT Images: False Positive Reduction Using Multi-View Convolutional Networks.

    Science.gov (United States)

    Setio, Arnaud Arindra Adiyoso; Ciompi, Francesco; Litjens, Geert; Gerke, Paul; Jacobs, Colin; van Riel, Sarah J; Wille, Mathilde Marie Winkler; Naqibullah, Matiullah; Sanchez, Clara I; van Ginneken, Bram

    2016-05-01

    We propose a novel Computer-Aided Detection (CAD) system for pulmonary nodules using multi-view convolutional networks (ConvNets), for which discriminative features are automatically learnt from the training data. The network is fed with nodule candidates obtained by combining three candidate detectors specifically designed for solid, subsolid, and large nodules. For each candidate, a set of 2-D patches from differently oriented planes is extracted. The proposed architecture comprises multiple streams of 2-D ConvNets, for which the outputs are combined using a dedicated fusion method to get the final classification. Data augmentation and dropout are applied to avoid overfitting. On 888 scans of the publicly available LIDC-IDRI dataset, our method reaches high detection sensitivities of 85.4% and 90.1% at 1 and 4 false positives per scan, respectively. An additional evaluation on independent datasets from the ANODE09 challenge and DLCST is performed. We showed that the proposed multi-view ConvNets is highly suited to be used for false positive reduction of a CAD system.

  13. Detection of circulating prostate tumor cells: alternative spliced variant of PSM induced false-positive result.

    Science.gov (United States)

    Hisatomi, Hisashi; Nagao, Kumi; Kawakita, Mutsuji; Matsuda, Tadashi; Hirata, Hiroyuki; Yamamoto, Shigeki; Nakamoto, Takaaki; Harasawa, Hiroshi; Kaneko, Noboru; Hikiji, Kazumasa; Tsukada, Yutaka

    2002-11-01

    RT-nested PCR has been introduced as a highly specific and sensitive assay method to detect the prostate-specific membrane antigen (PSM) mRNA in peripheral blood. However, appreciable percentages of false-positive cases have been reported. Additionally, primer sets reported previously could not discriminate between PSM and PSM', an alternatively spliced variant, mRNA. These isoforms can be produced from a single gene. Switches in alternative splicing patterns are often controlled with strict cell-type or developmental-stage specificity. Therefore, it is most important to discriminate between PSM mRNA and PSM' mRNA. Using our highly specific primer sets, PSM mRNA was detected in 3 of 24 peripheral blood samples of normal male volunteers (12.5%) and was not detected in peripheral blood of 11 normal female volunteers. PSM' mRNA was detected in 5 of 24 peripheral blood samples of normal male volunteers (20.8%) and in 4 of 11 of normal female volunteers (36.4%). PSM' mRNA induced false-positive results, it is important for genetic diagnosis of prostate cancer to discriminate between PSM and PSM' using our primer sets with high specificity. The advances in the uniquely designed primer sets may allow researchers to detect a real PSM mRNA without PSM' mRNA.

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

    Directory of Open Access Journals (Sweden)

    Cyril R Pernet

    2013-01-01

    Full Text Available 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.

  15. 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.

  16. 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

  17. 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.)

  18. 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/.

  19. Implications of false negative and false positive diagnosis in lymph node staging of NSCLC by means of ¹⁸F-FDG PET/CT.

    Directory of Open Access Journals (Sweden)

    Shaolei Li

    Full Text Available BACKGROUND: Integrated ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT is widely performed in hilar and mediastinal lymph node (HMLN staging of non-small cell lung cancer (NSCLC. However, the diagnostic efficiency of PET/CT remains controversial. This retrospective study is to evaluate the accuracy of PET/CT and the characteristics of false negatives and false positives to improve specificity and sensitivity. METHODS: 219 NSCLC patients with systematic lymph node dissection or sampling underwent preoperative PET/CT scan. Nodal uptake with a maximum standardized uptake value (SUV(max >2.5 was interpreted as PET/CT positive. The results of PET/CT were compared with the histopathological findings. The receiver operating characteristic (ROC curve was generated to determine the diagnostic efficiency of PET/CT. Univariate and multivariate analysis were conducted to detect risk factors of false negatives and false positives. RESULTS: The sensitivity, specificity, positive predictive value (PPV, negative predictive value (NPV, and accuracy of PET/CT in detecting HMLN metastases were 74.2% (49/66, 73.2% (112/153, 54.4% (49/90, 86.8% (112/129, and 73.5% (161/219. The ROC curve had an area under curve (AUC of 0.791 (95% CI 0.723-0.860. The incidence of false negative HMLN metastases was 13.2% (17 of 129 patients. Factors that are significantly associated with false negatives are: concurrent lung disease or diabetes (p4.0 (p=0.009. Postoperatively, 45.5% (41/90 patients were confirmed as false positive cases. The univariate analysis indicated age > 65 years old (p=0.009, well differentiation (p=0.002, and SUV(max of primary tumor ≦4.0 (p=0.007 as risk factors for false positive uptake. CONCLUSION: The SUV(max of HMLN is a predictor of malignancy. Lymph node staging using PET/CT is far from equal to pathological staging account of some risk factors. This study may provide some aids to pre-therapy evaluation and

  20. The difficulty of avoiding false positives in genome scans for natural selection.

    Science.gov (United States)

    Mallick, Swapan; Gnerre, Sante; Muller, Paul; Reich, David

    2009-05-01

    Several studies have found evidence for more positive selection on the chimpanzee lineage compared with the human lineage since the two species split. A potential concern, however, is that these findings may simply reflect artifacts of the data: inaccuracies in the underlying chimpanzee genome sequence, which is of lower quality than human. To test this hypothesis, we generated de novo genome assemblies of chimpanzee and macaque and aligned them with human. We also implemented a novel bioinformatic procedure for producing alignments of closely related species that uses synteny information to remove misassembled and misaligned regions, and sequence quality scores to remove nucleotides that are less reliable. We applied this procedure to re-examine 59 genes recently identified as candidates for positive selection in chimpanzees. The great majority of these signals disappear after application of our new bioinformatic procedure. We also carried out laboratory-based resequencing of 10 of the regions in multiple chimpanzees and humans, and found that our alignments were correct wherever there was a conflict with the published results. These findings throw into question previous findings that there has been more positive selection in chimpanzees than in humans since the two species diverged. Our study also highlights the challenges of searching the extreme tails of distributions for signals of natural selection. Inaccuracies in the genome sequence at even a tiny fraction of genes can produce false-positive signals, which make it difficult to identify loci that have genuinely been targets of selection.

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

    Directory of Open Access Journals (Sweden)

    Philip C Hill

    Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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.

  2. Acridine orange staining as a replacement for subculturing of false-positive blood cultures with the BACTEC NR 660.

    OpenAIRE

    Hunter, J.S.

    1993-01-01

    Despite the customization of growth index thresholds within individual laboratories, use of the BACTEC NR 660 automated blood culture system results in a number of false-positive cultures. The results of Gram staining, acridine orange staining, and subculturing to agar media were evaluated on 210 false-positive blood cultures over a 6-month period. Inclusion of acridine orange staining in the routine workup of false-positive blood cultures can eliminate the need for subculturing.

  3. False Positive STEMI Activations in a Regional Network: Comprehensive Analysis and Clinical Impact. Results From the Catalonian Codi Infart Network.

    Science.gov (United States)

    Regueiro, Ander; Fernández-Rodríguez, Diego; Freixa, Xavier; Bosch, Xavier; Martín-Yuste, Victoria; Brugaletta, Salvatore; Roqué, Mercè; Sabaté, Manel; Masotti, Mónica

    2017-07-12

    ST-segment elevation myocardial infarction (STEMI) network activation by a noncardiologist reduces delay times but may increase the rate of false-positive STEMI diagnoses. We aimed to determine the prevalence, predictors, and clinical impact of false-positive activations within the Catalonian STEMI network (Codi Infart). From January 2010 through December 2011, all consecutive patients treated within the Codi Infart network were included. Code activations were classified as appropriate if they satisfied both electrocardiogram and clinical STEMI criteria. Appropriate activations were classified as false positives using 2 nonexclusive definitions: a) "angiographic" if a culprit coronary artery was not identified, and b) "clinical" if the discharge diagnosis was other than STEMI. In total, 5701 activations were included. Appropriate activation was performed in 87.8% of the episodes. The rate of angiographic false positives was 14.6%, while the rate of clinical false positives was 11.6%. Irrespective of the definition, female sex, left bundle branch block, and previous myocardial infarction were independent predictors of false-positive STEMI diagnoses. Using the clinical definition, hospitals without percutaneous coronary intervention and patients with complications during the first medical contact also had a false-positive STEMI diagnoses rate higher than the mean. In-hospital and 30-day mortality rates were similar for false-positive and true-positive STEMI patients after adjustment for possible confounders. False-positive STEMI diagnoses were frequent. Outcomes were similar for patients with a true-positive or false-positive STEMI diagnosis treated within a STEMI network. The presence of any modifiable predictors of a false-positive STEMI diagnosis warrants careful assessment to optimize the use of STEMI networks. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  4. False-positive pH aspirates after nasogastric tube insertion in head and neck tumour.

    Science.gov (United States)

    Sellers, Claudia Kate

    2012-08-27

    Nasogastric (NG) feeding tubes are commonly inserted to supplement enteral nutrition in certain patient groups, including those with head and neck cancers where swallowing may be compromised. An NHS National Patient Safety Alert was released in 2011 detailing ongoing cases of significant morbidity and mortality attached to the incorrect placement of NG feeding tubes in hospital inpatients. Since 2005, there were 21 deaths and 79 cases of harm nationally due to feeding into the lung through misplaced tubes. pH testing remains the first-line method of placement confirmation, with chest x-ray used when no aspirate is gained or where pH testing fails to confirm suitable acidity. We present a case report describing false-positive NG tube placement confirmation tests in a patient with head and neck cancer, who was administered feed into lung parenchyma with significant morbidity. We discuss the case for specific NG tube placement protocols in head and neck cancer patients.

  5. Quantification of false positive reduction in nucleic acid purification on hemorrhagic fever DNA.

    Energy Technology Data Exchange (ETDEWEB)

    James, Conrad D.; Pohl, Kenneth Roy; Derzon, Mark Steven; McClain, Jaime; Achyuthan, Komandoor

    2006-11-01

    Columbia University has developed a sensitive highly multiplexed system for genetic identification of nucleic acid targets. The primary obstacle to implementing this technology is the high rate of false positives due to high levels of unbound reporters that remain within the system after hybridization. The ability to distinguish between free reporters and reporters bound to targets limits the use of this technology. We previously demonstrated a new electrokinetic method for binary separation of kb pair long DNA molecules and oligonucleotides. The purpose of this project 99864 is to take these previous demonstrations and further develop the technique and hardware for field use. Specifically, our objective was to implement separation in a heterogeneous sample (containing target DNA and background oligo), to perform the separation in a flow-based device, and to develop all of the components necessary for field testing a breadboard prototype system.

  6. Pulmonary sequestration: a (131)I whole body scintigraphy false-positive result.

    Science.gov (United States)

    Spinapolice, Elena Giulia; Chytiris, S; Fuccio, C; Leporati, P; Volpato, G; Villani, L; Trifirò, G; Chiovato, L

    2014-08-01

    A 35-year-old woman affected by a well-differentiated papillary thyroid carcinoma was referred to our hospital to perform a (131)Iodine ((131)I) whole body scintigraphy for restaging purpose. The patient had been previously treated with total thyroidectomy and three subsequent doses of (131)I for the ablation of a remnant jugular tissue and a suspected metastatic focus at the superior left hemi-thorax. In spite of the previous treatments with (131)I, planar and tomographic images showed the persistence of an area of increased uptake at the superior left hemi-thorax. This finding prompted the surgical resection of the lesion. Histological examination of the surgical specimen showed the presence of a pulmonary tissue consistent with pulmonary sequestration. Even though rare, pulmonary sequestration should be included in the potential causes of false-positive results of radioiodine scans.

  7. Influence of population prevalences on numbers of false positives: an overlooked entity.

    Science.gov (United States)

    Cronin, Paul; Kelly, Aine Marie

    2011-09-01

    Disease prevalence alters the number of true positives (TP), true negatives (TN), false negatives (FN), and false positives (FP), even if the sensitivity and specificity of a test stays the same. We illustrate this using data for the detection of suspected acute pulmonary embolism (PE) from the Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II). We chose PE because of the clinical significance of the disease, the low prevalence of PE in the patient population being tested with CTPA with the widespread adoption of CTPA, and the serious clinical consequences of anticoagulation therapy in FP patients. Based on PIOPED II data (sensitivity 83%, specificity 96%), at a disease prevalence of approximately 5%, the number of FP patients is greater than the number of TP patients. Scaled to the US population, at a disease prevalence of 5%, there would be 139,800 FPs and 3,356,200 TNs. Assuming a mortality rate of 0.5% and a 3.0% rate of major bleeding secondary to anticoagulation therapy for well-controlled patients, if all FP patients received anticoagulation, there would be 699 deaths and 4194 major bleeding complications. At a prevalence of approximately 5% for PE, the number of FPs approaches or is greater than the number of TPs for CTPA for the detection of suspected acute PE. Patients with FP results may receive unnecessary, potentially harmful treatment with anticoagulation therapy. Population prevalence of disease needs to be taken into account along with the diagnostic accuracy of a test, because this may significantly affect downstream patient outcomes. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

  8. Automated detection of pulmonary nodules in CT: false positive reduction by combining multiple classifiers

    Science.gov (United States)

    Suárez-Cuenca, Jorge Juan; Guo, Wei; Li, Qiang

    2011-03-01

    The purpose of this study was to investigate the usefulness of various classifier combination methods for improving the performance of a CAD system for pulmonary nodule detection in CT. We employed CT cases in the publicly available lung image database consortium (LIDC) dataset, which included 85 CT cases with 110 nodules. We first used six individual classifiers for nodule detection in CT, including linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), artificial neural network (ANN), and three types of support vector machines (SVM). Five informationfusion methods were then employed to combine the classifiers' outputs for improving detection performance. The five combination methods included two supervised (likelihood ratio method and neural network) and three unsupervised ones (the mean, the product, and the majority-vote of the output scores from the six individual classifiers). Leave-one-caseout was employed to train and test individual classifiers and supervised combination methods. At a sensitivity of 80 %, the numbers of false positives per case for the six individual classifiers were 6.1 for LDA, 19.9 for QDA, 8.6 for ANN, 23.7 for SVM-dot, 17.0 for SVM-poly, and 23.35 for SVM-ANOVA; the numbers of false positives per case for the five combination methods were 3.4 for the majority-vote rule, 6.2 for the mean, 5.7 for the product, 9.7 for the neural network, and 28.1 for the likelihood ratio method. The majority-vote rule achieved higher performance levels than other combination methods. It also achieved higher performance than the best individual classifier, which is not the case for other combination methods.

  9. Eliminating false positive C4 sugar tests on New Zealand Manuka honey.

    Science.gov (United States)

    Rogers, Karyne M; Somerton, Kerry; Rogers, Pamela; Cox, Julie

    2010-08-30

    Carbon isotope analyses (delta(13)C) of some New Zealand Manuka honeys show that they often fail the internationally recognised Association of Official Analytical Chemists sugar test (AOAC method 998.12) which detects added C(4) sugar, although these honeys are from unadulterated sources. Failure of these high value products is detrimental to the New Zealand honey industry, not only in lost export revenue, but also in brand and market reputation damage. The standard AOAC test compares the carbon isotope value of the whole honey and corresponding protein isolated from the same honey. Differences between whole honey and protein delta(13)C values should not be greater than +1.0 per thousand, as it indicates the possibility of adulteration with syrups or sugars from C(4) plants such as high fructose corn syrup or cane sugar.We have determined that during the standard AOAC method, pollen and other insoluble components are isolated with the flocculated protein. These non-protein components have isotope values which are considerably different from those of the pure protein, and can shift the apparent delta(13)C value of protein further away from the delta(13)C value of the whole honey, giving a false positive result for added C(4) sugar. To eliminate a false positive C(4) sugar test for Manuka honey, prior removal of pollen and other insoluble material from the honey is necessary to ensure that only the pure protein is isolated. This will enable a true comparison between whole honey and protein delta(13)C isotopes. Furthermore, we strongly suggest this modification to the AOAC method be universally adopted for all honey C(4) sugar tests. 2010 John Wiley & Sons, Ltd.

  10. A new method with flexible and balanced control of false negatives and false positives for hit selection in RNA interference high-throughput screening assays.

    Science.gov (United States)

    Zhang, Xiaohua Douglas

    2007-08-01

    The z-score method and its variants for testing mean difference are commonly used for hit selection in high-throughput screening (HTS) assays. Strictly standardized mean difference (SSMD) offers a way to measure and classify the short interfering RNA (siRNA) effects. In this article, based on SSMD, the authors propose a new testing method for hit selection in RNA interference (RNAi) HTS assays. This SSMD-based method allows the differentiation between siRNAs with large and small effects on the assay output and maintains flexible and balanced control of both the false-negative rate, in which the siRNAs with strong effects are not selected as hits, and the restricted false-positive rate, in which the siRNAs with weak or no effects are selected as hits. This method directly addresses the size of siRNA effects represented by the strength of difference between an siRNA and a negative reference, whereas the classic z-score method and t-test of testing no mean difference address whether the mean of an siRNA is exactly the same as the mean of a negative reference. This method can readily control the false-negative rate, whereas it is nontrivial for the classic z-score method and t-test to control the false-negative rate. Therefore, theoretically, the SSMD-based method offers better control of the sizes of siRNA effects and the associated false-positive and false-negative rates than the commonly used z-score method and t-test for hit selection in HTS assays. The SSMD-based method should generally be applicable to any assay in which the end point is a difference in signal compared to a reference sample, including those for RNAi, receptor, enzyme, and cellular function.

  11. False-positive buprenorphine by CEDIA in patients prescribed amisulpride or sulpiride.

    Science.gov (United States)

    Birch, M A; Couchman, L; Pietromartire, S; Karna, T; Paton, C; McAllister, R; Marsh, A; Flanagan, R J

    2013-05-01

    Buprenorphine is a potent partial opioid agonist that is analyzed in urine to (i) monitor adherence to maintenance or detoxification therapy and (ii) detect illicit use. Buprenorphine analysis is commonly conducted on urine by immunoassay, but is subject to cross-reactivity from other drugs/drug metabolites, including morphine, codeine and dihydrocodeine. This study reports false-positive buprenorphine analysis [Thermo Fisher Scientific cloned enzyme donor immunoassay (CEDIA)] in patients who denied unauthorized buprenorphine use prior to sampling, but who had been prescribed amisulpride. In two cases, confirmatory analysis by liquid chromatography-tandem mass spectrometry was negative (sulpiride in the CEDIA buprenorphine assay is low (estimated at 0.003 and 0.002%, respectively), it remains a significant consideration given the likely high concentrations of these compounds in urine relative to the low cutoff of the buprenorphine assay. Neither amisulpride nor sulpiride was listed as potential sources of interference on the CEDIA data sheet when this work was performed. These findings highlight the importance of confirming immunoassay-positive buprenorphine results using a more selective analytical technique.

  12. False-positive methadone urine drug screen in a patient treated with quetiapine.

    Science.gov (United States)

    Lasić, Davor; Uglesić, Boran; Zuljan-Cvitanović, Marija; Supe-Domić, Daniela; Uglesić, Lovro

    2012-06-01

    We present a case of T.M. admitted to University Department of Psychiatry, Split University Hospital Center, in Croatia, because of the acute psychotic reaction (F23.9). The patient's urine tested positive for methadone without a history of methadone ingestion. Urine drug screen was performed with the COBAS Integra Methadone II test kit (kinetic interaction of microparticles in solution /KIMS/ methodology) by Roche. Drugs that have been shown to cross-react with methadone feature a tricyclic structure with a sulfur and nitrogen atom in the middle ring, which is common for both quetiapine and methadone. Therefore, it is plausible that this structural similarity between quetiapine and methadone could underlie the cross-reactivity on methadone drug screen. Besides quetiapine, a number of routinely prescribed medications have been associated with triggering false-positive urine drug screen results. Verification of the test results with a different screening test or additional analytical tests should be performed to avoid adverse consequences for the patients.

  13. Searching for Long-Period Companions and False Positives within the APOGEE Catalog of Companion Candidates

    Science.gov (United States)

    Nguyen, Duy; Troup, Nicholas William; Majewski, Steven R.

    2017-01-01

    The Sloan Digital Sky Survey (SDSS) Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a large-scale, high-resolution, H-band, spectroscopic survey that has acquired high S/N spectra of 146,000 stars distributed across the Galactic bulge, disk, and halo with a radial velocity (RV) precision of ~100 m/s. We follow up stellar companion detections from the APOGEE DR12 catalog of 382 total APOGEE-identified companions, of which 376 are previously unknown companion candidates. The APOGEE team strives not only to continue expanding the census of extrasolar companions, but also to confirm and characterize our RV detections through a variety of means.We present findings from our investigation of the Kozai mechanism, which explains the development of close-orbiting binaries through an ejected third companion. To do so, we are undertaking a targeted search for long-period companions with hopes to provide further evidence for the Kozai mechanism. This hunt for longer period companions begins with a search for long-term RV trends within the APOGEE data. We have also obtained diffraction-limited imaging using speckle interferometry at WIYN and Gemini North Observatories, as well as AO LMIRcam images from the LBT, to make direct searches for long-period stellar companions.It is critical to purge our companion candidate detections of false positives, and we discuss several methods we are pursuing to do this. For example, highly active stars have been observed to mimic RV measurements. We have obtained optical high-resolution spectral follow-ups from the ARC 3.5m, the HET, and MMT to analyze potential stellar activity indicators such as Calcium H and K. Emission detected in these well-known stellar activity indicators suggests a false radial velocity measurement.

  14. 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 disappea

  15. 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 disappea

  16. False-positive rapid plasma reagin testing in patients with acute Plasmodium vivax malaria: a case control study.

    Science.gov (United States)

    Maves, Ryan C; Dean, Katherine; Gadea, Nilda; Halsey, Eric S; Graf, Paul C F; Lescano, Andres G

    2014-01-01

    Non-treponemal tests such as the rapid plasma reagin (RPR) assay are mainstays of syphilis diagnosis, but false-positive tests are common. We identified false-positive RPR titers in 8.2% of patients with malaria due to Plasmodium vivax in northern Peru. Similar rates were not detected in patients with other acute febrile illnesses.

  17. Multiple myeloma as a major cause of false-positive galactomannan tests in adult patients with cancer.

    Science.gov (United States)

    Ko, Jae-Hoon; Peck, Kyong Ran; Lee, Ji Yong; Cho, Sun Young; Ha, Young Eun; Kang, Cheol-In; Chung, Doo Ryeon; Kim, Kihyun; Kang, Eun-Suk; Song, Jae-Hoon

    2016-02-01

    The galactomannan (GM) test is a useful method for early diagnosis of invasive aspergillosis. Recently, multiple myeloma has newly been suggested to be related to false-positive results of GM. We performed a case-control study to validate this finding. Electronic medical records were reviewed for patients admitted March through June 2014. Patients with false-positive GM results were selected as cases and those with negatives as controls. To verify the results of the four-month analysis, additional analysis was performed in multiple myeloma patients over a three-year period. There were 30 false-positive and 316 negative cases during the four-month period. Among the factors evaluated, multiple myeloma was the only significant factor in the adjusted analysis (OR = 3.59, CI 1.28-10.04). In the three-year analysis of 145 multiple myeloma patients, 25.5% showed false-positive results, which was 3 times higher than overall. GM false-positivity was not related to serum monoclonal protein level or type of immunoglobulin. GM optical density indexes (ODIs) in all false positives were lower than 3.0. Multiple myeloma was a major cause of GM false-positivity in adult cancer patients. GM was false-positive in 25.5% of multiple myeloma patients with GM ODIs lower than 3.0. Copyright © 2015 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  18. Astrophysical false positives in direct imaging for exoplanets: a white dwarf close to a rejuvenated star

    Science.gov (United States)

    Zurlo, A.; Vigan, A.; Hagelberg, J.; Desidera, S.; Chauvin, G.; Almenara, J. M.; Biazzo, K.; Bonnefoy, M.; Carson, J. C.; Covino, E.; Delorme, P.; D'Orazi, V.; Gratton, R.; Mesa, D.; Messina, S.; Moutou, C.; Segransan, D.; Turatto, M.; Udry, S.; Wildi, F.

    2013-06-01

    Context. As is the case for all techniques involved in the research for exoplanets, direct imaging has to take into account the probability of so-called astrophysical false positives, which are phenomena that mimic the signature of the objects we are seeking. Aims: In this work we present the case of a false positive found during a direct-imaging survey conducted with VLT/NACO. A promising exoplanet candidate was detected around the K2-type star HD 8049 in July 2010. Its contrast of ΔH = 7.05 at 1.57 arcsec allowed us to assume a 35 MJup companion at 50 projected AU, for the nominal system age and heliocentric distance. Methods: To check whether it was gravitationally bound to the host star, as opposed to an unrelated background object, we re-observed the system one year later and concluded a high probability of a bound system. We also used radial velocity measurements of the host star, spanning a time range of ~30 yr, to constrain the companion's mass and orbital properties, as well as to probe the host star's spectral age indicators and general spectral energy distribution. We also obtained U-band imaging with EFOSC and near-infrared spectroscopy for the companion. Results: Combining all these information we conclude that the companion of HD 8049 is a white dwarf (WD) with temperature Teff = 18 800 ± 2100 K and mass MWD = 0.56 ± 0.08 M⊙. The significant radial velocity trend combined with the imaging data indicates that the most probable orbit has a semi-major axis of about 50 AU. The discrepancy between the age indicators speaks against a bona-fide young star. The moderately high level of chromospheric activity and fast rotation, mimicking the properties of a young star, might be induced by the exchange of mass with the progenitor of the WD. This example demonstrates some of the challenges in determining accurate age estimates and identifications of faint companions. Based on observations collected at La Silla and Paranal Observatory, ESO (Chile): Programs

  19. A False Positive For Ocean Glint on Exoplanets: the Latitude-Albedo Effect

    CERN Document Server

    Cowan, Nicolas B; 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 lightcurves. 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 th...

  20. The Transiting Exoplanet Survey Satellite: Simulations of planet detections and astrophysical false positives

    CERN Document Server

    Sullivan, Peter W; Berta-Thompson, Zachory K; Charbonneau, David; Deming, Drake; Dressing, Courtney D; Latham, David W; Levine, Alan M; McCullough, Peter R; Morton, Timothy; Ricker, George R; Vanderspek, Roland; Woods, Deborah

    2015-01-01

    The Transiting Exoplanet Survey Satellite (TESS) is a NASA-sponsored Explorer mission that will perform a wide-field survey for planets that transit bright host stars. Here, we predict the properties of the transiting planets that TESS will detect along with the eclipsing binary stars that produce false-positive photometric signals. The predictions are based on Monte Carlo simulations of the nearby population of stars, occurrence rates of planets derived from Kepler, and models for the photometric performance and sky coverage of the TESS cameras. We expect that TESS will find approximately 1700 transiting planets from 200,000 pre-selected target stars. This includes 556 planets smaller than twice the size of Earth, of which 419 are hosted by M dwarf stars and 137 are hosted by FGK dwarfs. Approximately 130 of the R < 2 R_Earth planets will have host stars brighter than K = 9. Approximately 48 of the planets with R < 2 R_Earth lie within or near the habitable zone (0.2 < S/S_Earth < 2), and between...

  1. 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.

  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. Long-term results of the Medtronic Mosaic porcine bioprosthesis in the aortic position.

    Science.gov (United States)

    Anselmi, Amedeo; Flécher, Erwan; Ruggieri, Vito Giovanni; Harmouche, Majid; Langanay, Thierry; Corbineau, Hervé; Verhoye, Jean-Philippe; Leguerrier, Alain

    2014-06-01

    We addressed the long-term results of the Medtronic Mosaic porcine prosthesis in the aortic position. From 1994 to 2004, 1007 Mosaic valves were used for aortic valve replacement. The data were prospectively collected, retrospectively analyzed, and stratified according to patient age at surgery (group 1, 80 years), using both actual (cumulative risks) and actuarial methods. Operative mortality was 5% (valve related in 14%). Globally, 8122.17 patient-years were available (average follow-up, 8.5 ± 3.9 years; 99.8% complete). Overall, survival at 15 years was lower among the elderly strata (P < .0001). Freedom from structural valve deterioration (SVD) was 95.1% (actual) and 86.3% (actuarial; 24 SVD events). Survival free from SVD was lower in group 1 (P = .003) but comparable among the other groups. Overall freedom at 15 years from the composite endpoint (any valve-related adverse events) was 82% (actual) and 71.3% (actuarial). No meaningful intergroup differences were found in survival free from the composite endpoint (P = .9) or freedom from valve-related mortality (P = .8). Younger patients at surgery did not show accelerated degeneration. No relationship could be established between prosthetic size and SVD. The implantation of a bioprosthesis in patients aged 70 years or older remains fully justified. The rate of SVD was higher in younger patients, mainly owing to their greater life expectancy. Patients younger than 70 can receive a bioprosthesis, provided that the correct information regarding the expected durability has been provided. This might be better accomplished through the actual methodology. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  4. Factors influencing accuracy of referral and the likelihood of false positive referral by optometrists in Bradford, United Kingdom.

    Science.gov (United States)

    Davey, Christopher James; Scally, Andrew J; Green, Clare; Mitchell, Edwin S; Elliott, David B

    2016-01-01

    Levels of false positive referral to ophthalmology departments can be high. This study aimed to evaluate commonality between false positive referrals in order to find the factors which may influence referral accuracy. In 2007/08, a sample of 431 new Ophthalmology referrals from the catchment area of Bradford Royal Infirmary were retrospectively analysed. The proportion of false positive referrals generated by optometrists decreases with experience at a rate of 6.2% per year since registration (p<0.0001). Community services which involved further investigation done by the optometrist before directly referring to the hospital were 2.7 times less likely to refer false positively than other referral formats (p=0.007). Male optometrists were about half as likely to generate a false positive referral than females (OR=0.51, p=0.008) and as multiple/corporate practices in the Bradford area employ less experienced and more female staff, independent practices generate about half the number of false positive referrals (OR=0.52, p=0.005). Clinician experience has the greatest effect on referral accuracy although there is also a significant effect of gender with women tending to refer more false positives. This may be due to a different approach to patient care and possibly a greater sensitivity to litigation. The improved accuracy of community services (which often refer directly after further investigation) supports further growth of these schemes. Copyright © 2015 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  5. Diagnostic performance of serological tests for swine brucellosis in the presence of false positive serological reactions.

    Science.gov (United States)

    Dieste-Pérez, L; Blasco, J M; de Miguel, M J; Moriyón, I; Muñoz, P M

    2015-04-01

    Swine brucellosis caused by Brucella suis biovar 2 is an emerging disease in Europe. Currently used diagnostic tests for swine brucellosis detect antibodies to the O-polysaccharide (O-PS) of Brucella smooth lipopolysaccharide (S-LPS) but their specificity is compromised by false-positive serological reactions (FPSRs) when bacteria carrying cross-reacting O-PS infect pigs. FPSRs occur throughout Europe, and the only tool available for a specific B. suis diagnosis is the intradermal test with Brucella protein extracts free of O-PS or S-LPS. Using sera of 162 sows naturally infected by B. suis biovar 2, 406 brucellosis-free sows, and 218 pigs of brucellosis-free farms affected by FPSR, we assessed the diagnostic performance of an indirect ELISA with rough LPS (thus devoid of O-PS) and of gel immunodiffusion, counterimmunoelectrophoresis, latex agglutination and indirect ELISA with O-PS free proteins in comparison with several S-LPS tests (Rose Bengal, complement fixation, gel immunodiffusion and indirect ELISA). When adjusted to 100% specificity, the sensitivity of the rough LPS ELISA was very low (30%), and adoption of other cut-offs resulted in poor specificity/sensitivity ratios. Although their specificity was 100%, the sensitivity of protein tests (ELISA, latex agglutination, counterimmunoelectrophoresis, and gel immunodiffusion) was only moderate (45, 58, 61 and 63%, respectively). Among S-LPS tests, gel immunodiffusion was the only test showing acceptable sensitivity/specificity (68 and 100%, respectively). Despite these shortcomings, and when the purpose is to screen out FPSR at herd level, gel immunodiffusion tests may offer a technically simple and practical alternative to intradermal testing.

  6. Modelling the cumulative risk of a false-positive screening test.

    Science.gov (United States)

    Hubbard, Rebecca A; Miglioretti, Diana L; Smith, Robert A

    2010-10-01

    The goal of a screening test is to reduce morbidity and mortality through the early detection of disease; but the benefits of screening must be weighed against potential harms, such as false-positive (FP) results, which may lead to increased healthcare costs, patient anxiety, and other adverse outcomes associated with diagnostic follow-up procedures. Accurate estimation of the cumulative risk of an FP test after multiple screening rounds is important for program evaluation and goal setting, as well as informing individuals undergoing screening what they should expect from testing over time. Estimation of the cumulative FP risk is complicated by the existence of censoring and possible dependence of the censoring time on the event history. Current statistical methods for estimating the cumulative FP risk from censored data follow two distinct approaches, either conditioning on the number of screening tests observed or marginalizing over this random variable. We review these current methods, identify their limitations and possibly unrealistic assumptions, and propose simple extensions to address some of these limitations. We discuss areas where additional extensions may be useful. We illustrate methods for estimating the cumulative FP recall risk of screening mammography and investigate the appropriateness of modelling assumptions using 13 years of data collected by the Breast Cancer Surveillance Consortium (BCSC). In the BCSC data we found evidence of violations of modelling assumptions of both classes of statistical methods. The estimated risk of an FP recall after 10 screening mammograms varied between 58% and 77% depending on the approach used, with an estimate of 63% based on what we feel are the most reasonable modelling assumptions.

  7. Is the false-positive rate in mammography in North America too high?

    Science.gov (United States)

    Le, Michelle T; Mothersill, Carmel E; Seymour, Colin B; McNeill, Fiona E

    2016-09-01

    The practice of investigating pathological abnormalities in the breasts of females who are asymptomatic is primarily employed using X-ray mammography. The importance of breast screening is reflected in the mortality-based benefits observed among females who are found to possess invasive breast carcinoma prior to the manifestation of clinical symptoms. It is estimated that population-based screening constitutes a 17% reduction in the breast cancer mortality rate among females affected by invasive breast carcinoma. In spite of the significant utility that screening confers in those affected by invasive cancer, limitations associated with screening manifest as potential harms affecting individuals who are free of invasive disease. Disease-free and benign tumour-bearing individuals who are subjected to diagnostic work-up following a screening examination constitute a population of cases referred to as false positives (FPs). This article discusses factors contributing to the FP rate in mammography and extends the discussion to an assessment of the consequences associated with FP reporting. We conclude that the mammography FP rate in North America is in excess based upon the observation of overtreatment of in situ lesions and the disproportionate distribution of detriment and benefit among the population of individuals recalled for diagnostic work-up subsequent to screening. To address the excessive incidence of FPs in mammography, we investigate solutions that may be employed to remediate the current status of the FP rate. Subsequently, it can be suggested that improvements in the breast-screening protocol, medical litigation risk, image interpretation software and the implementation of image acquisition modalities that overcome superimposition effects are promising solutions.

  8. 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.

  9. Risk Factors Associated with False Positive HIV Test Results in a Low-Risk Urban Obstetric Population

    Directory of Open Access Journals (Sweden)

    Tamara T. Chao

    2012-01-01

    Full Text Available Objective. To examine risk factors for false positive HIV enzyme immunoassay (EIA testing at delivery. Study Design. A review of pregnant women who delivered at Parkland Hospital between 2005 and 2008 was performed. Patients routinely received serum HIV EIA testing at delivery, with positive results confirmed through immunofluorescent testing. Demographics, HIV, hepatitis B surface antigen (HBsAg, and rapid plasma reagin (RPR results were obtained. Statistical analyses included Pearson's chi-square and Student's t-test. Results. Of 47,794 patients, 47,391 (99% tested negative, 145 (0.3% falsely positive, 172 (0.4% positive, and 86 (0.2% equivocal or missing HIV results. The positive predictive value of EIA was 54.3%. Patients with false positive results were more likely nulliparous (43% versus 31%, <0.001 and younger (23.9±5.7 versus 26.2±5.9 years, <0.001. HIV positive patients were older than false positive patients and more likely positive for HBsAg and RPR. Conclusion. False positive HIV testing at delivery using EIA is associated with young maternal age and nulliparity in this population.

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

    Science.gov (United States)

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

    2013-12-01

    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.

  11. 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.

  12. False-positive fluorodeoxyglucose positron emission tomography results after chemotherapy in patients with metastatic seminoma.

    Science.gov (United States)

    Decoene, Jasper; Winter, Christian; Albers, Peter

    2015-01-01

    The treatment of residual masses after chemotherapy in seminomas remains a controversial topic. Postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) in all patients would lead to severe overtreatment with a high rate of complications and additional procedures. For this reason, fluorodeoxyglucose positron emission tomography (FDG-PET) was introduced. FDG-PET has an accuracy of 88%. In 15% of cases, FDG-PET findings are false positive (FP) with unclear consequences. Therefore, we retrospectively investigated the rate of unnecessary procedures due to FP results on FDG-PET. Between July 2003 and September 2013 we performed 305 PC-RPLNDs in 277 patients, 22 because of metastatic seminoma. Of them, 11 patients had a preoperative FDG-PET at least 6 weeks after chemotherapy. Indication for surgery was a marker-negative progression of the lesion in 7 patients who did not undergo FDG-PET, a marker-negative progression with a negative result on FDG-PET in 2 patients, and a positive result on FDG-PET with normal markers in 9 patients. Furthermore, PC-RPLND was indicated in 3 patients because of ureteral compression/infiltration with ureteral stents or nephrostomies. In 1 patient, there was uncertainty whether the initial retroperitoneal tumor contained choriocarcinoma elements. Standardized uptake values (SUVs) were recorded for all patients undergoing FDG-PET. The FDG-PET findings were FP in 7 of 11 (64%) patients. The median age of the patients was 45.4 years (39-49). The median SUV in the patients was 6.6 (3.1-11.6), and the median diameter of the residual mass was 6.8 cm (2.9-11). In 4 of 7 patients, intraoperative or postoperative complications occurred (polar artery ligation with functional loss, bilateral non-nerve-sparing technique with retrograde ejaculation, ureteral replacement with an ileal segment, and pulmonary embolism). In patients with metastatic seminoma who received chemotherapy, FDG-PET is a valuable tool to evaluate whether the residual mass

  13. To Control False Positives in Gene-Gene Interaction Analysis: Two Novel Conditional Entropy-Based Approaches: e81984

    National Research Council Canada - National Science Library

    Xiaoyu Zuo; Shaoqi Rao; An Fan; Meihua Lin; Haoli Li; Xiaolei Zhao; Jiheng Qin

    2013-01-01

    ...) were developed for detecting non-linear dependence between genetic loci, but they are potentially at the risk of inflated false positive error, in particular when the main effects at one or both loci are salient...

  14. To control false positives in gene-gene interaction analysis: two novel conditional entropy-based approaches

    National Research Council Canada - National Science Library

    Zuo, Xiaoyu; Rao, Shaoqi; Fan, An; Lin, Meihua; Li, Haoli; Zhao, Xiaolei; Qin, Jiheng

    2013-01-01

    ...) were developed for detecting non-linear dependence between genetic loci, but they are potentially at the risk of inflated false positive error, in particular when the main effects at one or both loci are salient...

  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. The molecular mimicry and its possible role in origin of false-positive results in HCV-infection testing

    Directory of Open Access Journals (Sweden)

    Benkovskaya L. K.

    2013-09-01

    Full Text Available The main reason for the false positive results of the detection of antibodies to HCV is considered the unspecific binding of the blood serum immunoglobulins with the components of the test-systems’ immunosorbent, what is observed in various pathologies. When considering the issues of diagnosis, prevention and treatment of infectious diseases examined the impact of antigenic heterogeneity and molecular mimicry. With regarding to hepatitis C this phenomenon more illustrated in terms of pathogenesis, autoimmune, extrahepatic lesions. This does not exclude the influence of antigenic mimicry on the specificity of serological tests for anti-HCV detection. Aim. Estimation the frequency of false-positive reactions of anti-HCV testing in patients with chronic somatic diseases and assessment of the antigenic mimicry’s role in their occurrence. Methods. Total anti-HCV, antibodies to the single viruses’ protein, and false positive sera antibodies’ interaction with microbial origin combinations (mimicrins were determined by ELISA. Mimicrins were separated from the cultural medium after cultivation Staphylococcus aureus, Micobacterium tuberculosis and Candida albicans. Results. Upon detection of anti-HCV in patients with chronic pathologies detected a significant number of false-positive results are more likely in patients with diabetes and among healthy individuals – in pregnant women.The majorities of false positive sera interacted with mimicrins. Conclusions. The antigenic crossings over between mimicrins and antibodies in the structure of false positive sera must be considered during the evaluation of the specific diagnostics’ results in the persons with different pathologic states.

  17. A semiparametric censoring bias model for estimating the cumulative risk of a false-positive screening test under dependent censoring.

    Science.gov (United States)

    Hubbard, Rebecca A; Miglioretti, Diana L

    2013-03-01

    False-positive test results are among the most common harms of screening tests and may lead to more invasive and expensive diagnostic testing procedures. Estimating the cumulative risk of a false-positive screening test result after repeat screening rounds is, therefore, important for evaluating potential screening regimens. Existing estimators of the cumulative false-positive risk are limited by strong assumptions about censoring mechanisms and parametric assumptions about variation in risk across screening rounds. To address these limitations, we propose a semiparametric censoring bias model for cumulative false-positive risk that allows for dependent censoring without specifying a fixed functional form for variation in risk across screening rounds. Simulation studies demonstrated that the censoring bias model performs similarly to existing models under independent censoring and can largely eliminate bias under dependent censoring. We used the existing and newly proposed models to estimate the cumulative false-positive risk and variation in risk as a function of baseline age and family history of breast cancer after 10 years of annual screening mammography using data from the Breast Cancer Surveillance Consortium. Ignoring potential dependent censoring in this context leads to underestimation of the cumulative risk of false-positive results. Models that provide accurate estimates under dependent censoring are critical for providing appropriate information for evaluating screening tests.

  18. Assessment of Cardiac Device Position on Supine Chest Radiograph in the ICU: Introduction and Applicability of the Aortic Valve Location Ratio.

    Science.gov (United States)

    Ouweneel, Dagmar M; Sjauw, Krischan D; Wiegerinck, Esther M A; Hirsch, Alexander; Baan, Jan; de Mol, Bas A J M; Lagrand, Wim K; Planken, R Nils; Henriques, José P S

    2016-10-01

    The use of intracardiac assist devices is expanding, and correct position of these devices is required for optimal functioning. The aortic valve is an important landmark for positioning of those devices. It would be of great value if the device position could be easily monitored on plain supine chest radiograph in the ICU. We introduce a ratio-based tool for determination of the aortic valve location on plain supine chest radiograph images, which can be used to evaluate intracardiac device position. Retrospective observational study. Large academic medical center. Patients admitted to the ICU and supported by an intracardiac assist device. We developed a ratio to determine the aortic valve location on supine chest radiograph images. This ratio is used to assess the position of a cardiac assist device and is compared with echocardiographic findings. Supine anterior-posterior chest radiographs of patients with an aortic valve prosthesis (n = 473) were analyzed to determine the location of the aortic valve. We calculated several ratios with the potential to determine the position of the aortic valve. The aortic valve location ratio, defined as the distance between the carina and the aortic valve, divided by the thoracic width, was found to be the best performing ratio. The aortic valve location ratio determines the location of the aortic valve caudal to the carina, at a distance of 0.25 ± 0.05 times the thoracic width for male patients and 0.28 ± 0.05 times the thoracic width for female patients. The aortic valve location ratio was validated using CT images of patients with angina pectoris without known valvular disease (n = 95). There was a good correlation between cardiac device position (Impella) assessed with the aortic valve location ratio and with echocardiography (n = 53). The aortic valve location ratio enables accurate and reproducible localization of the aortic valve on supine chest radiograph. This tool is easily applicable and can be used for

  19. Background parenchymal enhancement at breast MR imaging: normal patterns, diagnostic challenges, and potential for false-positive and false-negative interpretation.

    Science.gov (United States)

    Giess, Catherine S; Yeh, Eren D; Raza, Sughra; Birdwell, Robyn L

    2014-01-01

    At magnetic resonance (MR) imaging, both normal and abnormal breast tissue enhances after contrast material administration. The morphology and temporal degree of enhancement of pathologic breast tissue relative to normal breast tissue form the basis of MR imaging's diagnostic accuracy in the detection and diagnosis of breast disease. Normal parenchymal enhancement at breast MR imaging is termed background parenchymal enhancement (BPE). BPE may vary in degree and distribution in different patients as well as in the same patient over time. Typically BPE is minimal or mild in overall degree, with a bilateral, symmetric, diffuse distribution and slow early and persistent delayed kinetic features. However, BPE may sometimes be moderate or marked in degree, with an asymmetric or nondiffuse distribution and rapid early and plateau or washout delayed kinetic features. These patterns cause diagnostic difficulty because these features can be seen with malignancy. This article reviews typical and atypical patterns of BPE seen at breast MR imaging. The anatomic and physiologic influences on BPE in women undergoing diagnostic and screening breast MR imaging are reviewed. The potential for false-positive and false-negative interpretations due to BPE are discussed. Radiologists can improve their interpretive accuracy by increasing their understanding of various BPE patterns, influences on BPE, and the potential effects of BPE on MR imaging interpretation.

  20. Exploring Habitability Markers, Biosignatures, and Their False Positives Using Spectral Models of Terrestrial Exoplanets

    Science.gov (United States)

    Schwieterman, Edward W.

    )2 feature in a variety of simulated atmospheres with different N2 abundances with both synthetic direct-imaging and transit transmission spectra. Third, I investigate observational indicators of planetary mechanisms that may generate abiotic oxygen (O2 or O3) on exoplanets, leading to potential "false positives" for life. Abiotic production of O2 from CO2 photolysis potentially leads to detectable amounts of CO as a byproduct. Oxygen build up from massive H-loss during a runaway greenhouse could leave behind more O2 than could be plausibly produced by biology. In this case density dependent O4 features would be strong and potentially indicative of this process. I investigate the strength and detectability of CO (at 2.35 and 4.6 mum) and O4 (at 0.345, 0.36, 0.38, 0.445, 0.475, 0.53, 0.57, 0.63, 1.06, and 1.27 mum) absorption for these abiotic oxygen scenarios in both transmission and direct-imaging spectroscopy. Finally, I present an interdisciplinary study of nonphotosynthetic pigments as alternative surface reflectance biosignatures, in contrast to direct photosynthetic signatures like the vegetation red edge. This study includes reflectance measurements of a variety of pigmented organisms in the laboratory, illustrating a wide range of spectral diversity. I also model the spectra of hypothetical planets containing nonphotosynthetic pigment biosignatures including the confounding spectral effects of the atmosphere. I find that these signatures could potentially be observable in disk-averaged spectra depending on the fraction of the planet containing the signature. Organisms with nonphotosynthetic pigments will produce reflectance signatures different than that of the commonly referenced vegetation red edge, and push us to broaden our understanding of what surface biosignatures might look like on Earth-like exoplanets once remote characterization of these worlds becomes possible.

  1. [A pseudo-outbreak of pharyngeal gonorrhoea related to a false-positive PCR-result

    NARCIS (Netherlands)

    Verzijl, A.; Berretty, P.J.; Erceg, A.; Krekels, G.A.; Brule, A.J. van den; Boel, C.H.

    2007-01-01

    Nucleic acid amplification tests, including the polymerase chain reaction (PCR), are sensitive and specific tests that are often used for diagnosing sexually transmitted diseases (STDs). A pseudo-outbreak of pharyngeal gonorrhoea in a group of prostitutes turned out to have been caused by false-posi

  2. 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....

  3. High prevalence of false-positive plateau phenomena during VO2max testing in adolescents.

    Science.gov (United States)

    Beltrami, Fernando G; Wong, Del P; Noakes, Timothy D

    2014-09-01

    It is believed that a plateau in oxygen consumption (VO2) at the end of an incremental exercise test identifies the upper limits of cardiovascular capacity. We investigated how different criteria influence the frequency with which the "plateau phenomenon" is detected and the prevalence at which "false" plateau phenomena occurs during sub-maximal exercise. Cross-sectional. Six different criteria with 3 different sampling intervals each were used to identify the "plateau phenomenon" from a single data set comprising 63 incremental exercise tests along with secondary criteria based on target heart rate (HR) and respiratory exchange ratio (RER). A single criterion from the original 18 (HALF) was also used to detect the incidence of any plateau phenomena during each test. The plateau phenomenon was detected in 16-82% of the tests depending on the criteria used, mostly as a result of the different sampling intervals. HALF identified 103 "plateau phenomena" but 73 (70.9%) of these occurred during sub-maximal exercise and so were "false". "False" plateaus were verified by at least one secondary criterion in 27% of cases. Participants reached the HR and RER targets after 83.6 ± 11.7% and 81.9 ± 18.1% of total test duration, respectively. The wide range in the percentage of plateau phenomena detected by different criteria plus the high rate (71%) of "false" plateau during sub-maximal exercise could indicate that this phenomenon is a calculation artifact rather than an indicator of true physiological events. Secondary criteria can be reached early in exercise and often identify "false" plateau phenomena as "true". Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  4. Human tissue valves in aortic position: determinants of reoperation and valve regurgitation

    NARCIS (Netherlands)

    T.P. Willems (Tineke); E.W. Steyerberg (Ewout); V.E. Kleyburg-Linkers; E. Bos (Egbert); L.A. van Herwerden (Lex); J.R.T.C. Roelandt (Jos); J.J.M. Takkenberg (Hanneke)

    2001-01-01

    textabstractBACKGROUND: Human tissue valves for aortic valve replacement have a limited durability that is influenced by interrelated determinants. Hierarchical linear modeling was used to analyze the relation between these determinants of durability and valve

  5. Chronic Kidney Disease Is Positively and Diabetes Mellitus Is Negatively Associated with Abdominal Aortic Aneurysm

    Science.gov (United States)

    Uchida, Haruhito A.; Kakio, Yuki; Umebayashi, Ryoko; Okuyama, Yuka; Fujii, Yasuhiro; Ozawa, Susumu; Yoshida, Masashi; Oshima, Yu; Sano, Shunji; Wada, Jun

    2016-01-01

    Background and Aims Chronic kidney disease (CKD) and diabetes mellitus (DM) are considered as risk factors for cardiovascular diseases. The purpose of this study was to clarify the relationship of CKD and DM with the presence of abdominal aortic aneurysm (AAA). Methods We enrolled 261 patients with AAA (AAA+) and age-and-sex matched 261 patients without AAA (AAA-) at two hospitals between 2008 and 2014, and examined the association between the risk factors and the presence of AAA. Furthermore, in order to investigate the prevalence of AAA in each group, we enrolled 1126 patients with CKD and 400 patients with DM. Results The presence of CKD in patients with AAA+ was significantly higher than that in patients with AAA- (AAA+; 65%, AAA-; 52%, P = 0.004). The presence of DM in patients with AAA+ was significantly lower than that in patients with AAA- (AAA+; 17%, AAA-; 35%, P < 0.001). A multivariate logistic regression analysis demonstrated that hypertension, ischemic heart disease and CKD were independent determinants, whereas, DM was a negatively independent determinant, for the presence of AAA. The prevalence of AAA in patients with CKD 65 years old and above was 5.1%, whereas, that in patients with DM 65 years old and above was only 0.6%. Conclusion CKD is a positively associated with the presence of AAA. In contrast, DM is a negatively associated with the presence of AAA in Japanese population. PMID:27764090

  6. 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.)

  7. A False Positive Dengue Fever Rapid Diagnostic Test Result in a Case of Acute Parvovirus B19 Infection.

    Science.gov (United States)

    Izumida, Toshihide; Sakata, Hidenao; Nakamura, Masahiko; Hayashibara, Yumiko; Inasaki, Noriko; Inahata, Ryo; Hasegawa, Sumiyo; Takizawa, Takenori; Kaya, Hiroyasu

    2016-01-01

    An outbreak of dengue fever occurred in Japan in August 2014. We herein report the case of a 63-year-old man who presented with a persistent fever in September 2014. Acute parvovirus B19 infection led to a false positive finding of dengue fever on a rapid diagnostic test (Panbio Dengue Duo Cassette(TM)). To the best of our knowledge, there are no previous reports of a false positive result for dengue IgM with the dengue rapid diagnostic test. We believe that epidemiological information on the prevalence of parvovirus B19 is useful for guiding the interpretation of a positive result with the dengue rapid diagnostic test.

  8. A Pattern Matching Algorithm for Reducing False Positive in Signature Based Intrusion Detection System

    Directory of Open Access Journals (Sweden)

    T. Sree Kala,

    2016-04-01

    Full Text Available Nowadays the organizations are facing the number of threats every day in the form of viruses and attack etc. Since many different mechanisms were preferred by organizations in the form of intrusion detection and prevention system to protect its organizations from these kinds of attacks. Intrusion Detection System (IDS is considered as a system integrated with intelligent subsystems. In this paper the signature based intrusion detection system is discussed. There are different pattern matching algorithms available to detect intrusion. Brute force and Knuth-Morris-Pratt are the single keyword pattern matching algorithms. If one or more occurrence of pattern present in the input text, then there is an intrusion and the intrusion alarm will be sent. The occurrence of false alarm will be high in intrusion detection. In this paper the string matching algorithm to reduce the percentage of false alarm will be discussed.

  9. Positive Psychology and Adolescent Mental Health: False Promise or True Breakthrough?

    Science.gov (United States)

    Kelley, Thomas M.

    2004-01-01

    The emerging field of positive psychology has pledged to improve the mental health of American adolescents. Yet, without a principle-based conceptual foundation to guide its study of optimal youth functioning, positive psychology will ultimately fail to keep its promise. This paper suggests that the principles of Mind, Thought and Consciousness…

  10. Positive Psychology and Adolescent Mental Health: False Promise or True Breakthrough?

    Science.gov (United States)

    Kelley, Thomas M.

    2004-01-01

    The emerging field of positive psychology has pledged to improve the mental health of American adolescents. Yet, without a principle-based conceptual foundation to guide its study of optimal youth functioning, positive psychology will ultimately fail to keep its promise. This paper suggests that the principles of Mind, Thought and Consciousness…

  11. Asymptotically false-positive-maximizing attack on non-binary Tardos codes

    CERN Document Server

    Simone, Antonino

    2011-01-01

    We use a method recently introduced by Simone and Skoric to study accusation probabilities for non-binary Tardos fingerprinting codes. We generalize the pre-computation steps in this approach to include a broad class of collusion attack strategies. We analytically derive properties of a special attack that asymptotically maximizes false accusation probabilities. We present numerical results on sufficient code lengths for this attack, and explain the abrupt transitions that occur in these results.

  12. [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.

  13. Aortic dissection

    Science.gov (United States)

    Aortic aneurysm - dissecting; Chest pain - aortic dissection; Thoracic aortic aneurysm - dissection ... the chest and abdomen (the descending aorta). Aortic dissection most often happens because of a tear or ...

  14. False positives and false negatives measure less than 0.001% in labeling ssDNA with osmium tetroxide 2,2’-bipyridine

    Directory of Open Access Journals (Sweden)

    Anastassia Kanavarioti

    2016-10-01

    Full Text Available Osmium tetroxide 2,2’-bipyridine (OsBp is known to react with pyrimidines in ssDNA and preferentially label deoxythymine (T over deoxycytosine (C. The product, osmylated DNA, was proposed as a surrogate for nanopore-based DNA sequencing due to OsBp’s “perfect” label attributes. Osmylated deoxyoligos translocate unassisted and measurably slow via sub-2 nm SiN solid-state nanopores, as well as via the alpha-hemolysin (α-HL pore. Both nanopores discriminate clearly between osmylated and intact nucleobase; α-HL was also shown to discriminate between osmylated T and osmylated C. Experiments presented here confirm that the kinetics of osmylation are comparable for short oligos and long ssDNA and show that pyrimidine osmylation is practically complete in two hours at room temperature with less than 15 mM OsBp. Under the proposed labeling conditions: deoxyoligo backbone degradation measures less than 1/1,000,000; false positives such as osmylated deoxyadenine (A and osmylated deoxyguanine (G measure less than 1/100,000; false negatives, i.e., unosmylated C measure less than 1/10,000; and unosmylated T must measure substantially lower than 1/10,000 due to the 27-fold higher reactivity of T compared to C. However, osmylated C undergoes degradation that amounts to about 1–2% for the duration of the labeling protocol. This degradation may be further characterized, possibly suppressed, and the properties of the degradation products via nanopore translocation can be evaluated to assure base calling quality in a DNA sequencing effort.

  15. Suspected aortic dissection and other aortic disorders: multi-detector row CT in 373 cases in the emergency setting.

    Science.gov (United States)

    Hayter, Robert G; Rhea, James T; Small, Andrew; Tafazoli, Faranak S; Novelline, Robert A

    2006-03-01

    To retrospectively review the authors' experience with multi-detector row computed tomography (CT) for detection of aortic dissection in the emergency setting. The investigation was institutional review board approved, did not require informed patient consent, and was HIPAA compliant. In 373 clinical evaluations in the emergency setting, 365 patients suspected of having aortic dissection and/or other aortic disorders underwent multidetector CT. Criteria for acute aortic disorder were confirmed by using surgical and pathologic diagnoses or findings at clinical follow-up and any subsequent imaging as the reference standard. Positive cases were characterized according to type of disorder interpreted. Resulting sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated by using two-way contingency tables. All cases found to be negative for acute aortic disorders were grouped according to alternative CT findings. Sixty-seven (18.0%) of the 373 cases were interpreted as positive for acute aortic disorder. One hundred twelve acute aortic disorders were identified in these 67 cases: 23 acute aortic dissections, 14 acute aortic intramural hematomas, 20 acute penetrating aortic ulcers, 44 new or enlarging aortic aneurysms, and 11 acute aortic ruptures. Three hundred five (81.8%) cases were interpreted as negative for acute aortic disorder. In 48 negative cases, multidetector CT depicted alternative findings that accounted for the clinical presentation. Of these, three included both acute aortic disorders and alternative findings, and 45 included only alternative findings. One (0.3%) case was indeterminate for acute aortic disorder. Overall, 112 findings were interpreted as positive for acute aortic disorder, an alternative finding, or both at CT. No interpretations were false-positive, one was false-negative, 67 were true-positive, and 304 were true-negative. Sensitivity, specificity, PPV, NPV, and accuracy were

  16. 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...... 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....... 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...

  17. 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 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.

  18. 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.

    2013-01-01

    Detection and quantitation of protein-ligand binding interactions is important in many areas of biological research. The Stability of Proteins from Rates of Oxidation (SPROX) technique 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 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. PMID:24114261

  19. [Serologic study on the prevalence of HIV, HBV infection and on the false positive reaction of VDRL at a prison].

    Science.gov (United States)

    Capoccia, A; Ranieri, R; Busnelli, M; Passaretti, B; Milella, A M; Vecchi, L

    1991-03-01

    Prisoners are considered to be a high risk population for HIV and HBV infection. Aim of this study was to determine the prevalence of HIV, HBV infection and of the VDRL false positivity by performing screening tests in 496 prisoners of Monza in 1987. About a third of prisoners was HIV infected (with a high prevalence in drug addicts) and about a half had a contact with HBV virus. We observed a very common association between HIV and HBV infections. About ten per cent of HIV infected presented a false positivity for VDRL while one per cent of not infected did. Our data show that in Italian prison HIV and HBV infections are spreadly diffused. False positivity for VDRL may be due not only to drug addiction but also to the immunological variations connected with AIDS.

  20. 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.

  1. 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.

  2. 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.

  3. Newly Shaped Intra‐Aortic Balloons Improve the Performance of Counterpulsation at the Semirecumbent Position: An In Vitro Study

    Science.gov (United States)

    Kolyva, Christina; Pepper, John R.

    2016-01-01

    Abstract The major hemodynamic benefits of intra‐aortic balloon pump (IABP) counterpulsation are augmentation in diastolic aortic pressure (P aug) during inflation, and decrease in end‐diastolic aortic pressure (ΔedP) during deflation. When the patient is nursed in the semirecumbent position these benefits are diminished. Attempts to change the shape of the IAB in order to limit or prevent this deterioration have been scarce. The aim of the present study was to investigate the hemodynamic performance of six new IAB shapes, and compare it to that of a traditional cylindrical IAB. A mock circulation system, featuring an artificial left ventricle and an aortic model with 11 branches and physiological resistance and compliance, was used to test one cylindrical and six newly shaped IABs at angles 0, 10, 20, 30, and 40°. Pressure was measured continuously at the aortic root during 1:1 and 1:4 IABP support. Shape 2 was found to consistently achieve, in terms of absolute magnitude, larger ΔedP at angles than the cylindrical IAB. Although ΔedP was gradually diminished with angle, it did so to a lesser degree than the cylindrical IAB; this diminishment was only 53% (with frequency 1:1) and 40% (with frequency 1:4) of that of the cylindrical IAB, when angle increased from 0 to 40°. During inflation Shape 1 displayed a more stable behavior with increasing angle compared to the cylindrical IAB; with an increase in angle from 0 to 40°, diastolic aortic pressure augmentation dropped only by 45% (with frequency 1:1) and by 33% (with frequency 1:4) of the drop reached with the cylindrical IAB. After compensating for differences in nominal IAB volume, Shape 1 generally achieved higher P aug over most angles. Newly shaped IABs could allow for IABP therapy to become more efficient for patients nursed at the semirecumbent position. The findings promote the idea of personalized rather than generalized patient therapy for the achievement of higher IABP therapeutic efficiency

  4. Urease-positive bacteria in the stomach induce a false-positive reaction in a urea breath test for diagnosis of Helicobacter pylori infection.

    Science.gov (United States)

    Osaki, Takako; Mabe, Katsuhiro; Hanawa, Tomoko; Kamiya, Shigeru

    2008-07-01

    This study investigated the influence of urease-positive non-Helicobacter pylori bacteria on the results of a urea breath test (UBT) to evaluate the diagnostic utility of a UBT using film-coated [(13)C]urea tablets. The UBT was performed in 102 patients treated with a proton pump inhibitor and antibiotics for the eradication of H. pylori. Urease-producing bacteria other than H. pylori were isolated and identified from the oral cavity and stomach. In 4/102 patients, the UBT gave false-positive results. These false-positive results were found to be caused by the presence of urease-positive bacteria in the oral cavity and stomach. Five bacterial species with urease activity (Proteus mirabilis, Citrobacter freundii, Klebsiella pneumoniae, Enterobacter cloacae and Staphylococcus aureus) were subsequently isolated from the oral cavity and/or stomach. As there was no correlation between the in vitro urease activity of urease-positive non-H. pylori bacteria and the UBT value, and all of the patients with a false-positive UBT result were suffering from atrophic gastritis, it is possible that the false-positive results in the UBT were a result of colonization of urease-positive bacteria and gastric hypochlorhydric conditions. Thus, for the diagnosis of H. pylori infection using a UBT, the influence of stomach bacteria must be considered when interpreting the results.

  5. Sporadic bilateral adrenal medullary hyperplasia: apparent false positive MIBG scan and expected MRI findings

    Energy Technology Data Exchange (ETDEWEB)

    Yung, Babington C.K.; Loke, Tony K.L.; Tse, T.W.; Tsang, M.W.; Chan, James C.S. E-mail: jcschan@ha.org.hk

    2000-10-01

    Adrenal medullary hyperplasia is a rare cause of clinical symptoms and biochemical findings identical to pheochromocytoma occurring mostly in multiple endocrine neoplasia patients. The scenario of positive MIBG scan, but no focal lesion found on CT and MRI led to diagnostic and management difficulties. Like pheochromocytoma, surgical excision can lead to clinical and biochemical recovery. We report this unusual case of sporadic bilateral adrenal medullary hyperplasia, with hypertension and biochemical abnormalities alleviated after surgical adrenalectomy. Based on T2 values reported in literature, high signal focal lesions may not appear on T2-weighted MRI images until development of frank pheochromocytoma. MIBG scan remains the most sensitive imaging modality for this condition.

  6. Patients' & healthcare professionals' values regarding true- & false-positive diagnosis when colorectal cancer screening by CT colonography: discrete choice experiment.

    Directory of Open Access Journals (Sweden)

    Darren Boone

    Full Text Available PURPOSE: To establish the relative weighting given by patients and healthcare professionals to gains in diagnostic sensitivity versus loss of specificity when using CT colonography (CTC for colorectal cancer screening. MATERIALS AND METHODS: Following ethical approval and informed consent, 75 patients and 50 healthcare professionals undertook a discrete choice experiment in which they chose between "standard" CTC and "enhanced" CTC that raised diagnostic sensitivity 10% for either cancer or polyps in exchange for varying levels of specificity. We established the relative increase in false-positive diagnoses participants traded for an increase in true-positive diagnoses. RESULTS: Data from 122 participants were analysed. There were 30 (25% non-traders for the cancer scenario and 20 (16% for the polyp scenario. For cancer, the 10% gain in sensitivity was traded up to a median 45% (IQR 25 to >85 drop in specificity, equating to 2250 (IQR 1250 to >4250 additional false-positives per additional true-positive cancer, at 0.2% prevalence. For polyps, the figure was 15% (IQR 7.5 to 55, equating to 6 (IQR 3 to 22 additional false-positives per additional true-positive polyp, at 25% prevalence. Tipping points were significantly higher for patients than professionals for both cancer (85 vs 25, p<0.001 and polyps (55 vs 15, p<0.001. Patients were willing to pay significantly more for increased sensitivity for cancer (p = 0.021. CONCLUSION: When screening for colorectal cancer, patients and professionals believe gains in true-positive diagnoses are worth much more than the negative consequences of a corresponding rise in false-positives. Evaluation of screening tests should account for this.

  7. Internal Impingement of the Shoulder: A Risk of False Positive Test Outcomes in External Impingement Tests?

    Directory of Open Access Journals (Sweden)

    Tim Leschinger

    2017-01-01

    Full Text Available Background. External impingement tests are considered as being particularly reliable for identifying subacromial and coracoid shoulder impingement mechanisms. The purpose of the present study was to evaluate if these tests are likely to provoke an internal shoulder impingement mechanism which, in cases of a pathologic condition, can lead to a positive test result. Method. In 37 subjects, the mechanical contact between the glenoid rim and the rotator cuff (RC was measured quantitatively and qualitatively in external impingement test positions using an open MRI system. Results. Mechanical contact of the supraspinatus with the posterosuperior glenoid was present in 30 subjects in the Neer test. In the Hawkins test, the subscapularis was in contact with the anterosuperior glenoid in 33 subjects and the supraspinatus in 18. In the horizontal impingement test, anterosuperior contact of the supraspinatus with the glenoid was identified in 35 subjects. Conclusion. The Neer, Hawkins, and horizontal impingement tests are likely to provoke the mechanism of an internal shoulder impingement. A posterosuperior internal impingement mechanism is being provoked predominately in the Neer test. The Hawkins test narrows the distance between the insertions of the subscapularis and supraspinatus and the anterosuperior labrum, which leads to an anterosuperior impingement mechanism.

  8. The impact of a false-positive MRI on the choice for mastectomy in BRCA mutation carriers is limited.

    NARCIS (Netherlands)

    Hoogerbrugge-van der Linden, N.; Kamm, Y.J.; Bult, P.; Landsbergen, K.M.; Bongers, E.M.; Brunner, H.G.; Bonenkamp, H.J.; Hullu, JA de; Ligtenberg, M.J.; Boetes, C.

    2008-01-01

    PURPOSE: To assess the false-positive rate of breast cancer surveillance by magnetic resonance imaging (MRI) in BRCA mutation carriers and the impact of an abnormal mammography or breast MRI on the patients' decision for prophylactic mastectomy. PATIENTS AND METHODS: A total of 196 BRCA mutation

  9. 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

  10. Doctor can't make lab pay damages for false-positive HIV test.

    Science.gov (United States)

    1997-08-22

    The Texas Court of Appeals ruled that physician [name removed] was not eligible for damages from a laboratory that misreported HIV test results for one of her patients. [Name removed] sued Pathlab, Inc., a laboratory that had a policy of performing an ELISA test and a Western blot test, but that only reported the ELISA result unless a physician specifically requested and paid for the Western blot results. One of Dr. [name removed]'s patients was diagnosed as HIV-positive in error; the patient sued [name removed] and Pathlab. All claims against Dr. [name removed] were dismissed. The court ruled that Dr. [name removed] could not seek damages against Pathlab because this would have amounted to an improper attempt to gain indemnification.

  11. 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.

  12. Distinguishing binders from false positives by free energy calculations: fragment screening against the flap site of HIV protease.

    Science.gov (United States)

    Deng, Nanjie; Forli, Stefano; He, Peng; Perryman, Alex; Wickstrom, Lauren; Vijayan, R S K; Tiefenbrunn, Theresa; Stout, David; Gallicchio, Emilio; Olson, Arthur J; Levy, Ronald M

    2015-01-22

    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.

  13. Predicting residue contacts using pragmatic correlated mutations method: reducing the false positives

    Directory of Open Access Journals (Sweden)

    Alexov Emil G

    2006-11-01

    Full Text Available Abstract Background Predicting residues' contacts using primary amino acid sequence alone is an important task that can guide 3D structure modeling and can verify the quality of the predicted 3D structures. The correlated mutations (CM method serves as the most promising approach and it has been used to predict amino acids pairs that are distant in the primary sequence but form contacts in the native 3D structure of homologous proteins. Results Here we report a new implementation of the CM method with an added set of selection rules (filters. The parameters of the algorithm were optimized against fifteen high resolution crystal structures with optimization criterion that maximized the confidentiality of the predictions. The optimization resulted in a true positive ratio (TPR of 0.08 for the CM without filters and a TPR of 0.14 for the CM with filters. The protocol was further benchmarked against 65 high resolution structures that were not included in the optimization test. The benchmarking resulted in a TPR of 0.07 for the CM without filters and to a TPR of 0.09 for the CM with filters. Conclusion Thus, the inclusion of selection rules resulted to an overall improvement of 30%. In addition, the pair-wise comparison of TPR for each protein without and with filters resulted in an average improvement of 1.7. The methodology was implemented into a web server http://www.ces.clemson.edu/compbio/recon that is freely available to the public. The purpose of this implementation is to provide the 3D structure predictors with a tool that can help with ranking alternative models by satisfying the largest number of predicted contacts, as well as it can provide a confidence score for contacts in cases where structure is known.

  14. A new yield simulator for transiting planets and false positives: application to the Next Generation Transit Survey

    Science.gov (United States)

    Günther, Maximilian N.; Queloz, Didier; Demory, Brice-Olivier; Bouchy, Francois

    2017-03-01

    We present a yield simulator to predict the number and characteristics of planets, false positives and false alarms in transit surveys. The simulator is based on a galactic model and the planet occurrence rates measured by the Kepler mission. It takes into account the observation window function and measured noise levels of the investigated survey. Additionally, it includes vetting criteria to identify false positives. We apply this simulator to the Next Generation Transit Survey (NGTS), a wide-field survey designed to detect transiting Neptune-sized exoplanets. We find that red noise is the main limitation of NGTS up to 14 mag, and that its obtained level determines the expected yield. Assuming a red noise level of 1 mmag, the simulation predicts the following for a 4-yr survey: 4 ± 3 Super-Earths, 19 ± 5 Small Neptunes, 16 ± 4 Large Neptunes, 55 ± 8 Saturn-sized planets and 150 ± 10 Jupiter-sized planets, along with 4688 ± 45 eclipsing binaries and 843 ± 75 background eclipsing binaries. We characterize the properties of these objects to enhance the early identification of false positives and discuss follow-up strategies for transiting candidates.

  15. Concurrent combined verification: reducing false positives in automated NMR structure verification through the evaluation of multiple challenge control structures.

    Science.gov (United States)

    Golotvin, Sergey S; Pol, Rostislav; Sasaki, Ryan R; Nikitina, Asya; Keyes, Philip

    2012-06-01

    Automated structure verification using (1)H NMR data or a combination of (1)H and heteronuclear single-quantum correlation (HSQC) data is gaining more interest as a routine application for qualitative evaluation of large compound libraries produced by synthetic chemistry. The goal of this automated software method is to identify a manageable subset of compounds and data that require human review. In practice, the automated method will flag structure and data combinations that exhibit some inconsistency (i.e. strange chemical shifts, conflicts in multiplicity, or overestimated and underestimated integration values) and validate those that appear consistent. One drawback of this approach is that no automated system can guarantee that all passing structures are indeed correct structures. The major reason for this is that approaches using only (1)H or even (1)H and HSQC spectra often do not provide sufficient information to properly distinguish between similar structures. Therefore, current implementations of automated structure verification systems allow, in principle, false positive results. Presented in this work is a method that greatly reduces the probability of an automated validation system passing incorrect structures (i.e. false positives). This novel method was applied to automatically validate 127 non-proprietary compounds from several commercial sources. Presented also is the impact of this approach on false positive and false negative results.

  16. Pokorny's complaint: the insoluble problem of the overwhelming number of false positives generated by suicide risk assessment

    Science.gov (United States)

    Nielssen, Olav; Wallace, Duncan; Large, Matthew

    2017-01-01

    Alex Pokorny's 1983 prospective study of suicide found that 96.3% of high-risk predictions were false positives, and that more than half of the suicides occurred in the low-risk group and were hence false negatives. All subsequent prospective studies, including the recent US Army Study To Assess Risk and Resilience in Servicemembers (STARRS), have reported similar results. We argue that since risk assessment cannot be a practical basis for interventions aimed at reducing suicide, the alternative is for mental health services to carefully consider what amounts to an adequate standard of care, and to adopt the universal precaution of attempting to provide that to all of our patients.

  17. 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.

  18. Kepler Eclipsing Binary Stars. VIII. Identification of False Positive Eclipsing Binaries and Re-extraction of New Light Curves

    CERN Document Server

    Abdul-Masih, Michael; Conroy, Kyle; Bloemen, Steven; Boyajian, Tabetha; Doyle, Laurance R; Johnston, Cole; Kostov, Veselin; Latham, David W; Matijevic, Gal; Shporer, Avi; Southworth, John

    2016-01-01

    The Kepler Mission has provided unprecedented, nearly continuous photometric data of $\\sim$200,000 objects in the $\\sim$105 deg$^{2}$ field of view from the beginning of science operations in May of 2009 until the loss of the second reaction wheel in May of 2013. The Kepler Eclipsing Binary Catalog contains information including but not limited to ephemerides, stellar parameters and analytical approximation fits for every known eclipsing binary system in the Kepler Field of View. Using Target Pixel level data collected from Kepler in conjunction with the Kepler Eclipsing Binary Catalog, we identify false positives among eclipsing binaries, i.e. targets that are not eclipsing binaries themselves, but are instead contaminated by eclipsing binary sources nearby on the sky and show eclipsing binary signatures in their light curves. We present methods for identifying these false positives and for extracting new light curves for the true source of the observed binary signal. For each source, we extract three separa...

  19. Using the minimum description length principle to reduce the rate of false positives of best-fit algorithms.

    Science.gov (United States)

    Fang, Jie; Ouyang, Hongjia; Shen, Liangzhong; Dougherty, Edward R; Liu, Wenbin

    2014-12-01

    The inference of gene regulatory networks is a core problem in systems biology. Many inference algorithms have been proposed and all suffer from false positives. In this paper, we use the minimum description length (MDL) principle to reduce the rate of false positives for best-fit algorithms. The performance of these algorithms is evaluated via two metrics: the normalized-edge Hamming distance and the steady-state distribution distance. Results for synthetic networks and a well-studied budding-yeast cell cycle network show that MDL-based filtering is more effective than filtering based on conditional mutual information (CMI). In addition, MDL-based filtering provides better inference than the MDL algorithm itself.

  20. Extended Durability of a Cloth-Covered Star-Edwards Caged Ball Prosthesis in Aortic Position

    Directory of Open Access Journals (Sweden)

    Yusuf Ata

    2009-01-01

    Full Text Available The Starr-Edwards caged ball valve is one of the oldest cardiac valve prosthesis and was widely used all around the world in the past decades. Despite the long-term results that have been reported there are only a few cases reported that exceed 30 years of durability. Here in, we report a 53-year-old patient with a well-functioning 35-year-old aortic Starr-Edwards caged ball prosthesis.

  1. Do one-time intracompartmental pressure measurements have a high false-positive rate in diagnosing compartment syndrome?

    Science.gov (United States)

    Whitney, Augusta; O'Toole, Robert V; Hui, Emily; Sciadini, Marcus F; Pollak, Andrew N; Manson, Theodore T; Eglseder, W Andrew; Andersen, Romney C; Lebrun, Christopher; Doro, Christopher; Nascone, Jason W

    2014-02-01

    Intracompartmental pressure measurements are frequently used in the diagnosis of compartment syndrome, particularly in patients with equivocal or limited physical examination findings. Little clinical work has been done to validate the clinical use of intracompartmental pressures or identify associated false-positive rates. We hypothesized that diagnosis of compartment syndrome based on one-time pressure measurements alone is associated with a high false-positive rate. Forty-eight consecutive patients with tibial shaft fractures who were not suspected of having compartment syndrome based on physical examinations were prospectively enrolled. Pressure measurements were obtained in all four compartments at a single point in time immediately after induction of anesthesia using a pressure-monitoring device. Preoperative and intraoperative blood pressure measurements were recorded. The same standardized examination was performed by the attending surgeon preoperatively, postoperatively, and during clinical follow-up for 6 months to assess clinical evidence of acute or late compartment syndrome. No clinical evidence of compartment syndrome was observed postoperatively or during follow-up until 6 months after injury. Using the accepted criteria of delta P of 30 mm Hg from preoperative diastolic blood pressure, 35% of cases (n = 16; 95% confidence interval, 21.5-48.5%) met criteria for compartment syndrome. Raising the threshold to delta P of 20 mm Hg reduced the false-positive rate to 24% (n = 11; 95% confidence interval, 11.1-34.9%). Twenty-two percent (n = 10; 95% confidence interval, 9.5-32.5%) exceeded absolute pressure of 45 mm Hg. A 35% false-positive rate was found for the diagnosis of compartment syndrome in patients with tibial shaft fractures who were not thought to have compartment syndrome by using currently accepted criteria for diagnosis based solely on one-time compartment pressure measurements. Our data suggest that reliance on one-time intracompartmental

  2. Differential Gene Expression Segregates Cattle Confirmed Positive for Bovine Tuberculosis from Antemortem Tuberculosis Test-False Positive Cattle Originating from Herds Free of Bovine Tuberculosis

    Directory of Open Access Journals (Sweden)

    Ailam Lim

    2012-01-01

    Full Text Available Antemortem tests for bovine tuberculosis (bTB currently used in the US measure cell-mediated immune responses against Mycobacterium bovis. Postmortem tests for bTB rely on observation of gross and histologic lesions of bTB, followed by bacterial isolation or molecular diagnostics. Cumulative data from the state of Michigan indicates that 98 to 99% of cattle that react positively in antemortem tests are not confirmed positive for bTB at postmortem examination. Understanding the fundamental differences in gene regulation between antemortem test-false positive cattle and cattle that have bTB may allow identification of molecular markers that can be exploited to better separate infected from noninfected cattle. An immunospecific cDNA microarray was used to identify altered gene expression (≤0.01 of 122 gene features between antemortem test-false positive cattle and bTB-infected cattle following a 4-hour stimulation of whole blood with tuberculin. Further analysis using quantitative real-time PCR assays validated altered expression of 8 genes that had differential power (adj  ≤0.05 to segregate cattle confirmed positive for bovine tuberculosis from antemortem tuberculosis test-false positive cattle originating from herds free of bovine tuberculosis.

  3. 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. PMID:26342055

  4. [False positive result in mammography and its association with the presence of obesity: a case-control study].

    Science.gov (United States)

    Castro-Ibarra, Marisela; Menchaca-Díaz, Rufino; Cabrales-Ruvalcaba, J Jesús; Luna-V Gómez, Rosa Alicia

    2016-01-01

    To analyze the association between a false positive result in mammography and obesity, inside the breast cancer early detection program in women affiliated to the Institute of Security and Social Services for Government and Municipality workers of the State of Baja California (ISSSTECALI). A case-control, retrospective study was done in women affiliated to ISSSTECALI to whom a mammography was performed between 2009 and 2012. Women with a false positive result in mammography were included as cases. Controls were women with a true negative result in mammography. Three controls were randomly selected for each case. Obesity was established with the body mass index (BMI) consigned in the woman's clinical file. Age and estrogen replacement therapy were included as co-variables. Seventy nine cases were identified and 237 controls were included. Obesity was observed in 54.4% of cases and in 41.3% of controls (odds ratio: 1.69; 95% confidence interval for odds ratio: 1.01-2.82; p value: 0.043). A logistic regression model including covariables maintained the observed association (p = 0.044). No association was found with analyzed co-variables. A false positive result in mammography was associated with the presence of obesity.

  5. 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.

  6. To control false positives in gene-gene interaction analysis: two novel conditional entropy-based approaches.

    Directory of Open Access Journals (Sweden)

    Xiaoyu Zuo

    Full Text Available Genome-wide analysis of gene-gene interactions has been recognized as a powerful avenue to identify the missing genetic components that can not be detected by using current single-point association analysis. Recently, several model-free methods (e.g. the commonly used information based metrics and several logistic regression-based metrics were developed for detecting non-linear dependence between genetic loci, but they are potentially at the risk of inflated false positive error, in particular when the main effects at one or both loci are salient. In this study, we proposed two conditional entropy-based metrics to challenge this limitation. Extensive simulations demonstrated that the two proposed metrics, provided the disease is rare, could maintain consistently correct false positive rate. In the scenarios for a common disease, our proposed metrics achieved better or comparable control of false positive error, compared to four previously proposed model-free metrics. In terms of power, our methods outperformed several competing metrics in a range of common disease models. Furthermore, in real data analyses, both metrics succeeded in detecting interactions and were competitive with the originally reported results or the logistic regression approaches. In conclusion, the proposed conditional entropy-based metrics are promising as alternatives to current model-based approaches for detecting genuine epistatic effects.

  7. Application of computer-extracted breast tissue texture features in predicting false-positive recalls from screening mammography

    Science.gov (United States)

    Ray, Shonket; Choi, Jae Y.; Keller, Brad M.; Chen, Jinbo; Conant, Emily F.; Kontos, Despina

    2014-03-01

    Mammographic texture features have been shown to have value in breast cancer risk assessment. Previous models have also been developed that use computer-extracted mammographic features of breast tissue complexity to predict the risk of false-positive (FP) recall from breast cancer screening with digital mammography. This work details a novel locallyadaptive parenchymal texture analysis algorithm that identifies and extracts mammographic features of local parenchymal tissue complexity potentially relevant for false-positive biopsy prediction. This algorithm has two important aspects: (1) the adaptive nature of automatically determining an optimal number of region-of-interests (ROIs) in the image and each ROI's corresponding size based on the parenchymal tissue distribution over the whole breast region and (2) characterizing both the local and global mammographic appearances of the parenchymal tissue that could provide more discriminative information for FP biopsy risk prediction. Preliminary results show that this locallyadaptive texture analysis algorithm, in conjunction with logistic regression, can predict the likelihood of false-positive biopsy with an ROC performance value of AUC=0.92 (pclinical implications of using prediction models incorporating these texture features may include the future development of better tools and guidelines regarding personalized breast cancer screening recommendations. Further studies are warranted to prospectively validate our findings in larger screening populations and evaluate their clinical utility.

  8. Canadian Cardiovascular Society/Canadian Society of Cardiac Surgeons/Canadian Society for Vascular Surgery Joint Position Statement on Open and Endovascular Surgery for Thoracic Aortic Disease.

    Science.gov (United States)

    Appoo, Jehangir J; Bozinovski, John; Chu, Michael W A; El-Hamamsy, Ismail; Forbes, Thomas L; Moon, Michael; Ouzounian, Maral; Peterson, Mark D; Tittley, Jacques; Boodhwani, Munir

    2016-06-01

    In 2014, the Canadian Cardiovascular Society (CCS) published a position statement on the management of thoracic aortic disease addressing size thresholds for surgery, imaging modalities, medical therapy, and genetics. It did not address issues related to surgical intervention. This joint Position Statement on behalf of the CCS, Canadian Society of Cardiac Surgeons, and the Canadian Society for Vascular Surgery provides recommendations about thoracic aortic disease interventions, including: aortic valve repair, perfusion strategies for arch repair, extended arch hybrid reconstruction for acute type A dissection, endovascular management of arch and descending aortic aneurysms, and type B dissection. The position statement is constructed using Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology, and has been approved by the primary panel, an international secondary panel, and the CCS Guidelines Committee. Advent of endovascular technology has improved aortic surgery safety and extended the indications of minimally invasive thoracic aortic surgery. The combination of safer open surgery with endovascular treatment has improved patient outcomes in this rapidly evolving subspecialty field of cardiovascular surgery.

  9. Hepatitis C virus infection and biological false-positive syphilis test:a single-center experience

    Institute of Scientific and Technical Information of China (English)

    Wei-Fang Zhu; Shui-Ying Lei; Lan-Juan Li

    2011-01-01

    BACKGROUND: Rapidplasmaregainpositiveand/ortreponema pallidum hemagglutination negative [RPR(+)/TPHA(-)] results were designated as biologic false-positive (BFP). There are limited data about BFP reactions against syphilis in patients with hepatitis C virus (HCV) infection. This study aimed to determine the prevalence of BFP reactions for syphilis in patients with HCV infection in a large sample and assess the relationship between BFP reactions and HCV infection. METHODS:  A total of 2656 patients with positive anti-HCV and 5600 healthy control subjects were enrolled in this study. Hepatitis C serology was determined by a second generation ELISA test for HCV antibody. Syphilis serology was determined by the RPR test. Those subjects with reactive RPR positive underwent the TPHA test. Demographics and laboratory data were collected by trained clinicians. RESULTS: Among 2656 patients, 111 (4.2%) had a reactive RPR test. Of the 111 patients who were subjected to reactive RPR test, 30 (27.0%) showed HCV(+)/RPR(+). Of 5600 healthy controls, 80 (1.4%) had a reactive RPR test. Fourteen (17.5%) controls with HCV(-)/RPR(+) had a non-reactive TPHA test. These represented 1.1% of all HCV-positive and 0.3% of all HCV-negative subjects (P0.05). CONCLUSIONS: The data of this study demonstrate that HCV infection is associated with a false-positive RPR test. In this study BFPs were significantly more common in HCV positive patients compared to HCV-negative ones. Eosinophil abnormality can be considered as a predictor for BFP. Excessive BFPs must be considered in assessing the frequency of syphilis in a HCV-positive population and the importance of the treponemal specific serologic test should be emphasized for a diagnosis of syphilis in such population.

  10. The clinical impact of a false-positive urine cocaine screening result on a patient's pain management.

    Science.gov (United States)

    Kim, James A; Ptolemy, Adam S; Melanson, Stacy E F; Janfaza, David R; Ross, Edgar L

    2015-06-01

    The urine of a patient admitted for chest and epigastric pain tested positive for cocaine using an immunoassay-based drug screening method (positive/negative cutoff concentration 150 ng/mL). Despite the patient's denial of recent cocaine use, this positive cocaine screening result in conjunction with a remote history of drug misuse impacted the patient's recommended pain therapy. Specifically, these factors prompted the clinical team to question the appropriateness of opioids and other potentially addictive therapeutics during the treatment of cancer pain from previously undetected advanced pancreatic carcinoma. After pain management and clinical pathology consultation, it was decided that the positive cocaine screening result should be confirmed by gas chromatography-mass spectrometry (GC-MS) testing. This more sensitive and specific analytical technique revealed that both cocaine and its primary metabolite benzoylecgonine were undetectable (i.e., less than the assay detection limit of 50 ng/mL), thus indicating that the positive urine screening result was falsely positive. With this confirmation, the pain management service team was reassured in offering intrathecal pump (ITP) therapy for pain control. ITP implantation was well tolerated, and the patient eventually achieved excellent pain relief. However, ITP therapy most likely would not have been utilized without the GC-MS confirmation testing unless alternative options failed and extensive vigilant monitoring was initiated. As exemplified in this case, confirmatory drug testing should be performed on specimens with unexpected immunoassay-based drug screening results. To our knowledge, this is the first report of a false-positive urine cocaine screening result and its impact on patient management. Wiley Periodicals, Inc.

  11. A New Yield Simulator for Transiting Planets and False Positives: Application to the Next Generation Transit Survey

    CERN Document Server

    Günther, Maximilian N; Demory, Brice-Olivier; Bouchy, Francois

    2016-01-01

    We present a yield simulator to predict the number and characteristics of planets, false positives and false alarms in transit surveys. The simulator is based on a galactic model and the planet occurrence rates measured by the Kepler mission. It takes into account the observation window function and measured noise levels of the investigated survey. Additionally, it includes vetting criteria to identify false positives. We apply this simulator to the Next Generation Transit Survey (NGTS), a wide-field survey designed to detect transiting Neptune-sized exoplanets. We find that red noise is the main limitation of NGTS up to 14th magnitude, and that its obtained level determines the expected yield. Assuming a red noise level of 1 mmag, the simulation predicts the following for a four-year survey: 4+-3 Super-Earths, 19+-5 Small Neptunes, 16+-4 Large Neptunes, 55+-8 Saturn-sized planets and 150+-10 Jupiter-sized planets, along with 4688+-45 eclipsing binaries and 843+-75 background eclipsing binaries. We characteri...

  12. False positive VDRL (BFP-STS) and systemic lupus erythematosus; new data in clinico-laboratory associations.

    Science.gov (United States)

    Al Attia, Haider M

    2002-12-01

    To investigate the relationships between clinical features and serological parameters in systemic lupus erythematosus (SLE) patients with false positive venereal disease research laboratory (VDRL) test (BFP-STS) and those without. The records of 74 patients with SLE were reviewed. These were divided on the basis of the presence of a biologically false positive serological test (BFP-STS) (n = 18) or its absence (n = 56). The clinical features and serological parameters were subsequently evaluated in each group. A biologically false positive serological test was found in 18 patients (24.5%). Clinically, they had a significantly higher frequency of malar rash (P < 0.02), hemolytic anaemia (P < 0.02) and SLE-related antiphospholipid (APL) syndrome (P < 0.02). Neuropsychiatric lupus was more frequent in the group without BFP-STS. Moreover, subacute cutaneous LE (SCLE), Raynaud's phenomenon, livedo reticularis (LR) and cardiopulmonary complications were present only in the latter group. There was no significant association between BFP-STS and other autoantibodies including Extractable nuclear antigen (ENAs), however, there was a significant association with C3 hypocomplementemia (P < 0.05). Half of the patients with BFP-STS were positive for anticardiolipin antibodies (aCL Abs) vs. 28% in the negative group (P = NS). The study suggests that the clinical and serological relevance of BFP-STS in lupus patients may vary from those described in relation to other antiphospholipid determinants. Our patients appeared to have sparing of certain major organ systems, yet there was a greater tendency to developing Antiphospholipid (APL) syndrome and hemolytic anaemia.

  13. Bovine Pericardial Patch Augmentation of One Insufficient Aortic Valve Cusp with Twenty-three-year Positive Clinical Follow-up Independent of the Patch Degeneration

    Science.gov (United States)

    Evora, Paulo Roberto Barbosa; Arcêncio, Lívia; Evora, Patrícia Martinez; Menardi, Antônio Carlos; Chahud, Fernando

    2017-01-01

    Scientific progress shall ultimately boost the current acceptance level for conservative aortic valve surgery. The present text aimed to report the 23-year long-term follow-up of one patient operated with bovine pericardium cusp extension. Growing confidence in the efficacy of the operation will allow a more expeditious indication for surgical treatment, as is already the case in mitral valve repair. This change of attitude will certainly make it possible for patients to be sent for operation in mild aortic valve regurgitation. The present report reinforces the concept and highlights the impression that the aortic valvoplasty, independent of the progressive bovine pericardium degeneration, may positively change the natural history of the aortic valve insufficiency.

  14. Yersinia enterocolitica serotype O:9 cultured from Swedish sheep showing serologically false-positive reactions for Brucella melitensis.

    Science.gov (United States)

    Chenais, Erika; Bagge, Elisabeth; Lambertz, Susanne Thisted; Artursson, Karin

    2012-01-01

    In a herd of 20 sheep in Sweden, a country where brucellosis has never been diagnosed in sheep or goats, a total of six sheep were found serologically positive to Brucella melitensis in two different rounds of sampling. Yersinia enterocolitica serotype O:9 could at the time of the second sampling be isolated from four sheep, one of them at the same time serologically positive for B. melitensis. The article describes the case and gives some background information on brucellosis and Y. enterocolitica in general as well as a more specific description of the Swedish surveillance program for B. melitensis and the test procedures used. The problem with false-positive reactions, in particular its implications for surveillance programs in low prevalence or officially brucellosis-free countries, is discussed.

  15. Six consecutive false positive cases from cell-free fetal DNA testing in a single referring centre

    Science.gov (United States)

    Dugo, Nella; Padula, Francesco; Mobili, Luisa; Brizzi, Cristiana; D’Emidio, Laura; Cignini, Pietro; Mesoraca, Alvaro; Bizzoco, Domenico; Cima, Antonella; Giorlandino, Claudio

    2014-01-01

    Introduction recent studies have proposed the introduction of cell-free fetal DNA testing (NIPT-Non Invasive Prenatal Testing) in routine clinical practice emphasizing its high sensibility and specificity. In any case, false positive and false negative findings may result from placental mosaicism, because cell-free fetal DNA originates mainly from placenta. Case we report six cases of women who underwent chorionic villus sampling (CVS) or amniocentesis to confirm the results from NIPT: two Turner syndromes, two Triple X, one Patau syndrome, one Edward syndrome. Results using classic cytogenetic analysis and, also, Array - Comparative Genomic Hybridization (Array CGH) the karyotype of all 5 fetuses was found to be normal. Conclusion results from NIPT must always be confirmed by invasive prenatal diagnosis. It is mandatory to inform the patient that the CVS and amniocentesis still represent the only form of prenatal diagnostic test available. PMID:25332757

  16. Modeling and computational analysis of the hemodynamic effects of crossing the limbs in an aortic endograft ("ballerina" position).

    Science.gov (United States)

    Georgakarakos, Efstratios; Xenakis, Antonios; Manopoulos, Christos; Georgiadis, George S; Tsangaris, Sokrates; Lazarides, Miltos K

    2012-08-01

    To evaluate the displacement forces acting on an aortic endograft when the iliac limbs are crossed ("ballerina" position). An endograft model was computationally reconstructed based on data from a patient whose infrarenal aortic aneurysm had an endovascular stent-graft implanted with the iliac limbs crossed. Computational fluid dynamics analysis determined the maximum displacement force on the endograft and separately on the bifurcation and iliac limbs. Its analogue model was reconstructed for comparison, assuming the neck, main body, and total length constant but considering the iliac limbs to be deployed in the usual bifurcated mode. Calculations were repeated after developing "idealized" models of both the bifurcated and crossed-limbs endografts with straight main bodies and no neck angulation or curved iliac segments. The vector of the total force was directed anterocaudal for both the typical bifurcated and the crossed-limbs configurations, with the forces in the latter slightly reduced and the vertical component accounting for most of the force in both configurations. Idealized crossed-limbs and bifurcated configurations differed only in the force on the iliac limbs, but this difference disappeared in the realistic models. Crossing of the iliac limbs can slightly affect the direction of the displacement forces. Although this configuration can exert larger forces on the limbs than in the bifurcated mode, this effect can be blunted by concomitant modifications in the geometry of the main body and other parts of the endograft, making its hemodynamic behavior resemble that of a typically positioned endograft.

  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. Aortic insufficiency

    Science.gov (United States)

    ... page, please enable JavaScript. Aortic insufficiency is a heart valve disease in which the aortic valve does not close ... aortic insufficiency Images Aortic insufficiency References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  19. 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

  20. Kepler Eclipsing Binary Stars. VIII. Identification of False Positive Eclipsing Binaries and Re-extraction of New Light Curves

    Science.gov (United States)

    Abdul-Masih, Michael; Prša, Andrej; Conroy, Kyle; Bloemen, Steven; Boyajian, Tabetha; Doyle, Laurance R.; Johnston, Cole; Kostov, Veselin; Latham, David W.; Matijevič, Gal; Shporer, Avi; Southworth, John

    2016-04-01

    The Kepler mission has provided unprecedented, nearly continuous photometric data of ∼200,000 objects in the ∼105 deg2 field of view (FOV) from the beginning of science operations in May of 2009 until the loss of the second reaction wheel in May of 2013. The Kepler Eclipsing Binary Catalog contains information including but not limited to ephemerides, stellar parameters, and analytical approximation fits for every known eclipsing binary system in the Kepler FOV. Using target pixel level data collected from Kepler in conjunction with the Kepler Eclipsing Binary Catalog, we identify false positives among eclipsing binaries, i.e., targets that are not eclipsing binaries themselves, but are instead contaminated by eclipsing binary sources nearby on the sky and show eclipsing binary signatures in their light curves. We present methods for identifying these false positives and for extracting new light curves for the true source of the observed binary signal. For each source, we extract three separate light curves for each quarter of available data by optimizing the signal-to-noise ratio, the relative percent eclipse depth, and the flux eclipse depth. We present 289 new eclipsing binaries in the Kepler FOV that were not targets for observation, and these have been added to the catalog. An online version of this catalog with downloadable content and visualization tools is maintained at http://keplerEBs.villanova.edu.

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

    Science.gov (United States)

    Hannoush, Zeina C.; Palacios, Juan D.; Kuker, Russ A.

    2017-01-01

    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. PMID:28246564

  2. 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.)

  3. Balancing the false negative and positive rates in suspect screening with high-resolution Orbitrap mass spectrometry using multivariate statistics.

    Science.gov (United States)

    Vergeynst, Leendert; Van Langenhove, Herman; Demeestere, Kristof

    2015-02-17

    Modern high-resolution mass spectrometry (HRMS) enables full-spectrum trace level analysis of emerging environmental organic contaminants. This raises the opportunity for post-acquisition suspect screening when no reference standards are a priori available. When setting up a conventional screening identification train based on successively different identification criteria including mass error and isotope fit, the false negative rate typically accumulates upon advancing through the decision tree. The challenge is thus to elaborate a well-balanced screening, in which the different criteria are equally stringent, leading to a controllable number of false negatives. Presented is a novel suspect screening approach using liquid-chromatography Orbitrap HRMS. Based on a multivariate statistical model, the screening takes into account the accurate mass error of the mono isotopic ion and up to three isotopes, isotope ratios, and a peak/noise filter. As such, for the first time, controlling the overall false negative rate of the screening algorithm to a desired level (5% in this study) is achieved. Simultaneously, a well-balanced identification decision is guaranteed taking the different identification criteria as a whole in a holistic statistical approach. Taking into account 1, 2, and 3 isotopes decreases the false positive rate from 22, 2.8 to <0.3%, but the cost of increasing the median limits of identification from 200, 2000 to 2062 ng L(-1), respectively, should also be considered. As proof of concept, 7 biologically treated wastewaters were screened toward 77 suspect pharmaceuticals resulting in the indicative identification of 25 suspects. Subsequently obtained reference standards allowed confirmation for 19 out of these 25 pharmaceutical contaminants.

  4. General false positive ELISA reactions in visceral leishmaniasis. Implications for the use of enzyme immunoassay analyses in tropical Africa.

    Science.gov (United States)

    Elshafie, Amir I; Mullazehi, Mohammed; Rönnelid, Johan

    2016-04-01

    Leishmaniasis is a neglected disease in tropical countries. Clinical and laboratory features may mimic autoimmune diseases and this can complicate the Leishmania diagnosis. Due to our previous investigation for false anti-CCP2 reactivity in Leishmania-infected subjects and our interest in immunity against the joint-specific collagen type II (CII) in rheumatoid arthritis (RA) we investigated the same cohort for anti-CII antibodies. We found elevated anti-CII reactivity in Leishmania-infected patients as compared to controls. When anti-CII OD values were compared with BSA-blocked control plates we found higher reactivity against BSA than in CII-coated plates in many Leishmania-infected patients. The percentage of such false positive anti-CII reactions increased with inflammatory activity, and was found in almost all Leishmania patients with highly active inflammatory disease, but was as low in Sudanese healthy controls as well as among Swedish RA patients. The correlation coefficients between false positive anti-CII and anti-CCP2 measured with a commercial ELISA were highest for patients with the most inflammatory disease but non-significant for Sudanese controls and Swedish RA patients, arguing that our findings may have general implications for ELISA measurements in leishmaniasis. ELISA investigations in areas endemic for leishmaniasis might benefit from individual-specific control wells for each serum sample. This approach might also be applicable to other geographical areas or patient groups with high incidence of inflammatory and infectious diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. False-positive F-18 FDG uptake in PET/CT studies in pediatric patients with abdominal Burkitt's lymphoma.

    Science.gov (United States)

    Riad, Raef; Omar, Walid; Sidhom, Iman; Zamzam, Manal; Zaky, Iman; Hafez, Magdy; Abdel-Dayem, Hussein M

    2010-03-01

    In pediatric patients with abdominal Burkitt's lymphoma, the involvement of the gastrointestinal tract and abdominal lymph nodes are the main presenting feature of the disease. Chemotherapy is the main treatment modality and could be preceded by surgical excision of the abdominal masses. To achieve cure or long-term disease-free survival a balance has to be struck between aggressive chemotherapy and the probability of tumor necrosis secondary to treatment complicated by acute infections, perforation or intestinal bleeding. F-18 fluorodeoxyglucose-positron emission tomography/computed tomography (F-18 FDG-PET/CT) has been recommended over conventional imaging modalities for the follow-up of these patients and for monitoring treatment response. As the incidences of postchemotherapy complications are high, the positive predictive value of PET/CT studies in these patients is very low and the false-positive rate is high from acute infections and tumor necrosis. Accordingly, histopathological confirmation of positive lesions on F-18 FDG-PET/CT studies is essential. This is especially important as post-therapy complications might present with nonspecific and nonurgent symptoms. At the same time initiating a second course of salvage chemotherapy is risky. Retrospectively reviewed F-18 FDG-PET/CT studies for 28 pediatric patients with abdominal Burkitt's lymphoma and diffuse large B-cell lymphoma after their treatment with chemotherapy or surgery. Four positive studies were found. All had pathological verification and were because of acute inflammation and tumor necrosis and there was no evidence of viable tumor cells. One patient had multiple recurrent lesions in the abdomen after the initial surgical excision and before starting chemotherapy. The incidence of acute complications in this series is 10.7%. This study confirms the high incidence of tumor necrosis and inflammation after chemotherapy for the abdominal Burkitt's lymphoma and consequently, the incidence of true-positive

  6. 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

  7. Experimental Null Method to Guide the Development of Technical Procedures and to Control False-Positive Discovery in Quantitative Proteomics.

    Science.gov (United States)

    Shen, Xiaomeng; Hu, Qiang; Li, Jun; Wang, Jianmin; Qu, Jun

    2015-10-02

    Comprehensive and accurate evaluation of data quality and false-positive biomarker discovery is critical to direct the method development/optimization for quantitative proteomics, which nonetheless remains challenging largely due to the high complexity and unique features of proteomic data. Here we describe an experimental null (EN) method to address this need. Because the method experimentally measures the null distribution (either technical or biological replicates) using the same proteomic samples, the same procedures and the same batch as the case-vs-contol experiment, it correctly reflects the collective effects of technical variability (e.g., variation/bias in sample preparation, LC-MS analysis, and data processing) and project-specific features (e.g., characteristics of the proteome and biological variation) on the performances of quantitative analysis. To show a proof of concept, we employed the EN method to assess the quantitative accuracy and precision and the ability to quantify subtle ratio changes between groups using different experimental and data-processing approaches and in various cellular and tissue proteomes. It was found that choices of quantitative features, sample size, experimental design, data-processing strategies, and quality of chromatographic separation can profoundly affect quantitative precision and accuracy of label-free quantification. The EN method was also demonstrated as a practical tool to determine the optimal experimental parameters and rational ratio cutoff for reliable protein quantification in specific proteomic experiments, for example, to identify the necessary number of technical/biological replicates per group that affords sufficient power for discovery. Furthermore, we assessed the ability of EN method to estimate levels of false-positives in the discovery of altered proteins, using two concocted sample sets mimicking proteomic profiling using technical and biological replicates, respectively, where the true-positives

  8. Can elevated lactate and LDH produce a false positive enzymatic ethanol result in live patients presenting to the emergency department?

    Science.gov (United States)

    Nacca, Nicholas; Hodgman, Michael J; Lao, Kirselle; Elkins, Matthew; Holland, Michael G

    2017-08-16

    There have been allegations in the courtroom that elevated serum lactic acid in trauma victims can yield a falsely elevated serum ethanol assay. Most hospitals utilize an indirect method of ethanol measurement where a serum sample is added to a mix of alcohol dehydrogenase and oxidized nicotinamide adenine dinucleotide (NAD+). This allows any ethanol in the patient's serum to be metabolized to acetaldehyde, and in the process results in the reduction of NAD + to NADH. NADH is then measured using spectrophotometry. The courtroom allegation stems from the concept that oxidation of lactate to pyruvate by lactate dehydrogenase (LDH) results in the same molar-for-molar reduction of NAD + to NADH, and could therefore theoretically cause patients with elevated lactate and LDH to have a falsely elevated ethanol concentration. Patients with elevated lactic acid and LDH concentrations who presented to a university hospital from 20 April 2015 to 13 December 2015 were identified to provide possible test specimens. If a sufficient amount of serum was available, the sample was used to re-run the lactate and LDH concentration simultaneously with an enzymatic ethanol assay. Any samples that had elevated lactic acid and LDH concentrations on this retesting, and also yielded a positive ethanol concentration, were sent for confirmatory gas chromatography testing of ethanol concentrations. A control group of 20 samples with normal lactate and LDH were included. A total of 37 samples were included in the final analysis. Only 4 patients had an elevated enzymatic ethanol concentration, and all 4 also had a measurable GC ethanol concentration. The lactate in this dataset ranged from 2.4 to 24.2 mmol/L, with a mean of 6.53 mmol/L (normal value 0.5-2.2). The LDH ranged from 242 to 8838 U/L with a mean of 1695 U/L (normal value 122-225 U/L). Twenty control samples were run on patients with normal lactate and LDH, none of which yielded a positive enzymatic ethanol result

  9. A semi-parametric censoring bias model for estimating the cumulative risk of a false-positive screening test under dependent censoring

    OpenAIRE

    Hubbard, Rebecca A.; Miglioretti, Diana L.

    2013-01-01

    False-positive test results are among the most common harms of screening tests and may lead to more invasive and expensive diagnostic testing procedures. Estimating the cumulative risk of a false-positive screening test result after repeat screening rounds is therefore important for evaluating potential screening regimens. Existing estimators of the cumulative false-positive risk are limited by strong assumptions about censoring mechanisms and parametric assumptions about variation in risk ac...

  10. Unusual False-Positive Mesenteric Lymph Nodes Detected by PET/CT in a Metastatic Survey of Lung Cancer

    Directory of Open Access Journals (Sweden)

    Hirohiko Kamiyama

    2016-06-01

    Full Text Available Positron emission tomography/computed tomography (PET/CT is a credible diagnostic modality for detecting primary and metastatic malignancy. PET/CT sometimes shows false positives and negatives, which make clinical diagnosis difficult. A 42-year-old man who had undergone right upper lobectomy for lung cancer 1 year previously had PET/CT for a metastatic survey of the lung. The lung cancer was stage IB (pT2N0M0 bronchioloalveolar carcinoma. PET/CT showed massive 18F-fluorodeoxyglucose (FDG uptake in the mesenteric lymph nodes. Because the mesentery is an unusual site of metastasis, the patient was under watchful observation. Another PET/CT after 6 months still showed FDG uptake in the same location, with a slightly increased standard uptake value. A systemic survey was performed, but it did not reveal any malignancies or inflammatory diseases. Eventually, the patient underwent probing laparoscopic surgery. For complete resection of the lymph nodes, laparoscopic ileocecal resection was performed. Histologically, the resected lymph nodes showed reactive lymphadenitis. Glucose transporter 1 immunostainings of the lung cancer and the lymph node were positive and partially positive, respectively. Although PET/CT is a powerful diagnostic modality, clinical interpretation of unusual results is difficult.

  11. Insights into acute aortic dissection

    NARCIS (Netherlands)

    Trimarchi, S.

    2012-01-01

    Aortic dissection represents one of the most catastrophic and complex cardiovascular diseases. Its origin is related to an intimal tear with course of blood flow into the aortic wall and division of the aortic lumen into two different lumens, defined as the true and false lumen, separated by a

  12. 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...... mating a library gene deletion haploid to such a conditional centromere strain, which corresponds to the chromosome carrying the gene deletion, loss of heterozygosity (LOH) at the gene deletion locus can be generated in these otherwise hybrid diploids. The use of hybrid diploid strains permits...... 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...

  13. 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.

  14. Aortic growth rates in chronic aortic dissection

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, A.M. [Department of Radiology, Division of Thoracic Radiology, University of Michigan Medical Center (United States)]. E-mail: ainekell@med.umich.edu; Quint, L.E. [Department of Radiology, Division of Thoracic Radiology, University of Michigan Medical Center (United States); Nan, B. [School of Public Health, University of Michigan, Ann Arbor, Michigan (United States); Zheng, J. [School of Public Health, University of Michigan, Ann Arbor, Michigan (United States); Cronin, P. [Department of Radiology, Division of Thoracic Radiology, University of Michigan Medical Center (United States); Deeb, G.M. [Division of Cardiac Surgery, University of Michigan Medical Center (United States); Williams, D.M. [Division of Vascular Interventional Imaging, University of Michigan Medical Center (United States)

    2007-09-15

    Aim: To determine and compare rates of descending aortic enlargement and complications in chronic aortic dissection with and without a proximal aortic graft. Methods and materials: Fifty-two patients with dissection involving the descending aorta and who had undergone at least two computed tomography (CT) examinations at our institution between November, 1993 and February, 2004 were identified, including 24 non-operated patients (four type A, 20 type B) and 28 operated patients (type A). CT examinations per patient ranged from two to 10, and follow-up ranged from 1-123 months (mean 49 months, median 38.5 months). On each CT image, the aortic short axis (SA), false lumen (FL), and true lumen (TL) diameters were measured at the longitudinal midpoint of the dissection and at the point of maximum aortic diameter. Complications were tabulated, including aortic rupture and aortic enlargement requiring surgery. Results: For non-operated patients, the midpoint and maximum point SA, TL, and FL diameters increased significantly over time. For operated patients, the midpoint and maximum point SA and FL diameters increased significantly over time. In both groups, aortic enlargement was predominantly due to FL expansion. Diameter increases in non-operated patients were significantly larger than those in operated patients. The rate of change in aortic diameter was constant, regardless of aortic size. Four non-operated and six operated patients developed aortic complications. Conclusions: In patients with a dissection involving the descending thoracic aorta, the FL increased in diameter over time, at a constant rate, and to a greater degree in non-operated patients (mostly type B) compared with operated patients (all type A)

  15. False positive hepatitis C antibody test results in left ventricular assist device recipients: increased risk with age and transfusions

    Science.gov (United States)

    Lee, Doreen; Colovai, Adriana; Levy, Dana; Vasovic, Ljiljana; Roach, Keith W.; Shuter, Jonathan; Goldstein, Daniel; D’Alessandro, David; Jorde, Ulrich P.; Muggia, Victoria A.

    2017-01-01

    Left ventricular assist devices (LVADs) have been successfully used in patients with heart failure. However, LVADs may trigger immune activation, leading to higher frequencies of autoantibodies. We describe the clinical, epidemiological, and laboratory characteristics of LVAD recipients with false positive hepatitis C (FPHC) serology among 39 consecutive adult LVAD recipients who bridged to heart transplantation from January 2007 to January 2013 at Montefiore Medical Center. FPHC patients were identified as those with post-LVAD positive hepatitis C ELISA antibody tests and negative confirmatory testing with hepatitis C RNA PCR and/or radioimmunoblot assay. Ten (26%) patients previously seronegative for hepatitis C were found to have FPHC after device placement. Of the 39 patients, 32 had HeartMate II devices. The mean age at LVAD placement was 55 years. FPHC correlated with older age at the time of LVAD implantation and with receipt of packed red blood cell transfusions, but not with gender, fresh frozen plasma transfusions, panel reactive antibodies, globulin fraction, rheumatoid factor, or anticardiolipin antibodies. Clinicians should be aware of this increased risk of FPHC in older LVAD patients and those more heavily transfused in order to avoid unnecessary apprehension and possible delay in transplantation. Further studies should be done to evaluate the possible relationship between transfused blood products and immunomodulation. PMID:28203425

  16. 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.

  17. Public health consequences of a false-positive laboratory test result for Brucella--Florida, Georgia, and Michigan, 2005.

    Science.gov (United States)

    2008-06-01

    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.

  18. Analysis of positional candidate genes in the AAA1 susceptibility locus for abdominal aortic aneurysms on chromosome 19

    Directory of Open Access Journals (Sweden)

    Ferrell Robert E

    2011-01-01

    Full Text Available Abstract Background Abdominal aortic aneurysm (AAA is a complex disorder with multiple genetic risk factors. Using affected relative pair linkage analysis, we previously identified an AAA susceptibility locus on chromosome 19q13. This locus has been designated as the AAA1 susceptibility locus in the Online Mendelian Inheritance in Man (OMIM database. Methods Nine candidate genes were selected from the AAA1 locus based on their function, as well as mRNA expression levels in the aorta. A sample of 394 cases and 419 controls was genotyped for 41 SNPs located in or around the selected nine candidate genes using the Illumina GoldenGate platform. Single marker and haplotype analyses were performed. Three genes (CEBPG, PEPD and CD22 were selected for DNA sequencing based on the association study results, and exonic regions were analyzed. Immunohistochemical staining of aortic tissue sections from AAA and control individuals was carried out for the CD22 and PEPD proteins with specific antibodies. Results Several SNPs were nominally associated with AAA (p CEBPG, peptidase D (PEPD, and CD22. Haplotype analysis found a nominally associated 5-SNP haplotype in the CEBPG/PEPD locus, as well as a nominally associated 2-SNP haplotype in the CD22 locus. DNA sequencing of the coding regions revealed no variation in CEBPG. Seven sequence variants were identified in PEPD, including three not present in the NCBI SNP (dbSNP database. Sequencing of all 14 exons of CD22 identified 20 sequence variants, five of which were in the coding region and six were in the 3'-untranslated region. Five variants were not present in dbSNP. Immunohistochemical staining for CD22 revealed protein expression in lymphocytes present in the aneurysmal aortic wall only and no detectable expression in control aorta. PEPD protein was expressed in fibroblasts and myofibroblasts in the media-adventitia border in both aneurysmal and non-aneurysmal tissue samples. Conclusions Association testing

  19. [Dynamic and cinematic evaluation of the function of bioprosthesis in the aortic position: tester of cardiac valves].

    Science.gov (United States)

    Bustamante, J; Santamaría, J; Infante, O; Flores, P; Juárez, A

    1996-01-01

    Twenty four pericardial valvular prostheses were tested in a valvular tester device. The valves considered were: 12 valves of the model that has being already in clinical use, manufactured in the Instituto Nacional de Cardiología "Ignacio Chávez", (INC II) and 12 valves of a model in an experimental stage, (PRT I.) The inner diameter in the two group considered were: 17, 19 and 21 mm. All the valves were tested in the aortic position in the valvular tester device. Behavior of the valvular prostheses were examined at various rates of pulsation, 60, 77, 105 and 159 per minute, with an ejection volume of 70 and 80 ml (range of flows between 4200 and 12720 ml min1). The pressure of the ventricular and aortic cameras were registered continuously, by external transducers, and in the other hand, the kinetic of the valves and the degree of opening were evaluated for direct view trough an special window. The grade of incompetence was too evaluated and expressed in percent of the stroke volume. The transvalvular pressure gradient was lower in INC II model valves, specially at moderate and high flows, and at same time had a largest functional area. The degree of incompetence was higher in the 19 and 21 mm diameter valvular subgroups than the same subgroups in the PRT I model. In relation to the 17 mm subgroup, significant differences were not find. The use of the valvular tester showed a basic utility in the hydrodynamic evaluation of the news bioprostheses design, and so in the quality control of the valves than has being manufacturing.

  20. Magnetic resonance angiography of the aortic arch and its main arteries directed to the brain with use of head neck coil. With special reference to relation between high position of the aortic arch and kinked vertebral and carotid arteries

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Hitoshi [Saitama Medical School, Moroyama (Japan)

    1996-12-01

    We studied 316 individuals who requested general health examinations (March 1993 to February 1995), and who underwent blood tests, urinalysis and MRA with a head neck coil, and 25 volunteers underwent the same examinations. The head neck coil used covered the head, neck and upper thorax, and each individual coil could transmit and receive signals. Three-dimensional time of flight MRA was employed in the investigation. The saturation pulse was placed in a coronal direction behind the slab to suppress the venous inflow signals. Our results indicate that in all individuals, MRA clearly demonstrated the aorta and its main branches extending up to the circle of Willis. It was possible to rotate the reconstructed 3-D image around the body axis permitting the visualization of secondary or more peripheral branches, depending on their size and direction. The severity of V1 kinking, classified by using the modified Mets criteria, correlated well with advancing age. V1 kinking was first evident in the third decade of life, while kinking of the internal carotid artery appeared in the fourth decade. The highest level of the aortic arch was evaluated in terms of the aorto-C2 (A-C2) distance, i.e., the distance measured from the C2 level, where the vertebral artery curved laterally in the transverse foramen of C2, and the A level, where the upper margin of the aortic arch was highest. Shortening of the A-C2 distance was noted with aging, and a good correlation between increased height of the aortic arch and aging was seen. As compared to conventional contrast arteriography, MRA of the aortic arch and its branch arteries extending into the cranium does provide accurate data. A high position of the aortic arch, buckling of the great vessels, and tortuosity, kinking and coiling of the vertebral and carotid arteries are clearly shown. (K.H.)

  1. Predicting radiologists' true and false positive decisions in reading mammograms by using gaze parameters and image-based features

    Science.gov (United States)

    Gandomkar, Ziba; Tay, Kevin; Ryder, Will; Brennan, Patrick C.; Mello-Thoms, Claudia

    2016-03-01

    Radiologists' gaze-related parameters combined with image-based features were utilized to classify suspicious mammographic areas ultimately scored as True Positives (TP) and False Positives (FP). Eight breast radiologists read 120 two-view digital mammograms of which 59 had biopsy proven cancer. Eye tracking data was collected and nearby fixations were clustered together. Suspicious areas on mammograms were independently identified based on thresholding an intensity saliency map followed by automatic segmentation and pruning steps. For each radiologist reported area, radiologist's fixation clusters in the area, as well as neighboring suspicious areas within 2.5° of the center of fixation, were found. A 45-dimensional feature vector containing gaze parameters of the corresponding cluster along with image-based characteristics was constructed. Gaze parameters included total number of fixations in the cluster, dwell time, time to hit the cluster for the first time, maximum number of consecutive fixations, and saccade magnitude of the first fixation in the cluster. Image-based features consisted of intensity, shape, and texture descriptors extracted from the region around the suspicious area, its surrounding tissue, and the entire breast. For each radiologist, a userspecific Support Vector Machine (SVM) model was built to classify the reported areas as TPs or FPs. Leave-one-out cross validation was utilized to avoid over-fitting. A feature selection step was embedded in the SVM training procedure by allowing radial basis function kernels to have 45 scaling factors. The proposed method was compared with the radiologists' performance using the jackknife alternative free-response receiver operating characteristic (JAFROC). The JAFROC figure of merit increased significantly for six radiologists.

  2. False positive dengue NS1 antigen test in a traveller with an acute Zika virus infection imported into Switzerland.

    Science.gov (United States)

    Gyurech, Danielle; Schilling, Julian; Schmidt-Chanasit, Jonas; Cassinotti, Pascal; Kaeppeli, Franz; Dobec, Marinko

    2016-01-01

    We report the first case of an acute Zika virus infection imported into Switzerland by a traveller returning from Canoa Quebrada, Ceará state, in the north-eastern part of Brazil. Due to a false positive dengue virus NS1 antigen test, IgG antibody seroconversion and a suggestive clinical picture,an acute dengue fever was initially considered. However, because of lack of specific IgM-antibodies, stationary IgG antibody titre and a negative dengue virus PCR test result, a dengue virus infection was excluded and a cross-reaction with other, causative flaviviruses was postulated. Based on recent reports of Zika fever cases in the north-eastern parts of Brazil, an acute Zika virus infection was suspected. Because of a lack of commercially available Zika virus diagnostic tests, the case was confirmed in the WHO reference laboratory. As the clinical presentation of Zika virus infection can be confused with dengue fever and chikungunya fever, and because of possible public health implications, all patients returning from affected areas should be additionally tested for Zika virus. This case illustrates the urgent medical need for a broadly available assay capable of differentiating Zika from Dengue infections.

  3. A unified methodology based on sparse field level sets and boosting algorithms for false positives reduction in lung nodules detection.

    Science.gov (United States)

    Saien, Soudeh; Moghaddam, Hamid Abrishami; Fathian, Mohsen

    2017-08-09

    This work aims to develop a unified methodology for the false positives reduction in lung nodules computer-aided detection schemes. The 3D region of each detected nodule candidate is first reconstructed using the sparse field method for accurately segmenting the objects. This technique enhances the level set modeling by restricting the computations to a narrow band near the evolving curve. Then, a set of 2D and 3D relevant features are extracted for each segmented candidate. Subsequently, a hybrid undersampling/boosting algorithm called RUSBoost is applied to analyze the features and discriminate real nodules from non-nodules. The performance of the proposed scheme was evaluated by using 70 CT images, randomly selected from the Lung Image Database Consortium and containing 198 nodules. Applying RUSBoost classifier exhibited a better performance than some commonly used classifiers. It effectively reduced the average number of FPs to only 3.9 per scan based on a fivefold cross-validation. The practical implementation, applicability for different nodule types and adaptability in handling the imbalanced data classification insure the improvement in lung nodules detection by utilizing this new approach.

  4. Microarray analysis of cytoplasmic versus whole cell RNA reveals a considerable number of missed and false positive mRNAs.

    Science.gov (United States)

    Trask, Heidi W; Cowper-Sal-lari, Richard; Sartor, Maureen A; Gui, Jiang; Heath, Catherine V; Renuka, Janhavi; Higgins, Azara-Jane; Andrews, Peter; Korc, Murray; Moore, Jason H; Tomlinson, Craig R

    2009-10-01

    With no known exceptions, every published microarray study to determine differential mRNA levels in eukaryotes used RNA extracted from whole cells. It is assumed that the use of whole cell RNA in microarray gene expression analysis provides a legitimate profile of steady-state mRNA. Standard labeling methods and the prevailing dogma that mRNA resides almost exclusively in the cytoplasm has led to the long-standing belief that the nuclear RNA contribution is negligible. We report that unadulterated cytoplasmic RNA uncovers differentially expressed mRNAs that otherwise would not have been detected when using whole cell RNA and that the inclusion of nuclear RNA has a large impact on whole cell gene expression microarray results by distorting the mRNA profile to the extent that a substantial number of false positives are generated. We conclude that to produce a valid profile of the steady-state mRNA population, the nuclear component must be excluded, and to arrive at a more realistic view of a cell's gene expression profile, the nuclear and cytoplasmic RNA fractions should be analyzed separately.

  5. Cell Shaving and False-Positive Control Strategies Coupled to Novel Statistical Tools to Profile Gram-Positive Bacterial Surface Proteomes.

    Science.gov (United States)

    Solis, Nestor; Cordwell, Stuart J

    2016-01-01

    A powerful start to the discovery and design of novel vaccines, and for better understanding of host-pathogen interactions, is to profile bacterial surfaces using the proteolytic digestion of surface-exposed proteins under mild conditions. This "cell shaving" approach has the benefit of both identifying surface proteins and their surface-exposed epitopes, which are those most likely to interact with host cells and/or the immune system, providing a comprehensive overview of bacterial cell topography. An essential requirement for successful cell shaving is to account for (or minimize) cellular lysis that can occur during the shaving procedure and thus generate data that is biased towards non-surface (e.g., cytoplasmic) proteins. This is further complicated by the presence of "moonlighting" proteins, which are proteins predicted to be intracellular but with validated surface or extracellular functions. Here, we describe an optimized cell shaving protocol for Gram-positive bacteria that uses proteolytic digestion and a "false-positive" control to reduce the number of intracellular contaminants in these datasets. Released surface-exposed peptides are analyzed by liquid chromatography (LC) coupled to high-resolution tandem mass spectrometry (MS/MS). Additionally, the probabilities of proteins being surface exposed can be further calculated by applying novel statistical tools.

  6. Analysis of false positive detection of HCV antibody by ELISA%HCV抗体ELISA检测假阳性分析

    Institute of Scientific and Technical Information of China (English)

    张力; 张文娟

    2014-01-01

    Objective To discuss the false positive problem when the S/CO mean of HCV Ab test by ELISA is between 1 to 3.8. Methods 26 cases whose first S/CO mean(3 times by ELISA) was between 1 to 3.8 and 20 cases of normal healthy people were chosen. Do blood test again from 2 months to 6 months. Results 6 cases among 26 cases of reactive result of first ELISA tested negative in the second experiment.20 normal individuals tested negative twice by ELISA.There is significance difference between two test(P<0.01). Conclusion If detection of HCV Ab by ELISA is reactive,should be regularly reviewed,or do other tests.%目的:探讨HCV抗体ELISA检测1<S/CO均值<3.8时假阳性问题。方法筛选HCV抗体ELISA首次检测1<S/CO(3次均值)<3.8共26例,正常体检人群20例,2~6月之间再次抽血检测。结果26例首次检测ELISA有反应性其中6例再次检测为阴性,最终该6例患者确诊为阴性,20例正常体检人群2次均为阴性。两次检测比较结果有显著性差异(P<0.01)。结论 HCV抗体ELISA检测有反应性时应定期复查或做其它检测。

  7. 前交叉韧带损伤MRI诊断假阳性和假阴性分析%Analysis on False Positive and False Negative of MRI in Anterior Cruciate Ligament injury

    Institute of Scientific and Technical Information of China (English)

    李彦娴; 袁曙光; 赵新湘; 侯瑞鸿

    2011-01-01

    目的 探讨MRI对前交叉韧带损伤诊断的假阳性及假阴性,提高MRI诊断水平.方法 回顾性分析68例(72膝)膝关节外伤后临床怀疑前交叉韧带损伤患者的MRI检查结果,并与关节镜检查结果 进行对照分析.结果 本组68例(72膝)膝关节外伤患者中,以关节镜结果 为标准,MRI诊断结果:真阳性数52例,真阴性数13例,假阳性数5例,假阴性数2例.灵敏度、特异度、假阳性率及假阴性率分别为96.3%,72.2%,6.9%,2.8%,诊断正确率90.3%.结论 MRI是诊断前交叉韧带损伤极有价值的无创方法,但存在一定的假阳性和假阴性,需要结合患者临床病史和更细致的MRI分析.%Objective To investigate the false positive and the false negative of anterior cruciate ligament tear at MR imaging , so that to improve MRI diagnosis for anterior cruciate ligament tear. Methods MR imaging results in 68 cases ( 72 knees) suspected with anterior cruciate ligament tear clinically were retrospectively reviewed and compared with that of arthroscopy. Results Of 68 patients (72 knees) ,the results of arthroscopy were taken as gold standard ,MRI diagnostic results of anterior cruciate ligament injury were as follows: true positive in 52 cases, true negative in 13 cases, false positive in 5 cases and false negative in 2 cases. The sensitivity , specificity, false positive rate, false negative rate and accuracy in diagnosing anterior cruciate ligamcnt tear with MR imaging were 96. 3 % , 72. 2% , 6. 9% , 2. 8% , 90. 3 % respectively . Conclusion MRI is a very valuable and non-invasive mcthod for the diagnosis of anterior cruciate ligament injury, but which is still with false positive and false negative , so MR imaging findings is necessary to combine clinical examination,otherwise,more detailcd MRI analysis should be done to give precise diagnosis.

  8. False-positive tests for syphilis associated with human immunodeficiency virus and hepatitis B virus infection among intravenous drug abusers. Valencian Study Group on HIV Epidemiology.

    Science.gov (United States)

    Hernández-Aguado, I; Bolumar, F; Moreno, R; Pardo, F J; Torres, N; Belda, J; Espacio, A

    1998-11-01

    The role of HIV, hepatitis C virus, and hepatitis B virus infections in the production of biological false-positive reactions for syphilis was evaluated in two large samples of intravenous drug abusers and homosexual men attending AIDS prevention centers in Spain. A significantly increased odds ratio (OR) for false-positive tests for syphilis [OR 2.23, 95% confidence intervals (CI) 1.76-2.83] was observed for HIV-seropositive intravenous drug abusers; biological false-positive reactions were also more frequent (OR 1.73, 95% CI 1.30-2.31) among intravenous drug abusers who were hepatitis B virus seropositive but not among those who were hepatitis C virus seropositive (OR 0.90; 95% CI 0.48-1.69). Among homosexuals, the association between HIV and biological false-positive reactions was restricted to subjects who were also intravenous drug abusers, indicating the crucial role of intravenous drug abuse. Only 20.5% of intravenous drug abusers with a previous biological false-positive reaction yielded a false-positive result in their subsequent visit.

  9. False positive circumsporozoite protein ELISA: a challenge for the estimation of the entomological inoculation rate of malaria and for vector incrimination

    Directory of Open Access Journals (Sweden)

    Trung Ho Dinh

    2011-07-01

    Full Text Available Abstract Background The entomological inoculation rate (EIR is an important indicator in estimating malaria transmission and the impact of vector control. To assess the EIR, the enzyme-linked immunosorbent assay (ELISA to detect the circumsporozoite protein (CSP is increasingly used. However, several studies have reported false positive results in this ELISA. The false positive results could lead to an overestimation of the EIR. The aim of present study was to estimate the level of false positivity among different anopheline species in Cambodia and Vietnam and to check for the presence of other parasites that might interact with the anti-CSP monoclonal antibodies. Methods Mosquitoes collected in Cambodia and Vietnam were identified and tested for the presence of sporozoites in head and thorax by using CSP-ELISA. ELISA positive samples were confirmed by a Plasmodium specific PCR. False positive mosquitoes were checked by PCR for the presence of parasites belonging to the Haemosporidia, Trypanosomatidae, Piroplasmida, and Haemogregarines. The heat-stability and the presence of the cross-reacting antigen in the abdomen of the mosquitoes were also checked. Results Specimens (N = 16,160 of seven anopheline species were tested by CSP-ELISA for Plasmodium falciparum and Plasmodium vivax (Pv210 and Pv247. Two new vector species were identified for the region: Anopheles pampanai (P. vivax and Anopheles barbirostris (Plasmodium malariae. In 88% (155/176 of the mosquitoes found positive with the P. falciparum CSP-ELISA, the presence of Plasmodium sporozoites could not be confirmed by PCR. This percentage was much lower (28% or 5/18 for P. vivax CSP-ELISAs. False positive CSP-ELISA results were associated with zoophilic mosquito species. None of the targeted parasites could be detected in these CSP-ELISA false positive mosquitoes. The ELISA reacting antigen of P. falciparum was heat-stable in CSP-ELISA true positive specimens, but not in the false positives

  10. Utility of TL-201 SPECT in clarifying false-positive FDG-PET findings due to osteoradionecrosis in head and neck cancer.

    Science.gov (United States)

    Wang, Chih-Hsiu; Liang, Ji-An; Ding, Hueisch-Jy; Yang, Shih-Neng; Yen, Kuo-Yang; Sun, Shung-Shung; Kao, Chia-Hung

    2010-12-01

    This study aimed to determine whether Tl-201 single photon emission CT (SPECT) is potentially useful in differentiating false-positive fluorodeoxyglucose positron emission tomography (FDG-PET) findings caused by osteoradionecrosis (ORN) from recurrent head and neck cancer after radiotherapy. Five patients were recruited. Dual-phase FDG-PET and dual-phase Tl-201 SPECT were performed for each patient. All 5 patients proved to have ORN without recurrent cancer. By visual interpretation, the results were 4 positive versus 1 negative for PET, and 4 negative versus 1 positive for Tl-201 SPECT. The Tl-201 SPECT clarified 3 of the 4 false-positive PETs to be ORN. Dual-phase semiquantitative studies showed decreased standardized uptake value (SUV) over time in 3 of the 4 false-positive PETs and decreased lesion/background ratio over time in the false-positive Tl-201 SPECT. The Tl-201 SPECT may help clarify suspected false-positive FDG uptake caused by ORN. Dual-phase FDG-PET and dual-phase Tl-201 SPECT may also have some value.

  11. Effects of Noninvasive Positive-Pressure Ventilation with Different Interfaces in Patients with Hypoxemia after Surgery for Stanford Type A Aortic Dissection

    OpenAIRE

    Yang, Yi; Sun, Lizhong; Liu, Nan; Hou, Xiaotong; Wang, Hong; Jia, Ming

    2015-01-01

    Background Hypoxemia is a severe perioperative complication that can substantially increase intensive care unit and hospital stay and mortality. The aim of this study was to determine the effects of non-invasive positive-pressure ventilation (NIPPV) in patients with hypoxemia after surgery for Stanford type A aortic dissection, and to compare the effects of helmet and mask NIPPV. Material/Methods We recruited 40 patients who developed hypoxemia within 24 h after extubation after surgery for S...

  12. Survey of False-positive Reactivity of Latex Agglutination Test for Kala-azar (Katex) without Urine Sample Boiling Process in Autoimmune Patients.

    Science.gov (United States)

    Ghatee, Mohammad Amin; Kanannejad, Zahra; Sharifi, Iraj; Askari, Asma; Bamorovat, Mehdi

    2017-06-01

    Latex agglutination test for Kala-azar (KAtex) is an easy, inexpensive, and field-applicable antigen detection test. However, the main drawback of this method is the boiling step applied to remove false positivity of the test. This study was conducted to survey false positivity results of latex agglutination test for KAtex without boiling process in urine of some autoimmune patients. Ninety-two urine samples from autoimmune patients including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), scleroderma, autoimmune vasculitis, vitiligo, pemphigus and Wagner cases and 20 urine samples from healthy individuals were collected from Kerman Province in Southeastern Iran in 2010-2011. All urine samples were checked by KAtex after boiling for 5 min false positivity rate of the test was surveyed in different healthy and patients groups while boiling process was removed. Rheumatoid factor (RF) then was checked in sera of all cases to evaluate the relationship between RF and KAtex false positivity. All samples represented negative results with KAtex when boiling was performed (100% specificity). Then, 20% positivity was evident in healthy cases. False-positive reactivity was more prominent observed in patient groups than healthy individuals, except in vitiligo. However, a significant difference was only observed in RA group (Pboiling process removal.

  13. Marked discrepancy in pressure gradient between Doppler and catheter examinations on Medtronic Mosaic valve in aortic position.

    Science.gov (United States)

    Ito, Toshiaki; Maekawa, Atsuo; Fujii, Genyo; Sawaki, Sadanari; Hoshino, Satoshi; Hayashi, Yasunari

    2012-12-01

    A 71-year-old woman underwent aortic valve replacement with 23 mm Medtronic Mosaic Ultra valve 4 years ago because of aortic stenosis. Although she had been asymptomatic since the operation, echocardiography showed 4 m/s of transprosthetic valve flow that implied early prosthetic valve failure. Catheter examination revealed that the mean transvalvular pressure gradient during systole was 15.1 mmHg on simultaneous pressure recording, and calculated valve area 1.82 cm(2). Her body surface area was 1.56 m(2). Prosthetic valve failure and prosthesis-patient mismatch were both denied. The discrepancy between Doppler study data and catheter data seemed to be due to fluid dynamical pressure recovery phenomenon. Net pressure difference between the left ventricle and the aorta may be significantly smaller than that estimated using Bernoulli's equation from transvalvular flow speed in some patients after aortic valve replacement.

  14. A subpopulation of large granular von Willebrand Ag negative and CD105 positive endothelial cells, isolated from abdominal aortic aneurysms, overexpress ICAM-1 and Fas antigen.

    Science.gov (United States)

    Páez, Araceli; Archundia, Abel; Méndez Cruz, René; Rodríguez, Emma; López Marure, Rebeca; Masso, Felipe; Aceves, José Luis; Flores, Leopoldo; Montaño, Luis F

    2002-01-01

    The aim of this work was to determine whether there is a pre-established basal condition of the endothelial cells isolated from aortic abdominal aneurysm that might augment immune effector mechanisms and thus provide us an insight into the possible causes of aneurysm rupture. Endothelial cells isolated from saccular aortic aneurysm fragments were analyzed by cytofluorometry for the expression of different immune response-related molecules. Our results showed that there is a subpopulation of granule-rich, CD105 positive and von Willebrand antigen negative endothelial cells that have an enhanced basal expression of ICAM-1, and Fas antigen, but, interestingly, no apoptotic bodies were detected. Control endothelial cells derived from healthy areas of the same abdominal aortas did not show such enhanced expression. We conclude that in the endothelium that lines abdominal aorta aneurysms there is, at least, one endothelial cell subpopulation with an apparent inhibition of programmed cell death and in a proinflammatory activation status.

  15. Recall Latencies, Confidence, and Output Positions of True and False Memories: Implications for Recall and Metamemory Theories

    Science.gov (United States)

    Jou, Jerwen

    2008-01-01

    Recall latency, recall accuracy rate, and recall confidence were examined in free recall as a function of recall output serial position using a modified Deese-Roediger-McDermott paradigm to test a strength-based theory against the dual-retrieval process theory of recall output sequence. The strength theory predicts the item output sequence to be…

  16. 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 GC/M

  17. 18FECH PET/CT脑显像在脑占位诊断中的价值分析%Analysis of false positive and false negative of 18FECH PET/CT in brain lesions

    Institute of Scientific and Technical Information of China (English)

    程欣; 崔瑞雪; 党永红; 潘慧; 李方

    2011-01-01

    Objective: Because of the high uptake of [18F]fluoro-2-deoxy-D-glucose{18FDG)in brain, its disadvantage in brain lesion positron emission tomography and computer tomography (PET/CT) imaging. [18F]Flunroethyl-dimethyl-2-hydroxyethylammonium(18FECH)background uptake in brain was low. It could improve the sensitive and specificity of brain lesions diagnosis. We analyzed the false positive and false negative in 18FECH PET imaging in brain lesions with the aim of improving the accuracy of diagnosis with 18FECH PET imaging. Methods: 58 patients with brain lesion were studied using 18FDG PET and 18FECH PET/CT brain imaging. It was considered a positive result that increased tracer uptake relative to the surrounding background radioactivity in 18FECH PET/CT imaging, the maximal standardized uptake value (SUVmax) for lesion and peritumoral regions was measured, and a lesion-to-normal tissue uptake ratio (LNR) was calculated. LNK >2 that was considered a positive result. There were eleven false negative and false negative. The diagnoses of all patients were verified by biopsy or operation under neuronavigation guidance, and pathology including immunohistochemistry. Results: l.Five were false positive (one tuberculous granuloma, one necrosis of cerebral infarction, one pilosity hardenability gliocyte proliferation, one hemorrhage caused by vascular malformation and one demyelination). 2. Six were false negative (one dysembryoplastic neuroepithelial tumor, two grade Ⅱ glioma , one grade Ⅱ oligodendroglioma, one grade Ⅱ oligoastrcytoma and one grade Ⅲ anaplastic oligoastrcytoma). 3. The rate of false positive was 13.2%(5/38), the rate of false negative was 15.8%(6/38), the accuracy of 18FECH PET/CT was 71.1%(27/38). Conclusion: 18FECH PET/CT clearly reveals the location and extent of the tumors and has a role in qualitative diagnosis. Howeve, it also has a certain rate of false positivity and false negativity.%目的:由于大脑皮层对氟代脱氧葡萄糖([18F

  18. Problems of false positive laboratory tests during qualification to the ”Program of severe plaque psoriasis treatment” on the basis of two cases

    Directory of Open Access Journals (Sweden)

    Dorota Jaśkiewicz-Nyckowska

    2015-03-01

    Full Text Available Introduction. Qualification of patients for the therapeutic program of severe plaque psoriasis should be preceded by many tests. Abnormal test results require further evaluation and possibly implementation of treatment. False positive results lead to prolongation of the qualification process and may cause disqualification of the patient. Objective. To draw attention to qualification to a drug program. Case reports . A screening test for Lyme disease performed in a 45-year-old man, during qualification for biological treatment, was positive, but verification by Western blot showed a negative result. It caused significant prolongation of the qualification process. In a 26-year-old patient the QuantiFERON test gave a positive result. It was repeated in another laboratory and a negative result was established. Conclusions . False-positive results may result in disqualification from biological treatment. Exchange of experience between doctors is essential for improving inclusion criteria of patients for biological therapy.

  19. ABIOTIC O{sub 2} LEVELS ON PLANETS AROUND F, G, K, AND M STARS: POSSIBLE FALSE POSITIVES FOR LIFE?

    Energy Technology Data Exchange (ETDEWEB)

    Harman, C. E.; Kasting, J. F. [Geosciences Department, Pennsylvania State University, University Park, PA 16802 (United States); Schwieterman, E. W. [NASA Astrobiology Institute—Virtual Planetary Laboratory (United States); Schottelkotte, J. C., E-mail: ceharmanjr@psu.edu [Astronomy Department, Pennsylvania State University, University Park, PA 16802 (United States)

    2015-10-20

    In the search for life on Earth-like planets around other stars, the first (and likely only) information will come from the spectroscopic characterization of the planet's atmosphere. Of the countless number of chemical species terrestrial life produces, only a few have the distinct spectral features and the necessary atmospheric abundance to be detectable. The easiest of these species to observe in Earth's atmosphere is O{sub 2} (and its photochemical byproduct, O{sub 3}). However, O{sub 2} can also be produced abiotically by photolysis of CO{sub 2}, followed by recombination of O atoms with each other. CO is produced in stoichiometric proportions. Whether O{sub 2} and CO can accumulate to appreciable concentrations depends on the ratio of far-ultraviolet (FUV) to near-ultraviolet (NUV) radiation coming from the planet's parent star and on what happens to these gases when they dissolve in a planet's oceans. Using a one-dimensional photochemical model, we demonstrate that O{sub 2} derived from CO{sub 2} photolysis should not accumulate to measurable concentrations on planets around F- and G-type stars. K-star, and especially M-star planets, however, may build up O{sub 2} because of the low NUV flux from their parent stars, in agreement with some previous studies. On such planets, a “false positive” for life is possible if recombination of dissolved CO and O{sub 2} in the oceans is slow and if other O{sub 2} sinks (e.g., reduced volcanic gases or dissolved ferrous iron) are small. O{sub 3}, on the other hand, could be detectable at UV wavelengths (λ < 300 nm) for a much broader range of boundary conditions and stellar types.

  20. Contamination in the Kepler Field. Identification of 685 KOIs as False Positives Via Ephemeris Matching Based On Q1-Q12 Data

    CERN Document Server

    Coughlin, Jeffrey L; Bryson, Stephen T; Burke, Christopher J; Caldwell, Douglas A; Christiansen, Jessie L; Haas, Michael R; Howell, Steve B; Jenkins, Jon M; Kolodziejczak, Jeffery J; Mullally, Fergal R; Rowe, Jason F

    2014-01-01

    The Kepler mission has to date found almost 6,000 planetary transit-like signals, utilizing three years of data for over 170,000 stars at extremely high photometric precision. Due to its design, contamination from eclipsing binaries, variable stars, and other transiting planets results in a significant number of these signals being false positives. This directly affects the determination of the occurrence rate of Earth-like planets in our Galaxy, as well as other planet population statistics. In order to detect as many of these false positives as possible, we perform ephemeris matching among all transiting planet, eclipsing binary, and variable star sources. We find that 685 Kepler Objects of Interest - 12% of all those analyzed - are false positives as a result of contamination, due to 409 unique parent sources. Of these, 118 have not previously been identified by other methods. We estimate that ~35% of KOIs are false positives due to contamination, when performing a first-order correction for observational ...

  1. Reducing the probability of false positive research findings by pre-publication validation – Experience with a large multiple sclerosis database

    Directory of Open Access Journals (Sweden)

    Heinz Moritz

    2008-04-01

    Full Text Available Abstract Background Published false positive research findings are a major problem in the process of scientific discovery. There is a high rate of lack of replication of results in clinical research in general, multiple sclerosis research being no exception. Our aim was to develop and implement a policy that reduces the probability of publishing false positive research findings. We have assessed the utility to work with a pre-publication validation policy after several years of research in the context of a large multiple sclerosis database. Methods The large database of the Sylvia Lawry Centre for Multiple Sclerosis Research was split in two parts: one for hypothesis generation and a validation part for confirmation of selected results. We present case studies from 5 finalized projects that have used the validation policy and results from a simulation study. Results In one project, the "relapse and disability" project as described in section II (example 3, findings could not be confirmed in the validation part of the database. The simulation study showed that the percentage of false positive findings can exceed 20% depending on variable selection. Conclusion We conclude that the validation policy has prevented the publication of at least one research finding that could not be validated in an independent data set (and probably would have been a "true" false-positive finding over the past three years, and has led to improved data analysis, statistical programming, and selection of hypotheses. The advantages outweigh the lost statistical power inherent in the process.

  2. Histologic changes associated with false-negative sentinel lymph nodes after preoperative chemotherapy in patients with confirmed lymph node-positive breast cancer before treatment.

    Science.gov (United States)

    Brown, Alexandra S; Hunt, Kelly K; Shen, Jeannie; Huo, Lei; Babiera, Gildy V; Ross, Merrick I; Meric-Bernstam, Funda; Feig, Barry W; Kuerer, Henry M; Boughey, Judy C; Ching, Christine D; Gilcrease, Michael Z

    2010-06-15

    A wide range of false-negative rates has been reported for sentinel lymph node (SLN) biopsy after preoperative chemotherapy. The purpose of this study was to determine whether histologic findings in negative SLNs after preoperative chemotherapy are helpful in assessing the accuracy of SLN biopsy in patients with confirmed lymph node-positive disease before treatment. Eighty-six patients with confirmed lymph node-positive disease at presentation underwent successful SLN biopsy and axillary dissection after preoperative chemotherapy at a single institution between 1994 and 2007. Available hematoxylin and eosin-stained sections from patients with negative SLNs were reviewed, and associations between histologic findings in the negative SLNs and SLN status (true negative vs false negative) were evaluated. Forty-seven (55%) patients had at least 1 positive SLN, and 39 (45%) patients had negative SLNs. The false-negative rate was 22%, and the negative predictive value was 67%. The negative SLNs from 17 of 34 patients with available slides had focal areas of fibrosis, some with associated foamy parenchymal histiocytes, fat necrosis, or calcification. These histologic findings occurred in 15 (65%) of 23 patients with true-negative SLNs and in only 2 (18%) of 11 patients with false-negative SLNs (P = .03, Fisher exact test, 2-tailed). The lack of these histologic changes had a sensitivity and specificity for identifying a false-negative SLN of 82% and 65%, respectively. Absence of treatment effect in SLNs after chemotherapy in patients with lymph node-positive disease at initial presentation has good sensitivity but low specificity for identifying a false-negative SLN.

  3. Invasive pulmonary mycosis due to Chaetomium globosum with false-positive galactomannan test: a case report and literature review.

    Science.gov (United States)

    Capoor, Malini R; Agarwal, Poojan; Goel, Manoj; Jain, Sarika; Shivaprakash, Mandya Rudramurthy; Honnavar, Prasanna; Gupta, Sunita; Chakrabarti, Arunaloke

    2016-03-01

    In this case, the authors report Chaetomium globosum as a cause of invasive pulmonary infection in a patient with Wegener's granulomatosis. Fungal hyphae (KOH and Calcofluor) were seen on direct microscopy of lung biopsy sample and bronchoalveolar lavage (BAL) sample. C. globosum isolated on culture clinched the diagnosis of invasive pulmonary infection by Chaetomium spp. A positive galactomannan of serum and BAL was repeatedly seen and was utilised for follow-up and as prognostic marker in patient management. The patient was successfully treated with liposomal amphotericin B followed by voriconazole. All the Chaetomium infections reported till date since 1980 are reviewed. Chaetomium spp. with its unique ecology has a hidden clinical potential to cause invasive mould infections.

  4. Incidence of and factors associated with false positives in laboratory diagnosis of norovirus infection by amplification of the RNA-dependent RNA polymerase gene.

    Directory of Open Access Journals (Sweden)

    Fang-Ru Lin

    Full Text Available BACKGROUND: Conventional reverse transcription-polymerase chain reaction (RT-PCR amplification of the RNA-dependent RNA polymerase (RdRp gene remains a used method for the rapid detection of norovirus (NV in clinical laboratories. The incidence of and factors associated with false positives in this assay have not been previously evaluated. METHODS/PRINCIPAL FINDINGS: After an NV outbreak caused by the GII.4 Sydney strain in 2012, we reanalysed 250 stool samples positive for NV by RdRp gene detection. True positives were confirmed in 154 (61.6% samples by successful amplification and sequencing confirmation of the viral protein 1 gene. Of the remaining 96 samples that underwent RT-PCR for the RdRp gene, 34 samples yielded PCR products of the expected length. However, the sequences of the amplicons belonged to the human genome, with 91-97% matched nucleotide sequences, indicating false positives. Multivariate analysis of the clinical features of the patients identified a positive stool culture for bacteria (adjusted odds ratio [aOR] 9.07, 95% adjusted confidence interval [aCI] 2.17-37.92, P = .003 and the use of parenteral antibiotics (aOR 5.55, 95% aCI 1.21-24.73, P = .027 as significant and independent factors associated with false positives. CONCLUSION: Conventional RT-PCR targeting the RdRp gene of NV can lead to false positives in patients with bacterial enterocolitis by incidental amplification of DNA from a human source.

  5. Resolution, target density and labeling effects in colocalization studies - suppression of false positives by nanoscopy and modified algorithms.

    Science.gov (United States)

    Xu, Lei; Rönnlund, Daniel; Aspenström, Pontus; Braun, Laura J; Gad, Annica K B; Widengren, Jerker

    2016-03-01

    Colocalization analyses of fluorescence images are extensively used to quantify molecular interactions in cells. In recent years, fluorescence nanoscopy has approached resolutions close to molecular dimensions. However, the extent to which image resolution influences different colocalization estimates has not been systematically investigated. In this work, we applied simulations and resolution-tunable stimulated emission depletion microscopy to evaluate how the resolution, molecular density and label size of targeted molecules influence estimates of the most commonly used colocalization algorithms (Pearson correlation coefficient, Manders' M1 and M2 coefficients), as well as estimates by the image cross-correlation spectroscopy method. We investigated the practically measureable extents of colocalization for stimulated emission depletion microscopy with positive and negative control samples with an aim to identifying the strengths and weaknesses of nanoscopic techniques for colocalization studies. At a typical optical resolution of a confocal microscope (200-300 nm), our results indicate that the extent of colocalization is typically overestimated by the tested algorithms, especially at high molecular densities. Only minor effects of this kind were observed at higher resolutions (algorithm, used in combination with correlation-based methods like the Pearson coefficient and the image cross-correlation spectroscopy approach, to set intensity thresholds separating background noise from signals.

  6. 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...... an efficient method to pinpoint true positive and known causal mutations, decreasing the need of downstream interpretation of variants to a minimum. The combination of whole exome and RNA sequencing efficiently reduced the number of detected mutations. We show that the inclusion of RNA sequencing...... 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....

  7. 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.

  8. False-positive serology following intravenous immunoglobulin and plasma exchange through transfusion of fresh frozen plasma in a patient with pemphigus vulgaris.

    Science.gov (United States)

    Nomura, Hisashi; Honda, Haruki; Egami, Shohei; Yokoyama, Tomoaki; Fujimoto, Atsushi; Ishikawa, Makiko; Sugiura, Makoto

    2015-04-01

    Intravenous immunoglobulin therapy and plasma exchange through transfusion of fresh frozen plasma are therapeutic options for patients with refractory pemphigus vulgaris. Passive acquisition of various clinically important antibodies through these therapies can occur, leading to false serology and negatively affecting patients' clinical care. It is recommended that dermatologists recognize the possibility of these phenomena and interpret them appropriately. Here, we report false-positive serology following intravenous immunoglobulin therapy and plasma exchange through transfusion of fresh frozen plasma in a patient with refractory pemphigus vulgaris. We also discuss the measure for misinterpretation and unnecessary clinical intervention.

  9. False Teeth

    African Journals Online (AJOL)

    FOMCS2

    More than 80% of the respondents used traditional medicine alone or in combination with modern .... Table 2. Perceived causes of false teeth and millet disease in Bushenyi district ..... “Killer” canine removal and its sequelae in Addis Ababa.

  10. Criteria to interpret cancer biomarker increments crossing the recommended cut-off compared in a simulation model focusing on false positive signals and tumour detection time

    DEFF Research Database (Denmark)

    Lund, Flemming; Hyltoft Petersen, Per; Pedersen, Merete Frejstrup;

    2014-01-01

    BACKGROUND: Several criteria have been proposed to interpret increments in serological cancer biomarker concentrations starting from low baseline concentrations crossing the cut-off. None of the criteria have been compared for their ability to signal tumour growth when ≤2% false positive results...... are accepted. METHODS: The cancer biomarker Tissue Polypeptide Antigen was used as an example. Seven criteria to interpret increments in concentrations were investigated by computer simulations. Firstly, for each criterion, we identified a baseline concentration stratified for three levels of biological...... that different types of criteria should be used within different intervals of below cut-off level concentrations if the rate of false positive signals of marker increments should be kept ≤2%....

  11. Neisseria gonorrhoeae False-Positive Result Obtained from a Pharyngeal Swab by Using the Roche cobas 4800 CT/NG Assay in New Zealand in 2012

    OpenAIRE

    Upton, Arlo; Bromhead, Collette; Whiley, David M

    2013-01-01

    The Roche cobas 4800 CT/NG assay is a commonly used commercial system for screening for Neisseria gonorrhoeae infection, and previous studies have shown the method to be highly sensitive and specific for urogenital samples. We present the first confirmed clinical N. gonorrhoeae false-positive result using the cobas 4800 NG assay, obtained from testing a pharyngeal swab sample and caused by cross-reaction with a commensal Neisseria strain.

  12. Unusual False Positive Radioiodine Uptake on (131)I Whole Body Scintigraphy in Three Unrelated Organs with Different Pathologies in Patients of Differentiated Thyroid Carcinoma: A Case Series.

    Science.gov (United States)

    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.

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

    OpenAIRE

    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 organis...

  14. 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.

  15. 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

    A sandwich ELISA for quantification of the endometrial protein PP14 revealed false positive reactions in 81% of male sera (n = 54). The PP14 ELISA was based on two monoclonal antibodies (Mabs) with different epitope specificities--a catcher and a biotinylated indicator. The monoclonal antibodies ...... of human anti-mouse IgG antibodies (HAMA), described to create false positive results, may be due to a crossreacting fraction of the polyclonal circulating antibodies against bovine IgG.......A sandwich ELISA for quantification of the endometrial protein PP14 revealed false positive reactions in 81% of male sera (n = 54). The PP14 ELISA was based on two monoclonal antibodies (Mabs) with different epitope specificities--a catcher and a biotinylated indicator. The monoclonal antibodies...... 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...

  16. When the Single Matters more than the Group (II): Addressing the Problem of High False Positive Rates in Single Case Voxel Based Morphometry Using Non-parametric Statistics.

    Science.gov (United States)

    Scarpazza, Cristina; Nichols, Thomas E; Seramondi, Donato; Maumet, Camille; Sartori, Giuseppe; Mechelli, Andrea

    2016-01-01

    In recent years, an increasing number of studies have used Voxel Based Morphometry (VBM) to compare a single patient with a psychiatric or neurological condition of interest against a group of healthy controls. However, the validity of this approach critically relies on the assumption that the single patient is drawn from a hypothetical population with a normal distribution and variance equal to that of the control group. In a previous investigation, we demonstrated that family-wise false positive error rate (i.e., the proportion of statistical comparisons yielding at least one false positive) in single case VBM are much higher than expected (Scarpazza et al., 2013). Here, we examine whether the use of non-parametric statistics, which does not rely on the assumptions of normal distribution and equal variance, would enable the investigation of single subjects with good control of false positive risk. We empirically estimated false positive rates (FPRs) in single case non-parametric VBM, by performing 400 statistical comparisons between a single disease-free individual and a group of 100 disease-free controls. The impact of smoothing (4, 8, and 12 mm) and type of pre-processing (Modulated, Unmodulated) was also examined, as these factors have been found to influence FPRs in previous investigations using parametric statistics. The 400 statistical comparisons were repeated using two independent, freely available data sets in order to maximize the generalizability of the results. We found that the family-wise error rate was 5% for increases and 3.6% for decreases in one data set; and 5.6% for increases and 6.3% for decreases in the other data set (5% nominal). Further, these results were not dependent on the level of smoothing and modulation. Therefore, the present study provides empirical evidence that single case VBM studies with non-parametric statistics are not susceptible to high false positive rates. The critical implication of this finding is that VBM can be used

  17. Transcatheter aortic valve implantation: role of multi-detector row computed tomography to evaluate prosthesis positioning and deployment in relation to valve function.

    NARCIS (Netherlands)

    Delgado, V.; Ng, A.C.; Veire, N.R. van de; Kley, F. van der; Schuijf, J.D.; Tops, L.F.; Weger, A. de; Tavilla, G.; Roos, A. de; Kroft, L.J.; Schalij, M.J.; Bax, J.J.

    2010-01-01

    AIMS: Aortic regurgitation after transcatheter aortic valve implantation (TAVI) is one of the most frequent complications. However, the underlying mechanisms of this complication remain unclear. The present evaluation studied the anatomic and morphological features of the aortic valve annulus that m

  18. Biological false-positive tests comprise a high proportion of Venereal Disease Research Laboratory reactions in an analysis of 300,000 sera.

    Science.gov (United States)

    Geusau, Alexandra; Kittler, Harald; Hein, Ulrike; Dangl-Erlach, Edda; Stingl, Georg; Tschachler, Erwin

    2005-11-01

    This retrospective study on syphilis screening at the sexually transmitted infection (STI) unit of a University Department emphasizes the necessity of a treponemal-specific test as the appropriate screening test. The Venereal Disease Research Laboratory (VDRL) test for syphilis screening may, under certain circumstances, yield positive results in patients not infected with Treponema pallidum, a phenomenon referred to as biological false-positive (BFP) VDRL test. The aim of this study was to determine the frequency of BFP tests in a large sample of sera. In this retrospective study, we analysed the results of parallel VDRL and T. pallidum haemagglutination (TPHA) testing of a total of 514,940 blood samples obtained from patients at the Vienna General Hospital between January 1988 and November 1999. Patients' sera with incomplete data on stage and sex and duplicate sera were excluded, leaving 300,000 sera for analysis. The seroprevalence for syphilis was 1.77% (n = 5320), as determined by a positive TPHA test. It was significantly higher in male than in female patients (2.03% versus 1.58%, PVDRL. With regard to reactivity in VDRL testing, 2799 patients (0.92%) of the study population were positive, of whom 736 (26%) were biological false positive. BFP reactivity was found in 0.24% of all patients and was significantly higher in women than in men (0.27% versus 0.20%, PVDRL at 1:0 and 1:2 dilutions without a positive treponemal test was not reported. The subgroup of HIV-positive patients (n = 1415) revealed a 10-fold higher rate of BFP tests (2.1% versus 0.24), an effect being statistically significant. In a low syphilis prevalence population, BFP reactions comprise a high proportion of all VDRL reactors. Therefore, the use of the VDRL as a screening procedure is challenged.

  19. SERIAL NECK ULTRASOUND IS MORE LIKELY TO IDENTIFY FALSE-POSITIVE ABNORMALITIES THAN CLINICALLY SIGNIFICANT DISEASE IN LOW-RISK PAPILLARY THYROID CANCER PATIENTS.

    Science.gov (United States)

    Yang, Samantha Peiling; Bach, Ariadne M; Tuttle, R Michael; Fish, Stephanie A

    2015-12-01

    American Thyroid Association (ATA) low-risk papillary thyroid cancer (PTC) patients without structural evidence of disease on initial posttreatment evaluation have a low risk of recurrence. Despite this, most patients undergo frequent surveillance neck ultrasound (US). The objective of the study was to evaluate the clinical utility of routine neck US in ATA low-risk PTC patients with no structural evidence of disease after their initial thyroid surgery. We performed a retrospective review of 171 ATA low-risk PTC patients after total thyroidectomy, with or without radioactive iodine (RAI) ablation, who had a neck US without suspicious findings after therapy. The main outcome measure was a comparison of the frequency of finding false-positive US abnormalities and the frequency of identifying structural disease recurrence. Over a median follow-up of 8 years, 171 patients underwent a median of 5 neck US (range 2-17). Structural recurrence with low-volume disease (≤1 cm) was identified in 1.2% (2/171) of patients at a median of 2.8 years (range 1.6-4.1 years) after their initial diagnosis. Recurrence was associated with rising serum thyroglobulin (Tg) level in 1 of the 2 patients and was detected without signs of biochemical recurrence in the other patient. Conversely, false-positive US abnormalities were identified in 67% (114/171) of patients after therapy, leading to additional testing without identifying clinically significant disease. In ATA low-risk patients without structural evidence of disease on initial surveillance evaluation, routine screening US is substantially more likely to identify false-positive results than clinically significant structural disease recurrence.

  20. Preventing intense false positive and negative reactions attributed to the principle of ELISA to re-investigate antibody studies in autoimmune diseases.

    Science.gov (United States)

    Terato, Kuniaki; Do, Christopher T; Cutler, Dawn; Waritani, Takaki; Shionoya, Hiroshi

    2014-05-01

    To study the possible involvement of potential environmental pathogens in the pathogenesis of autoimmune diseases, it is essential to investigate antibody responses to a variety of environmental agents and autologous components. However, none of the conventional ELISA buffers can prevent the false positive and negative reactions attributed to its principal, which utilizes the high binding affinity of proteins to plastic surfaces. The aims of this study are to reveal all types of non-specific reactions associated with conventional buffer systems, and to re-investigate antibody responses to potential environmental pathogenic and autologous antigens in patients with autoimmune diseases using a newly developed buffer system "ChonBlock™" by ELISA. Compared to conventional buffers, the new buffer was highly effective in reducing the most intense false positive reaction caused by hydrophobic binding of immunoglobulin in sample specimens to plastic surfaces, "background (BG) noise reaction", and other non-specific reactions without interfering with antigen-antibody reactions. Applying this buffer, we found that IgG antibody responses to Escherichia coli O111:B4, E. coli lipopolysaccharide (LPS) and peptidoglycan polysaccharide (PG-PS) were significantly lower or tended to be lower in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), whereas IgA antibody responses to these antigens were equal or tended to be higher compared to normal controls. As a consequence, the IgA/IgG antibody ratios against these agents were significantly higher in patients with RA and SLE, except for Crohn's disease, which showed significantly higher IgG responses to these antigens. To assay antibodies in human sera, it is indispensable to eliminate false positive and negative reactions by using an appropriate buffer system, and to include antigen non-coated blank wells to determine BG noise reactions of invidual samples. Finally, based on our preliminary analysis in

  1. Evaluation of false-positive results on Tc myocardial scintigraphy in patients with coronary artery bypass grafting including left internal thoracic artery-left anterior descending artery grafting

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Koichi; Shibata, Takahiro [Jikei Univ., Tokyo (Japan). School of Medicine; Imai, Kamon

    2000-11-01

    Stress myocardial scintigraphy in patients who have undergone coronary artery bypass grafting (CABG) frequently shows false-positive results. To investigate the reason for these false-positive results, two different stress tests-adenosine triphosphate (ATP) stress testing and ergometer exercise testing, and Tc-tetrofosmin myocardial scintigraphy were performed with a 1-day stress/rest protocol. The subjects were 6 patients with a history of myocardial infarction (MI) and 14 patients with a history of angina pectoris (AP) who had undergone CABG that included left internal thoracic artery-left anterior descending artery grafting. Graft patency was confirmed with coronary angiography. Short-axis images were reconstructed with single photon emission tomography. The severity of perfusion defects on short-axis images was evaluated quantitatively with a normal database as severity score, and the difference in severity score between stress and rest was defined as fill-in. Fill-in on the ATP stress test was 3.1{+-}7.0 in the AP group and 16.3{+-}13.2 in the MI group (p<0.01). Fill-in on the exercise stress test was 2.7{+-}8.3 in the AP group and 34.8{+-}20.6 in the MI group (p<0.01). In the MI group, fill-in on the exercise stress test was significantly greater than that on the ATP stress test (p<0.05). The exercise time and the amount of exercise stress in patients with MI were significantly greater than those in patients with AP. In conclusion, coronary flow reserve may play a role in false positive-finding on myocardial perfusion scintigraphy in patients who have undergone CABG. (author)

  2. 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.

  3. False-positive rifampicin resistance on Xpert® MTB/RIF caused by a silent mutation in the rpoB gene.

    Science.gov (United States)

    Mathys, V; van de Vyvere, M; de Droogh, E; Soetaert, K; Groenen, G

    2014-10-01

    The Xpert® MTB/RIF assay detects the presence of Mycobacterium tuberculosis and its resistance to rifampicin (RMP) directly in sputum samples. Discrepant results were observed in a case of smear-positive pulmonary tuberculosis that was Xpert-resistant but phenotypically susceptible to RMP. Complementary investigations (repeat Xpert, Genotype®MTBDRplus assay and sequencing of the rpoB gene) revealed the presence of a silent mutation in the rpoB gene, leading to the conclusion of a false-positive Xpert result. As misinterpretation of Xpert results may lead to inappropriate treatment, the presence of rpoB mutations should be confirmed by sequencing the rpoB gene.

  4. 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.

  5. The background rate of false positives: Combining simulations of gravitational wave events with an unsupervised algorithm for transient identification in crowded image-subtracted data

    Science.gov (United States)

    Ackley, Kendall; Eikenberry, Stephen; Klimenko, Sergey; LIGO Collaboration

    2016-03-01

    We are now entering the era of multimessenger gravitational wave (GW) astronomy with the completion of the first observing run of Advanced LIGO. Multiwavelength electromagnetic (EM) emission is expected to accompany gravitational radiation from compact object binary mergers, such as those between neutron stars and stellar-mass black holes, where Advanced LIGO is most sensitive to their detection. Attempting to perform EM follow-up over the 10-100s deg2 error regions will be faced with many challenges, including the identification and removal of O (105) false positive transients that appear as a commotion of background events and as image artifacts in crowded image-subtracted fields. We present an update to our automated unsupervised algorithm including how our pipeline uses the existing coherent WaveBurst pipeline in an attempt to develop optimized EM follow-up schema. Our end-to-end pipeline combines simulated GW events with actual observational data from a number of ground-based optical observatories, including PTF, ROTSE, and DECam. Our performance is reported both in terms of the number of coincident false positives as well as the efficiency of recovery.

  6. False-positive amphetamine/ecstasy (MDMA/3,4-methylenedioxymethamphetamine) (CEDIA) and ecstasy (MDMA/3,4-methylenedioxymethamphetamine) (DRI) test results with fenofibrate.

    Science.gov (United States)

    Kaplan, Yusuf Cem; Erol, Almla; Karadaş, Barş

    2012-10-01

    This case report describes a false-positive amphetamine/ecstasy [3,4-methylenedioxymethamphetamine (MDMA)] and ecstasy (MDMA) screen after therapeutic use of antihyperlipidemic drug, fenofibrate. A 60-year-old male patient was admitted to inpatient psychiatry unit with the diagnosis of alcohol dependency. He was prescribed diazepam 30 mg/day, thiamine 300 mg/day, and naltrexone 50 mg/day. He had also been using fenofibrate 267 mg/day for 3 years for hyperlipidemia and trazodone 100 mg/day for 5 months for insomnia. On routine, urine drugs-of-abuse screening amphetamine/MDMA (CEDIA) test was positive for 4 different occasions and MDMA (DRI) test was positive on 5 different occasions. Gas chromatography/mass spectrometry confirmation of the first positive 3 samples were negative for amphetamine and MDMA. After discontinuation of fenofibrate, amphetamine/MDMA, and MDMA immunoassay results turned out to be negative. Caution should be given to interpretation of amphetamine/MDMA (CEDIA) and MDMA (DRI) tests in patients taking fenofibrate. Specific confirmation with a suitable method should be used to prevent erroneous interpretations.

  7. On the risk of false positive identification using multiple ion monitoring in qualitative mass spectrometry: large-scale intercomparisons with a comprehensive mass spectral library.

    Science.gov (United States)

    Stein, Stephen E; Heller, David N

    2006-06-01

    Analysts involved in qualitative mass spectrometry have long debated the minimum data requirements for demonstrating that signals from an unknown sample are identical to those from a known compound. Often this process is carried out by comparing a few selected ions acquired by multiple ion monitoring (MIM), with due allowance for expected variability in response. In a few past experiments with electron-ionization mass spectrometry (EI-MS), the number of ions selected and the allowable variability in relative abundance were tested by comparing one spectrum against a library of mass spectra, where library spectra served to represent potential false positive signals in an analysis. We extended these experiments by carrying out large-scale intercomparisons between thousands of spectra and a library of one hundred thousand EI mass spectra. The results were analyzed to gain insights into the identification confidence associated with various numbers of selected ions. A new parameter was investigated for the first time, to take into account that a library spectrum with a different base peak than the search spectrum may still cause a false positive identification. The influence of peak correlation among the specific ions in all the library mass spectra was also studied. Our computations showed that (1) false positive identifications can result from similar compounds, or low-abundance peaks in unrelated compounds if the method calls for detection at very low levels; (2) a MIM method's identification confidence improves in a roughly continuous manner as more ions are monitored, about one order of magnitude for each additional ion selected; (3) full scan spectra still represent the best alternative, if instrument sensitivity is adequate. The use of large scale intercomparisons with a comprehensive library is the only way to provide direct evidence in support of these conclusions, which otherwise depend on the judgment and experience of individual analysts. There are

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

    Energy Technology Data Exchange (ETDEWEB)

    Altinmakas, S. [Maltepe Univ., Istanbul (Turkey) Medical Faculty; Dagdeviren, B.; Turkmen, M.; Gursurer, M.; Say, B.; Tezel, T.; Ersek, B.

    2000-03-01

    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 {mu}g/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

  9. Aortic stenosis

    Science.gov (United States)

    ... Images Aortic stenosis Heart valves References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil ... ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/ ...

  10. Myeloma, source of false positive of parathyroid scintigraphy with {sup 99m}Tc-MIBI; Le myelome, source de faux-positif de la scintigraphie parathyroidienne au 99mTc-MIBI

    Energy Technology Data Exchange (ETDEWEB)

    Zaabar, L.; Ben Sellem, D.; El Ajmi, W.; Slim, I.; Letaief, B.; Mhiri, A.; Ben Slimene, M.F. [Institut Salah Azaiez, Service de medecine nucleaire, Tunis (Tunisia)

    2010-07-01

    Purpose: Considering a specificity of the MIBI dual-phase parathyroid scintigraphy with {sup 99m}Tc-MIBI presents false positives which number has declined since the systematic implementation of the SPECT. We report a case of a superior mediastinal false-positive. Conclusions: the myeloma represents a potential cause of false-positive of parathyroid scintigraphy with {sup 99m}Tc-MIBI. (N.C.)

  11. 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.

  12. Abdominal Aortic Aneurysm (AAA)

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Abdominal Aortic Aneurysm (AAA) Abdominal aortic aneurysm (AAA) occurs when atherosclerosis ... an abdominal aortic aneurysm treated? What is an abdominal aortic aneurysm? The aorta, the largest artery in the body, ...

  13. Reply to 'Influence of cosmic ray variability on the monsoon rainfall and temperature': a false-positive in the field of solar-terrestrial research

    CERN Document Server

    Laken, Benjamin A

    2015-01-01

    A litany of research has been published claiming strong solar influences on the Earth's weather and climate. Much of this work includes documented errors and false-positives, yet is still frequently used to substantiate arguments of global warming denial. This manuscript reports on a recent study by Badruddin & Aslam (2014), hereafter BA14, which claimed a highly significant ($p=1.4\\times10^{-5}$) relationship between extremes in the intensity of the Indian monsoon and the cosmic ray flux. They further speculated that the relationship they observed may apply across the entire tropical and sub-tropical belt, and be of global importance. However, their statistical analysis---and consequently their conclusions---were wrong. Specifically, their error resulted from an assumption that their data's underlying distribution was Gaussian. But, as demonstrated in this work, their data closely follow an ergodic chaotic distribution biased towards extreme values. From a probability density function, calculated using a...

  14. Filter-based feature selection and support vector machine for false positive reduction in computer-aided mass detection in mammograms

    Science.gov (United States)

    Nguyen, V. D.; Nguyen, D. T.; Nguyen, T. D.; Phan, V. A.; Truong, Q. D.

    2015-02-01

    In this paper, a method for reducing false positive in computer-aided mass detection in screening mammograms is proposed. A set of 32 features, including First Order Statistics (FOS) features, Gray-Level Occurrence Matrix (GLCM) features, Block Difference Inverse Probability (BDIP) features, and Block Variation of Local Correlation coefficients (BVLC) are extracted from detected Regions-Of-Interest (ROIs). An optimal subset of 8 features is selected from the full feature set by mean of a filter-based Sequential Backward Selection (SBS). Then, Support Vector Machine (SVM) is utilized to classify the ROIs into massive regions or normal regions. The method's performance is evaluated using the area under the Receiver Operating Characteristic (ROC) curve (AUC or AZ). On a dataset consisting about 2700 ROIs detected from mini-MIAS database of mammograms, the proposed method achieves AZ=0.938.

  15. 18 F-FDG avid lesion due to coexistent fibrous dysplasia in a child of embryonal rhabdomyosarcoma: Source of false positive FDG-PET

    Directory of Open Access Journals (Sweden)

    Basu Sandip

    2010-01-01

    Full Text Available With increasing use of 18 F-fluorodeoxyglucose (FDG-positron emission tomography (PET in the current oncological practice, there is a growing body of evidence of false positive scans due to various benign conditions. In this communication we present intensely avid 18 F-FDG uptake in fibrous dysplasia of right tibia in a 12-year-old child suffering from embryonal rhabdomyosarcoma (ERMS that could have been easily mistaken to be a metastatic focus if not carefully correlated. The patient was a case of ERMS (presenting with left cervical mass with intrathoracic extension who was treated successfully with chemotherapy and was referred for FDG-PET to evaluate the disease status. His whole body survey was unremarkable except for an intensely avid FDG uptake (SUV max 8.5 in shaft of right tibia. The scan was extended up to foot in view of the fact that a prior bone scan had shown a focal uptake in the similar location. Efforts were undertaken to elucidate the exact etiopathology of the aforementioned 18 F-FDG uptake because the rest of the whole body survey was unremarkable. A plain radiograph (both anteroposterior and lateral views of the right tibia showed patchy sclerosis involving the middle diaphysis of the right tibia suggesting a fibrous defect. The computed tomography (CT scan of the same region showed cortical thickening and increased density within the medullary cavity in the shaft of the tibia. A histopathological diagnosis was sought for and the lesion was subsequently proven to be fibrous dysplasia by histopathology of the bone piece obtained from the right tibial lesion by J needle biopsy. The present case is a useful addition to the current body of literature of false positive 18 F-FDG-PET study due to a benign skeletal pathology and underscores the importance of high index of suspicion and careful clinicoradiopathologic correlation, whenever one comes across such an unusual PET finding.

  16. False-positive myeloperoxidase binding activity due to DNA/anti-DNA antibody complexes: a source for analytical error in serologic evaluation of anti-neutrophil cytoplasmic autoantibodies.

    Science.gov (United States)

    Jethwa, H S; Nachman, P H; Falk, R J; Jennette, J C

    2000-09-01

    Anti-myeloperoxidase antibodies (anti-MPO) are a major type of anti-neutrophil cytoplasmic antibody (ANCA). While evaluating anti-MPO monoclonal antibodies from SCG/Kj mice, we observed several hybridomas that appeared to react with both MPO and DNA. Sera from some patients with systemic lupus erythematosus (SLE) also react with MPO and DNA. We hypothesized that the MPO binding activity is a false-positive result due to the binding of DNA, contained within the antigen binding site of anti-DNA antibodies, to the cationic MPO. Antibodies from tissue culture supernatants from 'dual reactive' hybridomas were purified under high-salt conditions (3 M NaCl) to remove any antigen bound to antibody. The MPO and DNA binding activity were measured by ELISA. The MPO binding activity was completely abrogated while the DNA binding activity remained. The MPO binding activity was restored, in a dose-dependent manner, by the addition of increasing amount of calf-thymus DNA (CT-DNA) to the purified antibody. Sera from six patients with SLE that reacted with both MPO and DNA were treated with DNase and showed a decrease in MPO binding activity compared with untreated samples. MPO binding activity was observed when CT-DNA was added to sera from SLE patients that initially reacted with DNA but not with MPO. These results suggest that the DNA contained within the antigen binding site of anti-DNA antibodies could bind to the highly cationic MPO used as substrate antigen in immunoassays, resulting in a false-positive test.

  17. 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.

  18. Development of a method that eliminates false-positive results due to nerve growth factor interference in the assessment of fulranumab immunogenicity.

    Science.gov (United States)

    Dai, Sheng; Schantz, Allen; Clements-Egan, Adrienne; Cannon, Michael; Shankar, Gopi

    2014-05-01

    Fulranumab, a human IgG2 monoclonal antibody that neutralizes nerve growth factor (NGF), is currently in development for the treatment of pain. Our initial immunogenicity test method was found to be prone to NGF interference, leading to a high apparent incidence of anti-drug antibody (ADA) in phase 1 studies. The ADA immunoassay comprised a homogeneous bridging electrochemiluminescence (ECL) format with biotin and ruthenium-labeled fulranumab bound together ("bridged") by ADA in test samples for detection. In this assay, NGF produced a false-positive signal due to its ability to bridge fulranumab molecules. Thus, we developed a specificity assay to eliminate the NGF false-positive results. We encountered the challenge of eliminating drug interference as well as drug target interference, and discovered that the acid-dissociation-based pretreatment of samples used for mitigating drug interference dramatically increased drug target interference. Several strategies were investigated to eliminate the NGF interference; yet only one strategy specifically removed NGF and produced true fulranumab-specific ADA results by using competitive inhibition with fulranumab and utilizing an alternative NGF binding antibody to eliminate NGF interference. Using this new method, we confirmed that the high apparent anti-fulranumab antibody incidence (>60%) in clinical study samples was in fact due to fulranumab-bound NGF released during the acid-dissociation step of the ADA testing method. We conclude that our revised method accurately identifies anti-fulranumab antibodies by incorporating steps to eliminate fulranumab and NGF interference. We advise that acid-dissociation pretreatment must not be universally applied to improve ADA assays without investigating its bioanalytical risks versus benefits.

  19. Impact of Lymphoid Follicles and Histiocytes on the False Positive FDG Uptake of Lymph Nodes in Non Small Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Seong Young; Min, Jung Joon; Song, Ho Chun; Choi, Chan; Na, Kook Joo; Bom, Hee Seung [Chonnam National Univ. Hwasun Hospital, Hwasun (Korea, Republic of)

    2011-09-15

    Although {sup 18F} fluorodeoxyglucose (FDG) PET/CT has improved the accuracy of evaluating lymph node (LN) staging in non small cell lung cancer (NSCLC), false positive results remain a problem. The reason why benign LNs show high FDG uptake is still unclear. The aim of this study was to identify molecular and pathological characteristics of benign LNs showing high FDG uptake. We studied 108 mediastinal LNs of pathologically benign nature obtained from 43 patients with NSCLC who underwent FDG PET/CT and surgery. We measured the following parameters in each LN: maximum standardized uptake value (maxSUV), short diameter, maximum Hounsfield unit (maxHU) value, occupied proportions of lymphoid follicles, histiocytes in extrafollicular space and the degree of glucose transporter 1 (Glut1) expression. We compared the parameters between two LN groups according to maxSUV. There were 74 LNs showing maxSUV{>=}3.0 (group 1) and 34 LNs with maxSUV<3.0 (group 2). The size of LN (p<0.001) and maxHU (p=0.003) in group 1 was higher than that in group 2. Histologically, the occupied proportions of lymphoid follicles (p=0.031) or histiocytes (p=0.004) were higher in group 1. The Glut1 expression of lymphoid follicles (p=0.035) or histiocytes (p=0.005) was also higher in group 1. Lymphoid follicular hyperplasia and histiocyte infiltration associated with Glut1 overexpression are important molecular and pathological mechanisms for false positive FDG uptake in benign mediastinal LNs in patients with NSCLC.

  20. Reinforced aortic root reconstruction for acute type A aortic dissection involving the aortic root

    Directory of Open Access Journals (Sweden)

    Han Qing-qi

    2013-06-01

    Full Text Available OBJECTIVE: There are debates regarding the optimal approach for AAAD involving the aortic root. We described a modified reinforced aortic root reconstruction approach for treating AAAD involving the aortic root. METHODS: A total of 161 patients with AAAD involving the aortic root were treated by our modified reinforced aortic root reconstruction approach from January 1998 to December 2008. Key features of our modified approach were placement of an autologous pericardial patch in the false lumen, lining of the sinotubular junction lumen with a polyester vascular ring, and wrapping of the vessel with Teflon strips. Outcome measures included post-operative mortality, survival, complications, and level of aortic regurgitation. RESULTS: A total of 161 patients were included in the study (mean age: 43.3 1 15.5 years. The mean duration of follow-up was 5.1 1 2.96 years (2-12 years. A total of 10 (6.2% and 11 (6.8% patients died during hospitalization and during follow-up, respectively. Thirty-one (19.3% patients experienced postoperative complications. The 1-, 3-, 5-, and 10-year survival rates were 99.3%, 98%, 93.8%, and 75.5%, respectively. There were no instances of recurrent aortic dissection, aortic aneurysm, or pseudoaneurysm during the entire study period. The severity of aortic regurgitation dramatically decreased immediately after surgery (from 28.6% to 0% grade 3-4 and thereafter slightly increased (from 0% to 7.2% at 5 years and 9.1% at 10 years. CONCLUSION: This modified reinforced aortic root reconstruction was feasible, safe and durable/effective, as indicated by its low mortality, low postoperative complications and high survival rate.

  1. 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.

  2. Using a reference when defining an abnormal MRI reduces false-positive MRI results-a longitudinal study in two cohorts at risk for rheumatoid arthritis.

    Science.gov (United States)

    Boer, Aleid C; Burgers, Leonie E; Mangnus, Lukas; Ten Brinck, Robin M; Nieuwenhuis, Wouter P; van Steenbergen, Hanna W; Reijnierse, Monique; Huizinga, Tom W J; van der Helm van Mil, Annette H M

    2017-10-01

    The use of hand and foot MRI in the diagnostic process of RA has been advocated. Recent studies showed that MRI is helpful in predicting progression from clinically suspect arthralgia (CSA) to clinical arthritis, and from undifferentiated arthritis (UA) to RA. Symptom-free persons can also show inflammation on MRI. This study aimed to evaluate if MRI findings in symptom-free volunteers are relevant when defining a positive MRI. Two hundred and twenty-five CSA patients and two hundred and one UA patients underwent MRI of MCP, wrist and MTP joints at baseline and were followed for 1 year on progression to arthritis and RA, respectively, as reported previously. MRI was considered positive if ⩾ 1 joint showed inflammation (called uncorrected definition), or if ⩾ 1 joint had inflammation that was present in < 5% of persons of the same age category at the same location (called 5% corrected definition). Test characteristics were compared for both definitions. By using MRI data of symptom-free volunteers as reference, specificity of MRI-detected inflammation increased from 22 to 56% in CSA patients, and from 10 to 36% in UA patients. The sensitivity was not affected; it was 88 and 85% in CSA patients and 93 and 93% in UA patients. The accuracy also increased, from 32 to 60% in CSA patients and 22 to 44% in UA patients. The use of a reference population resulted in a substantial reduction of false-positive results, without influencing the sensitivity. Although common for other tests in medicine, this phenomenon is novel for MRI in the early detection of RA.

  3. Massive-training artificial neural network (MTANN) for reduction of false positives in computer-aided detection of polyps: Suppression of rectal tubes.

    Science.gov (United States)

    Suzuki, Kenji; Yoshida, Hiroyuki; Näppi, Janne; Dachman, Abraham H

    2006-10-01

    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

  4. Development of a sensitive and false-positive free PMA-qPCR viability assay to quantify VBNC Escherichia coli and evaluate disinfection performance in wastewater effluent.

    Science.gov (United States)

    Kibbee, Richard J; Örmeci, Banu

    2017-01-01

    The detection and quantification of viable Escherichia coli cells in wastewater treatment plant effluent is very important as it is the main disinfection efficacy parameter for assessing its public health risk and environmental impact. The aim of this study was to develop a sensitive and false-positive free propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR) assay to quantify the viable but non-culturable (VBNC) E. coli present in secondary wastewater effluent after chlorine disinfection. The qPCR target was the E. coli uidA gene, and native Taq was used to eliminate false positives caused by the presence of contaminant E. coli DNA in recombinant Taq polymerase reagents. Due to issues with qPCR inhibitors in wastewater, this study explored several pre-DNA extraction treatment methods for qPCR inhibitor removal. PMA-qPCR validation was done using salmon testes DNA (Sketa DNA) as an exogenous control added directly to the wastewater samples and amplified using a separate qPCR assay. After disinfection of secondary effluent with 2ppm chlorine at the plant, the mean Log10 CFU reduction in E. coli was 2.85 from a mean CFU of 3.48/10mL compared to 0.21 Log10 CCE mean reduction of the uidA gene from a mean CCE of 3.16/10mL. The VBNC cell concentrations were calculated as 2.32 Log10/10mL by subtracting the colony forming units (CFU) obtained from membrane filtration from the calculated CFU equivalent (CCE) values obtained from PMA-qPCR. These results demonstrate the effective use of a PMA-qPCR method for the quantification of the E. coli uidA gene and indicate there are high numbers (2.01×10(3)CCE/100mL) of VBNC E. coli cells leaving the wastewater treatment plant in the final effluent after chlorine treatment. VBNC bacterial cells are of concern as they have the potential to resuscitate and grow, regain virulence, affect natural microbiome in the discharge sites, and pass on antimicrobial resistant genes to other microorganisms. Copyright © 2016

  5. Prevalent false positives of azoospermia factor a (AZFa) microdeletions caused by single-nucleotide polymorphism rs72609647 in the sY84 screening of male infertility

    Institute of Scientific and Technical Information of China (English)

    Qing Wu; Hui-Juan Shi; Guo-Wu Chen; Tao-Fei Yan; Hui Wang; Yu-Ling Liu; Zheng Li; Shi-Wei Duan; Fei Sun; Yun Feng

    2011-01-01

    Multiplex polymerase chain reaction (PCR) has been widely used to detect Y-chromosome microdeletions,which is one of the major causes of male infertility.Both the European Academy of Andrology (EAA) and the European Molecular Genetics Quality Network (EMQN) have recommended the use of sY84 and sY86 markers for the detection of azoospermia factor a (AZFa) microdeletion during DNA testing for male infertility.In this study,a large-scale analysis of AZF microdeletion in a total of 630 Chinese males,including healthy semen donors (n=200),infertile males with normal sperm count (n=226) and patients with either nonobstructive azoospermia or severe oligozoospermia (n=204),was performed.A series of nine sequence-tagged site (STS) markers from the AZF region of the Y chromosome was used to detect microdeletions.All primers were designed based on the recommendations of the National Center for Biotechnology Information.An unusually high incidence (73/630,11.6%) of sY84-absent but sY86-present genotypes was observed in the AZFa microdeletion screening.Sequencing the sY84-flanking region revealed a total of 73 patients with sY84-absent but sY86-present genotypes have a T-to-G transversion at the fifth base from the 5' end of the reverse sY84 primer.These prevalent false positives,which were not only observed in infertile men,but also observed in donors,resulted from a single-nucleotide polymorphism (SNP) named rs72609647 in the targeting sequence of the reverse sY84 primer.Our study suggests that a pre-screening of existence of rs72609647 polymorphism can prevent the frequent false positive results of AZFa microdeletions detection in the infertile Chinese males.Given the SNP rs72609647 was recently found in a deep sequencing of a Chinese individual,the current EAA and EMQN standards may need to be scrutinized among different populations to avoid the potential genetic variations in the primer binding sequences.

  6. [Surgical technique of aortic valve replacement for small aortic annulus in elderly patients].

    Science.gov (United States)

    Hata, T; Fujiwara, K; Furukawa, H; Tsushima, Y; Yoshitaka, H; Kuinose, M; Minami, H; Ishida, A; Tamura, K; Totsugawa, T; Kanemitsu, H; Ozawa, M

    2006-04-01

    Recent reports have shown that aortic valve replacement in elderly patients over 65 years with atherosclerotic aortic stenosis and a small aortic annulus is possible by using a small sized bioprosthesis (Carpentier-Edwards pericardial valve). Here we present out surgical technique. Firstly, the native calcified aortic valve was removed completely to gain total exposure of the surrounding aortic root and sinus of Valsalva like Bentall procedure. Secondly, a small sized bioprosthesis was implanted with intermittent noneverting mattress 2-0 sutures with spaghetti and small polytetrafluoroethylene (PTFE) felt. Aortic annulus is the dilated by inserting Hegar dilator sizing from 25 to 27 mm. Therefore, aortic valve replacement for small aortic annulus in intra- or supra-annular position should be easily accomplished. Good surgical results and hemodynamic state were achieved in 25 consecutive cases using this technique.

  7. [Aortic aneurysm].

    Science.gov (United States)

    Villar, Fernando; Pedro-Botet, Juan; Vila, Ramón; Lahoz, Carlos

    2013-01-01

    Aortic aneurysm is one important cause of death in our country. The prevalence of abdominal aortic aneurism (AAA) is around 5% for men older than 50 years of age. Some factors are associated with increased risk for AAA: age, hypertension, hypercholesterolemia, cardiovascular disease and, in particular, smoking. The medical management of patients with an AAA includes cardiovascular risk treatment, particularly smoking cessation. Most of major societies guidelines recommend ultrasonography screening for AAA in men aged 65 to 75 years who have ever smoked because it leads to decreased AAA-specific mortality. Copyright © 2013 Elsevier España, S.L. y SEA. All rights reserved.

  8. Small intestinal bacterial overgrowth as an uncommon cause of false positive lactose hydrogen breath test among patients with diarrhea-predominant irritable bowel syndrome in Asia.

    Science.gov (United States)

    Wang, Yilin; Xiong, Lishou; Gong, Xiaorong; Li, Weimin; Zhang, Xiangsong; Chen, Minhu

    2015-06-01

    It has been reported that small intestinal bacterial overgrowth (SIBO) may lead to false positive diagnoses of lactose malabsorption (LM) in irritable bowel syndrome patients. The aim of this study was to determine the influence of SIBO on lactose hydrogen breath test (HBT) results in these patients. Diarrhea-predominant irritable bowel syndrome patients with abnormal lactose HBTs ingested a test meal containing (99m) Tc and lactose. The location of the test meal and the breath levels of hydrogen were recorded simultaneously by scintigraphic scanning and lactose HBT, respectively. The increase in hydrogen concentration was not considered to be caused by SIBO if ≥ 10% of (99m) Tc accumulated in the cecal region at the time or before of abnormal lactose HBT. LM was present in 84% (31/37) of irritable bowel syndrome patients. Twenty of these patients agreed to measurement of oro-cecal transit time. Only three patients (15%) with abnormal lactose HBT might have had SIBO. The median oro-cecal transit time between LM and lactose intolerance patients were 75 min and 45 min, respectively (Z=2.545, P=0.011). Most of irritable bowel syndrome patients with an abnormal lactose HBT had LM. SIBO had little impact on the interpretation of lactose HBTs. The patients with lactose intolerance had faster small intestinal transit than LM patients. © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.

  9. Specificity and false positive rates of the Test of Memory Malingering, Rey 15-item Test, and Rey Word Recognition Test among forensic inpatients with intellectual disabilities.

    Science.gov (United States)

    Love, Christopher M; Glassmire, David M; Zanolini, Shanna Jordan; Wolf, Amanda

    2014-10-01

    This study evaluated the specificity and false positive (FP) rates of the Rey 15-Item Test (FIT), Word Recognition Test (WRT), and Test of Memory Malingering (TOMM) in a sample of 21 forensic inpatients with mild intellectual disability (ID). The FIT demonstrated an FP rate of 23.8% with the standard quantitative cutoff score. Certain qualitative error types on the FIT showed promise and had low FP rates. The WRT obtained an FP rate of 0.0% with previously reported cutoff scores. Finally, the TOMM demonstrated low FP rates of 4.8% and 0.0% on Trial 2 and the Retention Trial, respectively, when applying the standard cutoff score. FP rates are reported for a range of cutoff scores and compared with published research on individuals diagnosed with ID. Results indicated that although the quantitative variables on the FIT had unacceptably high FP rates, the TOMM and WRT had low FP rates, increasing the confidence clinicians can place in scores reflecting poor effort on these measures during ID evaluations.

  10. Possibility of false-positive detection for sporozoites in mosquitos (Diptera: Culicidae) by nested polymerase chain reaction using Plasmodium yoelii genomic DNA.

    Science.gov (United States)

    Tsuzuki, A; Toma, T; Miyagi, I; Toma, H; Arakawa, T; Sato, Y; Kobayashi, J; Mugissa, M F

    2001-06-01

    Anopheles stephensi Liston and An. saperoi Bohart and Ingram infected with the rodent malaria parasite Plasmodium yoelii nigeriense. They were examined 12 and 19 days after blood feeding for sporozoites in head with anterior thorax (HT) and oocysts in abdomen with posterior thorax (AB) by light microscopy and by the nested polymerase chain reaction (nested PCR-based on the amplification of the sequences of the small subunit ribosomal RNA gene). The detection rate of parasite DNA by nested PCR in HT samples 12 days after blood feeding was similar to that by microscopic method. However, in HT samples 19 days after blood feeding, the rate by the PCR method was higher than that by the microscopic method. The incidence of sporozoites in salivary glands of infected mosquitos for 12 days after blood sucking was examined by the PCR method. Parasite DNA in HT of Aedes albopictus Skuse (a non vector for the rodent malaria) as well as An. stephensi and An. saperoi was detected for up to 4 days after feeding on mouse with the rodent malaria parasites. The results indicate that when the PCR method is used for detection of sporozoites of human malaria in mosquitos collected in the field, there are possibilities of including false-positive data for mosquitos that have just or recently fed on human blood infected with malaria (erythrocytic form).

  11. A Discovery of a Candidate Companion to a Transiting System KOI-94: A Direct Imaging Study for a Possibility of a False Positive

    CERN Document Server

    Takahashi, Yasuhiro H; Hirano, Teruyuki; Kuzuhara, Masayuki; Tamura, Motohide; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Hashimoto, Jun; Sato, Bun'ei; Abe, Lyu; Brandner, Wolfgang; Brandt, Timothy D; Carson, Joseph C; Currie, Thayne; Egner, Sebastian; Feldt, Markus; Goto, Miwa; Grady, Carol A; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko S; Henning, Thomas; Hodapp, Klaus W; Ishii, Miki; Iye, Masanori; Janson, Markus; Kandori, Ryo; Knapp, Gillian R; Kwon, Jungmi; Matsuo, Taro; McElwain, Michael W; Miyama, Shoken; Morino, Jun-Ichi; Moro-Martin, Amaya; Nishimura, Tetsuo; Pyo, Tae-Soo; Serabyn, Eugene; Suenaga, Takuya; Suto, Hiroshi; Suzuki, Ryuji; Takami, Michihiro; Takato, Naruhisa; Terada, Hiroshi; Thalmann, Christian; Tomono, Daigo; Turner, Edwin L; Watanabe, Makoto; Wisniewski, John; Yamada, Toru; Takami, Hideki; Usuda, Tomonori

    2013-01-01

    We report a discovery of a companion candidate around one of {\\it Kepler} Objects of Interest (KOIs), KOI-94, and results of our quantitative investigation of the possibility that planetary candidates around KOI-94 are false positives. KOI-94 has a planetary system in which four planetary detections have been reported by {\\it Kepler}, suggesting that this system is intriguing to study the dynamical evolutions of planets. However, while two of those detections (KOI-94.01 and 03) have been made robust by previous observations, the others (KOI-94.02 and 04) are marginal detections, for which future confirmations with various techniques are required. We have conducted high-contrast direct imaging observations with Subaru/HiCIAO in $H$ band and detected a faint object located at a separation of $\\sim0.6''$ from KOI-94. The object has a contrast of $\\sim 1\\times 10^{-3}$ in $H$ band, and corresponds to an M type star on the assumption that the object is at the same distance of KOI-94. Based on our analysis, KOI-94....

  12. Target surveillance of blood culture positive samples and control of false positive%血培养阳性标本的目标性监测与假阳性的控制

    Institute of Scientific and Technical Information of China (English)

    覃凌; 王慕云

    2012-01-01

    OBJECTIVE To provide objective guidelines for the clinical diagnosis and rational application of antibiotics by analyzing the reasons of the false positive of blood culture and exploring the effect on its incidence after taking corresponding countermeasures. METHODS We monitored all the positive blood culture cases to find the causes of the false positive cases from Jan to Jun 2008. and the interventions were adopted in response to the problems since Jul 2008, the follow-up of the blood culture positive cases was performed during the period of Jul 2008 -Dec 2010. RESULTS The conditional pathogens were dominated in the blood cultured positive cases during Jan-Jun 2008, among which coagulase-negative Staphylococcus accounted for 83. 33%, the rate of false positive blood culture was 35. 29%, while descending to 8. 70% from Jul to Dec 2010 after taking the control measures (x2 =9. 172,P = 0. 002). CONCLUSION By applying quality control administration mode in target surveillance of blood culture positive, taking correct intervention measures such as instituting standardized blood culture sampling procedure and emphasizing the relevant knowledge and operation skills of the nurses as well as the intensifying the quality supervision and assessment, we can improve the quality of submission of the blood culture specimens, reduce the rate of false positive and ensure the accuracy of the examination results.%目的 分析医院血培养假阳性的原因,探讨采取相关措施后对其发生率的影响,为指导临床诊断及合理应用抗菌药物提供客观依据.方法 对2008年1-6月所有血培养阳性的病例进行目标追踪监测,了解假阳性率,分析产生的原因;2008年7月针对问题采取相应的干预措施,持续追踪2008年7月-2010年12月血培养阳性病例.结果 2008年1-6月血培养假阳性病例的病原菌分布以条件致病菌为主,其中凝固酶阴性葡萄球菌占83.33%,血培养假阳性率高达35.29

  13. Effect of heart rate on the hemodynamics of bileaflet mechanical heart valves' prostheses (St. Jude Medical) in the aortic position and in the opening phase: A computational study.

    Science.gov (United States)

    Jahandardoost, Mehdi; Fradet, Guy; Mohammadi, Hadi

    2016-03-01

    To date, to the best of the authors' knowledge, in almost all of the studies performed around the hemodynamics of bileaflet mechanical heart valves, a heart rate of 70-72 beats/min has been considered. In fact, the heart rate of ~72 beats/min does not represent the entire normal physiological conditions under which the aortic or prosthetic valves function. The heart rates of 120 or 50 beats/min may lead to hemodynamic complications, such as plaque formation and/or thromboembolism in patients. In this study, the hemodynamic performance of the bileaflet mechanical heart valves in a wide range of normal and physiological heart rates, that is, 60-150 beats/min, was studied in the opening phase. The model considered in this study was a St. Jude Medical bileaflet mechanical heart valve with the inner diameter of 27 mm in the aortic position. The hemodynamics of the native valve and the St. Jude Medical valve were studied in a variety of heart rates in the opening phase and the results were carefully compared. The results indicate that peak values of the velocity profile downstream of the valve increase as heart rate increases, as well as the location of the maximum velocity changes with heart rate in the St. Jude Medical valve model. Also, the maximum values of shear stress and wall shear stresses downstream of the valve are proportional to heart rate in both models. Interestingly, the maximum shear stress and wall shear stress values in both models are in the same range when heart rate is valve model when heart rate is >90 beats/min (up to ~40% growth compared to that of the native valve). The findings of this study may be of importance in the hemodynamic performance of bileaflet mechanical heart valves. They may also play an important role in design improvement of conventional prosthetic heart valves and the design of the next generation of prosthetic valves, such as percutaneous valves.

  14. Is it time to rethink how neuropsychological tests are used to diagnose mild forms of HIV-associated neurocognitive disorders? Impact of false-positive rates on prevalence and power.

    Science.gov (United States)

    Meyer, Ana-Claire L; Boscardin, W John; Kwasa, Judith K; Price, Richard W

    2013-01-01

    Between 0 and 48% of normal HIV-uninfected individuals score below threshold neuropsychological test scores for HIV-associated neurocognitive disorders (HAND) or are false positives. There has been little effort to understand the effect of varied interpretations of research criteria for HAND on false-positive frequencies, prevalence and analytic estimates. The proportion of normal individuals scoring below Z score thresholds drawn from research criteria for HAND, or false-positive frequencies, was estimated in a normal Kenyan population and a simulated normal population using varied interpretations of research criteria for HAND. We calculated the impact of false-positive frequencies on prevalence estimates and statistical power. False-positive frequencies of 2-74% were observed for asymptomatic neurocognitive impairment/mild neurocognitive disorder and 0-8% for HIV-associated dementia. False-positive frequencies depended on the definition of an abnormal cognitive domain, Z score thresholds and neuropsychological battery size. Misclassification led to clinically important overestimation of prevalence and dramatic decreases in power. Minimizing false-positive frequencies is critical to decrease bias in prevalence estimates and minimize reductions in power in studies of association, particularly for mild forms of HAND. We recommend changing the Z score threshold to ≤-1.5 for mild impairment, limiting analysis to 3-5 cognitive domains and using the average Z score to define an abnormal domain. © 2013 S. Karger AG, Basel.

  15. Respostas falso-positivas na triagem auditiva neonatal universal: possíveis causas False-positive results in newborn universal hearing screening: possible causes

    Directory of Open Access Journals (Sweden)

    Maria Cristina Silva Simonek

    2011-04-01

    Full Text Available OBJETIVO: avaliar a ocorrência de respostas falso-positivas na Triagem Auditiva dentro de uma maternidade particular, suas possíveis causas e soluções. MÉTODOS: foram avaliados 1.110 recém-nascidos eutróficos entre 6 e 48 horas de vida no berçário, com o analisador de Emissões Otoacústicas Evocadas Transientes (EOATE modelo Echochek da Ilodynamics Ltd. Na ausência de resposta, foi realizada a manipulação do meato acústico externo (Manobra Facilitadora e colhido novo resultado. Os que falharam foram retestados em 15 dias. RESULTADOS: 50,09% dos RN falhou na primeira tentativa. Após a manobra facilitadora, 24,41% continuou falhando, mas demonstraram EOATE presentes no reteste. O tempo médio de internação foi de 42,27 h, sendo 93,42% oriundos de cesareana. Pertenciam a convênios particulares padrão enfermaria 98% e 2% quarto individual. A idade média do grupo que passou foi de 24,14 h (± 10,21 e a do grupo que falhou 19,19 horas (±8,43. Possuíam menos de 24 horas de vida no momento do teste 66,12% dos RN, foi constatado vérnix obliterante em 4.9%. CONLUSÃO: face a alta precoce hospitalar, é necessário que o Fonoaudiólogo realize o teste antes das 48 horas de vida do RN. Desta forma, além das causas biológicas inerentes a faixa etária, detectou-se um problema estrutural de administração hospitalar, que independe da habilidade ou experiência do Fonoaudiólogo. A Manobra Facilitadora é altamente recomendada.PURPOSE: to investigate the rate of false positive responses in a hospital - based newborn hearing screening program (NHS, their possible causes and solutions. METHODS: during the period we evaluated 1,110 regular nursery newborns, age 6 to 48 hours with Transient Evoked Otoacoustic Emissions (TEOAEs, Echocheck, Ilodynamics Ltd model., at the nurseries, before discharge. In case of absence of response, the ear canal was manipulated. Infants that failed the screening were retested fifteen days after birth

  16. What are the Best Ways to Reduce the False positive Rate of 18F FDG PET/CT in Patients with Breast Cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Evangelista, Laura; Baretta, Zora; Vinante, Lorenzo; Sotti, Guido [Istituto Oncologico Veneto, Padova (Italy)

    2011-03-15

    Dear Editor, We were interested to read the recent article by Park et al that described the interpretation of physiologic and benign sites of {sup 18F} fluorodeoxyglucose (18F FDG) uptake on positron emission tomography/computed tomography (PET/CT) imaging og patients with breast cancer. The central messages were: (1) to know and (2) to discriminate the main sites of FDG avidity, avoiding a misinterpretation and thus reducing the false positive rate. Some considerations referring to the report can be made. The authors declared that several normal and altered physiologic foci and various benign lesions demonstrated significant FDG uptake in patients with breast cancer and the accurate interpretation of these findings can be challenging for clinicians; they concluded that {sup t}o avoid misinterpretations, we suggest that careful attention to these normal or altered physiological FDG uptake patterns and hypermetabolic benign disease is required for more accurate image interpretation for the correct staging and detection of disease recurrence in patients with breast cancer.{sup I}n our Department, in cases of indeterminate or inconclusive PET/CT exams, we try to conclude for pathological or physiological uptake on the basis of abnormal/normal correspondence of CT findings, considering the natural history of disease (i.e. loco regional lymph node or others) and using specific protocols (i.e. dual time PET/CT). As reported in the literature, metabolic abnormalities detected on PET images can be precisely localised anatomically by hardware fusion with the CT images obtained in the same sitting; the CT portion of PET/CT, in fact, provides anatomical details and offers an anatomical mapping for FDG distribution. Moreover, an accurate lesion localisation leads to accurate staging, a clear advantage of PET/CT over PET alone in the clinical situation. Some steps could be taken to reduce the false positive rate of PET/CT in breast cancer: 1. Prolonging the time between the

  17. Contamination in the Kepler field. Identification of 685 KOIs as false positives via ephemeris matching based ON Q1-Q12 data

    Energy Technology Data Exchange (ETDEWEB)

    Coughlin, Jeffrey L.; Thompson, Susan E.; Burke, Christopher J.; Caldwell, Douglas A.; Jenkins, Jon M.; Mullally, Fergal R.; Rowe, Jason F. [SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Bryson, Stephen T.; Haas, Michael R.; Howell, Steve B. [NASA Ames Research Center, M/S 244-30, Moffett Field, CA 94035 (United States); Christiansen, Jessie L. [NASA Exoplanet Science Institute, California Institute of Technology, Pasadena CA 91125 (United States); Kolodziejczak, Jeffery J., E-mail: jeffrey.l.coughlin@nasa.gov [NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States)

    2014-05-01

    The Kepler mission has to date found almost 6000 planetary transit-like signals, utilizing three years of data for over 170,000 stars at extremely high photometric precision. Due to its design, contamination from eclipsing binaries, variable stars, and other transiting planets results in a significant number of these signals being false positives (FPs). This directly affects the determination of the occurrence rate of Earth-like planets in our Galaxy, as well as other planet population statistics. In order to detect as many of these FPs as possible, we perform ephemeris matching among all transiting planet, eclipsing binary, and variable star sources. We find that 685 Kepler Objects of Interest (KOIs)—12% of all those analyzed—are FPs as a result of contamination, due to 409 unique parent sources. Of these, 118 have not previously been identified by other methods. We estimate that ∼35% of KOIs are FPs due to contamination, when performing a first-order correction for observational bias. Comparing single-planet candidate KOIs to multi-planet candidate KOIs, we find an observed FP fraction due to contamination of 16% and 2.4% respectively, bolstering the existing evidence that multi-planet KOIs are significantly less likely to be FPs. We also analyze the parameter distributions of the ephemeris matches and derive a simple model for the most common type of contamination in the Kepler field. We find that the ephemeris matching technique is able to identify low signal-to-noise FPs that are difficult to identify with other vetting techniques. We expect FP KOIs to become more frequent when analyzing more quarters of Kepler data, and note that many of them will not be able to be identified based on Kepler data alone.

  18. 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

    2017-03-16

    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.

  19. Curved planar reformation and optimal path tracing (CROP) method for false positive reduction in computer-aided detection of pulmonary embolism in CTPA

    Science.gov (United States)

    Zhou, Chuan; Chan, Heang-Ping; Guo, Yanhui; Wei, Jun; Chughtai, Aamer; Hadjiiski, Lubomir M.; Sundaram, Baskaran; Patel, Smita; Kuriakose, Jean W.; Kazerooni, Ella A.

    2013-03-01

    The curved planar reformation (CPR) method re-samples the vascular structures along the vessel centerline to generate longitudinal cross-section views. The CPR technique has been commonly used in coronary CTA workstation to facilitate radiologists' visual assessment of coronary diseases, but has not yet been used for pulmonary vessel analysis in CTPA due to the complicated tree structures and the vast network of pulmonary vasculature. In this study, a new curved planar reformation and optimal path tracing (CROP) method was developed to facilitate feature extraction and false positive (FP) reduction and improve our PE detection system. PE candidates are first identified in the segmented pulmonary vessels at prescreening. Based on Dijkstra's algorithm, the optimal path (OP) is traced from the pulmonary trunk bifurcation point to each PE candidate. The traced vessel is then straightened and a reformatted volume is generated using CPR. Eleven new features that characterize the intensity, gradient, and topology are extracted from the PE candidate in the CPR volume and combined with the previously developed 9 features to form a new feature space for FP classification. With IRB approval, CTPA of 59 PE cases were retrospectively collected from our patient files (UM set) and 69 PE cases from the PIOPED II data set with access permission. 595 and 800 PEs were manually marked by experienced radiologists as reference standard for the UM and PIOPED set, respectively. At a test sensitivity of 80%, the average FP rate was improved from 18.9 to 11.9 FPs/case with the new method for the PIOPED set when the UM set was used for training. The FP rate was improved from 22.6 to 14.2 FPs/case for the UM set when the PIOPED set was used for training. The improvement in the free response receiver operating characteristic (FROC) curves was statistically significant (p<0.05) by JAFROC analysis, indicating that the new features extracted from the CROP method are useful for FP reduction.

  20. A very low geno2pheno false positive rate is associated with poor viro-immunological response in drug-naive patients starting a first-line HAART.

    Directory of Open Access Journals (Sweden)

    Daniele Armenia

    Full Text Available We previously found that a very low geno2pheno false positive rate (FPR ≤ 2% defines a viral population associated with low CD4 cell count and the highest amount of X4-quasispecies. In this study, we aimed at evaluating whether FPR ≤ 2% might impact on the viro-immunological response in HIV-1 infected patients starting a first-line HAART.The analysis was performed on 305 HIV-1 B subtype infected drug-naïve patients who started their first-line HAART. Baseline FPR (% values were stratified according to the following ranges: ≤ 2; 2-5; 5-10; 10-20; 20-60; >60. The impact of genotypically-inferred tropism on the time to achieve immunological reconstitution (a CD4 cell count gain from HAART initiation ≥ 150 cells/mm(3 and on the time to achieve virological success (the first HIV-RNA measurement 60; p = 0.008. The overall proportion of patients achieving virological success was 95.5% by 12 months of therapy. Multivariable Cox analyses showed that patients having pre-HAART FPR ≤ 2% had a significant lower relative adjusted hazard [95% C.I.] both to achieve immunological reconstitution (0.37 [0.20-0.71], p = 0.003 and to achieve virological success (0.50 [0.26-0.94], p = 0.031 than those with pre-HAART FPR >60%.Beyond the genotypically-inferred tropism determination, FPR ≤ 2% predicts both a poor immunological reconstitution and a lower virological response in drug-naïve patients who started their first-line therapy. This parameter could be useful to identify patients potentially with less chance of achieving adequate immunological reconstitution and virological undetectability.

  1. Relapse of pulmonary tuberculosis: a rare cause of false-positive of the scintigraphy with iodine 131; Sequelles de tuberculose pulmonaire: une rare cause de faux-positif de la scintigraphie a l'iode 131

    Energy Technology Data Exchange (ETDEWEB)

    Ungureanu, C.M.; Angoue, O.; Blagosklonov, O.; Boulahdour, H. [Service de medecine nucleaire, CHU Jean-Minjoz, Besancon, (France); Manzoni, P. [service de radiologie, CHU Jean-Minjoz, Besancon, (France)

    2009-05-15

    The whole body scintigraphy with {sup 131}I is used in the follow up of the differentiated thyroid cancer. It is important to know the causes of false positive before decision of treatment by iodine 131. We present the case of a patient with a pulmonary fixation that was a false positive of {sup 131}I, of rare etiology. The after-effects of tuberculosis are able to fix iodine 131 and then to give false positive. scintigraphy. This etiology of false positive is rare and is worthy to be known because the lung is frequently an area of metastases in the thyroid cancer and the incidence of tuberculosis is increasing. (N.C.)

  2. Aortic Valve Disease

    Science.gov (United States)

    ... Tricuspid Valve Disease Cardiac Rhythm Disturbances Thoracic Aortic Aneurysm Pediatric and Congenital Heart Disease Heart abnormalities that are ... Transplantation End-stage Lung Disease Adult Lung Transplantation Pediatric Lung ... Aortic Aneurysm Aortic Valve Disease Overview The human heart has ...

  3. Massive-training support vector regression and Gaussian process for false-positive reduction in computer-aided detection of polyps in CT colonography.

    Science.gov (United States)

    Xu, Jian-Wu; Suzuki, Kenji

    2011-04-01

    A massive-training artificial neural network (MTANN) has been developed for the reduction of false positives (FPs) in computer-aided detection (CADe) of polyps in CT colonography (CTC). A major limitation of the MTANN is the long training time. To address this issue, the authors investigated the feasibility of two state-of-the-art regression models, namely, support vector regression (SVR) and Gaussian process regression (GPR) models, in the massive-training framework and developed massive-training SVR (MTSVR) and massive-training GPR (MTGPR) for the reduction of FPs in CADe of polyps. The authors applied SVR and GPR as volume-processing techniques in the distinction of polyps from FP detections in a CTC CADe scheme. Unlike artificial neural networks (ANNs), both SVR and GPR are memory-based methods that store a part of or the entire training data for testing. Therefore, their training is generally fast and they are able to improve the efficiency of the massive-training methodology. Rooted in a maximum margin property, SVR offers excellent generalization ability and robustness to outliers. On the other hand, GPR approaches nonlinear regression from a Bayesian perspective, which produces both the optimal estimated function and the covariance associated with the estimation. Therefore, both SVR and GPR, as the state-of-the-art nonlinear regression models, are able to offer a performance comparable or potentially superior to that of ANN, with highly efficient training. Both MTSVR and MTGPR were trained directly with voxel values from CTC images. A 3D scoring method based on a 3D Gaussian weighting function was applied to the outputs of MTSVR and MTGPR for distinction between polyps and nonpolyps. To test the performance of the proposed models, the authors compared them to the original MTANN in the distinction between actual polyps and various types of FPs in terms of training time reduction and FP reduction performance. The authors' CTC database consisted of 240 CTC

  4. Bicuspid Aortic Valve

    Science.gov (United States)

    2006-08-01

    aortic valvular disease, endocarditis, ascending aortic aneurysm and aortic dissection.1-4 There is also an association of BAV with coarctation of...for aortic aneurysm , patients with BAV appear to have additional risks for aortic disease. Nistri et al.12 reported significant aortic root...Congenital heart disease in patients with Turner’s syndrome. Italian study group for Turner syndrome (ISGTS). J Pediatr 1998; 133:688-692. 7. Schmid

  5. Aortic Stenosis.

    Science.gov (United States)

    Bakaeen, Faisal G; Rosengart, Todd K; Carabello, Blase A

    2017-01-03

    This issue provides a clinical overview of aortic stenosis, focusing on screening, diagnosis, treatment, and practice improvement. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.

  6. 3D printing based on cardiac CT assists anatomic visualization prior to transcatheter aortic valve replacement.

    Science.gov (United States)

    Ripley, Beth; Kelil, Tatiana; Cheezum, Michael K; Goncalves, Alexandra; Di Carli, Marcelo F; Rybicki, Frank J; Steigner, Mike; Mitsouras, Dimitrios; Blankstein, Ron

    2016-01-01

    3D printing is a promising technique that may have applications in medicine, and there is expanding interest in the use of patient-specific 3D models to guide surgical interventions. To determine the feasibility of using cardiac CT to print individual models of the aortic root complex for transcatheter aortic valve replacement (TAVR) planning as well as to determine the ability to predict paravalvular aortic regurgitation (PAR). This retrospective study included 16 patients (9 with PAR identified on blinded interpretation of post-procedure trans-thoracic echocardiography and 7 age, sex, and valve size-matched controls with no PAR). 3D printed models of the aortic root were created from pre-TAVR cardiac computed tomography data. These models were fitted with printed valves and predictions regarding post-implant PAR were made using a light transmission test. Aortic root 3D models were highly accurate, with excellent agreement between annulus measurements made on 3D models and those made on corresponding 2D data (mean difference of -0.34 mm, 95% limits of agreement: ± 1.3 mm). The 3D printed valve models were within 0.1 mm of their designed dimensions. Examination of the fit of valves within patient-specific aortic root models correctly predicted PAR in 6 of 9 patients (6 true positive, 3 false negative) and absence of PAR in 5 of 7 patients (5 true negative, 2 false positive). Pre-TAVR 3D-printing based on cardiac CT provides a unique patient-specific method to assess the physical interplay of the aortic root and implanted valves. With additional optimization, 3D models may complement traditional techniques used for predicting which patients are more likely to develop PAR. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  7. Output Position and Word Relatedness Effects in a DRM Paradigm: Support for a Dual-Retrieval Process Theory of Free Recall and False Memories

    Science.gov (United States)

    Barnhardt, T. M.; Choi, H.; Gerkens, D. R.; Smith, S. M.

    2006-01-01

    Five experiments investigated predictions--derived from a dual-retrieval process approach to free recall (Brainerd, C. J., Wright, R., Reyna, V. F., & Payne, D. G. (2002). Dual-retrieval processes in free and associative recall. Journal of Memory and Language, 46, 120-152.)--about false memories in a DRM-like paradigm. In all the experiments, the…

  8. Aortic valve bypass

    DEFF Research Database (Denmark)

    Lund, Jens T; Jensen, Maiken Brit; Arendrup, Henrik

    2013-01-01

    In aortic valve bypass (AVB) a valve-containing conduit is connecting the apex of the left ventricle to the descending aorta. Candidates are patients with symptomatic aortic valve stenosis rejected for conventional aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI...

  9. Quadricuspid Aortic Valve

    Directory of Open Access Journals (Sweden)

    Mehmet Taşar

    2013-03-01

    Full Text Available Quadricuspid aortic valve is an extremely rare congenital defect. Isolated form appears frequently. It is seen with aortic valve regurgitation in adulthood. This case report presents a rare clinical finding of an isolated quadricuspid aortic valve with aortic regurgitation in an 64-year-old female who was referred for cardiac evaluation due to newly identified murmur.

  10. Abiotic production of nitrous oxide by lightning. Implications for a false positive identification of life on Earth-Like Planets around quiescent M Dwarfs

    Science.gov (United States)

    Navarro, Karina F.; Navarro-Gonzalez, Rafael; McKay, Christopher P.

    _{2} dominated primitive Earth-like atmospheres. However, during the rise in atmospheric O _{2} at the start of the Proterozoic, the ocean became stratified (anoxic at the bottom and oxygenic at the surface). During this period, the emissions of N _{2}O were probably higher than today associated with a stronger microbial activity in the early anoxic ocean layer (Grenfell et al., 2011). Under this scenario, the predicted N _{2}O concentration would be about 3920 ppb, considering 10% the current atmospheric O _{2} concentrations, 100 times higher the current microbial N _{2}O flux, and a fainter Sun (94.3%) (Grenfell et al., 2011). This concentration would be still undetectable (Grenfell et al., 2011). A completely different scenario could be expected in Earth-like planets orbiting M dwarfs, which are the most abundant stars in the galaxy, representing about 75% of the total stellar population. M stars exhibit a large range in activity levels from very low levels of chromospheric and coronal activity, the so-called “quiescent” to high levels, the so-called “active" states. Photochemical models predict that the N _{2}O concentration would only increase to about 1,000 ppb for the current Earth orbiting an active M star, but surprisingly up to about 1,000 ppm for the current Earth orbiting a quiescent M star (Segura et al., 2005). Therefore, N _{2}O becomes a promising biomarker. Under this scenario it is important to constrain the abiotic sources of N _{2}O under different atmospheric conditions to avoid a false positive identification of life. Here we report an experimental study of the effects of lightning discharges on the nitrogen fixation rate during the evolution of the Earth’s early atmosphere from 10 to 1 percent of carbon dioxide in molecular nitrogen. We extended our study from no methane up to 1,000 ppm CH _{4}, which would be applicable to the postbiotic Earth (Tian et al., 2011). Lightning was simulated in the laboratory by a plasma generated with a

  11. MARVELS-1: A face-on double-lined binary star masquerading as a resonant planetary system; and consideration of rare false positives in radial velocity planet searches

    CERN Document Server

    Wright, Jason T; Mahadevan, Suvrath; Wang, Sharon X; Ford, Eric B; Payne, Matt; Lee, Brian L; Wang, Ji; Crepp, Justin R; Gaudi, B Scott; Eastman, Jason; Pepper, Joshua; Ge, Jian; Fleming, Scott W; Ghezzi, Luan; Gonzalez-Hernandez, Jonay I; Cargile, Phillip; Stassun, Keivan G; Wisniewski, John; Dutra-Ferreira, Leticia; de Mello, Gustavo F Porto; Maia, Marcio A G; da Costa, Luiz Nicolaci; Ogando, Ricardo L C; Santiago, Basilio X; Schneider, Donald P; Hearty, Fred R

    2013-01-01

    We have analyzed new and previously published radial velocity observations of MARVELS-1, known to have an ostensibly substellar companion in a ~6- day orbit. We find significant (~100 m/s) residuals to the best-fit model for the companion, and these residuals are naively consistent with an interior giant planet with a P = 1.965d in a nearly perfect 3:1 period commensuribility (|Pb/Pc - 3| < 10^{-4}). We have performed several tests for the reality of such a companion, including a dynamical analysis, a search for photometric variability, and a hunt for contaminating stellar spectra. We find many reasons to be critical of a planetary interpretation, including the fact that most of the three-body dynamical solutions are unstable. We find no evidence for transits, and no evidence of stellar photometric variability. We have discovered two apparent companions to MARVELS-1 with adaptive optics imaging at Keck; both are M dwarfs, one is likely bound, and the other is likely a foreground object. We explore false-al...

  12. MARVELS-1: A Face-on Double-lined Binary Star Masquerading as a Resonant Planetary System and Consideration of Rare False Positives in Radial Velocity Planet Searches

    Science.gov (United States)

    Wright, Jason T.; Roy, Arpita; Mahadevan, Suvrath; Wang, Sharon X.; Ford, Eric B.; Payne, Matt; Lee, Brian L.; Wang, Ji; Crepp, Justin R.; Gaudi, B. Scott; Eastman, Jason; Pepper, Joshua; Ge, Jian; Fleming, Scott W.; Ghezzi, Luan; González-Hernández, Jonay I.; Cargile, Phillip; Stassun, Keivan G.; Wisniewski, John; Dutra-Ferreira, Leticia; Porto de Mello, Gustavo F.; Maia, Márcio A. G.; Nicolaci da Costa, Luiz; Ogando, Ricardo L. C.; Santiago, Basilio X.; Schneider, Donald P.; Hearty, Fred R.

    2013-06-01

    We have analyzed new and previously published radial velocity (RV) observations of MARVELS-1, known to have an ostensibly substellar companion in a ~6 day orbit. We find significant (~100 m s-1) residuals to the best-fit model for the companion, and these residuals are naïvely consistent with an interior giant planet with a P = 1.965 days in a nearly perfect 3:1 period commensurability (|Pb /Pc - 3| MARVELS-1 with adaptive optics imaging at Keck; both are M dwarfs, one is likely bound, and the other is likely a foreground object. We explore false-alarm scenarios inspired by various curiosities in the data. Ultimately, a line profile and bisector analysis lead us to conclude that the ~100 m s-1 residuals are an artifact of spectral contamination from a stellar companion contributing ~15%-30% of the optical light in the system. We conclude that origin of this contamination is the previously detected RV companion to MARVELS-1, which is not, as previously reported, a brown dwarf, but in fact a G dwarf in a face-on orbit.

  13. MARVELS-1: A FACE-ON DOUBLE-LINED BINARY STAR MASQUERADING AS A RESONANT PLANETARY SYSTEM AND CONSIDERATION OF RARE FALSE POSITIVES IN RADIAL VELOCITY PLANET SEARCHES

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Jason T.; Roy, Arpita; Mahadevan, Suvrath; Wang, Sharon X.; Fleming, Scott W. [Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802 (United States); Ford, Eric B.; Payne, Matt; Lee, Brian L.; Ge, Jian [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055 (United States); Wang, Ji [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Crepp, Justin R. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Gaudi, B. Scott; Eastman, Jason [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Pepper, Joshua; Cargile, Phillip; Stassun, Keivan G. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Ghezzi, Luan [Observatorio Nacional, Rua General Jose Cristino, 77, Rio de Janeiro, RJ 20921-400 (Brazil); Gonzalez-Hernandez, Jonay I. [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Wisniewski, John [HL Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W Brooks St, Norman, OK 73019 (United States); Dutra-Ferreira, Leticia, E-mail: jtwright@astro.psu.edu [Laboratorio Interinstitucional de e-Astronomia (LIneA), Rua General Jose Cristino 77, Rio de Janeiro, RJ 20921-400 (Brazil); and others

    2013-06-20

    We have analyzed new and previously published radial velocity (RV) observations of MARVELS-1, known to have an ostensibly substellar companion in a {approx}6 day orbit. We find significant ({approx}100 m s{sup -1}) residuals to the best-fit model for the companion, and these residuals are naievely consistent with an interior giant planet with a P = 1.965 days in a nearly perfect 3:1 period commensurability (|P{sub b} /P{sub c} - 3| < 10{sup -4}). We have performed several tests for the reality of such a companion, including a dynamical analysis, a search for photometric variability, and a hunt for contaminating stellar spectra. We find many reasons to be critical of a planetary interpretation, including the fact that most of the three-body dynamical solutions are unstable. We find no evidence for transits, and no evidence of stellar photometric variability. We have discovered two apparent companions to MARVELS-1 with adaptive optics imaging at Keck; both are M dwarfs, one is likely bound, and the other is likely a foreground object. We explore false-alarm scenarios inspired by various curiosities in the data. Ultimately, a line profile and bisector analysis lead us to conclude that the {approx}100 m s{sup -1} residuals are an artifact of spectral contamination from a stellar companion contributing {approx}15%-30% of the optical light in the system. We conclude that origin of this contamination is the previously detected RV companion to MARVELS-1, which is not, as previously reported, a brown dwarf, but in fact a G dwarf in a face-on orbit.

  14. Successful Thrombolysis of Aortic Prosthetic Valve Thrombosis ...

    African Journals Online (AJOL)

    Arun Kumar Agnihotri

    Standard surgical treatment using cardiopulmonary bypass carries high maternal and fetal ... 35-year-old female patient presented in the first trimester of pregnancy with PVT at aortic position. .... to a greater risk than thrombolytic therapy does,.

  15. Infective endarteritis and false mycotic aneurysm complicating aortic coarctation

    Directory of Open Access Journals (Sweden)

    Ziadi Jaleleddine

    2012-01-01

    Full Text Available A 12-year-old boy with coarctation of aorta developed infective endarteritis and mycotic aneurysm at the site distal to coarctation. The computed tomography angiogram was very helpful in the diagnosis. Medical management and early surgical intervention was curative. Infective endarteritis in coarctation may be underdiagnosed.

  16. Aortic Annular Enlargement during Aortic Valve Replacement

    Directory of Open Access Journals (Sweden)

    Selman Dumani

    2016-09-01

    Full Text Available In the surgery of aortic valve replacement is always attempted, as much as possible, to implant the larger prosthesis with the mains goals to enhance the potential benefits, to minimise transvalvular gradient, decrease left ventricular size and avoid the phenomenon of patient-prosthesis mismatch. Implantation of an ideal prosthesis often it is not possible, due to a small aortic annulus. A variety of aortic annulus enlargement techniques is reported to avoid patient-prosthesis mismatch. We present the case that has submitted four three times open heart surgery. We used Manouguian technique to enlarge aortic anulus with excellent results during the fourth time of surgery.

  17. Clinical Research of Enzyme Linked Immunosorbent Assay for The Detection of Hepatitis B Virus Surface Antigen False Positive%酶联免疫法检测HBsAg假阳性临床研究

    Institute of Scientific and Technical Information of China (English)

    张海军

    2013-01-01

    目的:研究分析酶联免疫法(ELISA)检测乙肝病毒表面抗原(HBsAg)的假阳性情况.方法:对酶联免疫法检测HBsAg结果为阳性的1500例血清标本用金标法验证,并用化学发光仪微粒子捕捉免疫发光法(MEIA)定量检测HBsAg的含量,以确认酶联免疫法检测结果的假阳性.结果:1500例酶联免疫法检测HBsAg阳性的血清标本,其中1479例为真阳性,真阳性率为98.6%(1479/1500);21例为假阳性,假阳性率为1.4%(21/1500).结论:酶联免疫法检测HBsAg有一定的假阳性,临床检测时应高度注意,避免错报误诊.%Objective: To study enzyme linked immunosorbent assay ( ELISA ) in detecting hepatitis B virus surface antigen ( HBsAg ) of the false positive cases. Method: ELISA for detection of HBsAg results for 1500 cases with positive serum samples using the colloidal gold method validation, and using chemical luminous instrument microparticle enzyme lmmunoassay ( MEIA ) for quantitative detection of HBsAg content, to confirm the enzyme-linked immunosorbent assay for detection of false positive results. Result: 1500 cases of enzyme-linked immunosorbent assay for detection of HBsAg positive serum samples, including 1479 cases of true positive, true positive rate was 98. 6% ( 1479/1500 ); 21 were false positive, false positive rate was 1. 4% ( 21/1500 ). Conclusion: Enzyme-linked immunosorbent assay for detection of HBsAg have false positive, clinical test should be highly attention, avoid the error diagnosis.

  18. Application of PDCA cycle management method in reducing false positive rate of neonatal blood culture%PDCA 循环管理法在降低新生儿血培养假阳性率中的应用

    Institute of Scientific and Technical Information of China (English)

    闵凡云; 周传銮

    2013-01-01

    目的:探讨PDCA循环管理法在降低新生儿血培养假阳性率中的应用及临床效果,为指导临床诊断及合理应用抗菌药物提供客观依据。方法:对2010年7~12月新生儿科32例血培养阳性患儿进行目标追踪监测,了解分析假阳性发生原因并采取PDCA循环管理法,比较实施前后新生儿血培养假阳性率。结果:实施前血培养假阳性患儿病原菌分布以条件致病菌为主,实施前后血培养假阳性率比较差异有统计学意义( P<0.01)。结论:将PDCA循环管理法应用于新生儿血培养阳性目标性监测,可提高血培养标本送检质量,降低假阳性率,保证检验结果准确。%Objective:To explore the application of PDCA cycle management method in reducing false positive rate of neonatal blood culture and investigate the clinical effect in order to provide objective basis for guiding clinical diagnosis and reasonable application of anti -biotics.Methods:The target tracking monitoring was conducted to 32 newborns(born from July to December 2010) whose blood culture was positive to understand and analyze the false positive causes ,and the PDCA cycle management method was implemented .The false positive rate of neonatal blood culture was compared before and after the implementation of the PDCA cycle management method .Results:The con-ditionally pathogenic bacteria in the false positive blood culture was the main pathogen in the distribution before the implementation of the method;the difference in the comparison of the false positive rate of blood culture was statistically significant before and after the imple -mentation of the method(P<0.01).Conclusion:The PDCA cycle management method applied to the target tracking monitoring can im-prove the quality of blood culture specimens and reduce the false positive rate so as to ensure accurate test results .

  19. Aortic aneurysm repair - endovascular

    Science.gov (United States)

    EVAR; Endovascular aneurysm repair - aorta; AAA repair - endovascular; Repair - aortic aneurysm - endovascular ... Endovascular aortic repair is done because your aneurysm is very large, growing quickly, or is leaking or bleeding. You may have ...

  20. Aortic dissection (image)

    Science.gov (United States)

    Aortic dissection is a condition in which there is bleeding into and along the wall of the aorta (the ... the inner wall of the artery. Although aortic dissection can affect anybody, it is most often seen ...

  1. Abdominal aortic aneurysm

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000162.htm Abdominal aortic aneurysm To use the sharing features on this page, ... blood to the abdomen, pelvis, and legs. An abdominal aortic aneurysm occurs when an area of the aorta becomes ...

  2. False positive research on HPLC determining aflatoxin residues in Chinese herbal pieces%HPLC法测定中药饮片中黄曲霉毒素残留量的假阳性研究

    Institute of Scientific and Technical Information of China (English)

    郝爱鱼; 赵丽元; 刘英慧; 王戈; 金红宇; 毕秀玲; 门启鸣

    2013-01-01

    Objective: To establish an effective method of eliminating false positive results of aflatoxin residue analysis in Chinese herbal pieces by HPLC, and determine which varieties of traditional Chinese medicines (TCM) are easy to be disturbed by false positive, and define the chemical structure of disruptors. Methods: The samples were analyzed by the immunoaffinity column purification coupled with HPLC and post - column fluorescence detection under conditions of photochemical or non — photochemical derivation, and the ratios of peak areas under these two conditions were calculated and compared. Different HPLC conditions were set to analyze aflatoxin residues in the positive samples, and the analysis results were verified by HPLC - MS/MS. Results: Analysis results for samples of 71 varieties (120 batches) of Chinese herbal pieces demonstrated that there were 8 varieties (13 batches) positive, and 2 varieties (3 batches) were proved as false positive among the positive samples,which were consistent with the verification result by HPLC - MS/MS. The false positive varieties accounted for 2. 8% of the total varieties and the false positive samples accounted for 2. 5% of the total samples. The psoralen and isopsoralen were detected as the disruptors to aflatoxin B1. Conclusion: The method of immunoaffinity column purification and HPLC with post column photochemical derivation and fluorescence detection is suitable for analysis of aflatoxin residues in Chinese herbal pieces,which has a lower false positive rate. The false positive result could be excluded by the methods of peak area comparison with or without photochemical derivation and re - measurement with different HPLC conditions.%目的:建立HPLC法检测中药饮片中黄曲霉毒素残留量的假阳性排除方法,确定易产生假阳性的中药品种,确定干扰物质的化学结构.方法:采用免疫亲和柱净化(IAC)-HPLC-柱后光衍生荧光法测定黄曲霉毒素阳性样品在光衍生或不衍生

  3. False alarm rates of three third-generation pulse oximeters in PACU, ICU and IABP patients.

    Science.gov (United States)

    Lutter, Norbert O; Urankar, Sabine; Kroeber, Steffi

    2002-01-01

    The objective of this clinical study was to determine alarm rates--in particular the frequency of false positive alarms--of three third-generation pulse oximeters in the postanesthesia care unit (PACU), the intensive care unit (ICU), and in patients with an intra-aortic balloon pump (IABP): Nellcor Symphony N-3000, a Masimo IVY 2000, and Agilent Viridia CMS 2000. All alarms were classified into technical/physiological and false/correct. 235 consecutive ASA physical status I-IV patients after surgery were included into the study. In the PACU false positive alarms were rare: CMS n = 60, N-3000 n = 60, Masimo n = 87. Bland-Altman testing discovered only negligible differences of alarm rates and dropout times. Out of a total of 728 alarms 67.3% were classified as false positive in ICU-patients: 97 alarms by CMS, 176 by N-3000 and 218 by Masimo SET. If IABP was present, CMS indicated a significant smaller number of false positive alarms (n = 35, 7.2%) when compared to Masimo SET (n = 188, 38.9%) and N-3000 (n = 229, 47.4%), consecutively the majority of false positive alarms (76.2%) can be rated as a result of the interference of IABP. Unless IABP (and to a considerably smaller extent cardiac arrhythmia) is present the pulse oximeters do not differ significantly regarding sensitivity and specificity.

  4. Competitive binding experiments can reduce the false positive results of affinity-based ultrafiltration-HPLC: A case study for identification of potent xanthine oxidase inhibitors from Perilla frutescens extract.

    Science.gov (United States)

    Wang, Zhiqiang; Kwon, Shin Hwa; Hwang, Seung Hwan; Kang, Young-Hee; Lee, Jae-Yong; Lim, Soon Sung

    2017-03-24

    The purpose of this study was to assess the possibility of using competitive binding experiments with ultrafiltration-HPLC analysis to identify potent xanthine oxidase (XO) inhibitors from the Perilla frutescens extract as an attempt to reduce the number of false positive results. To isolate the enzyme-ligand complex from unbound compounds, the P. frutescens extract was either incubated in the absence of XO, in the presence of XO, or with the active site blocked XO before the ultrafiltration was performed. Allopurinaol was used as the XO active site blocker. The unbound compounds were subjected to HPLC analysis. The degree of total binding (TBD) and degree of specific binding (SBD) of each compound were calculated using the peak areas. TBD represents the binding affinities of compounds from the P. frutescens extract for the XO binding site. SBD represents the XO competitive binding between allopurinol and ligands from the extract samples. Two criteria were applied to select putative targets that could help avoid false positives. These include TBD>30% and SBD>10%. Using that approach, kaempferol-3-O-rutinoside, rosmarinic acid, methyl-rosmarinic acid, apigenin, and 4',5,7-trimethoxyflavone were identified, from total 11 compounds, as potent XO inhibitors. Finally, apigenin, 4',5,7-trimethoxyflavone, and luteolin were XO inhibitors verified through an XO inhibition assay and structural simulation of the complex. These results showed that the newly developed strategy has the advantage that the number of targets identified via ultrafiltration-HPLC can be narrowed from many false positives. However, not all false positives can be eliminated with this approach. Some potent inhibitors might also be excluded with the use of this method. The limitations of this method are also discussed herein. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. 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

    2016-09-01

    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 Ki 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.

  6. 透析患者血清HBsAg假阳性伴HIV可疑一例分析%Analysis of a Case of Serum False-Positive HBsAg and Suspicious HIV Antibody in Dialysis Patient

    Institute of Scientific and Technical Information of China (English)

    吴卫; 许少侠; 黄媛; 郭野; 司永珍; 杨卓; 谢田; 王巧凤; 崔巍

    2012-01-01

    HBsAg和HIV抗体的检测分别在HBV感染和HIV感染的诊疗中具有重要意义.现阶段HBsAg和HIV抗体主要通过血清免疫学方法检测,其中ELISA法检测HBsAg或HIV抗体的假阳性病例时有报道,而全自动化学发光免疫分析仪的假阳性病例较为少见.该文即报道了一例用全自动化学发光免疫分析仪检测透析患者血清HBsAg假阳性伴HIV抗体可疑的病例,并对可能的原因进行了深入探讨.%HBsAg and HIV antibody play important role in the diagnosis and treatment of HBV and HIV infection respectively. At present, HBsAg and HIV antibody are mainly detected by serum immunological techniques. Cases of false-positive HBsAg or HIV antibody detected by ELISA were reported occasionally while false-positive cases by automatic chemilumi-nescence immune analyzers were reported rarely. A case of serum false-positive HBsAg and suspicious HIV antibody detected by automatic chemiluminescence immune analyzers in dialysis patient is reported in t paper and analyzed for the possible reasons.

  7. 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 Ki 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.

  8. How useful are screening instruments for toddlers to predict outcome at age 4? General development, language skills, and symptom severity in children with a false positive screen for autism spectrum disorder.

    Science.gov (United States)

    Dereu, Mieke; Roeyers, Herbert; Raymaekers, Ruth; Meirsschaut, Mieke; Warreyn, Petra

    2012-10-01

    Screening instruments for autism spectrum disorder (ASD) often generate many false positives. It is argued that these children may have other developmental difficulties and are also in need of thorough assessment and early intervention. The current study looked at the predictive validity of positive screens on the Checklist for Early Signs of Developmental Disorders (CESDD) and the Early Screening of Autistic Traits questionnaire (ESAT) at age 2 towards language, cognitive function, and symptom severity at age 4. Children who screened positive on the ESAT scored lower for both language and cognitive functioning at age 4 compared with children who screened negative on the ESAT. Also, the more signs of ASD that were recognized on the CESDD or ESAT, the lower the scores for language and cognitive functioning at age 4. False positive screens could be differentiated from true positive screens on the CESDD only in symptom severity score on the Autism Diagnostic Observation Schedule (ADOS). It seems that early screeners for ASD also detect children with other developmental disorders and that diagnostic instruments such as the ADOS are warranted to differentiate between children with ASD and other developmental problems.

  9. Aortic dissection: magnetic resonance imaging.

    Science.gov (United States)

    Amparo, E G; Higgins, C B; Hricak, H; Sollitto, R

    1985-05-01

    Fifteen patients with suspected or known aortic dissection were imaged with magnetic resonance (MR). Thirteen of these patients were eventually shown to have dissection. In most instances the diagnosis was established by aortography and/or computed tomography (CT) prior to the MR study. Surgical proof (6/13) and/or aortographic proof (10/13) were available in 11/13 patients with aortic dissection. MR demonstrated the intimal flap and determined whether the dissection was type A or type B. In addition, MR: differentiated between the true and false lumens; determined the origins of the celiac, superior mesenteric, and renal arteries from the true or false lumen in the cases where the dissection extended into the abdominal aorta (8/12); allowed post-surgical surveillance of the dissection; and identified aortoannular ectasia in the three patients who had Marfan syndrome. In addition to the 13 cases with dissection, there were two cases in whom the diagnosis of dissection was excluded by MR. Our early experience suggests that MR can serve as the initial imaging test in clinically suspected cases of aortic dissection and that the information provided by MR is sufficient to manage many cases. Additionally, MR obviates the use of iodinated contrast media.

  10. 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.; Fabrycky, Daniel C.; Ford, Eric B.; Gauthier, Thomas N., III; Gilliland, Ronald L.; Holman, Matthew J.; Howell, Steve B.; Isaacson, Howard; Jenkins, Jon M.; Koch, David G.; Latham, David W.; Lissauer, Jack J.; Marcy, Geoffrey W.; Monet, David G.; Prsa, Andrej; Quinn, Samuel N.

    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.

  11. Comparative study of woman false positive rate in exercise treadmill before or after menopause%女性绝经前后运动平板试验假阳性率的对比研究

    Institute of Scientific and Technical Information of China (English)

    赵小鹏; 何大渊; 安光玉; 郑江红; 寇新惠; 胡冬青

    2009-01-01

    Objective To analyse the rate of coincidence to suspected coronary artery disease (CAD) patient between positive exercise treadmill testing (TET) and coronary angiography (CAG) test.Method Two hundred and sixty-eight chest pain patients positive in TET were performed CAG test,coronary stenosis exceed 50% was diagnosed CAD. Results One hundred and seventy-six patients (65.67%) was diagnosed by CAG, 105 male and 71 female in them. Ninety-two (34.33%) patients was negative in CAG test. The false positive rate of TET between post-menopause patients (30.12%, 25/83 ) andmale patients (28.08%, 41/146) was no significant difference(P > 0.05 ); the difference of false positive rate between pro-menopause patients (66.67%, 26/39) and male patients (28.08% ,41/146) was statistical significance (P 0.05).结论 胸痛患者在冠状动脉造影前行运动平板试验筛查,阳性者再行冠状动脉造影检查可大大提高冠状动脉造影检查的阳性率.女性绝经前患者运动平板试验假阳性率较男性患者和女性绝经后患者高.

  12. 影响新生儿听力筛查假阳性的因素分析%The Analysis of Influence Factors of Newborn Hearing Screening False Positive Rate

    Institute of Scientific and Technical Information of China (English)

    林莉

    2015-01-01

    目的:探讨临床上新生儿听力筛查假阳性以及复查率的影响因素。方法:对来本院筛查的4080例新生儿相关资料进行分析,对所有新生儿进行听力筛查,将初筛不通过的436例新生儿作为试验组,设置研究前初筛不通过的436例作为对照组,比较两组复查结果。结果:6组新生儿每组有680例,A组中110例初筛不通过,且81例假阳性;B组95例初筛不通过,57例假阳性;C组67例初筛不通过,40例假阳性;D组78例初筛不通过,62例假阳性;E组49例初筛不通过,24例假阳性;F组37例初筛不通过,18例假阳性;试验组新生儿出生42 d后349例进行复查,复查率为80.1%,高于对照组,两组比较差异有统计学意义(P<0.05)。结论:听力筛查是早期发现、早期干预听力障碍的重要手段,临床上加强宣传教育提高新生儿复查率。%Objective:To investigate the factors of newborn hearing screeningfalse positive and the clinical effect of review rate.Method:The related data analysis of 4080 cases of newborn in our hospital were selected, hearing screening of all newborns, the screening of 436 cases of neonatal fail as the experimental group, set before the study by screening 436 cases as the control group, two groups were compared the results of the review.Result:Six newborns in each group had 680 cases,A group of 110 cases without going through screening, and 81 cases were false-positive; B group of 95 cases without screening,57 cases were false-positive; C group of 67 cases screening were not passed, 40 cases were false-positive; D group of 78 cases without screening, 62 cases were false-positive; E group of 49 patients without screening, 24 cases were false-positive; F group, 37 cases without screening, 18 cases were false-positive.In the experimental group 349 cases for review, the review was 80.1% higher than the control group, the difference was statistically significant (P<0

  13. Assessment of two malaria rapid diagnostic tests in children under five years of age, with follow-up of false-positive pLDH test results, in a hyperendemic falciparum malaria area, Sierra Leone

    Directory of Open Access Journals (Sweden)

    De Smet Martin

    2010-01-01

    Full Text Available Abstract Background Most malaria rapid diagnostic tests (RDTs use HRP2 detection, including Paracheck-Pf®, but their utility is limited by persistent false positivity after treatment. PLDH-based tests become negative more quickly, but sensitivity has been reported below the recommended standard of 90%. A new pLDH test, CareStart™ three-line P.f/PAN-pLDH, claims better sensitivity with continued rapid conversion to negative. The study aims were to 1 compare sensitivity and specificity of CareStart™ to Paracheck-Pf® to diagnose falciparum malaria in children under five years of age, 2 assess how quickly false-positive CareStart™ tests become negative and 3 evaluate ease of use and inter-reader agreement of both tests. Methods Participants were included if they were aged between two and 59 months, presenting to a Médecins Sans Frontières community health centre in eastern Sierra Leone with suspected malaria defined as fever (axillary temperature > 37.5°C and/or history of fever in the previous 72 hours and no signs of severe disease. The same capillary blood was used for the RDTs and the blood slide, the latter used as the gold standard reference. All positive participants were treated with supervised artesunate and amodiaquine treatment for three days. Participants with a persistent false-positive CareStart™, but a negative blood slide on Day 2, were followed with repeated CareStart™ and blood slide tests every seven days until CareStart™ became negative or a maximum of 28 days. Results Sensitivity of CareStart™ was 99.4% (CI 96.8-100.0, 168/169 and of Paracheck-Pf®, 98.8% (95% CI 95.8-99.8, 167/169. Specificity of CareStart™ was 96.0% (CI 91.9-98.4, 167/174 and of Paracheck-Pf®, 74.7% (CI 67.6-81.0, 130/174 (p ® with excellent inter-reader agreement. Conclusions Both RDTs were highly sensitive, met WHO standards for the detection of falciparum malaria monoinfections where parasitaemia was >100 parasites/μl and were easy

  14. Supravalvular aortic stenosis in adult with anomalies of aortic arch vessels and aortic regurgitation

    Science.gov (United States)

    Valente, Acrisio Sales; Alencar, Polyanna; Santos, Alana Neiva; Lobo, Roberto Augusto de Mesquita; de Mesquita, Fernando Antônio; Guimarães, Aloyra Guedis

    2013-01-01

    The supravalvular aortic stenosis is a rare congenital heart defect being very uncommon in adults. We present a case of supravalvular aortic stenosis in adult associated with anomalies of the aortic arch vessels and aortic regurgitation, which was submitted to aortic valve replacement and arterioplasty of the ascending aorta with a good postoperative course. PMID:24598962

  15. 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.

    Science.gov (United States)

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

    2016-11-01

    Background Reference change values provide objective tools to assess the significance of a change in two consecutive results for a biomarker from an individual. The reference change value calculation is based on the assumption that within-subject biological variation has random fluctuation around 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 was based on standard deviations according to the assumption of normality, but was soon changed to coefficients of variation (CV) in the formula (reference change value = ± Z ċ 2(½) ċ CV). Z is being dependent on the desired probability of significance, which also defines the percentages of false-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 distributed and ln-normally distributed data. Conclusions The optimal choice of method to calculate reference change value limits requires knowledge of the distribution of data (normal or ln-normal) and, if possible, knowledge of the homeostatic set point.

  16. Frequent screening with serial neck ultrasound is more likely to identify false-positive abnormalities than clinically significant disease in the surveillance of intermediate risk papillary thyroid cancer patients without suspicious findings on follow-up ultrasound evaluation.

    Science.gov (United States)

    Peiling Yang, Samantha; Bach, Ariadne M; Tuttle, R Michael; Fish, Stephanie A

    2015-04-01

    American Thyroid Association (ATA) intermediate-risk thyroid cancer patients who achieve an excellent treatment response demonstrate a low risk of structural disease recurrence. Despite this fact, most patients undergo frequent surveillance neck ultrasound (US) during follow-up. The objective of the study was to evaluate the clinical utility of routine screening neck US in ATA intermediate-risk patients documented to have a nonstimulated thyroglobulin less than 1.0 ng/mL and a neck US without suspicious findings after therapy. Retrospective review of 90 ATA intermediate-risk papillary thyroid carcinoma patients treated with total thyroidectomy and radioactive iodine ablation in a tertiary referral center. A comparison between the frequency of finding false-positive US abnormalities and the frequency of identifying structural disease recurrence in the study cohort was measured. Over a median of 10 years, 90 patients had a median of six US (range 2-16). Structural disease recurrence was identified in 10% (9 of 90) at a median of 6.3 years. Recurrence was associated with other clinical indicators of disease in 5 of the 90 patients (5.6%, 5 of 90) and was detected without other signs of recurrence in four patients (4.8%, 4 of 84). False-positive US abnormalities were identified in 57% (51 of 90), leading to additional testing, which failed to identify clinically significant disease. In ATA intermediate-risk patients who have a nonstimulated thyroglobulin less than 1.0 ng/mL and a neck US without suspicious findings after therapy, frequent US screening during follow-up is more likely to identify false-positive abnormalities than clinically significant structural disease recurrence.

  17. Interpretation of captopril renal scintigraphy: report of a bilateral false positive case; Interpretation de la scintigraphie renale avec prise de captopril: a propos d`un faux positif bilateral

    Energy Technology Data Exchange (ETDEWEB)

    Patrois, F.; Hignette, C.; Froissart, M.; Prigent, A. [Hopital Broussais, 75 - Paris (France)

    1995-12-31

    Captopril renography is a quite sensitive (70-80%) and a very specific (90-95%) test for the diagnosis of renovascular hypertension induced by renal artery stenosis. Contrasting to morphological techniques (arteriography, intravenous digital subtraction angiography, duplex sonography, angio-MRI), captopril renography can predict the cure or improvement of hypertension after revascularization. Therefore captopril renography will discriminate the renal artery stenosis causing renovascular hypertension from incidental stenosis concomitant with essential hypertension. The test conditions and interpretation present some pitfalls we thereby would discuss, providing a case of bilateral false positive result. (authors). 22 refs., 6 figs.

  18. 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.

  19. Rapid 2nd-tier test for measurement of 3-OH-propionic and methylmalonic acids on dried blood spots: reducing the false-positive rate for propionylcarnitine during expanded newborn screening by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    la Marca, Giancarlo; Malvagia, Sabrina; Pasquini, Elisabetta; Innocenti, Marzia; Donati, Maria Alice; Zammarchi, Enrico

    2007-07-01

    The expansion of newborn screening programs has increased the number of newborns diagnosed with inborn errors of metabolism in the presymptomatic phase, but it has also increased the number of costly, stress-producing false-positive results. Because propionylcarnitine (C3) is one of the analytes most frequently responsible for false-positive results, we aimed to develop a rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to identify free methylmalonic (MMA) and 3-OH propionic (3OH-PA) acids in blood spots. We studied newborn screening spots from 250 healthy controls; 124 from infants with abnormal C3, of whom only 5 (4%) were truly affected; 124 from infants with altered isolated methylmalonylcarnitine; and 4 from clinically diagnosed patients. Whole blood was eluted from a 3.2-mm dried blood spot by a CH(3)CN/H(2)O 7:3 and 5 mL/L formic. This extract was injected into a LC-MS/MS equipped with pneumatically assisted electrospray without derivatization. Total analysis time was 5 min per sample. The assays were linear up to 3300 nmol/L for both metabolites. Intra- and interassay imprecision data were 3.6%-8% and 3.1%-6%, respectively, for MMA and 5.2%-20% and 3.6%-17% for 3OH-PA. Limit of detection and limit of quantitation were 1.95 and 4.2 micromol/L, respectively, for MMA and 8 and 10 micromol/L for 3OH-PA. The recoveries were 92.9%-106.1%. No deterioration was noted on the columns after 500 chromatographic runs. If the new method had been used as a 2nd-tier test for the 124 samples, only the 5 true positives would have been recalled for additional samples, and the positive predictive value would have been 100%. This method has the potential to markedly reduce false-positive results and the associated costs and anxiety. It may also be suitable for diagnosing and routinely monitoring blood spots for methylmalonic aciduria and propionic acidemia.

  20. Multiple multilayer stents for thoracoabdominal aortic aneurysm: a possible new tool for aortic endovascular surgery.

    Science.gov (United States)

    Tolva, Valerio Stefano; Bianchi, Paolo Guy; Cireni, Lea Valeria; Lombardo, Alma; Keller, Guido Carlo; Parati, Gianfranco; Casana, Renato Maria

    2012-01-01

    Endovascular surgery data are confirming the paramount role of modern endovascular tools for a safe and sure exclusion of thoracoabdominal lesions. A 57-year-old female presented with severe comorbidity affected by a 58 mm thoracoabdominal aortic aneurysm (TAAA). After patient-informed consent and local Ethical Committee and Italian Public Health Ministry authorization, three multilayer stents were implanted in the thoracoabdominal aortic tract, obtaining at a 20-month computed tomography scan follow up, a complete exclusion of the TAAA, with normal patency of visceral vessels. Multilayer stents can be used in thoracoabdominal aortic aneurysm, with positive results.

  1. False-Positive Results of 68ga-Dotatate and 11c-Cholıne Pet/CT in Patients with Hormone-Resistant Prostate Cancer at Biochemical Recurrence are Related to Inflamed Lesions

    Directory of Open Access Journals (Sweden)

    Omar Alonso

    2015-02-01

    Full Text Available Objective: For an oncological tracer is relevant to know the uptake in inflamed/infected lesions. Thus, in the framework of a prospective trial aiming to compare the clinical value of 68Ga-DOTATATE and 11C-Choline PET/CT in patients with hormoneresistant prostate cancer at biochemical recurrence, we evaluated the false-positive findings of both techniques. Methods: The study group comprised 64 prostate cancer patients with PSA relapse under androgen deprivation therapy, with a median trigger PSA level of 4.25 ng/mL (range: 0.22-291 ng/mL. Within 1-2 weeks, a PET/CT study was performed with 68Ga-DOTATATE and 11C-Choline with an approximately dose of 100 MBq and 400 MBq, respectively, using a 64-slice PET/CT with time-of-flight correction. Correlative imaging, histopathology and/or clinical follow-up were considered as reference standard. Results: Both techniques showed positive local, regional and distant findings in 31 patients. Results were concordant in 57 cases (89%, with discordant findings observed in patients with bone (n=2 and regional lymph nodes lesions (n=5. On a per patient basis, sensitivity, specificity, positive and negative predictive values with their 95% confidence intervals were the same for both techniques: 0.82 (0.65-0.93, 0.90 (0.73-0.98, 0.90 (0.73-0.98 and 0.81 (0.65-0.93, respectively. False-positive lesions (n=5 were found, for both tracers, in 3 patients and were located in the prostate bed (n=1 and regional lymph nodes (n=4, being 3 discordant. In all cases, pathology revealed non-specific inflammatory lesions. Conclusion: This study demonstrates avid 68Ga-DOTATATE and 11C-Choline accumulation in inflammatory tissue, which may limit the specificity of these techniques for the detection of occult metastatic disease.

  2. Valve Replacement with a Sutureless Aortic Prosthesis in a Patient with Concomitant Mitral Valve Disease and Severe Aortic Root Calcification.

    Science.gov (United States)

    Lio, Antonio; Scafuri, Antonio; Nicolò, Francesca; Chiariello, Luigi

    2016-04-01

    Aortic valve replacement with concomitant mitral valve surgery in the presence of severe aortic root calcification is technically difficult, with long cardiopulmonary bypass and aortic cross-clamp times. We performed sutureless aortic valve replacement and mitral valve annuloplasty in a 68-year-old man who had severe aortic stenosis and moderate-to-severe mitral regurgitation. Intraoperatively, we found severe calcification of the aortic root. We approached the aortic valve through a transverse aortotomy, performed in a higher position than usual, and we replaced the valve with a Sorin Perceval S sutureless prosthesis. In addition, we performed mitral annuloplasty with use of an open rigid ring. The aortic cross-clamp time was 63 minutes, and the cardiopulmonary bypass time was 83 minutes. No paravalvular leakage of the aortic prosthesis was detected 30 days postoperatively. Our case shows that the Perceval S sutureless bioprosthesis can be safely implanted in patients with aortic root calcification, even when mitral valve disease needs surgical correction.

  3. 三种方法联合检测避免梅毒诊断的假阳性结果%Combining three ways to avoid the false positive of screening Treponema pallidum

    Institute of Scientific and Technical Information of China (English)

    潘旭萍; 迟军晓

    2012-01-01

      Objective To investigate a method for avoiding the false positive of screening syphilis by Treponema pallidum antibody enzyme linked immunosorbent assay(TP-ELISA) though combining TP-ELISA with toluidine red unheated serum test(TRUST) and Treponema pallidum panicle agglutination test(TPPA). Methods The clinical samples were screened syphilis by TP-ELISA first, then the positive samples were further tested by TRUST and TPPA. Results There were 114 positive samples tested by TP-ELISA. Among them the number of the same result tested by TPPA was 111. The positive coincidence rate was 97.36%. Among the 111 positive samples,27 positive samples tested by TRUST were also positive tested by TPPA. The positive coincidence rate was 100%. There were 94 positive samples tested by TPPA among the remaining 97 negative samples tested by TRUST. The number of negative samples was 3. The mismatch rate was 2.64%. Conclusions The false positive result tested syphilis by TP-ELISA exists objectively. The positive samples from TP-ELISA were tested by TRUST and then were ascertained by TPPA. The positive result from TPPA can be diagnosed that syphilis antibody was positive. The negative result from TPPA can be diagnosed that syphilis antibody was negative.%  目的探讨用梅毒螺旋体抗体酶联免疫吸附试验(TP-ELISA)联合梅毒甲苯胺红不加热血清试验(TRUST)和梅毒螺旋体明胶凝集试验(TPPA)的方法避免TP-ELISA法筛查梅毒抗体的假阳性结果.方法用TP-ELISA法作为临床标本的梅毒筛查实验,对阳性标本进一步作TRUST和TPPA检测.结果 TP-ELlSA法检出114例梅毒阳性标本,TPPA确证阳性111例,阳性符合率为97.36%(111/114);其中27例TRUST阳性,TPPA确证试验均为阳性,阳性符合率为100%;97例TRUST阴性, TPPA确证阳性94例,阴性3例,不符合率为2.64%.结论 TP-ELISA法筛查梅毒存在一定比例的假阳性结果,对TP-ELlSA法测出的阳性标本先做TRUST试验,再用TPPA确证,阳性

  4. Acute Type A Aortic Dissection Successfully Managed with One-stage Surgery of Total Aortic Arch Replacement with Supra-aortic Transposition Plus Frozen Elephant Trunk Technique

    Directory of Open Access Journals (Sweden)

    Meng-Lin Lee

    2014-09-01

    Full Text Available Acute type A aortic dissection has long been a challenging issue. The surgical techniques traditionally vary with the anatomic extent of the aortic dissection. Simple ascending aortic grafting can be lifesaving, but the lesions beyond the aorta, which include the arch vessels and descending aorta, remain potential hazards. In this paper, we present a patient in which acute type A aortic dissection with lesions extending into descending thoracic aorta was successfully managed by total arch replacement with supra-aortic transposition plus the frozen elephant trunk technique to the descending aorta. A 67-year-old gentleman presented with severe tearing pain from the anterior to posterior chest. Computed tomography confirmed the diagnosis of acute type A dissection extending to the level of the right common iliac artery. An emergent operation was performed as in the aforementioned technique. The surgery went well and the patient was discharged without comorbidities on postoperative day 25. The patient had regular outpatient clinical follow-up. The follow-up computed tomography images showed adequate results with the obliteration of the false lumen. In conclusion, total aortic arch replacement with supra-aortic transposition plus frozen elephant trunk technique is a safe and feasible operative method for patients with detrimental acute type A aortic dissection.

  5. Gender differences in abdominal aortic aneurysms.

    Science.gov (United States)

    Hannawa, Kevin K; Eliason, Jonathan L; Upchurch, Gilbert R

    2009-01-01

    Abdominal aortic aneurysms (AAAs) comprise the tenth leading cause of death in Caucasian males 65 to 74 years of age and accounted for nearly 16,000 deaths overall in 2000. Therefore, understanding the pathophysiology of AAAs is an important undertaking. Clinically, multiple risk factors are associated with the development of AAAs, including increasing age, positive smoking history, and hypertension. Male gender is also a well-established risk factor for the development of an AAA, with a 4:1 male to female ratio. The reason for this gender disparity is unknown. The pathogenesis of AAAs formation is complex and multifactorial. Histologically, AAAs are characterized by early chemokine-driven leukocyte infiltration into the aortic wall. Subsequent destruction of elastin and collagen in the media and adventitia ensues owing to excessive local production of matrix-degrading enzymes and is accompanied by smooth muscle cell loss and thinning of the aortic wall. At present, no medical therapies are available to treat patients with aortic aneurysms, using only the crude measurement of aortic diameter as a threshold for which patients must undergo life-threatening and costly surgery. Defining the early mechanisms underlying gender-related differences in AAA formation is critical as understanding differences in disease patterns based on gender may allow us to develop new translational approaches to the prevention and treatment of patients with aortic aneurysms.

  6. Non-infectious Pseudoaneurysm of Ascending Aorta Following Redo-Aortic Valve Replacement

    Directory of Open Access Journals (Sweden)

    Nozari Younes

    2009-05-01

    Full Text Available A 46 year old man had been undergone Aortic valve replacement (AVR due to mechanical aortic valve endocarditis two month ago. He was referred to Imam Khomeini hospital because of dyspnea since two weeks ago. Echocardiography showed the false aneurysm, with an area of flow beyond the lumen of the aorta. This patient underwent reoperation, the previously implanted aortic valve was removed, meticulous debridement was performed in aortic valve annulus and adjacent part of the ascending aorta, and aortic valve and root replacement were performed.

  7. Endovascular repair for abdominal aortic aneurysm followed by type B dissection.

    Science.gov (United States)

    Shingaki, Masami; Kato, Masaaki; Motoki, Manabu; Kubo, Yoji; Isaji, Toshihiko; Okubo, Nobukazu

    2016-10-01

    An 86-year-old man with an abdominal aortic aneurysm was diagnosed with type B aortic dissection accompanied by a patent false lumen that started at the distal arch of the thoracic aorta and terminated at the left common iliac artery. Meticulous preoperative assessment detected 3 large intimal tears in the descending aorta, abdominal aortic aneurysm, and left common iliac artery. We performed single-stage thoracic and abdominal endovascular aneurysm repair and concomitant axillary-axillary bypass. The abdominal aortic aneurysm with type B aortic dissection was successfully treated using a single-stage endovascular stent graft, without any complications due to the careful preoperative examinations.

  8. 42 CFR 410.19 - Ultrasound screening for abdominal aortic aneurysms: Condition for and limitation on coverage.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Ultrasound screening for abdominal aortic aneurysms... screening for an abdominal aortic aneurysm as a result of an initial preventive physical examination (as... for an abdominal aortic aneurysm under Medicare program; and (3) Is included in at least one of...

  9. Conservative management of chronic aortic dissection with underlying aortic aneurysm

    Directory of Open Access Journals (Sweden)

    Mohammad Yusuf Beebeejaun

    2013-01-01

    Full Text Available Aortic dissection is one of the most common aortic emergencies affecting around 2000 Americans each year. It usually presents in the acute state but in a small percentage of patients aortic dissections go unnoticed and these patients survive without any adequate therapy. With recent advances in medical care and diagnostic technologies, aortic dissection can be successfully managed through surgical or medical options, consequently increasing the related survival rate. However, little is known about the optimal long-term management of patients suffering from chronic aortic dissection. The purpose of the present report is to review aortic dissection, namely its pathology and the current diagnostic tools available, and to discuss the management options for chronic aortic dissection, infiltrates or pleural effusions. Other tion. We report a patient in which chronic aortic dissection presented with recurring episodes of vomiting and also discuss the management plan of our patient who had a chronic aortic dissection as well as an underlying aortic aneurysm.

  10. False Positive FDG PET/CT Resulting from Fibrous Dysplasia of the Bone in the Work-Up of a Patient with Bladder Cancer: Case Report and Review of the Literature.

    Science.gov (United States)

    Aras, Mustafa; Ones, Tunc; Dane, Faysal; Nosheri, Omid; Inanir, Sabahat; Erdil, Tanju Yusuf; Turoglu, Halil Turgut

    2012-12-01

    Fibrous dysplasia of the bone (FDB) is a common, genetic, developmental disorder with a benign course. FDB can be seen anywhere throughout the skeleton. It is usually asymptomatic and found incidentally on imaging studies that are performed for other purposes. Although whole body 18 F-flourodeoxyglucose PET/CT (FDG PET/CT) is widely used in tumor imaging, infections and benign pathologies like FDB may cause false positive results. Herein we report the case of a 48-year-old FDB patient with transitional cell carcinoma of the urinary bladder. Restaging FDG PET/CT showed multiple mild to moderate hypermetabolic bone lesions which were initially misinterpreted as bone metastases. In this case report, we aimed to guide physicians in evaluating bone lesions in cancer patients with FDB in the light of the literature.

  11. Reducing false-positive biopsies: a pilot study to reduce benign biopsy rates for BI-RADS 4A/B assessments through testing risk stratification and new thresholds for intervention.

    Science.gov (United States)

    Flowers, Chris I; O'Donoghue, Cristina; Moore, Dan; Goss, Adeline; Kim, Danny; Kim, June-Ho; Elias, Sjoerd G; Fridland, Julia; Esserman, Laura J

    2013-06-01

    The aim of this study is to evaluate Breast Imaging Reporting and Data Systems (BI-RADS) 4A/B subcategory risk estimates for ductal carcinoma in situ (DCIS) and invasive cancer (IC), determining whether changing the proposed cutoffs to a higher biopsy threshold could safely increase cancer-to-biopsy yields while minimizing false-positive biopsies. A prospective clinical trial was performed to evaluate BI-RADS 4 lesions from women seen in clinic between January 2006 and March 2007. An experienced radiologist prospectively estimated a percent risk-estimate for DCIS and IC. Truth was determined by histopathology or 4-year follow-up negative for malignancy. Risk estimates were used to generate receiver-operating characteristic (ROC) curves. Biopsy rates, cancer-to-biopsy yields, and type of malignancies missed were then calculated across postulated risk thresholds. A total of 124 breast lesions were evaluated from 213 women. An experienced radiologist gave highly accurate risk estimates for IC, DCIS alone, or the combination with an area under ROC curve of 0.91 (95 % CI 0.84-0.99) (p biopsies avoided; cancer-to-biopsy yields of 36, 47, and 46 %; and associated chance of missing an IC of 0, 1, and 2 %, respectively. Expert radiologists estimate risk of IC and DCIS with a high degree of accuracy. Increasing the cut off point for recommending biopsy, substituting with a short-term follow-up protocol with biopsy if any change, may safely reduce the number of false-positive biopsies.

  12. Dextromethorphan reduces false-positive rate in bronchial provocation test with histamine%右美沙芬降低组胺肺功能激发试验假阳性率

    Institute of Scientific and Technical Information of China (English)

    吕智; 郑亚黎; 江兴堂

    2011-01-01

    目的:探讨组胺激发试验过程中咳嗽不良反应与阳性率的关系.方法:选取我院呼吸内科行组胺支气管激发试验患者120例,随机分为两组,试验前10 min分别予氢溴酸右美沙芬口服溶液30 mg与安慰剂口服,以咳嗽量表评价激发试验过程中咳嗽剧烈程度,并记录激发试验测试结果.3d后试验组激发试验阴性患者于试验前10 min口服安慰剂重新行激发试验.结果:试验组重度咳嗽发生率较对照组低;试验组重度咳嗽患者支气管激发试验阳性率亦较对照组下降;试验组激发试验阴性患者予安慰剂重复激发试验,结果仍全部为阴性.结论:氢溴酸右美沙芬可通过减轻咳嗽不良反应减少重度咳嗽的发生率,从而降低组胺肺功能试验假阳性率,且未出现明显假阴性.%Objective: To investigate the relationship between cough side-effect and false-positive rate in bronchial provocation test with histamine. Methods; A total of 120 patients were enrolled and randomly divided into 2 groups. Patients were treated with either oral solution of dextromethorphan hydrobromide or placebo 10 min before bronchial provocation test. The severity of cough was evaluated by cough scales. Results; The incidence rate of grade 3 cough side-effect and the positive rate of patients with grade 3 cough-side effect were lower in dextromethorphan group than in control group. No positive result was found in repeated tests of bronchial provocation 3 days after the first test in patients with negative result of dextromethorphan group. Conclusion; Dextromethorphan hydrobromide can relieve cough side-effect and thereby reduce false-positive rate in bronchial provocation test with histamine.

  13. Modelling of aortic aneurysm and aortic dissection through 3D printing.

    Science.gov (United States)

    Ho, Daniel; Squelch, Andrew; Sun, Zhonghua

    2017-03-01

    The aim of this study was to assess if the complex anatomy of aortic aneurysm and aortic dissection can be accurately reproduced from a contrast-enhanced computed tomography (CT) scan into a three-dimensional (3D) printed model. Contrast-enhanced cardiac CT scans from two patients were post-processed and produced as 3D printed thoracic aorta models of aortic aneurysm and aortic dissection. The transverse diameter was measured at five anatomical landmarks for both models, compared across three stages: the original contrast-enhanced CT images, the stereolithography (STL) format computerised model prepared for 3D printing and the contrast-enhanced CT of the 3D printed model. For the model with aortic dissection, measurements of the true and false lumen were taken and compared at two points on the descending aorta. Three-dimensional printed models were generated with strong and flexible plastic material with successful replication of anatomical details of aortic structures and pathologies. The mean difference in transverse vessel diameter between the contrast-enhanced CT images before and after 3D printing was 1.0 and 1.2 mm, for the first and second models respectively (standard deviation: 1.0 mm and 0.9 mm). Additionally, for the second model, the mean luminal diameter difference between the 3D printed model and CT images was 0.5 mm. Encouraging results were achieved with regards to reproducing 3D models depicting aortic aneurysm and aortic dissection. Variances in vessel diameter measurement outside a standard deviation of 1 mm tolerance indicate further work is required into the assessment and accuracy of 3D model reproduction. © 2017 The Authors. Journal of Medical Radiation Sciences published by John Wiley & Sons Australia, Ltd on behalf of Australian Society of Medical Imaging and Radiation Therapy and New Zealand Institute of Medical Radiation Technology.

  14. 新生儿血培养阳性标本的目标性监测和假阳性控制研究%Objective Monitoring and Research on the Control of False Positive About Neonatal Blood Culture Positive Samples

    Institute of Scientific and Technical Information of China (English)

    周传銮

    2016-01-01

    Objective To explore the causes of false positive in neonatal blood culture and its countermeasures and application value.Methods The positive cases of neonatal blood culture from January 2013 to December 2015 were retrospectively studied, to analyze the main causes of false positives and to timely apply the corresponding measures.Results Conditional pathogenic bacteria belongs to main false positive cases; the false positive rate before intervention is 24.6%, the false positive rate is 6.5% after intervention. The difference has statistical signiifcance (P<0.05). Conclusion In neonatal blood culture positive specimens, the false positive cases is more, which need to strengthen the timely target monitoring, to ensure the accuracy of the test, to provide more accurate and reliable reference information for clinical diagnosis and treatment.%目的:探究新生儿血培养中出现假阳性原因和应对策略及其应用价值。方法回顾性研究2013年1月~2015年12月新生儿血培养阳性病例,分析假阳性出现的主要原因,并及时地应用相应的对策。结果条件致病菌属于主要的假阳性病例的病原菌;干预前的假阳性率是24.6%,干预后的假阳性率是6.5%,差异有统计学意义(P<0.05)。结论在新生儿血培养阳性标本中,假阳性病例较多,需要及时地加强目标性监测,确保检验准确度,为临床诊治提供更加准确可靠的参考信息。

  15. [Chronic type A aortic dissection associated with Turner syndrome; report of a case].

    Science.gov (United States)

    Tanaka, Hideyuki; Kozaki, Tomofumi; Kume, Masazumi; Miyamoto, Shinji

    2014-12-01

    Aortic dissection is a critical but rare complication of Turner syndrome. This report describes a case of chronic aortic dissection in a patient with Turner syndrome. A 54-year-old woman, suffering from mild back pain for 1 month, was referred to our hospital with a diagnosis of Stanford type A chronic aortic dissection and a bicuspid aortic valve with moderate regurgitation. Computed tomography revealed aortic dissection, involving all arch branches, extending from the ascending to the abdominal aorta. The true lumen of the brachial artery was nearly obstructed by the thrombosed false lumen. Elective aortic arch repair and aortic valve replacement were successfully performed. The patient was diagnosed with 45, XO Turner syndrome after surgery. Taking aortopathy of Turner syndrome into consideration, surveillance of the residual aorta was performed. No rapidly progressive dilatation of the residual aorta was detected during the 6 years' follow-up.

  16. Atherosclerotic Aortic Plaques Detected by Transesophageal Echocardiography

    Institute of Scientific and Technical Information of China (English)

    赵云; 朱文玲; 倪超; 郭丽琳; 曾勇; 方理刚

    2002-01-01

    Objective To evaluate the predictive value of atherosclerotic aortic plaques in coronary artery disease (CAD) Methods In 50patients with suspected coronary artery disease, transesophageal echocardiography was performed to examine their thoracic aortas 2 weeks before or after coronary angiography. In the cases of coronary angiography studied, stenosis of the coronary artery ≥ 50 % was considered to be due to coronary artery disease,whereas the thickness of the intima ≥ 1.3 mm was taken to be the criteria for the presence of an atherosclerotic aortic plaque on the transesophageal echocardiographic test. Results Among the 50 patients, 37 cases were diagnosed as CAD and 13 cases were considered to be normal. The plaques of the thoracic aorta were observed in 34cases in the CAD group and 3 cases in the normal group. The sensitivity and specificity of aortic plaques for CAD were 91.9 % and 76.9%, respectively. The positive and negative predictive values of the aortic plaques for CAD were 91.9% and 76.9%, respectively. The accuracy was 88.0%. 80 percent of the patients with single- yes sel disease had thoracic aortic plaques, 92 percent of the patients with two-vessel disease and 100 percent of the patients with three-vessel disease had thoracic aortic plaques. There was a significant difference in the thickness of aortic intimas between the normal group and the CAD group. Conclusions Detectingatherosclerotic plaques in the thoracic aorta with transesophageal echocardiography may be of great value in predicting the presence and extent of coronary artery disease.

  17. False "highlighting" with Wood's lamp.

    Science.gov (United States)

    Silverberg, Jonathan I; Silverberg, Nanette B

    2014-01-01

    Wood's lamp evaluation is used to diagnose pigmentary disorders. For example, vitiligo typically demonstrates lesional enhancement under Wood's lamp evaluation. Numerous false positive enhancing lesions can be noted in the skin. We describe a 5-year-old Hispanic boy who had painted his face with highlighter, producing enhancing lesions under Wood's lamp. Physicians who use Wood's lamp should be aware that the appearance of markers and highlighter can mimic that of true clinical illnesses.

  18. Aortic Valve Stenosis

    Science.gov (United States)

    ... evaluation of aortic stenosis in adults. http://www.uptodate.com/home. Accessed April 29, 2014. Mohty D, ... Valvular heart disease in elderly adults. http://www.uptodate.com/home. Accessed May 2, 2014. Bonow RO, ...

  19. Bicuspid aortic valve

    Science.gov (United States)

    ... aortic disease. In: Otto CM, Bonow RO, eds. Valvular Heart Disease: A Companion to Braunwald's Heart Disease . 4th ed. ... PA: Elsevier Saunders; 2014:chap 13. Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  20. Aortic Valve Regurgitation

    Science.gov (United States)

    ... inside your heart that involves heart valves. Rheumatic fever. Rheumatic fever — a complication of strep throat and once a ... the United States — can damage the aortic valve. Rheumatic fever is still prevalent in developing countries but rare ...

  1. Endovascular Repair of Acute Uncomplicated Aortic Type B Dissection Promotes Aortic Remodelling

    DEFF Research Database (Denmark)

    Brunkwall, J; Kasprzak, P; Verhoeven, E

    2014-01-01

    treatment (BMT) with BMT and Gore TAG stent graft in patients with uncomplicated AD. The primary endpoint was a combination of incomplete/no false lumen thrombosis, aortic dilatation, or aortic rupture at 1 year. METHODS: The AD history had to be less than 14 days, and exclusion criteria were rupture......, impending rupture, malperfusion. Of the 61 patients randomised, 80% were DeBakey type IIIB. RESULTS: Thirty-one patients were randomised to the BMT group and 30 to the BMT+TAG group. Mean age was 63 years for both groups. The left subclavian artery was completely covered in 47% and in part in 17...

  2. [Inflammatory abdominal aortic aneurysm].

    Science.gov (United States)

    Ziaja, K; Sedlak, L; Urbanek, T; Kostyra, J; Ludyga, T

    2000-01-01

    The reported incidence of inflammatory abdominal aortic aneurysm (IAAA) is from 2% to 14% of patients with abdominal aortic aneurysm and the etiology of this disease is still discussed--according to the literature several pathogenic theories have been proposed. From 1992 to 1997 32 patients with IAAA were operated on. The patients were mostly symptomatic--abdominal pain was present in 68.75% cases, back pain in 31.25%, fever in 12.5% and weight loss in 6.25% of the operated patients. In all the patients ultrasound examination was performed, in 4 patients CT and in 3 cases urography. All the patients were operated on and characteristic signs of inflammatory abdominal aortic aneurysm like: thickened aortic wall, perianeurysmal infiltration or retroperitoneal fibrosis with involvement of retroperitoneal structures were found. In all cases surgery was performed using transperitoneal approach; in three cases intraoperatively contiguous abdominal organs were injured, which was connected with their involvement into periaortic inflammation. In 4 cases clamping of the aorta was done at the level of the diaphragmatic hiatus. 3 patients (9.37%) died (one patient with ruptured abdominal aortic aneurysm). Authors present diagnostic procedures and the differences in the surgical tactic, emphasizing the necessity of the surgical therapy in patients with inflammatory abdominal aortic aneurysm.

  3. Quantitative Aortic Distensibility Measurement Using CT in Patients with Abdominal Aortic Aneurysm: Reproducibility and Clinical Relevance

    Directory of Open Access Journals (Sweden)

    Yunfei Zha

    2017-01-01

    Full Text Available Purpose. To investigate the reproducibility of aortic distensibility (D measurement using CT and assess its clinical relevance in patients with infrarenal abdominal aortic aneurysm (AAA. Methods. 54 patients with infrarenal abdominal aortic aneurysm were studied to determine their distensibility by using 64-MDCT. Aortic cross-sectional area changes were determined at two positions of the aorta, immediately below the lowest renal artery (level 1. and at the level of its maximal diameter (level 2. by semiautomatic segmentation. Measurement reproducibility was assessed using intraclass correlation coefficient (ICC and Bland-Altman analyses. Stepwise multiple regression analysis was performed to assess linear associations between aortic D and anthropometric and biochemical parameters. Results. A mean distensibility of Dlevel  1.=(1.05±0.22×10-5  Pa-1 and Dlevel  2.=(0.49±0.18×10-5  Pa-1 was found. ICC proved excellent consistency between readers over two locations: 0.92 for intraobserver and 0.89 for interobserver difference in level 1. and 0.85 and 0.79 in level 2. Multivariate analysis of all these variables showed sac distensibility to be independently related (R2=0.68 to BMI, diastolic blood pressure, and AAA diameter. Conclusions. Aortic distensibility measurement in patients with AAA demonstrated high inter- and intraobserver agreement and may be valuable when choosing the optimal dimensions graft for AAA before endovascular aneurysm repair.

  4. 16-Detector row computed tomographic coronary angiography in patients undergoing evaluation for aortic valve replacement: comparison with catheter angiography

    Energy Technology Data Exchange (ETDEWEB)

    Manghat, N.E.; Morgan-Hughes, G.J.; Broadley, A.J.; Undy, M.B.; Wright, D.; Marshall, A.J.; Roobottom, C.A

    2006-09-15

    Aim: To evaluate the diagnostic accuracy of 16-detector row computed tomography (CT) in assessing haemodynamically significant coronary artery stenoses in patients under evaluation for aortic stenosis pre-aortic valve replacement. Subjects and methods: Forty consecutive patients under evaluation for severe aortic stenosis and listed for cardiac catheterization before potential aortic valve replacement underwent coronary artery calcium (CAC) scoring and retrospective electrocardiogram (ECG)-gated multi-detector row computed tomographic coronary angiography (MDCTA) using a GE Lightspeed 16-detector row CT within 1 month of invasive coronary angiography (ICA) for comparative purposes. All 13 major coronary artery segments of the American Heart Association model were evaluated for the presence of {>=}50% stenosis and compared to the reference standard. Data were analysed on a segment-by-segment basis and also in 'whole patient' terms. Results: A total of 412/450 segments from 35 patients were suitable for analysis. The overall accuracy of MDCTA for detection of segments with {>=}50% stenosis was high, with a sensitivity of 81.3%, specificity 95.0%, positive predictive value (PPV) 57.8%, and negative predictive value (NPV) 98.4%. On a 'whole-patient' basis, 100% (19/19) of patients with significant coronary disease were correctly identified and there were no false-negatives. Excluding patients with CAC >1000 from the analysis improved the accuracy of MDCTA to: sensitivity 90%, specificity 98.1%, PPV 60%, NPV 99.7%. Conclusion: Non-invasive 16-detector row MDCTA accurately excludes significant coronary disease in patients with severe aortic stenosis undergoing evaluation before aortic valve replacement and in whom ICA can therefore be avoided. Its segment-by-segment accuracy is improved further if CAC > 1000 is used as a gatekeeper to MDCTA.

  5. Modeling Kepler transit light curves as false positives: Rejection of blend scenarios for KOI-377, and strong evidence for a super-Earth-size planet in a multiple system

    CERN Document Server

    Torres, Guillermo; Batalha, Natalie M; Borucki, William J; Brown, Timothy M; Bryson, Stephen T; Buchhave, Lars A; Charbonneau, David; Ciardi, David R; Dunham, Edward W; Fabrycky, Daniel C; Ford, Eric B; Gautier, Thomas N; Gilliland, Ronald L; Holman, Matthew J; Howell, Steve B; Isaacson, Howard; Jenkins, Jon M; Koch, David G; Latham, David W; Lissauer, Jack J; Marcy, Geoffrey W; Monet, David G; Prsa, Andrej; Ragozzine, Darin; Rowe, Jason F; Sasselov, Dimitar D

    2010-01-01

    The high-precision 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 the result of an astrophysical false positive, we describe a procedure we refer to as BLENDER to model the photometry not in terms of a planet orbiting a star, but instead as a "blend". 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 the technique to the case of KOI-377, a particularly interesting Kepler 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 1.6-day period that would correspond to a super-Earth with a radius of 1.4 R(Earth), the smallest yet discovered. Using BLENDER together with constraints from high-resolution ima...

  6. Metabolitos del efavirenz como probable causa de falsos-positivos en test inmunológico para benzodiacepinas en orina False-positive immunoassay results for urine benzodiacepines probably caused by efavirenz metabolites

    Directory of Open Access Journals (Sweden)

    Patricia N. Quiroga

    2007-12-01

    Full Text Available En el tratamiento del síndrome de inmunodeficiencia adquirida (SIDA una de las drogas antirretrovirales usadas es el efavirenz (EFV. Existe una asociación entre el consumo de drogas de abuso y la probabilidad de adquirir el SIDA, razón por la cual se solicita su investigación en orina. Como método de screening para detectar el consumo de estas drogas se utilizan habitualmente los ensayos inmunológicos. Una característica especial de estos métodos son las reacciones cruzadas que pueden presentarse con sustancias estructuralmente relacionadas dando origen a resultados falsos positivos. Al analizar 18 muestras de orina de pacientes con SIDA, se observó un 78% de resultados falsos positivos para benzodiacepinas (BZD cuando fueron analizados mediante el ensayo inmunológico Triage® (Ascend Multi Immune Assay. El estudio confirmatorio por cromatografía gaseosa acoplada a espectrometría de masa (GC-MS reveló la ausencia de BZD en todos los casos y el 100% de los resultados falsos positivos observados correspondieron a las muestras de los pacientes tratados con EFV. Con el propósito de dilucidar el origen de esta reacción cruzada fueron aislados el EFV y sus metabolitos de las muestras de orina, mediante extracción en fase sólida (SPE y cromatografía en capa delgada de alta resolución (HPTLC, e identificados por cromatografía gaseosa- espectrometría de masa (GC-MS y GC-MS/MS/MS. Los resultados obtenidos en este estudio indicarían que los metabolitos del EFV (8-OH-EFV y/o 7-OH-EFV y no el EFV podrían ser los responsables de la reacción cruzada observada en el ensayo inmunológico.Efavirenz (EFV is an antiretroviral drug used in the acquired immunodeficiency syndrome (AIDS treatment. Immunoassay techniques have been widely used for abuse drug screening test. The presence of structurally related substances in urine samples can interfere by cross reactions causing false positive results. High percentage of false positive results (78

  7. Baryogenesis in false vacuum

    CERN Document Server

    Hamada, Yuta

    2016-01-01

    The null result in the LHC may indicate that the standard model is not drastically modified up to very high scale such as the GUT/string scale. Having this in the mind, we suggest a novel leptogenesis scenario realized in the false vacuum of the Higgs field. If the Higgs field develops the large vacuum expectation value in the early universe, the lepton number violating process is enhanced, which we use for baryogenesis. To demonstrate the scenario, several models are discussed. For example, we show that the observed baryon asymmetry is successfully generated in the standard model with a second Higgs doublet and a singlet scalar.

  8. False pop out.

    Science.gov (United States)

    Orsten-Hooge, Kimberley D; Portillo, Mary C; Pomerantz, James R

    2015-12-01

    A single, unique target often pops out quickly and efficiently from a field of homogenous distractors in visual search. Pop out has helped shape theories of visual attention and feature integration as well as to identify basic features in human vision. Here we report a new phenomenon, false pop out, wherein one of the homogenous distractors competes with the singleton target to pop out, perhaps by breaking an overall grouping or pattern emerging from the display. We show the effect occurs with more than 1 type of stimulus, and we discuss the implications of such a counterintuitive finding for theories of visual search.

  9. Bicuspid aortic valves: Diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, David J., E-mail: david.murphy@st-vincents.ie [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); McEvoy, Sinead H., E-mail: s.mcevoy@st-vincents.ie [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); Iyengar, Sri, E-mail: sri.iyengar@nhs.net [Department of Radiology, Plymouth Hospitals NHS Trust, Plymouth Devon PL6 8DH (United Kingdom); Feuchtner, Gudrun, E-mail: Gudrun.Feuchtner@i-med.ac.at [Department of Radiology, Innsbruck Medical University, Anichstr. 35, A-6020 Innsbruck (Austria); Cury, Ricardo C., E-mail: r.cury@baptisthealth.net [Department of Radiology, Baptist Cardiac and Vascular Institute, 8900 North Kendall Drive, Miami, FL 33176 (United States); Roobottom, Carl, E-mail: carl.roobottom@nhs.net [Department of Radiology, Plymouth Hospitals NHS Trust, Plymouth Devon PL6 8DH (United Kingdom); Plymouth University Peninsula Schools of Medicine and Dentistry (United Kingdom); Baumueller, Stephan, E-mail: Hatem.Alkadhi@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich (Switzerland); Alkadhi, Hatem, E-mail: stephan.baumueller@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich (Switzerland); Dodd, Jonathan D., E-mail: jonniedodd@gmail.com [Department of Radiology, St Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland)

    2014-08-15

    Objectives: To assess the diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT for bicuspid aortic valves. Materials and methods: The standard axial chest CT scans of 20 patients with known bicuspid aortic valves were blindly, randomly analyzed for (i) the appearance of the valve cusps, (ii) the largest aortic sinus area, (iii) the longest aortic cusp length, (iv) the thickest aortic valve cusp and (v) valve calcification. A second blinded reader independently analyzed the appearance of the valve cusps. Forty-two age- and sex-matched patients with known tricuspid aortic valves were used as controls. Retrospectively ECG-gated cardiac CT multiphase reconstructions of the aortic valve were used as the gold-standard. Results: Fourteen (21%) scans were scored as unevaluable (7 bicuspid, 7 tricuspid). Of the remainder, there were 13 evaluable bicuspid valves, ten of which showed an aortic valve line sign, while the remaining three showed a normal Mercedes-Benz appearance owing to fused valve cusps. The 35 evaluable tricuspid aortic valves all showed a normal Mercedes-Benz appearance (P = 0.001). Kappa analysis = 0.62 indicating good interobserver agreement for the aortic valve cusp appearance. Aortic sinus areas, aortic cusp lengths and aortic cusp thicknesses of ≥3.8 cm{sup 2}, 3.2 cm and 1.6 mm respectively on standard axial chest CT best distinguished bicuspid from tricuspid aortic valves (P < 0.0001 for all). Of evaluable scans, the sensitivity, specificity, positive and negative predictive values of standard axial chest CT in diagnosing bicuspid aortic valves was 77% (CI 0.54–1.0), 100%, 100% and 70% respectively. Conclusion: The aortic valve is evaluable in approximately 80% of standard chest 64-slice CT scans. Bicuspid aortic valves may be diagnosed on evaluable scans with good diagnostic accuracy. An aortic valve line sign, enlarged aortic sinuses and elongated, thickened valve cusps are specific CT

  10. Screening for Abdominal Aortic Aneurysm

    Science.gov (United States)

    Understanding Task Force Recommendations Screening for Abdominal Aortic Aneurysm The U.S. Preventive Services Task Force (Task Force) has issued a final recommendation statement on Screening for Abdominal Aortic Aneurysm. This final ...

  11. Abdominal aortic aneurysm repair - open

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007392.htm Abdominal aortic aneurysm repair - open To use the sharing features on this page, please enable JavaScript. Open abdominal aortic aneurysm repair is surgery to fix a widened part ...

  12. 两例无创产前基因检测假阳性病例的分析%Analysis of two false positive cases from noninvasive prenatal testing

    Institute of Scientific and Technical Information of China (English)

    陈雪娇; 戴美珍; 石卫武; 潘映秋; 章卫国; 章鸯; 吴志强

    2014-01-01

    Objective To track and analyze two false positive cases from non-invasive prenatal testing for potential fetal aneuploidy.Methods The two cases,respectively reported to have XO (+ + +) and T18 (1/20) XO (+),were analyzed with conventional karyotyping,fluorescence in situ hybridization (FISH) and massively parallel genomic sequencing (MPS).Results The first fetus,who was suspected for XO(+ + +),was verified to have super female syndrome (47,XXX/46,XX) due to confined placental mosaicism by karyotyping of amniotic fluid cells,FISH analysis of placenta and massively parallel sequencing (MPS) of fetal tissue.The second fetus,suspected to have trisomy 18 (1/20) XO(+),was verified to have Turner syndrome by karyotyping,FISH and MPS analyses of umbilical cord blood cells.And the karyotype was 45,X[48]/ 46,X,der(X)del(X) (p11.21)del(X) (q13.3)[62].Conclusion Non invasive prenatal testing carries a risk for false positive diagnosis of fetal sex chromosome and trisomy 18.Combined eytogenetic and molecular techniques are required to ensure an accurate diagnosis.%目的 分析2例无创产前基因检测假阳性病例,为患者提供精确的染色体诊断结果.方法 应用传统细胞核型分析、荧光原位杂交技术(fluorescence in situ hybridization,FISH)及大规模并行基因组测序技术(massively parallel sequencing,MPS)对2例无创基因检测分别提示XO(+++)和T18(1/20)XO(+)的胎儿进行检测分析.结果 例1的无创基因检测结果提示为XO(+++),经羊水细胞传统核型分析、胎盘FISH检测及胎儿组织MPS检测后确诊为胎盘特异性嵌合的超雌综合征嵌合体,核型为47,XXX/46,XX.例2的无创产前基因检测结果提示为T18(1/20) XO(+),经脐带血核型分析、MPS、FISH检测后确诊为特纳综合征,核型为45,X[48]/46,X,der(X) del(X) (p11.21)del(X) (q13.3)[62].结论 无创基因检测对于胎儿性染色体及18三体高危存在假阳性,提示在产前诊断中应合理联合应用各种不同的细胞

  13. O método da falsa posição na história e na educação matemática The false position method in history and in mathematics education

    Directory of Open Access Journals (Sweden)

    Cleide Farias de Medeiros

    2004-12-01

    Full Text Available Este texto coloca em uma perspectiva histórica o tratamento algébrico precoce que, costumeiramente, é dedicado ao ensino elementar da Aritmética. Defendendo que um tal tratamento algébrico precoce carrega vários pontos negativos para a formação do educando, o texto discute o "método da falsa posição" como uma alternativa viável para um tal ensino introdutório. Apontando as raízes históricas de tal método, o texto procura evidenciar as origens, aplicações e várias formas de visualizar este procedimento iterativo, desde a manipulação de materiais concretos, passando por aplicações geométricas, até atingir o Cálculo Numérico, como um dos procedimentos iterativos na resolução de equações lineares. Uma das conclusões é que, embora não seja o referido método, em sua forma mais simples, nenhum substitutivo para a resolução algébrica simbólica e moderna de equações e de sistemas de equações, ele se constitui certamente em um precioso trampolim para iniciarmos o salto em direção a um estudo mais formalizado. Particularmente, o método da falsa posição revela-se uma utilíssima ferramenta pedagógica na Educação Matemática, principalmente quando vinculado às suas origens históricas, suas abordagens concretas iniciais e suas associações com a Geometria e a Geometria Analítica.This text is a historical perspective on the early algebraic approach that is usually applied to the elementary teaching of Arithmetic. By arguing that such an initial algebraic treatment contains several drawbacks for elementary education, the ‘false position method' is discussed and is presented as a viable alternative for such introductory teaching. By pointing out the historical roots of the method, the text tries to make clear several ways of visualising this iterative procedure. This is done by incorporating the use of manipulatives and geometrical applications as well as the use of numerical calculus as an iterative

  14. [Congenital aortic stenosis].

    Science.gov (United States)

    Yamaguchi, M

    2001-08-01

    Recent advances in and controversies concerning the management of children with congenital valvular aortic stenosis are discussed. In neonates with critical aortic stenosis, improved survival has recently been reported after surgical open valvotomy and balloon valvuloplasty, although it is difficult at this point to compare the results of the two procedures and determine their differential indications. Good results have also been achieved after extended aortic valvuloplasty for recurrent aortic stenosis and/or insufficiency, but the length of follow-up in these patients is still short. The technique first reported in 1991 for bilateral enlargement fo a small annulus permits the insertion of an aortic valve 3-4 sizes larger than the native annulus. It entails no risk of distorting the mitral valve, damaging the conduction system or important branches of the coronary arteries, or resulting in left ventricular dysfunction. The Ross procedure is now widely applied in the West, with reports of early mortality rates of less than 5% and event-free survival rates of 80-90% during follow-up of 4-8 years. Longer follow-up and continued careful evaluation are required to resolve the issue of possible dilatation and subsequent neoaortic valve dysfunction and pulmonary stenosis due to allograft degeneration after pulmonary autograft root replacement in children.

  15. False color viewing device

    Science.gov (United States)

    Kronberg, J.W.

    1992-10-20

    A viewing device for observing objects in near-infrared false-color comprising a pair of goggles with one or more filters in the apertures, and pads that engage the face for blocking stray light from the sides so that all light reaching the user's eyes come through the filters. The filters attenuate most visible light and pass near-infrared (having wavelengths longer than approximately 700 nm) and a small amount of blue-green and blue-violet (having wavelengths in the 500 to 520 nm and shorter than 435 nm, respectively). The goggles are useful for looking at vegetation to identify different species and for determining the health of the vegetation, and to detect some forms of camouflage. 7 figs.

  16. 21 CFR 870.3535 - Intra-aortic balloon and control system

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intra-aortic balloon and control system 870.3535... balloon and control system (a) Identification. A intra-aortic balloon and control system is a device that... during certain life-threatening emergencies, and a control system for regulating the inflation and...

  17. Robotic aortic surgery.

    Science.gov (United States)

    Duran, Cassidy; Kashef, Elika; El-Sayed, Hosam F; Bismuth, Jean

    2011-01-01

    Surgical robotics was first utilized to facilitate neurosurgical biopsies in 1985, and it has since found application in orthopedics, urology, gynecology, and cardiothoracic, general, and vascular surgery. Surgical assistance systems provide intelligent, versatile tools that augment the physician's ability to treat patients by eliminating hand tremor and enabling dexterous operation inside the patient's body. Surgical robotics systems have enabled surgeons to treat otherwise untreatable conditions while also reducing morbidity and error rates, shortening operative times, reducing radiation exposure, and improving overall workflow. These capabilities have begun to be realized in two important realms of aortic vascular surgery, namely, flexible robotics for exclusion of complex aortic aneurysms using branched endografts, and robot-assisted laparoscopic aortic surgery for occlusive and aneurysmal disease.

  18. False positive reaction due to endogenous biotin activity in glandular epithelium of decidua Reação falso positiva em epitélio glandular da decídua devido a atividade endógena de biotina

    Directory of Open Access Journals (Sweden)

    Liliana Cruz Spano

    2005-06-01

    Full Text Available Biotin-labeled probe was used in an in situ hybridisation assay to localize virus infection in formalin-fixed, paraffin embedded tissues taken from eleven abortion cases. Probes for human cytomegalovirus (HCMV, human Parvovirus B19 (B19 and human adenovirus type 2 (HAd2, were labeled with biotin-11-dUTP by nick-translation reaction. Streptavidin-alkaline-phosphatase (SAP was used to detect biotin, followed by 4-nitroblue tetrazolium/5-bromo-4-chloro-3-indolyl phosphate (NBT/BCIP solution. Positive reaction was observed in nucleus of glandular ephitelium cells of decidua either in positive or in negative control at first and second gestational trimester. The reaction was not inhibited with blocking solution for alkaline phosphatase endogenous activity and it persisted even with probes omission. The use of adequate negative control permitted to reveal the presence of nuclear biotin in glandular epithelium of decidua, responsible for false positivity in detection systems involving streptavidin biotin system (StrepABC. The stained cells resembled to cytophatic effect due to herpesvirus, which could induce further misinterpretation. The results obtained in this study strongly recommend that DNA detection by in situ hybridisation reaction in gestational endometrium should be done without using StrepABC system.Sondas marcadas com biotina foram utilizadas neste trabalho para detecção de infecção viral por hibridização in situ em tecidos fixados com formalina e embebidos em parafina de 11 casos obtidos de abortamento. Sondas para citomegalovírus humano (HCMV, parvovírus B19 humano (B19 e adenovírus humano tipo 2 (HAd2, foram marcadas com biotina-11-dUTP através da reação de nick-translation. Estreptavidina conjugada com fosfatase alcalina (SAP seguida por solução de 4-nitro-azul de tetrazolio/5-bromo-4-cloro-3-indolil fosfato (NBT/BCIP foram utilizadas para detecção da biotina após a reação de hibridização. Reação positiva foi

  19. Aortic valve replacement

    DEFF Research Database (Denmark)

    Kapetanakis, Emmanouil I; Athanasiou, Thanos; Mestres, Carlos A

    2008-01-01

    BACKGROUND AND AIMS OF THE STUDY: Prompted by anecdotal evidence and observations by surgeons, an investigation was undertaken into the potential differences in implanted aortic valve prosthesis sizes, during aortic valve replacement (AVR) procedures, between northern and southern European...... countries. METHODS: A multi-institutional, non-randomized, retrospective analysis was conducted among 2,932 patients who underwent AVR surgery at seven tertiary cardiac surgery centers throughout Europe. Demographic and perioperative variables including valve size and type, body surface area (BSA) and early...

  20. Pneumomediastinum and the aortic nipple: the clinical relevance of the left superior intercostal vein.

    Science.gov (United States)

    Walters, Andy; Cassidy, Lindsey; Muhleman, Mitchel; Peterson, Ashley; Blaak, Christa; Loukas, Marios

    2014-07-01

    This article discusses the appearance of the "aortic nipple" in chest radiography, and reviews the embryology and anatomy of the left superior intercostal vein which causes the appearance of an "aortic nipple." This radiological sign is useful in differentiating certain thoracic pathologies, such as pneumomediastinum, pneumopericardium, and medial pneumothorax. Pneumomediastinum is an encompassing term describing the presence of air in the mediastinum, and may arise from a wide range of pathological conditions. Despite the well-described imaging of pneumomediastinum, it is sometimes difficult to differentiate from other conditions such as pneumopericardium and medial pneumothorax. A separate finding, "aortic nipple" is the radiographic term used to describe the lateral nipple-like projection from the aortic knob present in a small number of individuals. The aortic nipple corresponds to the end-on appearance of the left superior intercostal vein coursing around the aortic knob, and may be mistaken radiologically for lymphadenopathy or a neoplasm. Despite their relative independence, the aortic nipple is defined by new contours in cases of pneumomediastinum, taking on an "inverted aortic nipple" appearance. In this position, the inverted aortic nipple may facilitate radiographic discrimination of pneumomediastinum from similar conditions. This study aims to review the common clinical and radiographic features of both pneumomediastinum and the aortic nipple. The radiologic appearance of the aortic nipple occurring in unison with pneumomediastinum, and its potential role as a tool in the differentiation of pneumomediastinum from similarly presenting conditions will also be described. Copyright © 2013 Wiley Periodicals, Inc.

  1. Underpowered samples, false negatives, and unconscious learning

    OpenAIRE

    Vadillo, M. A.; Konstantinidis, E.; Shanks, D.R.

    2016-01-01

    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...

  2. Endovascular treatment of thoracic aortic diseases

    Directory of Open Access Journals (Sweden)

    Davidović Lazar

    2013-01-01

    Full Text Available Bacground/Aim. Endovascular treatment of thoracic aortic diseases is an adequate alternative to open surgery. This method was firstly performed in Serbia in 2004, while routine usage started in 2007. Aim of this study was to analyse initial experience in endovacular treatment of thoracic aortic diseses of three main vascular hospitals in Belgrade - Clinic for Vascular and Endovascular Surgery of the Clinical Center of Serbia, Clinic for Vascular Surgery of the Military Medical Academy, and Clinic for Vascular Surgery of the Institute for Cardiovascular Diseases “Dedinje”. Methods. Between March 2004. and November 2010. 41 patients were treated in these three hospitals due to different diseases of the thoracic aorta. A total of 21 patients had degenerative atherosclerotic aneurysm, 6 patients had penetrating aortic ulcer, 6 had posttraumatic aneurysm, 4 patients had ruptured thoracic aortic aneurysm, 1 had false anastomotic aneurysm after open repair, and 3 patients had dissected thoracic aneurysm of the thoracoabdominal aorta. In 15 cases the endovascular procedure was performed as a part of the hybrid procedure, after carotidsubclavian bypass in 4 patients and subclavian artery transposition in 1 patient due to the short aneurysmatic neck; in 2 patients iliac conduit was used due to hypoplastic or stenotic iliac artery; in 5 patients previous reconstruction of abdominal aorta was performed; in 1 patient complete debranching of the aortic arch, and in 2 patients visceral abdominal debranching were performed. Results. The intrahospital mortality rate (30 days was 7.26% (3 patients with ruptured thoracic aneurysms died. Endoleak type II in the first control exam was revealed in 3 patients (7. 26%. The patients were followed up in a period of 1-72 months, on average 29 months. The most devastating complication during a followup period was aortoesofageal fistula in 1 patient a year after the treatment of posttraumatic aneurysm. Conversion was

  3. Transcatheter valve implantation for patients with aortic stenosis: A position statement from the European Association of Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular Interventions (EAPCI)

    NARCIS (Netherlands)

    A. Vahanian (Alec); O. Alfieri (Ottavio); N. Al-Attar (Nawwar); M. Antunes (Manuel); J.J. Bax (Jeroen); B. Cormier (Bertrand); A. Cribier (Alain); P.P.T. de Jaegere (Peter); G. Fournial (Gerard); A.P. Kappetein (Arie Pieter); J. Kovac (Jan); S. Ludgate (Susanne); F. Maisano (Francesco); N. Moat (Neil); F.W. Mohr (Friedrich); P. Nataf (Patrick); L. Pié rard (Luc); J.L. Pomar (Jose); J. Schofer (Joachim); P. Tornos (Pilar); M. Tuzcu (Murat); B.A. van Hout (Ben); L.K. von Segesser (Ludwig); T. Walther (Thomas)

    2008-01-01

    textabstractAims: To critically review the available transcatheter aortic valve implantation techniques and their results, as well as propose recommendations for their use and development. Methods and results: A committee of experts including European Association of Cardio-Thoracic Surgery and Europ

  4. Unoperated aortic aneurysm

    DEFF Research Database (Denmark)

    Perko, M J; Nørgaard, M; Herzog, T M;

    1995-01-01

    From 1984 to 1993, 1,053 patients were admitted with aortic aneurysm (AA) and 170 (15%) were not operated on. The most frequent reason for nonoperative management was presumed technical inoperability. Survivals for patients with thoracic, thoracoabdominal, and abdominal AA were comparable...... hypertension were predictive of mortality, whereas...

  5. A Novel Marker of Impaired Aortic Elasticity in Never Treated Hypertensive Patients: Monocyte/High-Density Lipoprotein Cholesterol Ratio.

    Science.gov (United States)

    Yayla, Kadriye Gayretli; Canpolat, Uğur; Yayla, Çagri; Akboğa, Mehmet Kadri; Akyel, Ahmet; Akdi, Ahmet; Çiçek, Gökhan; Ozcan, Firat; Turak, Osman; Aydoğdu, Sinan

    2017-01-01

    Monocyte to high density lipoprotein cholesterol ratio (MHR) is generally understood to be a candidate marker of inflammation and oxidative stress. Therefore, we aimed to assess the association between MHR and aortic elastic properties in hypertensive patients. A total of 114 newly-diagnosed untreated patients with hypertension and 71 healthy subjects were enrolled. Aortic stiffness index, aortic strain and aortic distensibility were measured by using echocardiography. Patients with hypertension had a significantly higher MHR compared to the control group (p MHR with aortic stiffness index (r = 0.294, p MHR and high sensitivity C-reactive protein have a positive correlation (r = 0.30, p MHR was found to be an independent predictor of aortic distensibility and aortic stiffness index. In patients with newly-diagnosed untreated essential hypertension, higher MHR was significantly associated with impaired aortic elastic properties.

  6. Aortic PWV in Chronic Kidney Disease: A CRIC Ancillary Study

    Science.gov (United States)

    Townsend, Raymond R.; Wimmer, Neil J.; Chirinos, Julio A.; Parsa, Afshin; Weir, Matthew; Perumal, Kalyani; Lash, James P.; Chen, Jing; Steigerwalt, Susan P.; Flack, John; Go, Alan S.; Rafey, Mohammed; Rahman, Mahboob; Sheridan, Angela; Gadegbeku, Crystal A.; Robinson, Nancy A.; Joffe, Marshall

    2009-01-01

    Background Aortic PWV is a measure of arterial stiffness and has proved useful in predicting cardiovascular morbidity and mortality in several populations of patients, including the healthy elderly, hypertensives and those with end stage renal disease receiving hemodialysis. Little data exist characterizing aortic stiffness in patients with chronic kidney disease who are not receiving dialysis, and in particular the effect of reduced kidney function on aortic PWV. Methods We performed measurements of aortic PWV in a cross-sectional cohort of participants enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study to determine factors which predict increased aortic PWV in chronic kidney disease. Results PWV measurements were obtained in 2564 participants. The tertiles of aortic PWV (adjusted for waist circumference) were 10.2 m/sec with an overall mean (± S.D.) value of 9.48 ± 3.03 m/sec [95% CI = 9.35–9.61 m/sec]. Multivariable regression identified significant independent positive associations of age, blood glucose concentrations, race, waist circumference, mean arterial blood pressure, gender, and presence of diabetes with aortic PWV and a significant negative association with the level of kidney function. Conclusions The large size of this unique cohort, and the targeted enrollment of chronic kidney disease participants provides an ideal situation to study the role of reduced kidney function as a determinant of arterial stiffness. Arterial stiffness may be a significant component of the enhanced cardiovascular risk associated with kidney failure. PMID:20019670

  7. Extended contrast detection on fluoroscopy and angiography for image-guided trans-catheter aortic valve implantations (TAVI)

    Science.gov (United States)

    Liu, Yinxiao; Liao, Rui; Lv, Xudong

    2012-02-01

    Navigation and deployment of the prosthetic valve during trans-catheter aortic valve implantation (TAVI) can be greatly facilitated with 3-D models showing detailed anatomical structures. Fast and robust automatic contrast detection at the aortic root on X-ray images is indispensable for automatically triggering a 2-D/3-D registration to align the 3-D model. Previously, we have proposed an automatic method for contrast detection at the aortic root on fluoroscopic and angiographic sequences [4]. In this paper, we extend that algorithm in several ways, making it more robust to handle more general and difficult cases. Specifically, the histogram likelihood ratio test is multiplied with the histogram portion computation to handle faint contrast cases. Histogram mapping corrects sudden changes in the global brightness, thus avoiding potential false positives. Respiration and heart beating check further reduces the false positive rate. In addition, a probe mask is introduced to enhance the contrast feature curve when the dark ultrasound probe partially occludes the aortic root. Lastly, a semi-global registration method for aligning the aorta shape model is implemented to improve the robustness of the algorithm with respect to the selection of region of interest (ROI) containing the aorta. The extended algorithm was evaluated on 100 sequences, and improved the detection accuracy from 94% to 100%, compared to the original method. Also, the robustness of the extended algorithm was tested with 20 different shifts of the ROI, and the error rate was as low as 0.2%, in comparison to 6.6% for the original method.

  8. Clinical usefulness of the second peak of radial systolic blood pressure for estimation of aortic systolic blood pressure.

    Science.gov (United States)

    Kohara, K; Tabara, Y; Tomita, H; Nagai, T; Igase, M; Miki, T

    2009-08-01

    Central aortic blood pressure (BP), obtained from radial arterial waveform using the transfer function method (TFM), has been shown to have prognostic value independently of brachial BP. In this study, the relationship between peripheral systolic BP (SBP) and aortic SBP was evaluated. We further investigated whether TFM-derived aortic SBP can be estimated by information obtained from the radial waveform. The radial waveform was analysed to obtain the first peak of radial SBP (SBP1), second peak of radial SBP (SBP2), radial augmentation index (AI) (radial (SBP2-DBP)/(SBP1-DBP) x 100 and aortic SBP and AI using TFM in 233 subjects in the supine position. Measurements were repeated after changing position to the prone position. The constructed equation was validated in 149 community residents with different backgrounds. Radial SBP2 was closer to TFM-derived aortic SBP compared with brachial SBP. TFM-derived aortic SBP was approximated by the equation: aortic SBP=18.9-radial SBP2-0.03 x HR-0.214 x radial AI (r2=0.992). The equation was also applicable to predicting aortic SBP in the prone position as well as in different populations (mean difference between predicted aortic SBP and TFM-derived aortic SBP: -0.01+/-1.34 and 1.05+/-1.47 mm Hg, respectively). Radial arterial waveform analysis can be used for estimation of TFM-derived aortic SBP.

  9. Post-stenotic aortic dilatation

    Directory of Open Access Journals (Sweden)

    Jahangiri Marjan

    2006-03-01

    Full Text Available Abstract Aortic stenosis is the most common valvular heart disease affecting up to 4% of the elderly population. It can be associated with dilatation of the ascending aorta and subsequent dissection. Post-stenotic dilatation is seen in patients with AS and/or aortic regurgitation, patients with a haemodynamically normal bicuspid aortic valve and following aortic valve replacement. Controversy exists as to whether to replace the aortic root and ascending aorta at the time of aortic valve replacement, an operation that potentially carries a higher morbidity and mortality. The aetiology of post-stenotic aortic dilatation remains controversial. It may be due to haemodynamic factors caused by a stenotic valve, involving high velocity and turbulent flow downstream of the stenosis, or due to intrinsic pathology of the aortic wall. This may involve an abnormality in the process of extracellular matrix remodelling in the aortic wall including inadequate synthesis, degradation and transport of extracellular matrix proteins. This article reviews the aetiology, pathology and management of patients with post-stenotic aortic dilatation.

  10. Aortic stiffness in patients with cardiac syndrome X.

    Science.gov (United States)

    Gorgulu, Sevket; Uslu, Nevzat; Eren, Mehmet; Celik, Seden; Yildirim, Aydin; Dagdeviren, Bahadir; Tezel, Tuna

    2003-12-01

    Recently, the close relationship between aortic stiffness and cardiovascular mortality has aroused the interest of investigators in carrying out studies related to aortic stiffness. This study aims to investigate the aortic stiffness parameters in patients with cardiac syndrome X, a disorder that is believed to be a generalized disturbance of the vasodilator function of small arteries. 18 patients with typical chest pain and angiographically normal coronary arteries associated with a positive exercise test were included in the study. The control group consisted of 27 patients with angiographically normal coronary arteries and no ischaemia on exercise testing. Antianginal medication was withheld 4 weeks before the study and transthoracic echocardiography was performed using a Hewlett-Packard Sonos 1500 instrument with a 2.5 MHz phased array transducer. Ascending aorta diameters were measured on the M-mode tracing at a level 3 cm above the aortic valve. Diameter change, pulse pressure, aortic strain and distensibility were measured as aortic stiffness parameters. The aortic diameter change was less in the syndrome X group than in the control group (0.15 +/- 0.04 cm/m2 vs. 0.28 +/- 0.12 cm/m2, p < 0.001). Likewise, aortic strain (9 +/- 3% vs. 18 +/- 8%, p < 0.001) and distensibility (4.01 +/- 1.71 cm2 x dyn(-1) x 10(-3) vs. 9.95 +/- 5.08 cm2 x dyn(-1) x 10(-3), p < 0.001) was significantly lower in the syndrome X group than in the control group. The deterioration in aortic elasticity properties in patients with cardiac syndrome X suggests that this disease may be a more generalized disturbance of the vasculature.

  11. The additional value of three-dimensional transesophageal echocardiography in complex aortic prosthetic heart valve endocarditis.

    Science.gov (United States)

    Tanis, Wilco; Teske, Arco J; van Herwerden, Lex A; Chamuleau, Steven; Meijboom, Folkert; Budde, Ricardo P J; Cramer, Maarten-Jan

    2015-01-01

    Two-dimensional transthoracic and transesophageal echocardiography (2DTTE and 2DTEE) may fail to detect signs of prosthetic heart valve (PHV) endocarditis due to acoustic shadowing. Three-dimensional (3D) TEE may have additional value; however, data are scarce. This study was performed to investigate the additional value of 3DTEE for the detection of aortic PHV endocarditis and the extent of the disease process. Retrospective analysis of complex aortic PHV endocarditis cases that underwent 2DTTE, 2DTEE, and 3DTEE before surgery. Echocardiograms were individually assessed by 2 cardiologists blinded for the outcome. Surgical and pathological inspection served as the reference standard for vegetations and peri-annular extensions (abscesses/mycotic aneurysms). To determine if the proximal coronary arteries were involved in the inflammatory process as well, computed tomography angiography findings were added to reference standard. Fifteen aortic PHV endocarditis cases were identified. According to the reference standard, all 15 cases had peri-annular extensions, 13 of which had a close relationship with the proximal right and/or left coronary artery. In 6 of 15 patients, a vegetation was present. Combined 2DTTE/TEE missed 1/6 vegetations and 1/15 peri-annular extensions. After addition of 3DTEE, all vegetations (6/6) and peri-annular extensions (15/15) were detected, without adding false positives. Compared to 2DTEE, in 3/15 cases, 3DTEE resulted in better delineation of the anatomical relationship of the proximal coronary arteries to the peri-annular extensions. As a result, 3DTEE had an additional value in 5/15 cases. In complex aortic, PHV endocarditis 3DTEE may have additional value compared to 2D echocardiography. © 2014, Wiley Periodicals, Inc.

  12. 主动脉夹层术后低氧血症早期实施俯卧位通气的护理体会%The Nursing Experience of the Early Implementing Prone Position Ventilation in Aortic Dissection Postoperative Hypoxemia

    Institute of Scientific and Technical Information of China (English)

    董晨艳; 陈海燕

    2016-01-01

    目的:探讨俯卧位通气在Stanford A型主动脉夹层术后低氧血症早期应用效果及护理要点。方法对5例Stanford A型主动脉夹层术后低氧血症早期给予俯卧位通气及相关护理措施。结果经俯卧位通气治疗后患者低氧血症明显改善,无并发症发生,顺利转出监护室(ICU)。结论俯卧位通气及采取针对性的护理干预能改善患者低氧血症症状,促进患者康复。%Objective Discusses prone position ventilation in Stanford type A aortic dissection early postoperative hypoxemia application effect and nursing key points. Methods 5 cases of early postoperative hypoxemia Stanford type A aortic dissection prone position ventilation and related nursing measures. Results After treatment with prone position ventilation patients obviously improved hypoxemia, no complications occurred, smooth roll-out care unit (ICU). Conclusion Prone position ventilation and take corresponding nursing intervention can improve hypoxemia patients symptoms, promote patients recover.

  13. Tobacco smoking and aortic aneurysm

    DEFF Research Database (Denmark)

    Sode, Birgitte F; Nordestgaard, Børge G; Grønbæk, Morten

    2012-01-01

    BACKGROUND: We determined the predictive power of tobacco smoking on aortic aneurysm as opposed to other risk factors in the general population. METHODS: We recorded tobacco smoking and other risk factors at baseline, and assessed hospitalization and death from aortic aneurysm in 15,072 individuals...... General Population Study, respectively. According to the magnitude of the hazard ratios, tobacco consumption was the most important risk factor for hospitalization and death from aortic aneurysm, followed by male sex and hypertension in both cohorts. The population attributable risk of aortic aneurysm...... outcomes due to tobacco consumption was 64% and 47% in the Copenhagen City Heart Study and Copenhagen General Population Study, respectively, and ranked highest among population attributable risks of aortic aneurysm in both cohorts. The absolute 10-year risk for hospitalization or death from aortic...

  14. The distinctiveness heuristic in false recognition and false recall.

    Science.gov (United States)

    McCabe, David P; Smith, Anderson D

    2006-07-01

    The effects of generative processing on false recognition and recall were examined in four experiments using the Deese-Roediger-McDermott false memory paradigm (Deese, 1959; Roediger & McDermott, 1995). In each experiment, a Generate condition in which subjects generated studied words from audio anagrams was compared to a Control condition in which subjects simply listened to studied words presented normally. Rates of false recognition and false recall were lower for critical lures associated with generated lists, than for critical lures associated with control lists, but only in between-subjects designs. False recall and recognition did not differ when generate and control conditions were manipulated within-subjects. This pattern of results is consistent with the distinctiveness heuristic (Schacter, Israel, & Racine, 1999), a metamemorial decision-based strategy whereby global changes in decision criteria lead to reductions of false memories. This retrieval-based monitoring mechanism appears to operate in a similar fashion in reducing false recognition and false recall.

  15. Aortic allografts in treatment of aortic valve and ascending aorta prosthetic endocarditis

    Directory of Open Access Journals (Sweden)

    S.V. Spiridonov

    2017-03-01

    Full Text Available The aim – to assess short- and long-term results of aortic root replacement using aortic allografts in patients with prosthetic endocarditis. Materials and methods. Since February 2009 until June 2016 aortic valve and ascending aorta replacement using aortic allografts was performed in 26 patients with prosthetic endocarditis. In 50 % of cases at initial operation aortic valve replacement was performed, in another 50 % of cases – aortic valve and ascending aorta replacement. Echocardiography was performed 10 days, 3, 6 and 12 months, 2, 3 and 5 years after surgery. Analysis of long-term results included all cases of deaths, prosthesis-related complications and recurrence of endocarditis. Results. 30-day mortality was 23.1 %. Extracorporeal membranous oxygenation (ECMO was used only in 5 patients (19.2 %. Four patients were weaned from ECMO. We did not observe any allograft-related complications. During follow-up period there were no cases of reoperation due to structural allograft failure. Relapse of infection occurred in 1 patient (3.8 % four years after the operation and led to lethal outcome. Conclusion. Reoperations using allografts are an effective surgical treatment of prosthetic endocarditis. In majority of cases prosthetic endocarditis was caused by gram-positive cocci (Staphylococcus. In 84.6 % of cases it was associated with destruction of paravalvular structures and abscesses formation. Heart failure was a causative factor of different complications in these patients, which required ECMO in 19.2 % of patients. In 80 % of cases patients were weaned from ECMO. Allografts using for the treatment of prosthetic endocarditis is associated with high resistance to infection and with a significant rate of freedom from recurrence of endocarditis within 3 years after surgery.

  16. Ruptured abdominal aortic aneurysm.

    Science.gov (United States)

    Sachs, T; Schermerhorn, M

    2010-06-01

    Ruptured abdominal aortic aneurysm (AAA) continues to be one of the most lethal vascular pathologies we encounter. Its management demands prompt and efficient evaluation and repair. Open repair has traditionally been the mainstay of treatment. However, the introduction of endovascular techniques has altered the treatment algorithm for ruptured AAA in most major medical centers. We present recent literature and techniques for ruptured AAA and its surgical management.

  17. Infrarenal Aortic Occlusion

    Science.gov (United States)

    Traverso, L. W.; Baker, J. D.; Dainko, E. A.; Machleder, H. I.

    1978-01-01

    Twenty-eight patients with total occlusion of the infrarenal aorta have been seen at the UCLA Hospitals in the past 11 years. Claudication was the presenting complaint in all but one patient, with one-third having ischemic rest pain. The average age of these patients was 54 years, and their histories revealed a surprising absence of myocardial infarction, stroke, or diabetes, although 40% had essential hypertension. Heavy tobacco use, however, was characteristic of the entire group. Arteriography proved valuable in identifying and characterizing the vascular abnormalities, but posed problems in technique and interpretation. Significant distal arterial disease was detected radiographically in only 21% of these patients. Operative correction of the aortic occlusion was performed on 26 patients, 18 by aortic bypass grafts and eight by aorto-iliac endarterectomy, with one early postoperative death. Although the thrombus extended to the renal artery origins in 77% of the cases, a well-designed technical approach did not require renal artery occlusion. Using serial creatinine determinations, one case of renal insufficiency was detected which was associated with prolonged postoperative hypotension. Although the extent of distal disease was more severe in those who underwent bypass, symptoms of claudication returned earlier and were more prominent in the endarterectomy group. This recurrence of systems was not favorably altered by sympathectomy performed concomitantly with the initial procedure. Even though this condition seems to pose difficult technical obstacles and has a poor prognosis, infrarenal aortic occlusion can be successfully treated by aortic bypass, with favorable long-term results, if particular attention is paid to elements of the preoperative evaluation and the intraoperative technical requirements peculiar to this relatively uncommon disease entity. ImagesFig. 1.Fig. 2.Fig. 3. PMID:646479

  18. CT of thoracic aortic aneurysms.

    Science.gov (United States)

    Posniak, H V; Olson, M C; Demos, T C; Benjoya, R A; Marsan, R E

    1990-09-01

    Aneurysms of the thoracic aorta are most often the result of arteriosclerotic disease. Other causes include degeneration of the medial layer of the aortic wall, either idiopathically or due to genetic disorders such as Marfan syndrome; aortic dissection; trauma; syphilis and other bacterial infection; noninfective aortitis; and congenital anomaly. We review normal anatomy of the aorta and discuss our technique and interpretation of computed tomography (CT) in the evaluation of the thoracic aorta. We illustrate the CT appearance of different types of aortic aneurysms as well as discuss the use of CT for assessing complications of aneurysms, for postoperative follow-up, and in the differentiation of aortic aneurysm from a paraaortic mass.

  19. Micromanaging Abdominal Aortic Aneurysms

    Directory of Open Access Journals (Sweden)

    Lars Maegdefessel

    2013-07-01

    Full Text Available The contribution of abdominal aortic aneurysm (AAA disease to human morbidity and mortality has increased in the aging, industrialized world. In response, extraordinary efforts have been launched to determine the molecular and pathophysiological characteristics of the diseased aorta. This work aims to develop novel diagnostic and therapeutic strategies to limit AAA expansion and, ultimately, rupture. Contributions from multiple research groups have uncovered a complex transcriptional and post-transcriptional regulatory milieu, which is believed to be essential for maintaining aortic vascular homeostasis. Recently, novel small noncoding RNAs, called microRNAs, have been identified as important transcriptional and post-transcriptional inhibitors of gene expression. MicroRNAs are thought to “fine tune” the translational output of their target messenger RNAs (mRNAs by promoting mRNA degradation or inhibiting translation. With the discovery that microRNAs act as powerful regulators in the context of a wide variety of diseases, it is only logical that microRNAs be thoroughly explored as potential therapeutic entities. This current review summarizes interesting findings regarding the intriguing roles and benefits of microRNA expression modulation during AAA initiation and propagation. These studies utilize disease-relevant murine models, as well as human tissue from patients undergoing surgical aortic aneurysm repair. Furthermore, we critically examine future therapeutic strategies with regard to their clinical and translational feasibility.

  20. Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Disease

    DEFF Research Database (Denmark)

    Mylotte, Darren; Lefevre, Thierry; Søndergaard, Lars

    2014-01-01

    BACKGROUND: Limited information exists describing the results of transcatheter aortic valve (TAV) replacement in patients with bicuspid aortic valve (BAV) disease (TAV-in-BAV). OBJECTIVES: This study sought to evaluate clinical outcomes of a large cohort of patients undergoing TAV-in-BAV. METHODS...

  1. Giant Aortic Pseudoaneurysm with Stanford Type A Aortic Dissection after Aortic Valve Replacement

    Directory of Open Access Journals (Sweden)

    Mertay Boran

    2012-01-01

    Full Text Available Giant pseudoaneurysm of the ascending aorta is a rare but dreadful complication occurring several months or years after aortic surgery. Thoracic aortic aneurysms tend to be asymptomatic and were previously often diagnosed only after a complication such as dissection or rupture. We present a rare case of giant ascending aneurysm with Stanford type A aortic dissection occurring 6 years after aortic valve replacement and also illustrate the potential dimensions the ascending aorta may reach by a pseudoaneurysm and dissection after AVR.

  2. Association of Aortic Calcification on Plain Chest Radiography with Obstructive Coronary Artery Disease

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yeong Han; Chang, Jeong Ho [Dept. of Diagnostic Radiology, Daegu Catholic University Hospital, Daegu (Korea, Republic of); Park, Jong Sam [Dept. of Radiologic Tecnology, Daegu Health College, Daegu (Korea, Republic of)

    2009-03-15

    This study was conducted to determine an association between aortic calcification viewed on plain chest radiography and obstructive coronary artery disease. Retrospective review of all chest radiography obtained from consecutive patients undergoing coronary angiography. Chest PA images were reviewed by technical radiologist and radiologist. Considering the presence of aortic arch calcification, images were compared with the results of coronary angiography. In addition, the size of aortic arch calcification were divided into two groups - the smaller and the larger than 10 mm. Among the total 846 patients, the number of the patients with obstructive coronary artery disease is total 417 (88.3%) in males and 312 (83.4%) in females. Considering the presence of aortic arch calcification, the positive predictive value of relation between aortic arch calcification and obstructive coronary artery disease was 91.4% and the relative risk of the group with aortic arch calcification to the opposite group was 1.10. According to the size of aortic arch calcification and obstructive coronary artery disease, the positive predictive value was 91.9% and the relative risk between two groups was 1.04. This study shows that aortic calcification was closely associated with obstructive coronary artery disease. If the aortic calcification is notified on plain chest radiography, we strongly recommend to consult with doctor.

  3. Hypnotizability, not suggestion, influences false memory development.

    Science.gov (United States)

    Dasse, Michelle N; Elkins, Gary R; Weaver, Charles A

    2015-01-01

    Hypnotizability influences the development of false memories. In Experiment 1, participants heard a positive or negative suggestion regarding hypnosis and then listened to 8 Deese-Roediger-McDermott (DRM) false memory paradigm lists in a hypnotic state. Neither hypnosis nor prehypnotic suggestion affected memory. Highly hypnotizable participants were more accurate in recall and recognition. In Experiment 2, suggestions were delivered in the form of feedback. Participants heard a positive or negative suggestion about their performance prior to either the encoding or retrieval of 8 DRM lists. Neither accurate nor false memories were affected by the suggestion. Highly hypnotizable individuals recognized fewer critical lures if they received a negative suggestion about their performance. These results highlight the unusual role of hypnotizability in the creation of false memories.

  4. Aortic root geometry in aortic stenosis patients (a SEAS substudy)

    DEFF Research Database (Denmark)

    Bahlmann, Edda; Nienaber, Christoph A; Cramariuc, Dana

    2011-01-01

    AIMS: To report aortic root geometry by echocardiography in a large population of healthy, asymptomatic aortic stenosis (AS) patients in relation to current vendor-specified requirements for transcatheter aortic valve implantation (TAVI). METHODS AND RESULTS: Baseline data in 1481 patients...... with asymptomatic AS (mean age 67 years, 39% women) in the Simvastatin Ezetimibe in AS study were used. The inner aortic diameter was measured at four levels: annulus, sinus of Valsalva, sinotubular junction and supracoronary, and sinus height as the annulo-junctional distance. Analyses were based on vendor......-specified requirements for the aortic root geometry for current available prostheses, CoreValve and Edwards-Sapien. The ratio of sinus of Valsalva height to sinus width was 1:2. In multivariate linear regression analysis, larger sinus of Valsalva height was associated with older age, larger sinus of Valsalva diameter...

  5. 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

    BACKGROUND: Reference change values provide objective tools to assess the significance of a change in two consecutive results for a biomarker from an individual. The reference change value calculation is based on the assumption that within-subject biological variation has random fluctuation around...... 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...... was based on standard deviations according to the assumption of normality, but was soon changed to coefficients of variation (CV) in the formula (reference change value = ± Z ċ 2(½) ċ CV). Z is being dependent on the desired probability of significance, which also defines the percentages of false...

  6. Sleep deprivation and false memories.

    Science.gov (United States)

    Frenda, Steven J; Patihis, Lawrence; Loftus, Elizabeth F; Lewis, Holly C; Fenn, Kimberly M

    2014-09-01

    Many studies have investigated factors that affect susceptibility to false memories. However, few have investigated the role of sleep deprivation in the formation of false memories, despite overwhelming evidence that sleep deprivation impairs cognitive function. We examined the relationship between self-reported sleep duration and false memories and the effect of 24 hr of total sleep deprivation on susceptibility to false memories. We found that under certain conditions, sleep deprivation can increase the risk of developing false memories. Specifically, sleep deprivation increased false memories in a misinformation task when participants were sleep deprived during event encoding, but did not have a significant effect when the deprivation occurred after event encoding. These experiments are the first to investigate the effect of sleep deprivation on susceptibility to false memories, which can have dire consequences.

  7. Including aortic valve morphology in computational fluid dynamics simulations: initial findings and application to aortic coarctation.

    Science.gov (United States)

    Wendell, David C; Samyn, Margaret M; Cava, Joseph R; Ellwein, Laura M; Krolikowski, Mary M; Gandy, Kimberly L; Pelech, Andrew N; Shadden, Shawn C; LaDisa, John F

    2013-06-01

    Computational fluid dynamics (CFD) simulations quantifying thoracic aortic flow patterns have not included disturbances from the aortic valve (AoV). 80% of patients with aortic coarctation (CoA) have a bicuspid aortic valve (BAV) which may cause adverse flow patterns contributing to morbidity. Our objectives were to develop a method to account for the AoV in CFD simulations, and quantify its impact on local hemodynamics. The method developed facilitates segmentation of the AoV, spatiotemporal interpolation of segments, and anatomic positioning of segments at the CFD model inlet. The AoV was included in CFD model examples of a normal (tricuspid AoV) and a post-surgical CoA patient (BAV). Velocity, turbulent kinetic energy (TKE), time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) results were compared to equivalent simulations using a plug inlet profile. The plug inlet greatly underestimated TKE for both examples. TAWSS differences extended throughout the thoracic aorta for the CoA BAV, but were limited to the arch for the normal example. OSI differences existed mainly in the ascending aorta for both cases. The impact of AoV can now be included with CFD simulations to identify regions of deleterious hemodynamics thereby advancing simulations of the thoracic aorta one step closer to reality. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

  8. The Origin of Neointimal Smooth Muscle Cells in Transplant Arteriosclerosis from Recipient Bone-marrow Cells in Rat Aortic Allograft

    Institute of Scientific and Technical Information of China (English)

    SONG Zifang; LI Wei; ZHENG Qichang; SHANG Dan; SHU Xiaogang; GUAN Siming

    2007-01-01

    In order to investigate the origin of neointimal smooth muscle cells in transplant arteriosclerosis in rat aortic allograft, sex-mismatched bone marrow transplantation was performed from male Wistar rats to female Wistar rats. Four weeks after transplantation, the aortic transplant model was established by means of micro-surgery in rats. The recipients were divided into 4 groups: female Wistar-female Wistar aortic isografts, female SD-female Wistar aortic allografts, male SD-male Wistar aortic allografts, female SD-chimera Wistar aortic allografts. Eight weeks after transplantation, aortic grafts were removed at autopsy and processed for histological evaluation and immunohistochemistry. The results indicated that excessive accumulation of α-SMA-positive smooth muscle cells resulted in significant neointima formation and vascular lumen stricture in rat aortic allografts.Neointima assay revealed that the neointimal area and NIA/MA ratio of transplanted artery were significantly increased in all of aortic allograft groups as compared with those in aortic isograft group (P<0.01). Neointimal smooth muscle cells were harvested from cryostat sections of aortic allograft by microdissection method. The Sry gene-specific PCR was performed, and the result showed that a distinct DNA band of 225 bp emerged in the male-male aortic allograft group and chimera aortic allograft group respectively, but not in the female-female aortic allograft group. It was suggested that recipient bone-marrow cells, as the origin of neointimal smooth muscle cells, contributed to the pathological neointimal hyperplasia of aortic allograft and transplant arteriosclerosis.

  9. A special type of endovascular stent repair with complicated thoracic aneurysm and chronic type B dissection aligned in tandem: double perfusion in true and false distal aorta lumen

    Institute of Scientific and Technical Information of China (English)

    GAN Hui-li; ZHANG Jian-qun

    2008-01-01

    @@ Aortic dissection and aortic aneurysm are two of the most common catastrophic events involving the aorta. Thoracic endovascular aortic repair is now considered as a promising alternative to open surgical graft replacement, The aim of endovascular repair of a thoracic aneurysm is to exclude, and thus depressurize, the aneurismal wall and the aim of the endovascular repair of type B aortic dissection is to obliterate all of the false lumen through thrombosis after sealing the primary entry tears, thus to ensure the true lumen perfusion.

  10. Abdominal aortic aneurysm surgery

    DEFF Research Database (Denmark)

    Gefke, K; Schroeder, T V; Thisted, B

    1994-01-01

    The goal of this study was to identify patients who need longer care in the ICU (more than 48 hours) following abdominal aortic aneurysm (AAA) surgery and to evaluate the influence of perioperative complications on short- and long-term survival and quality of life. AAA surgery was performed in 553......, 78% stated that their quality of life had improved or was unchanged after surgery and had resumed working. These data justify a therapeutically aggressive approach, including ICU therapy following AAA surgery, despite failure of one or more organ systems....

  11. Time-resolved CT angiography in aortic dissection

    Energy Technology Data Exchange (ETDEWEB)

    Meinel, Felix G., E-mail: felix.meinel@med.uni-muenchen.de [Department of Clinical Radiology, Ludwig Maximilians-University, Marchioninistr. 15, 81377 Munich (Germany); Nikolaou, Konstantin, E-mail: konstantin.nikolaou@med.uni-muenchen.de [Department of Clinical Radiology, Ludwig Maximilians-University, Marchioninistr. 15, 81377 Munich (Germany); Weidenhagen, Rolf, E-mail: rolf.weidenhagen@med.uni-muenchen.de [Department of Surgery, Ludwig Maximilians-University, Marchioninistr. 15, 81377 Munich (Germany); Hellbach, Katharina, E-mail: katharina.hellbach@med.uni-muenchen.de [Department of Clinical Radiology, Ludwig Maximilians-University, Marchioninistr. 15, 81377 Munich (Germany); Helck, Andreas, E-mail: andreas.helck@med.uni-muenchen.de [Department of Clinical Radiology, Ludwig Maximilians-University, Marchioninistr. 15, 81377 Munich (Germany); Bamberg, Fabian, E-mail: fabian.bamberg@med.uni-muenchen.de [Department of Clinical Radiology, Ludwig Maximilians-University, Marchioninistr. 15, 81377 Munich (Germany); Reiser, Maximilian F., E-mail: maximilian.reiser@med.uni-muenchen.de [Department of Clinical Radiology, Ludwig Maximilians-University, Marchioninistr. 15, 81377 Munich (Germany); Sommer, Wieland H., E-mail: wieland.sommer@med.uni-muenchen.de [Department of Clinical Radiology, Ludwig Maximilians-University, Marchioninistr. 15, 81377 Munich (Germany)

    2012-11-15

    Objectives: We performed this study to assess feasibility and additional diagnostic value of time-resolved CT angiography of the entire aorta in patients with aortic dissection. Materials and methods: 14 consecutive patients with known or suspected aortic dissection (aged 60 {+-} 9 years) referred for aortic CT angiography were scanned on a dual-source CT scanner (Somatom Definition Flash; Siemens, Forchheim, Germany) using a shuttle mode for multiphasic image acquisition (range 48 cm, time resolution 6 s, 6 phases, 100 kV, 110 mAs/rot). Effective radiation doses were calculated from recorded dose length products. For all phases, CT densities were measured in the aortic lumen and renal parenchyma. From the multiphasic data, 3 phases corresponding to a triphasic standard CT protocol, served as a reference and were compared against findings from the time-resolved datasets. Results: Mean effective radiation dose was 27.7 {+-} 3.5 mSv. CT density of the true lumen peaked at 355 {+-} 53 HU. Compared to the simulated triphasic protocol, time-resolved CT angiography added diagnostic information regarding a number of important findings: the enhancement delay between true and false lumen (n = 14); the degree of membrane oscillation (n = 14); the perfusion delay in arteries originating from the false lumen (n = 9). Other additional information included true lumen collapse (n = 4), quantitative assessment of renal perfusion asymmetry (n = 2), and dynamic occlusion of aortic branches (n = 2). In 3/14 patients (21%), these additional findings of the multiphasic protocol altered patient management. Conclusions: Multiphasic, time-resolved CT angiography covering the entire aorta is feasible at a reasonable effective radiation dose and adds significant diagnostic information with therapeutic consequences in patients with aortic dissection.

  12. Transcatheter aortic valve implantation vs. surgical aortic valve replacement for treatment of severe aortic stenosis

    DEFF Research Database (Denmark)

    Siontis, George C M; Praz, Fabien; Pilgrim, Thomas

    2016-01-01

    AIMS: In view of the currently available evidence from randomized trials, we aimed to compare the collective safety and efficacy of transcatheter aortic valve implantation (TAVI) vs. surgical aortic valve replacement (SAVR) across the spectrum of risk and in important subgroups. METHODS AND RESULTS...

  13. [Aortic valve replacement for the small aortic annulus].

    Science.gov (United States)

    Oshima, H; Usui, A; Akita, T; Ueda, Y

    2006-04-01

    Aortic valve surgery for the small aortic annulus is still challenging for surgeons. Recently, the new types of high performance prosthesis have been developed and the chance of an aortic root enlargement (ARE) is decreasing. In this study, we propose the ideal strategy of the aortic surgery for the small aortic annulus. We analyzed the clinical records of 158 patients who underwent aortic valve replacement from August 1999 to October 2005 in our institution. The small aortic annulus was observed in 38 patients (24%). Fourteen patients of this group underwent ARE. Patient-prosthesis mismatch (PPM) was less frequently observed in patients with ARE compared to those without ARE. The additional time required for ARE was not considerable, and neither ischemic time nor cardiopulmonary bypass time was significantly prolonged by ARE. In conclusion, we have to select a prosthesis with sufficient orifice area to avoid PPM, otherwise we should choose an option of ARE. For this consideration, we definitely need the chart that demonstrates the relationship between the nominal size of various types of prostheses and the size of a patient's annulus that those prostheses actually fit.

  14. Balloon aortic valvuloplasty as a bridge to aortic valve replacement in a patient with severe calcific aortic stenosis.

    Science.gov (United States)

    Swinkels, B M; Jaarsma, W; Wely, L Relik-van; van Swieten, H A; Ernst, J M P G; Plokker, H W M

    2003-03-01

    This case report describes a patient with severe calcific aortic stenosis who was initially considered inoperable because of a very poor left ventricular function and severe pulmonary hypertension. After balloon aortic valvuloplasty, the clinical and haemodynamic status of the patient improved to such an extent that subsequent aortic valve replacement was considered possible and eventually proved to be successful. Balloon aortic valvuloplasty has value as a potential bridge to aortic valve replacement when the risks for surgery are considered to be too high.

  15. Valve-sparing aortic root replacement and aortic valve repair in a patient with acromegaly and aortic root dilatation

    Directory of Open Access Journals (Sweden)

    Karel Van Praet

    2015-07-01

    Full Text Available Aortic regurgitation and dilatation of the aortic root and ascending aorta are severe complications of acromegaly. The current trend for management of an aortic root aneurysm is valve-sparing root replacement as well as restoring the diameter of the aortic sinotubular junction (STJ and annulus. Our case report supports the recommendation that in patients with acromegaly, severe aortic root involvement may indicate the need for surgery.

  16. Aortic diameter >or = 5.5 cm is not a good predictor of type A aortic dissection: observations from the International Registry of Acute Aortic Dissection (IRAD)

    National Research Council Canada - National Science Library

    Pape, Linda A; Tsai, Thomas T; Isselbacher, Eric M; Oh, Jae K; O'gara, Patrick T; Evangelista, Arturo; Fattori, Rossella; Meinhardt, Gabriel; Trimarchi, Santi; Bossone, Eduardo; Suzuki, Toru; Cooper, Jeanna V; Froehlich, James B; Nienaber, Christoph A; Eagle, Kim A

    2007-01-01

    .... However, few studies of acute aortic dissection patients and aortic size exist. We used data from our registry of acute aortic dissection patients to better understand the relationship between aortic diameter and type A dissection...

  17. Aortic biomechanics in hypertrophic cardiomyopathy

    Science.gov (United States)

    Badran, Hala Mahfouz; Soltan, Ghada; Faheem, Nagla; Elnoamany, Mohamed Fahmy; Tawfik, Mohamed; Yacoub, Magdi

    2015-01-01

    Background: Ventricular-vascular coupling is an important phenomenon in many cardiovascular diseases. The association between aortic mechanical dysfunction and left ventricular (LV) dysfunction is well characterized in many disease entities, but no data are available on how these changes are related in hypertrophic cardiomyopathy (HCM). Aim of the work: This study examined whether HCM alone is associated with an impaired aortic mechanical function in patients without cardiovascular risk factors and the relation of these changes, if any, to LV deformation and cardiac phenotype. Methods: 141 patients with HCM were recruited and compared to 66 age- and sex-matched healthy subjects as control group. Pulse pressure, aortic strain, stiffness and distensibility were calculated from the aortic diameters measured by M-mode echocardiography and blood pressure obtained by sphygmomanometer. Aortic wall systolic and diastolic velocities were measured using pulsed wave Doppler tissue imaging (DTI). Cardiac assessment included geometric parameters and myocardial deformation (strain and strain rate) and mechanical dyssynchrony. Results: The pulsatile change in the aortic diameter, distensibility and aortic wall systolic velocity (AWS') were significantly decreased and aortic stiffness index was increased in HCM compared to control (P < .001) In HCM AWS' was inversely correlated to age(r = − .32, P < .0001), MWT (r = − .22, P < .008), LVMI (r = − .20, P < .02), E/Ea (r = − .16, P < .03) LVOT gradient (r = − 19, P < .02) and severity of mitral regurg (r = − .18, P < .03) but not to the concealed LV deformation abnormalities or mechanical dyssynchrony. On multivariate analysis, the key determinant of aortic stiffness was LV mass index and LVOT obstruction while the role LV dysfunction in aortic stiffness is not evident in this population. Conclusion: HCM is associated with abnormal aortic mechanical properties. The severity of cardiac

  18. Impact of Endografting on the Thoracic Aortic Anatomy: Comparative Analysis of the Aortic Geometry before and after the Endograft Implantation

    Energy Technology Data Exchange (ETDEWEB)

    Midulla, Marco, E-mail: marco.midulla@chru-lille.fr [University Hospital of Lille, Cardiovascular and Interventional Radiology (France); Moreno, Ramiro, E-mail: ramoroa@gmail.com [Rangueil University Hospital, Department of Radiology (France); Negre-Salvayre, Anne, E-mail: anne.negre-salvayre@inserm.fr [INSERM, UMR 1048, I2MC (France); Nicoud, Franc, E-mail: franck.nicoud@univ-montp2.fr [CNRS, UMR 5149 I3M, CC 051, University Montpellier II (France); Pruvo, Jean Pierre, E-mail: jean-pierre.pruvo@chru-lille.fr [University Hospital of Lille, Cardiovascular and Interventional Radiology (France); Haulon, Stephan, E-mail: stephan.haulon@chru-lille.fr [University Hospital of Lille, Department of Vascular Surgery (France); Rousseau, Hervé, E-mail: rousseau.h@chu-toulouse.fr [Rangueil University Hospital, Department of Radiology (France)

    2013-03-13

    PurposeAlthough the widespread acceptance of thoracic endovascular aortic repair (TEVAR) as a first-line treatment option for a multitude of thoracic aortic diseases, little is known about the consequences of the device implantation on the native aortic anatomy. We propose a comparative analysis of the pre- and postoperative geometry on a clinical series of patients and discuss the potential clinical implicationsMethodsCT pre- and postoperative acquisitions of 30 consecutive patients treated by TEVAR for different pathologies (20 thoracic aortic aneurysms, 6 false aneurysms, 3 penetrating ulcers, 1 traumatic rupture) were used to model the vascular geometry. Pre- and postoperative geometries were compared for each patient by pairing and matching the 3D models. An implantation site was identified, and focal differences were detected and described.ResultsSegmentation of the data sets was successfully performed for all 30 subjects. Geometry differences between the pre- and postoperative meshes were depicted in 23 patients (76 %). Modifications at the upper implantation site were detected in 14 patients (47 %), and among them, the implantation site involved the arch (Z0–3) in 11 (78 %).ConclusionModeling the vascular geometry on the basis of imaging data offers an effective tool to perform patient-specific analysis of the vascular geometry before and after the treatment. Future studies will evaluate the consequences of these changes on the aortic function.

  19. False Belief vs. False Photographs: A Test of Theory of Mind or Working Memory?

    Science.gov (United States)

    Callejas, Alicia; Shulman, Gordon L; Corbetta, Maurizio

    2011-01-01

    Theory of mind (ToM), the ability to reason about other people's thoughts and beliefs, has been traditionally studied in behavioral and neuroimaging experiments by comparing performance in "false belief" and "false photograph" (control) stories. However, some evidence suggests that these stories are not matched in difficulty, complicating the interpretation of results. Here, we more fully evaluated the relative difficulty of comprehending these stories and drawing inferences from them. Subjects read false belief and false photograph stories followed by comprehension questions that probed true ("reality" questions) or false beliefs ("representation" questions) appropriate to the stories. Stories and comprehension questions were read and answered, respectively, more slowly in the false photograph than false belief conditions, indicating their greater difficulty. Interestingly, accuracy on representation questions for false photograph stories was significantly lower than for all other conditions and correlated positively with participants' working memory span scores. These results suggest that drawing representational inferences from false photo stories is particularly difficult and places heavy demands on working memory. Extensive naturalistic practice with ToM reasoning may enable a more flexible and efficient mental representation of false belief stories, resulting in lower memory load requirements. An important implication of these results is that the differential modulation of right temporal-parietal junction (RTPJ) during ToM and "false photo" control conditions may reflect the documented negative correlation of RTPJ activity with working memory load rather than a specialized involvement in ToM processes.

  20. An Important but Forgotten Technique: Aortic Fenestration.

    Science.gov (United States)

    Yalcin, Mihriban; Tayfur, Kaptan Derya; Urkmez, Melih

    2016-10-01

    Aortic fenestration is a technique that treats organ ischemia in descending aortic dissection. Open surgical aortic fenestration is an effective yet uncommonly used and widely forgotten procedure. Here, we describe 2 patients suffering from chronic thoracoabdominal aortic dissection, and we aimed to identify under what circumstances surgical aortic fenestration should be applied, to assess its safety and efficacy. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. 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…

  2. A Study of False-Positive and False-Negative Error Rates in Cartridge Case Comparisons

    Science.gov (United States)

    2014-04-07

    Defense Biometrics and Forensics Office, Assistant Secretary of Defense (Research and Engineering), through the U.S. Department of Energy Contract No...official policies, either expressed or implied, of the Defense Biometrics and Forensics Office, Defense Forensic Science Center, or the U.S...Acknowledgements This work was supported by Defense Biometrics and Forensics Office through the U.S. Department of Energy under Contract No. DE-AC02

  3. Drug testing welfare recipients--false positives, false negatives, unanticipated opportunities.

    Science.gov (United States)

    Pollack, Harold A; Danziger, Sheldon; Jayakody, Rukmalie; Seefeldt, Kristin S

    2002-01-01

    Substance abuse and dependence are among the most common psychiatric disorders among pregnant and parenting women. These disorders among welfare recipients have attracted special concern. Chemical testing has been proposed to identify illicit drug use in this population. This analysis scrutinizes the potential value of drug testing, using recent data from the Women's Employment Study and the National Household Survey of Drug Abuse. One-fifth of recipients reported illicit substance use during the previous year. However, less than 5% satisfied diagnostic screening criteria for illicit drug dependence. Most recipients with psychiatric disorders or alcohol dependence reported no recent illicit drug use, and, thus, would not be detected through chemical tests. Although illicit drug users are rarely dependent, many face barriers to self-sufficiency. Screening and assessment programs should distinguish use from dependence, and should also identify alcohol dependence and psychiatric disorders. States should provide a range of treatment services to address these concerns.

  4. Clinical testing of Belarusian aortic stent graft system

    Directory of Open Access Journals (Sweden)

    А. П. Шкет

    2016-12-01

    Full Text Available Aim. The study looks at the results of clinical testing of the first Belarusian aortic stent graft system developed and manufactured by a team of specialists from RSPC "Cardiology", Minsk, Belarus, and Belarusian Technical University.Methods. The original system of aortic stent graft includes a delivery system and an aortic stent graft itself. It is used in surgical treatment of complicated and common aneurysms of the thoracic aorta, as well as in cases of concomitant thoracic aneurysms and heart pathology to be treated under cardiopulmonary bypass. Clinical testing of the stent graft was carried out according to the requirements of Ministry of Health of the Republic of Belarus on the basis of three different cardiac hospitals of the country. Results. All the three hospitals treated one patient each. The first patient underwent implantation of the stent graft into the descending thoracic aorta, with the thoracic aorta aneurysm isolated and the aortic valve replaced with bioprosthesis. The second patient underwent ascending aorta and aortic valve replacement with a conduit and implantation of aortic stent graft into the descending thoracic aorta. In the third patient the domestic aortic stent graft was implanted into the descending thoracic aorta with isolation of the thoracic aneurysm; aortic valve and ascending aorta were replaced with ‘MedEng' conduit and the aortic arch was also replaced, with the brachiocephalic arteries re-implanted in place. All the patients were followed-up for both early and long-term outcomes for more than 1 year and were examined by using CT angiography in the early postoperative period and after 1 year. Uncomplicated postoperative course was observed in all the patients. There were no complications in the long-term follow-up as well. CT angiography data confirmed good positioning of the stent graft and good isolation of the aneurysm lumen. Preoperative and postoperative СТ data of one patient are presented in the

  5. Early Results of Chimney Technique for Type B Aortic Dissections Extending to the Aortic Arch

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chen [Affiliated Hospital of Nantong University, Department of General Surgery (China); Tang, Hanfei; Qiao, Tong; Liu, Changjian; Zhou, Min, E-mail: 813477618@qq.com [The Affiliated Hospital of Nanjing University Medical School, Department of Vascular Surgery, Nanjing Drum Tower Hospital (China)

    2016-01-15

    ObjectiveTo summarize our early experience gained from the chimney technique for type B aortic dissection (TBAD) extending to the aortic arch and to evaluate the aortic remodeling in the follow-up period.MethodsFrom September 2011 to July 2014, 27 consecutive TBAD patients without adequate proximal landing zones were retrograde analyzed. Chimney stent-grafts were deployed parallel to the main endografts to reserve flow to branch vessels while extending the landing zones. In the follow-up period, aortic remodeling was observed with computed tomography angiography.ResultsThe technical success rate was 100 %, and endografts were deployed in zone 0 (n = 3, 11.1 %), zone 1 (n = 18, 66.7 %), and zone 2 (n = 6, 22.2 %). Immediately, proximal endoleaks were detected in 5 patients (18.5 %). During a mean follow-up period of 17.6 months, computed tomography angiography showed all the aortic stent-grafts and chimney grafts to be patent. Favorable remodeling was observed at the level of maximum descending aorta and left subclavian artery with expansion of true lumen (from 18.4 ± 4.8 to 25 ± 0.86 mm, p < 0.001 and 27.1 ± 0.62 to 28.5 ± 0.37 mm, p < 0.001) and depressurization of false lumen (from 23.7 ± 2.7 to 8.7 ± 3.8 mm, p < 0.001, from 5.3 ± 1.2 to 2.1 ± 2.1 mm, p < 0.001). While at the level of maximum abdominal aorta, suboptimal remodeling of the total aorta (from 24.1 ± 0.4 to 23.6 ± 1.5 mm, p = 0.06) and true lumen (from 13.8 ± 0.6 to 14.5 ± 0.4 mm, p = 0.08) was observed.ConclusionBased on our limited experience, the chimney technique with thoracic endovascular repair is demonstrated to be promising for TBAD extending to the arch with favorable aortic remodeling.

  6. Early and midterm outcomes of thoracic endovascular aortic repair (TEVAR) for acute and chronic complicated type B aortic dissection

    Science.gov (United States)

    Zhang, Min-Hong; Du, Xin; Guo, Wei; Liu, Xiao-Ping; Jia, Xin; Ge, Yang-Yang

    2017-01-01

    Abstract Thoracic endovascular aortic repair (TEVAR) in the current era has been chosen as a dominant and minimally invasive treatment for complicated aorta dissection. This study aimed to assess safety and feasibility of TEVAR in acute and chronic type B aortic dissection. Between January 2011 and December 2013, 85 patients with complicated type B aortic dissection undergoing TEVAR were divided into acute aortic dissection (AAD) (n = 60) group and chronic aortic dissection (CAD) group (n = 25). Computed tomography was used to evaluate postoperative changes in maximal aortic diameter and true and false lumen diameters at 3 levels during a mean follow-up period of 26.4 ± 15.6 months. The technical success rate was 100%. In-hospital and 30-day rates of death were 3.3% in acute group and 0 in chronic group. Postdischarge rates of type I leak, type II leak, and retrograde type A dissection were 6.7%, 5.2%, and 3.4% (acute) and 0%, 4.0%, and 4.0% (chronic), respectively. The maximal aorta diameter remained stable in all the 3 levels in both acute and chronic group. The cumulative freedom from all-cause mortality at 3 years was similar in acute and chronic groups (89.5% vs 95.5%, P = .308). The cumulative freedom from aortic-related mortality was also not significantly different in the acute and chronic groups (92.8% vs 95.2%, P = .531). In the thoracic aorta, TEVAR treatment resulted in a significant increase in true lumen (TL) diameter and decrease in false lumen (FL). However, in the abdominal aorta, TEVAR did not lead to significant change in TL and FL diameters. The rates of complete thrombosis thoracic false lumens were better than that in the abdominal false lumen. TEVAR was a safe and effect therapy for complicated acute and chronic type B dissection with low early and mid-term mortality and morbidity. PMID:28700467

  7. An effective method for controlling false discovery and false nondiscovery rates in genome-scale RNAi screens.

    Science.gov (United States)

    Zhang, Xiaohua Douglas

    2010-10-01

    In most genome-scale RNA interference (RNAi) screens, the ultimate goal is to select siRNAs with a large inhibition or activation effect. The selection of hits typically requires statistical control of 2 errors: false positives and false negatives. Traditional methods of controlling false positives and false negatives do not take into account the important feature in RNAi screens: many small-interfering RNAs (siRNAs) may have very small but real nonzero average effects on the measured response and thus cannot allow us to effectively control false positives and false negatives. To address for deficiencies in the application of traditional approaches in RNAi screening, the author proposes a new method for controlling false positives and false negatives in RNAi high-throughput screens. The false negatives are statistically controlled through a false-negative rate (FNR) or false nondiscovery rate (FNDR). FNR is the proportion of false negatives among all siRNAs examined, whereas FNDR is the proportion of false negatives among declared nonhits. The author also proposes new concepts, q*-value and p*-value, to control FNR and FNDR, respectively. The proposed method should have broad utility for hit selection in which one needs to control both false discovery and false nondiscovery rates in genome-scale RNAi screens in a robust manner.

  8. Abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Lindholt, Jes Sanddal

    2010-01-01

    Although the number of elective operations for abdominal aortic aneurysms (AAA) is increasing, the sex- and age-standardised mortality rate of AAAs continues to rise, especially among men aged 65 years or more. The lethality of ruptured AAA continues to be 80-95%, compared with 5-7% by elective...... inhibit further AAA progression. All 4 existing RCTs point in the same direction, viz. in favour of screening of men aged 65 and above. We found that screening significantly reduced AAA-related mortality by 67% within the first five years (NNT = 352). Restriction of screening to men with previous...... year gained was 157 euro [1,170 DKK] and the cost per QALY at 178 euro [1,326 DKK]. In all, the ethical dilemma of the prophylactic operation, and the limited psychological side effects seem not to outweigh the benefits of screening. Conclusively, we found that offering men aged 65-73 years screening...

  9. False allegation of child abduction.

    Science.gov (United States)

    Canning, Kathleen E; Hilts, Mark A; Muirhead, Yvonne E

    2011-05-01

    Cases in which a child has been falsely reported as missing or abducted can be extremely challenging to the law enforcement agencies responsible for their investigation. In the absence of a witnessed abduction or an obvious crime scene, it is difficult to determine whether a child has actually been abducted or has become a victim of a homicide and a false allegation. The purpose of this study was to examine falsely alleged kidnapping cases and identify successful investigative strategies. Sixty-one adjudicated false allegation cases involving 66 victims were analyzed. The mean age of the victim was 5 years. Victims came from generally unstable, high-risk family situations and were killed primarily by biological parents. Victims were killed because they were unwanted or viewed as an obstacle to a desired goal, or they were victims of abuse or maltreatment that ended in fatality.

  10. Sleep deprivation and false confessions.

    Science.gov (United States)

    Frenda, Steven J; Berkowitz, Shari R; Loftus, Elizabeth F; Fenn, Kimberly M

    2016-02-23

    False confession is a major contributor to the problem of wrongful convictions in the United States. Here, we provide direct evidence linking sleep deprivation and false confessions. In a procedure adapted from Kassin and Kiechel [(1996) Psychol Sci 7(3):125-128], participants completed computer tasks across multiple sessions and repeatedly received warnings that pressing the "Escape" key on their keyboard would cause the loss of study data. In their final session, participants either slept all night in laboratory bedrooms or remained awake all night. In the morning, all participants were asked to sign a statement, which summarized their activities in the laboratory and falsely alleged that they pressed the Escape key during an earlier session. After a single request, the odds of signing were 4.5 times higher for the sleep-deprived participants than for the rested participants. These findings have important implications and highlight the need for further research on factors affecting true and false confessions.

  11. Transcatheter Aortic Heart Valve Thrombosis

    DEFF Research Database (Denmark)

    Hansson, Nicolaj C; Grove, Erik L; Andersen, Henning R;

    2016-01-01

    BACKGROUND: There is increasing focus on transcatheter heart valve (THV) thrombosis. However, there are limited data on incidence, clinical implications and predisposing factors of THV thrombosis following transcatheter aortic valve replacement (TAVR). OBJECTIVES: We assessed the incidence...

  12. Adult thoracic and abdominal aortic

    Directory of Open Access Journals (Sweden)

    Randa O. Kaddah

    2016-06-01

    Conclusion: Aortic COA could be found in any segment of the aorta. Proper identification of the anatomical details and pressure gradient studies are important factors affecting the plan of management.

  13. CONGENITAL QUADRICUSPID AORTIC-VALVE

    NARCIS (Netherlands)

    BROUWER, MHJ; DEGRAAF, JJ; EBELS, T

    1993-01-01

    Two patients with a quadricuspid aortic valve are described, one of them with concomitant juxtaposed coronary orifices facing the right hand facing sinus. The etiology and incidence of this congenital anomaly will be discussed.

  14. Minimally invasive aortic valve replacement

    DEFF Research Database (Denmark)

    Foghsgaard, Signe; Schmidt, Thomas Andersen; Kjaergard, Henrik K

    2009-01-01

    In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy....... The 30-day mortality rate for the 98 patients was zero, although 14 of the 98 mini-sternotomies had to be converted to complete sternotomies intraoperatively due to technical problems. Such conversion doubled the operative time over that of the planned full sternotomies. In the group of patients whose...... is an excellent operation in selected patients, but its true advantages over conventional aortic valve replacement (other than a smaller scar) await evaluation by means of randomized clinical trial. The "extended mini-aortic valve replacement" operation, on the other hand, is a risky procedure that should...

  15. 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.

  16. Technical strategy for the endovascular management of ascending aortic pseudoaneurysm.

    Science.gov (United States)

    Gray, Bruce H; Langan, Eugene M; Manos, Ginger; Bair, Leah; Lysak, Steven Z

    2012-07-01

    We present two cases of ascending aortic pseudoaneurysm exclusion with off-the-shelf aortic stent grafts. The right common carotid artery was used for access to facilitate graft delivery. Control of graft deployment was aided using a compliant right atrial occlusion balloon to lower cardiac output at the time of deployment. Transesophageal echocardiography facilitated the sizing and positioning of the right atrial balloon and was used to survey the heart and ascending aorta on successful exclusion of the pseudoaneurysm. These simple maneuvers made an uncommon procedure straight forward, predictable, and successful. Copyright © 2012 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.

  17. Antibiotic therapy of aortic graft infection: treatment and prevention recommendations.

    Science.gov (United States)

    Hodgkiss-Harlow, Kelley D; Bandyk, Dennis F

    2011-12-01

    Surgical site infection (SSI) after aortic intervention, an uncommon but serious vascular condition, requires patient-specific antibiotic therapy. Effective treatment and prevention requires the vascular surgeon to be cognizant of changing SSI microbiology, advances in antibiotic delivery, and patient characteristics. The majority of aortic graft infections are caused by Gram-positive bacteria, with methicillin-resistant Staphylococcus aureus now the prevalent pathogen. Nasal carriage of methicillin-sensitive or methicillin-resistant S aureus strains, diabetes mellitus, recent hospitalization, a failed arterial reconstruction, and the presence of a groin incision are important SSI risk factors. Overall, the aortic SSI rate is higher than predicted by the Centers for Disease Control and Prevention's National Nosocomial Infections Surveillance risk category system; ranging from 5% after open or endovascular aortic interventions to as high as 10% to 15% after aortofemoral bypass or uni-aortoiliac grafting with femorofemoral bypass. Perioperative measures to reduce S aureus nares and skin colonization, administration of antibiotic prophylaxis, meticulous wound closure/care, and therapy directed to optimize patient host defense regulation mechanisms (eg, temperature, oxygenation, blood sugar) can minimize SSI occurrence. Antibiotic therapy for aortic graft infection should utilize bactericidal drugs that penetrate bacteria biofilms and can be delivered to the surgical site both parenterally and locally in the form of antibiotic-impregnated beads or prosthetic grafts. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. [Anesthesic management of thoracic aortic stent graft deployment using rapid ventricular pacing].

    Science.gov (United States)

    Yamagishi, Akio; Kunisawa, Takayuki; Katsumi, Norifumi; Nagashima, Michio; Takahata, Osamu; Iwasaki, Hiroshi

    2008-08-01

    Controlled hypotension is useful for accurate deployment of an aortic endograft. We describe the use of rapid ventricular pacing during thoracic aortic stent graft deployment. Anesthesia was induced and maintained with intravenous propofol and remifentanil. A pulmonary artery catheter with pacing function was introduced, and rapid ventricular pacing was started before stent graft deployment. Pacing mode was VVI and pacing rate was 120-160 beats min(-1). Aortic pressure and flow decreased immediately and were maintained at low levels during surgical manipulation. After stopping rapid ventricular pacing, heart rate and aortic pressure recovered immediately. Rapid ventricular pacing was performed 4 times, and there were no complications such as entailed arrhythmia. With rapid ventricular pacing maneuver, which is thought to cause a rapid change in cardiac output, continuous cardiac output measurement can be a useful monitor. This procedure has advantages over pharmacologic or other methods of aortic pressure reduction. Rapid ventricular pacing is safe and effective during stent graft positioning and deployment.

  19. [New aspects in aortic valve disease].

    Science.gov (United States)

    Tornos, P

    2001-01-01

    Renewed interest for aortic valve disease has evolved in recent years. Aortic valve replacement has become the second most frequent cause of cardiac surgery, following coronary bypass surgery. In addition, the etiologic and physiopathologic knowledge of this disorder has improved. In the present paper we analyze three aspects of the disease which are, at present, the subject of study and controversy: first, we discuss the possible relationship between degenerative aortic stenosis and atherosclerosis; second, the involvement of the aortic root in cases of bicuspid aortic valve; and third, the surgical indications in asymptomatic patients with either aortic stenosis or regurgitation.

  20. Diagnostic Mammograms Find More Cancers, and More False-Positives

    Science.gov (United States)

    ... prove to be unnecessary, he said. But, Dr. Debra Monticciolo, chair of the American College of Radiology ... surgery, University of Vermont College of Medicine, Burlington; Debra Monticciolo, M.D., professor, radiology, Texas A&M ...

  1. Protein-protein interaction assays: eliminating false positive interactions

    OpenAIRE

    Nguyen, Tuan N.; Goodrich, James A.

    2006-01-01

    Many methods commonly used to identify and characterize interactions between two or more proteins are variations of the immobilized protein-protein interaction assay (for example, glutathione S-transferase (GST) pulldown and coimmunoprecipitation). A potential, and often overlooked, problem with these assays is the possibility that an observed interaction is mediated not by direct contact between proteins, but instead by nucleic acid contaminating the protein preparations. As a negatively cha...

  2. Successful implantation of a second-generation aortic valve in severe aortic regurgitation secondary to a traumatic cusp lesion

    Energy Technology Data Exchange (ETDEWEB)

    Mangieri, Antonio [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); Latib, Azeem, E-mail: info@emocolumbus.it [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); EMO-GVM Centro Cuore Columbus, Milan (Italy); Aurelio, Andrea [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); Figini, Filippo [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); EMO-GVM Centro Cuore Columbus, Milan (Italy); Agricola, Eustachio; Rosa, Isabella; Stella, Stefano; Spagnolo, Pietro; Castiglioni, Alessandro [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); Colombo, Antonio [Cardio-Thoracic-Vascular Department, San Raffaele Institute, Milan (Italy); EMO-GVM Centro Cuore Columbus, Milan (Italy)

    2015-10-15

    A 67-year-old man with a dilated cardiomyopathy and severe aortic regurgitation (AR) secondary to a traumatic cusp lesion was referred to our institution because of progressive worsening of dyspnea. After formal discussion in the heart team, the patient was scheduled for TAVI (transcatheter aortic valve implantation). The pre procedural computed tomography scan revealed a minimum amount of calcium on the aortic valve and low position of coronary ostia. The TAVI procedure was performed with the implantation of a fully retrievable and repositionable aortic valve prosthesis (Direct Flow 29 mm, Direct Flow Medical, Santa Rosa, California) with an excellent result and no paravalvular leak. The TAVI devices designed for the treatment of calcific aortic stenosis have numerous limitations for the treatment of pure AR such as the risk of residual AR, the lack of repositionability and retrievability, and the need for valve- in-valve implantation. We believe that treatment of selected cases of pure AR with the Direct Flow valve is feasible and takes advantage of the retrievability of the prosthesis.

  3. [Central cannulation of the aorta by Seldinger technique in DeBakey type I acute aortic dissection with malperfusion of internal organs].

    Science.gov (United States)

    Barbukhatti, K O; Belash, S A; Kaleda, V I

    Described herein is a case report concerning the use of central cannulation of the aorta by Seldinger technique for DeBakey type I aortic dissection with the involvement of both femoral arteries and the brachiocephalic trunk, as well as with thrombosis of the false lumen from the level of the ascending aorta. This is followed by a brief review discussing the methods of instrumental control of the cannula position in the true lumen of the aorta, as well as peculiarities of using this technique of cannulation in various clinical situations.

  4. 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.

  5. Evolutionary Psychology and False Confession

    Science.gov (United States)

    Bering, Jesse M.; Shackelford, Todd K.

    2005-01-01

    This paper presents comments on Kassin's review, (see record 2005-03019-002) of the psychology of false confessions. The authors note that Kassin's review makes a compelling argument for the need for legal reform in police interrogation practices. Because his work strikes at the heart of the American criminal justice system--its fairness--the…

  6. The Danger of False Dichotomies.

    Science.gov (United States)

    LaBoskey, Vicky Kubler

    1998-01-01

    Responds to an article that examined 10 dichotomies in teacher education (SP 527 128), suggesting that too much time and energy are spent debating false dichotomies and addressing two specific dichotomies (preservice versus inservice and campus versus school site). Recommends that professional educators pool their energy and collaborate (rather…

  7. Transcatheter aortic valve implantation of the direct flow medical aortic valve with minimal or no contrast

    Energy Technology Data Exchange (ETDEWEB)

    Latib, Azeem, E-mail: alatib@gmail.com [Interventional Cardiology Unit, San Raffaele Scientific Institute and EMO-GVM Centro Cuore Columbus, Milan (Italy); Maisano, Francesco; Colombo, Antonio [Interventional Cardiology Unit, San Raffaele Scientific Institute and EMO-GVM Centro Cuore Columbus, Milan (Italy); Klugmann, Silvio [Azienda Ospedaliera Niguarda Ca Granda, Piazza Ospedale Maggiore 3, Milan (Italy); Low, Reginald; Smith, Thomas [University of California Davis, Davis, CA 95616 (United States); Davidson, Charles [Northwestern Memorial Hospital, Chicago, IL 60611 (United States); Harreld, John H. [Clinical Imaging Analytics, Guerneville, CA (United States); Bruschi, Giuseppe; DeMarco, Federico [Azienda Ospedaliera Niguarda Ca Granda, Piazza Ospedale Maggiore 3, Milan (Italy)

    2014-06-15

    The 18F Direct Flow Medical (DFM) THV has conformable sealing rings, which minimizes aortic regurgitation and permits full hemodynamic assessment of valve performance prior to permanent implantation. During the DISCOVER trial, three patients who were at risk for receiving contrast media, two due to severe CKD and one due to a recent hyperthyroid reaction to contrast, underwent DFM implantation under fluoroscopic and transesophageal guidance without aortography during either positioning or to confirm the final position. Valve positioning was based on the optimal angiographic projection as calculated by the pre-procedural multislice CT scan. Precise optimization of valve position was performed to minimize transvalve gradient and aortic regurgitation. Prior to final implantation, transvalve hemodynamics were assessed invasively and by TEE. The post-procedure mean gradients were 7, 10, 11 mm Hg. The final AVA by echo was 1.70, 1.40 and 1.68 cm{sup 2}. Total aortic regurgitation post-procedure was none or trace in all three patients. Total positioning and assessment of valve performance time was 4, 6, and 12 minutes. Contrast was only used to confirm successful percutaneous closure of the femoral access site. The total contrast dose was 5, 8, 12 cc. Baseline eGFR and creatinine was 28, 22, 74 mL/min/1.73 m{sup 2} and 2.35, 2.98, and 1.03 mg/dL, respectively. Renal function was unchanged post-procedure: eGFR = 25, 35, and 96 mL/min/1.73 m{sup 2} and creatinine = 2.58, 1.99, and 1.03 mg/dL, respectively. In conclusion, the DFM THV provides the ability to perform TAVI with minimal or no contrast. The precise and predictable implantation technique can be performed with fluoro and echo guidance.

  8. Traumatic aortic injury score (TRAINS): an easy and simple score for early detection of traumatic aortic injuries in major trauma patients with associated blunt chest trauma.

    Science.gov (United States)

    Mosquera, Victor X; Marini, Milagros; Muñiz, Javier; Asorey-Veiga, Vanesa; Adrio-Nazar, Belen; Boix, Ricardo; Lopez-Perez, José M; Pradas-Montilla, Gonzalo; Cuenca, José J

    2012-09-01

    To develop a risk score based on physical examination and chest X-ray findings to rapidly identify major trauma patients at risk of acute traumatic aortic injury (ATAI). A multicenter retrospective study was conducted with 640 major trauma patients with associated blunt chest trauma classified into ATAI (aortic injury) and NATAI (no aortic injury) groups. The score data set included 76 consecutive ATAI and 304 NATAI patients from a single center, whereas the validation data set included 52 consecutive ATAI and 208 NATAI patients from three independent institutions. Bivariate analysis identified variables potentially influencing the presentation of aortic injury. Confirmed variables by logistic regression were assigned a score according to their corresponding beta coefficient which was rounded to the closest integer value (1-4). Predictors of aortic injury included widened mediastinum, hypotension less than 90 mmHg, long bone fracture, pulmonary contusion, left scapula fracture, hemothorax, and pelvic fracture. Area under receiver operating characteristic curve was 0.96. In the score data set, sensitivity was 93.42 %, specificity 85.85 %, Youden's index 0.79, positive likelihood ratio 6.60, and negative likelihood ratio 0.08. In the validation data set, sensitivity was 92.31 % and specificity 85.1 %. Given the relative infrequency of traumatic aortic injury, which often leads to missed or delayed diagnosis, application of our score has the potential to draw necessary clinical attention to the possibility of aortic injury, thus providing the chance of a prompt specific diagnostic and therapeutic management.

  9. Spontaneous aortic dissection within an infrarenal AAA.

    Science.gov (United States)

    Griffin, Kathryn J; Bailey, Marc A; McAree, Barry; Mekako, Anthony; Berridge, David C; Nicholson, Tony; Scott, D Julian A

    2012-12-01

    Aortic dissection occurring in the infrarenal abdominal aorta is uncommon. We present the case of a patient presenting with an enlarging abdominal aortic aneurysm and concurrent dissection (with associated radiological imaging) and briefly discuss the literature relating to this phenomenon.

  10. Abdominal aortic aneurysm repair - open - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000240.htm Abdominal aortic aneurysm repair - open - discharge To use the sharing features ... References Orandi BJ, Black JH. Open repair of abdominal aortic aneurysms. In: Cameron JL, Cameron AM, eds. Current Surgical ...

  11. Abdominal aortic feminism.

    Science.gov (United States)

    Mortimer, Alice Emily

    2014-11-14

    A 79-year-old woman presented to a private medical practice 2 years previously for an elective ultrasound screening scan. This imaging provided the evidence for a diagnosis of an abdominal aortic aneurysm (AAA) to be made. Despite having a number of recognised risk factors for an AAA, her general practitioner at the time did not follow the guidance set out by the private medical professional, that is, to refer the patient to a vascular specialist to be entered into a surveillance programme and surgically evaluated. The patient became symptomatic with her AAA, was admitted to hospital and found to have a tender, symptomatic, 6 cm leaking AAA. She consented for an emergency open AAA repair within a few hours of being admitted to hospital, despite the 50% perioperative mortality risk. The patient spent 4 days in intensive care where she recovered well. She was discharged after a 12 day hospital stay but unfortunately passed away shortly after her discharge from a previously undiagnosed gastric cancer. 2014 BMJ Publishing Group Ltd.

  12. Thoracic aortopathy in Turner syndrome and the influence of bicuspid aortic valves and blood pressure: a CMR study

    Directory of Open Access Journals (Sweden)

    Hager Alfred

    2010-03-01

    Full Text Available Abstract Background To investigate aortic dimensions in women with Turner syndrome (TS in relation to aortic valve morphology, blood pressure, karyotype, and clinical characteristics. Methods and results A cross sectional study of 102 women with TS (mean age 37.7; 18-62 years examined by cardiovascular magnetic resonance (CMR- successful in 95, echocardiography, and 24-hour ambulatory blood pressure. Aortic diameters were measured by CMR at 8 positions along the thoracic aorta. Twenty-four healthy females were recruited as controls. In TS, aortic dilatation was present at one or more positions in 22 (23%. Aortic diameter in women with TS and bicuspid aortic valve was significantly larger than in TS with tricuspid valves in both the ascending (32.4 ± 6.7 vs. 26.0 ± 4.4 mm; p Conclusions Aortic dilatation was present in 23% of adult TS women, where aortic valve morphology, age and blood pressure were major determinants of the aortic diameter.

  13. [Syphilitic aortic aneurysm. A case report].

    Science.gov (United States)

    Ben Halima, A; Ibn Elhadj, Z; Essmat, W; Léfi, A; Kammoun, I; Zouaoui, W; Marrakchi, S; Chine, S; Gargouri, S; Keskes, H; Kachboura, S

    2006-05-01

    The incidence of tertiary syphilis has declined in recent years owing to the early recognition of the disease and use of antibiotics. As a result, syphilitic aortic aneurysms are rarely encountered nowadays. We report the case of a 65 years old man, who was admitted to our hospital in June 2004 for dyspnea, cough and chest discomfort. On physical examination, blood pressure was 130/80 mmHg with no significant laterality, pulse rate was 70 per minute and there was a decrease of breath sounds over the right lung. Laboratory findings revealed a slight elevation of the erythrocyte sedimentation rate. Serological studies for syphilis showed a positive venereal disease laboratory test (VDRL) at 1/32 and a positive Treponema pallidum hemagglutination test (TPHA) at 1/2560. The chest radiography showed a right para cardiac opacity measuring 16 x 12 cm. Fiber optic bronchoscopy showed an extrinsic compression of the right upper lobar bronchus. Gadolinium-enhanced magnetic resonance angiography and 16 multidetector-row spiral computed aortography showed a huge partially thrombosed saccular aneurysm of the ascending aorta measuring 132 mm in diameter. The circulating lumen measured 53 mm in its largest diameter. This aneurysm involved the innominate artery. There was no other arterial involvement. The patient was given a three week course of intravenous penicillin followed by a successful surgical procedure in September 2004 with ascending aortic replacement and innominate artery reimplantation. This case illustrates well a formerly common, but now extremely rare disease.

  14. Multiple multilayer stents for thoracoabdominal aortic aneurysm: a possible new tool for aortic endovascular surgery

    Directory of Open Access Journals (Sweden)

    Tolva VS

    2012-07-01

    Full Text Available Valerio Stefano Tolva,1,3 Paolo Guy Bianchi,1 Lea Valeria Cireni,1 Alma Lombardo,1 Guido Carlo Keller,1 Gianfranco Parati,2,3 Renato Maria Casana11Surgical Department Istituto Auxologico Italiano IRCCS, Milan, Italy; 2Department of Cardiology, Istituto Auxologico Italiano, Università degli Studi di Milano-Bicocca, Bicocca, Milan, Italy; 3Department of Internal Medicine, San Gerardo Hospital, Università degli Studi di Milano-Bicocca, Bicocca, Milan, ItalyPurpose: Endovascular surgery data are confirming the paramount role of modern endovascular tools for a safe and sure exclusion of thoracoabdominal lesions.Case report: A 57-year-old female presented with severe comorbidity affected by a 58 mm thoracoabdominal aortic aneurysm (TAAA. After patient-informed consent and local Ethical Committee and Italian Public Health Ministry authorization, three multilayer stents were implanted in the thoracoabdominal aortic tract, obtaining at a 20-month computed tomography scan follow up, a complete exclusion of the TAAA, with normal patency of visceral vessels.Conclusion: Multilayer stents can be used in thoracoabdominal aortic aneurysm, with positive results.Keywords: chimney technique, renal artery stenosis, thoracoabdominal aneurysm, vascular complication

  15. Current aortic endografts for the treatment of abdominal aortic aneurysms.

    Science.gov (United States)

    Colvard, Benjamin; Georg, Yannick; Chakfe, Nabil; Swanstrom, Lee

    2016-05-01

    Endovascular Aneurysm Repair is a widely adopted method of treatment for patients with abdominal aortic aneurysms. The minimally invasive approach offered with EVAR has become popular not only among physicians and patients, but in the medical device industry as well. Over the past 25 years the global market for aortic endografts has increased rapidly, resulting in a wide range of devices from various companies. Currently, there are seven endografts approved by the FDA for the treatment of abdominal aortic aneurysms. These devices offer a wide range of designs intended to increase inclusion criteria while decreasing technical complications such as endoleak and migration. Despite advances in device design, secondary interventions and follow-up requirements remain a significant issue. New devices are currently being studied in the U.S. and abroad and may significantly reduce complications and secondary interventions.

  16. The Acute aortic syndrome – what do we know and what should we know?

    DEFF Research Database (Denmark)

    Houlind, Kim Christian

    , complicating the distinction between an IMH and a thrombosed false lumen of an AD. In 2000 Shimizu et al(1) published a series of 96 patients admitted on the diagnosis ”Aortic dissection”. On CT evaluation 51 of these turned out to have an IMH without an intimal tear. Interestingly, this subgroup of patients......Aortic dissection (AD)was first described in 1760. Treatment options have been medical and surgical and are guided by the Stanford and De Bakey classifications based on the location of intimal tears and false lumens. More recently, endovascular treatment options have been suggested. Penetrating....... Intramural hematomas (IMH) are often found on CT-scans in patients with typical aortic pain. They are characterized by the presence of a hematoma in the media , but the absence of flow in the false lumen and the absence of a primary intimal tear. An intimal tear may, however, occur secondary to the IMH...

  17. Management of bicuspid aortic valve with or without involvement of ascending aorta and aortic root.

    Science.gov (United States)

    Neragi-Miandoab, S

    2014-06-01

    Patients with a bicuspid aortic valve (BAV) constitute a heterogeneous population with variable clinical presentation and complications. More than 50% of the patients who require aortic valve replacement have a BAV, a condition that may be associated with dilation of ascending aorta and aortic insufficiency caused by cusp disease or aortic root pathology. Of the potential BAV-related complications, dilation of the aortic root and ascending aorta are among the most serious. The dilation of ascending aorta and aortic root have been the subject of controversy. Whereas some surgeons believe that the dilation of the aorta is caused by the hemodynamic properties of the BAV, others believe that the dilation of the aortic root is secondary to genetic defects associated with the BAV. Management of a BAV should be tailored to each patient's clinical condition. The surgical approach varies from aortic valve replacement to combined aortic valve and root replacement to aortic-valve-sparing root replacement.

  18. Plasma cytokine levels and risks of abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Liao, Mengyang; Liu, Cong-Lin; Lv, Bing-Jie

    2015-01-01

    BACKGROUND: Abdominal aortic aneurysm (AAA) is characterized by inflammatory cell accumulation in AAA lesions that produce inflammatory cytokines and advance its pathogenesis. Peripheral cytokines may predict the degree or risk of AAA. METHODS AND RESULTS: ELISA determined plasma interleukin-6 (IL6......), IL10, IL17A, IFN-γ, and C-reactive protein (CRP) from 476 AAA patients and 200 controls. AAA patients had lower IL6, IFN-γ, IL10, IL17A, and higher CRP than controls. IL10 correlated positively with IFN-γ, IL17A, or IL6, but not CRP in control or AAA populations. IL10 associated negatively...... with systolic blood pressure, whereas CRP associated positively with diastolic blood pressure and body mass index. CRP was an independent AAA risk factor and correlated positively with aortic diameters before and after adjustments for other risk factors. IFN-γ, IL17A, and CRP correlated positively with cross...

  19. Comparison of diagnostic and therapeutic value of transesophageal echocardiography, intravascular ultrasonic imaging, and intraluminal phased-array imaging in aortic dissection with tear in the descending thoracic aorta (type B).

    Science.gov (United States)

    Bartel, Thomas; Eggebrecht, Holger; Müller, Silvana; Gutersohn, Achim; Bonatti, Johannes; Pachinger, Otmar; Erbel, Raimund

    2007-01-15

    Transesophageal echocardiography (TEE) and conventional intravascular ultrasound (IVUS) have limited capabilities in type B aortic dissection. To evaluate its diagnostic value, intraluminal phased-array imaging (IPAI) was compared with IVUS and TEE. In 23 patients with type B aortic dissection, IPAI was tested with respect to its ability to depict true lumen (TL) and false lumen (FL), to localize which abdominal arteries originate from the TL and FL, and to identify all entries and reentries. After the completion of TEE, 2 additional examiners performed angiography and positioned an AcuNav catheter inside the TL. An IVUS catheter was then introduced into the TL by a fourth examiner. All examiners were blinded to one another. Four additional patients with type B aortic dissection developed peripheral malperfusion due to TL collapse. Transvenous IPAI was used to guide emergency fenestration of the intimal flap. TL and FL could be equally well identified by all diagnostic methods. IPAI detected more entries than IVUS (3.0 +/- 1.2 vs 0.8 +/- 0.5, p 90% of the abdominal side branches. In all patients with peripheral malperfusion, successful emergency intimal flap fenestration was safely guided by IPAI. In conclusion, in the detailed diagnostic evaluation of type B aortic dissection, IPAI is superior to IVUS and TEE in detecting communications between the TL and FL. IPAI is also highly useful as a guiding tool for emergency intimal flap fenestration.

  20. Open aortic surgery after thoracic endovascular aortic repair.

    Science.gov (United States)

    Coselli, Joseph S; Spiliotopoulos, Konstantinos; Preventza, Ourania; de la Cruz, Kim I; Amarasekara, Hiruni; Green, Susan Y

    2016-08-01

    In the last decade, thoracic endovascular aortic aneurysm repair (TEVAR) has emerged as an appealing alternative to the traditional open aortic aneurysm repair. This is largely due to generally improved early outcomes associated with TEVAR, including lower perioperative mortality and morbidity. However, it is relatively common for patients who undergo TEVAR to need a secondary intervention. In select circumstances, these secondary interventions are performed as an open procedure. Although it is difficult to assess the rate of open repairs after TEVAR, the rates in large series of TEVAR cases (>300) have ranged from 0.4 to 7.9 %. Major complications of TEVAR that typically necessitates open distal aortic repair (i.e., repair of the descending thoracic or thoracoabdominal aorta) include endoleak (especially type I), aortic fistula, endograft infection, device collapse or migration, and continued expansion of the aneurysm sac. Conversion to open repair of the distal aorta may be either elective (as for many endoleaks) or emergent (as for rupture, retrograde complicated dissection, malperfusion, and endograft infection). In addition, in select patients (e.g., those with a chronic aortic dissection), unrepaired sections of the aorta may progressively dilate, resulting in the need for multiple distal aortic repairs. Open repairs after TEVAR can be broadly classified as full extraction, partial extraction, or full salvage of the stent-graft. Although full and partial stent-graft extraction imply failure of TEVAR, such failure is generally absent in cases where the stent-graft can be fully salvaged. We review the literature regarding open repair after TEVAR and highlight operative strategies.

  1. Outcome Knowledge and False Belief.

    Science.gov (United States)

    Ghrear, Siba E; Birch, Susan A J; Bernstein, Daniel M

    2016-01-01

    Virtually every social interaction involves reasoning about the perspectives of others, or 'theory of mind (ToM).' Previous research suggests that it is difficult to ignore our current knowledge when reasoning about a more naïve perspective (i.e., the curse of knowledge). In this Mini Review, we discuss the implications of the curse of knowledge for certain aspects of ToM. Particularly, we examine how the curse of knowledge influences key measurements of false belief reasoning. In closing, we touch on the need to develop new measurement tools to discern the mechanisms involved in the curse of knowledge and false belief reasoning, and how they develop across the lifespan.

  2. Outcome knowledge and false belief

    Directory of Open Access Journals (Sweden)

    Siba eGhrear

    2016-02-01

    Full Text Available Virtually every social interaction involves reasoning about the perspectives of others, or ‘theory of mind’. Previous research suggests that it is difficult to ignore our current knowledge when reasoning about a more naïve perspective (i.e., the curse of knowledge. In this Mini Review, we discuss the implications of the curse of knowledge for certain aspects of theory of mind. Particularly, we examine how the curse of knowledge influences key measurements of false belief reasoning. In closing, we touch on the need to develop new measurement tools to discern the mechanisms involved in the curse of knowledge and false belief reasoning, and how they develop across the lifespan.

  3. Outcome knowledge and false belief

    OpenAIRE

    Siba eGhrear; Susan eBirch; Daniel eBernstein

    2016-01-01

    Virtually every social interaction involves reasoning about the perspectives of others, or ‘theory of mind’. Previous research suggests that it is difficult to ignore our current knowledge when reasoning about a more naïve perspective (i.e., the curse of knowledge). In this Mini Review, we discuss the implications of the curse of knowledge for certain aspects of theory of mind. Particularly, we examine how the curse of knowledge influences key measurements of false belief reasoning. In closi...

  4. Aortic or Mitral Valve Replacement With the Biocor and Biocor Supra

    Science.gov (United States)

    2016-03-09

    Aortic Valve Insufficiency; Aortic Valve Regurgitation; Aortic Valve Stenosis; Aortic Valve Incompetence; Mitral Valve Insufficiency; Mitral Valve Regurgitation; Mitral Valve Stenosis; Mitral Valve Incompetence

  5. Aortic root replacement with a pulmonary autograft

    NARCIS (Netherlands)

    R.B. Hokken (Raymond)

    1997-01-01

    textabstractAortic valve disease in the pediatric age group is usually a consequence of congenital aortic stenosis, which may be isolated or may be a part of an anomaly of the left ventricular outflow tract or the aortic root. Management of these patients is difficult. Neonates and infants with seve

  6. Pitfalls in Suspected Acute Aortic Syndrome: Impact of Appropriate and If Required Repeated Imaging

    Directory of Open Access Journals (Sweden)

    C. Meier

    2015-01-01

    Full Text Available The incidence of acute aortic syndrome is low, but the spontaneous course is often life-threatening. Adequate ECG-gated imaging is fundamental within the diagnostic workup. We here report a case of a 53-year-old man presenting with atypical chest pain, slight increase of D dimers at admission, and extended diameter of the ascending aorta accompanied by mild aortic regurgitation. Interpretation of an initial contrast-enhanced computed tomography was false negative due to inadequate gating and motion artifacts, thereby judging a tiny contrast signal in the left anterior quadrant of the ascending aorta as a pseudointimal flap. By hazard, cardiac magnetic resonance imaging demonstrated an ulcer-like lesion superior to the aortic root, leading to aortic surgery at the last moment. As sensitivity of imaging is not 100%, this example underlines that second imaging studies might be necessary if the first imaging is negative, but the clinical suspicion still remains high.

  7. Experimental Study and Early Clinical Application Of a Sutureless Aortic Bioprosthesis

    Directory of Open Access Journals (Sweden)

    Walter J. Gomes

    2015-10-01

    Full Text Available ABSTRACT INTRODUCTION: The conventional aortic valve replacement is the treatment of choice for symptomatic severe aortic stenosis. Transcatheter technique is a viable alternative with promising results for inoperable patients. Sutureless bioprostheses have shown benefits in high-risk patients, such as reduction of aortic clamping and cardiopulmonary bypass, decreasing risks and adverse effects. OBJECTIVE: The objective of this study was to experimentally evaluate the implantation of a novel balloon-expandable aortic valve with sutureless bioprosthesis in sheep and report the early clinical application. METHODS: The bioprosthesis is made of a metal frame and bovine pericardium leaflets, encapsulated in a catheter. The animals underwent left thoracotomy and the cardiopulmonary bypass was established. The sutureless bioprosthesis was deployed to the aortic valve, with 1/3 of the structure on the left ventricular face. Cardiopulmonary bypass, aortic clamping and deployment times were recorded. Echocardiograms were performed before, during and after the surgery. The bioprosthesis was initially implanted in an 85 year-old patient with aortic stenosis and high risk for conventional surgery, EuroSCORE 40 and multiple comorbidities. RESULTS: The sutureless bioprosthesis was rapidly deployed (50-170 seconds; average=95 seconds. The aortic clamping time ranged from 6-10 minutes, average of 7 minutes; the mean cardiopulmonary bypass time was 71 minutes. Bioprostheses were properly positioned without perivalvar leak. In the first operated patient the aortic clamp time was 39 minutes and the patient had good postoperative course. CONCLUSION: The deployment of the sutureless bioprosthesis was safe and effective, thereby representing a new alternative to conventional surgery or transcatheter in moderate- to high-risk patients with severe aortic stenosis.

  8. [MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT].

    Science.gov (United States)

    Tabata, Minoru

    2016-03