969 resultados para False-door
Resumo:
The bovine papillomavirus type 2 (BPV-2) involvement in the aetiology of chronic enzootic haematuria associated to bracken fern ingestion has been suggested for a long time. However, a few reports have shown the presence of the BPV-2 in urinary bladder tumors of cattle. The aim of this study was to investigate the presence of the BPV-2 infection in the urinary bladder of cattle with chronic enzootic haematuria in Brazilian cattle herds. Sixty-two urinary bladders were collected from adult cattle in beef herds from the north region of the state of Paraná, Brazil. According to clinical and pathological finds the specimens were distributed in three groups: the group A was constituted by 22 urinary bladders with macroscopic lesions collected at necropsy of cattle with clinical signs of chronic enzootic haematuria; the group B by 30 urinary bladders with macroscopic lesions collected in a slaughterhouse of cows coming from bracken fern-endemic geographical region; and the group C (control) by 10 urinary bladders without macroscopic lesions collected from asymptomatic cattle in a bracken fern-free geographical region. By a semi-nested polymerase chain reaction (PCR) assay, with an internal control, a fragment of the BPV-2 L1 gene with 386 bp length was amplified in 36 (58%) urinary bladder. The rate of BPV-2 positive urinary bladders was 50% (11/22) for group A, 80% (24/30) for group B, and 10% (1/10) for group C (control). The rate of the positive results found in groups A and B that included urinary bladder samples with macroscopic lesions was 67% (35/52) and the detection of the BPV-2 in both groups was significantly higher (P < 0.05) than in the control group. RFLP with Rsa I and Hae III enzymes evaluated the specificity of the BPV-2 amplicons. The PCR internal control that amplified a 626 bp fragment of the ND5 gene of the bovine mitochondrial genome was amplified in all analyzed samples and excluded false-negatives or invalid results in the semi-nested PCR. These results suggest the BPV-2 involvement in the chronic enzootic haematuria aetiology and open the perspective of the development of new strategies for the control of this disease that is the major cause of economical losses in beef herds from many Brazilian geographical regions.
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Mutations in the GJB2 gene encoding the gap junction protein connexin 26 are responsible for up to 30% of all cases of autosomal recessive nonsyndromic hearing impairment (HI) with prelingual onset in most populations. The corresponding locus DFNB1, located on chromosome 13q11-q12, is also affected by three distinct deletions. These deletions extended distally to GJB2, which remains intact. We report a novel large deletion in DFNB1 observed in a patient presenting profound prelingual HI. This deletion was observed in trans to a GJB2 mutated allele carrying the p.Val84Met (V84M) mutation and was shown to be associated with hearing loss. The deletion caused a false homozygosity of V84M in the proband. Quantification of alleles by quantitative fluorescent multiplex PCR (QFM-PCR) enabled us to study the breakpoints of the deletion. The deleted segment extended through at least 920kb and removed the three connexin genes GJA3, GJB2 and GJB6. The distal breakpoint inside intron 2 of CRYL1 gene differed from the breakpoints of the known DFNB1 deletions. This case highlights the importance of screening for large deletions in molecular studies of GJB2.
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QUESTIONS UNDER STUDY: Our aim was to identify the barriers young men face to consult a health professional when they encounter sexual dysfunctions and where they turn to, if so, for answers. METHODS: We conducted an exploratory qualitative research including 12 young men aged 16-20 years old seen in two focus groups. Discussions were triggered through vignettes about sexual dysfunction. RESULTS: Young men preferred not to talk about sexual dysfunction problems with anyone and to solve them alone as it is considered an intimate and embarrassing subject which can negatively impact their masculinity. Confidentiality appeared to be the most important criterion in disclosing an intimate subject to a health professional. Participants raised the problem of males' accessibility to services and lack of reason to consult. Two criteria to address the problem were if it was long-lasting or considered as physical. The Internet was unanimously considered as an initial solution to solve a problem, which could guide them to a face-to-face consultation if necessary. CONCLUSIONS: Results suggest that Internet-based tools should be developed to become an easy access door to sexual health services for young men. Wherever they consult and for whatever problem, sexual health must be on the agenda.
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Small mammals are found naturally infected by Schistosoma mansoni, becoming a confounding factor for control programs of schistosomiasis in endemic areas. The aims of this study were: to investigate the infection rates by S. mansoni on the water-rat Nectomys squamipes during four years in endemic areas of Sumidouro, state of Rio de Janeiro, using mark-recapture technique; to compare two diagnostic methods for schistosomiasis; and to evaluate the effects of the chemotherapy in the human infected population on the rodent infection rates. The rodent infection rates of S. mansoni increased when rodent population sizes were lower. Coprology and serology results presented the same trends along time and were correlated. Serology could detect recent infection, including the false negatives in the coprology. The chemotherapy in the humans could not interrupt the rodent infection. Rodents can increase the schistosomiaisis transmission where it already exists, they probably maintain the transmission cycle in the nature and can be considered as biological indicators of the transmission sites of this parasite since they are highly susceptible to infection. The water-rats may present different levels of importance in the transmission dynamics of S. mansoni infection cycle for each area, and can be considered important wild-reservoirs of this human disease.
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Introduction: Coronary magnetic resonance angiography (MRA) is a medical imaging technique that involves collecting data from consecutive heartbeats, always at the same time in the cardiac cycle, in order to minimize heart motion artifacts. This technique relies on the assumption that coronary arteries always follow the same trajectory from heartbeat to heartbeat. Until now, choosing the acquisition window in the cardiac cycle was based exclusively on the position of minimal coronary motion. The goal of this study was to test the hypothesis that there are time intervals during the cardiac cycle when coronary beat-to-beat repositioning is optimal. The repositioning uncertainty values in these time intervals were then compared with the intervals of low coronary motion in order to propose an optimal acquisition window for coronary MRA. Methods: Cine breath-hold x-ray angiograms with synchronous ECG were collected from 11 patients who underwent elective routine diagnostic coronarography. Twenty-three bifurcations of the left coronary artery were selected as markers to evaluate repositioning uncertainty and velocity during cardiac cycle. Each bifurcation was tracked by two observers, with the help of a user-assisted algorithm implemented in Matlab (The Mathworks, Natick, MA, USA) that compared the trajectories of the markers coming from consecutive heartbeats and computed the coronary repositioning uncertainty with steps of 50ms until 650ms after the R-wave. Repositioning uncertainty was defined as the diameter of the smallest circle encompassing the points to be compared at the same time after the R-wave. Student's t-tests with a false discovery rate (FDR, q=0.1) correction for multiple comparison were applied to see whether coronary repositioning and velocity vary statistically during cardiac cycle. Bland-Altman plots and linear regression were used to assess intra- and inter-observer agreement. Results: The analysis of left coronary artery beat-to-beat repositioning uncertainty shows a tendency to have better repositioning in mid systole (less than 0.84±0.58mm) and mid diastole (less than 0.89±0.6mm) than in the rest of the cardiac cycle (highest value at 50ms=1.35±0.64mm). According to Student's t-tests with FDR correction for multiple comparison (q=0.1), two intervals, in mid systole (150-200ms) and mid diastole (550-600ms), provide statistically better repositioning in comparison with the early systole and the early diastole. Coronary velocity analysis reveals that left coronary artery moves more slowly in end systole (14.35±11.35mm/s at 225ms) and mid diastole (11.78±11.62mm/s at 625ms) than in the rest of the cardiac cycle (highest value at 25ms: 55.96±22.34mm/s). This was confirmed by Student's t-tests with FDR correction for multiple comparison (q=0.1, FDR-corrected p-value=0.054): coronary velocity values at 225, 575 and 625ms are not much different between them but they are statistically inferior to all others. Bland-Altman plots and linear regression show that intra-observer agreement (y=0.97x+0.02 with R²=0.93 at 150ms) is better than inter-observer (y=0.8x+0.11 with R²=0.67 at 150ms). Discussion: The present study has demonstrated that there are two time intervals in the cardiac cycle, one in mid systole and one in mid diastole, where left coronary artery repositioning uncertainty reaches points of local minima. It has also been calculated that the velocity is the lowest in end systole and mid diastole. Since systole is less influenced by heart rate variability than diastole, it was finally proposed to test an acquisition window between 150 and 200ms after the R-wave.
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Reconstructive procedures after resection of nasal basal cell carcinoma (BCC) vary depending on the subunit involved. The aim of the present study was to assess the influence of the location of the BCC on the rate of incomplete excisions, so we made a retrospective analysis of all nasal BCC excised at our hospital between 2002 and 2005. The incomplete excision rate was 24/148 (16%). More incomplete excision occurred on the alae (n=13) when compared to the dorsum (n=2) of the nose (p<0.05). Eight two-staged procedures resulted in incomplete resection, whereas 9 (6%) frozen section analyses were false-negative. BCC were most likely to be incompletely excised on the nasal tip and alae, and both subunits required more elaborate reconstructions. This, however, was not the result of poor estimation of the extent of the tumour and reluctance to excise more challenging areas widely for reconstruction, but to the method chosen to eradicate the tumour.
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Quintessence: L'impact du dépistage sur la mortalité du cancer du sein est avéré. Il baisse, indépendamment de la qualité du dépistage, en raison des importants progrès thérapeutiques des 20 dernières années.Les programmes de dépistage ont contribué à sensibiliser à la détection précoce, à améliorer la qualité de la mammographie et la prise en charge du cancer mammaire. Ces bénéfices s'étendent au-delà du dépistage et conduisent à sous-estimer l'effet du dépistage sur la mortalité.Les risques et les bénéfices du dépistage sont plus complexes à quantifier dans les programmes que dans les essais randomisés ; le recours à des méthodes appropriées et rigoureuses est nécessaire.Les faux-positifs et le surdiagnostic liés au dépistage n'ont pas diminué, augmentant le rapport risque/bénéfice de la mammographie.
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Background. The use of hospital discharge administrative data (HDAD) has been recommended for automating, improving, even substituting, population-based cancer registries. The frequency of false positive and false negative cases recommends local validation. Methods. The aim of this study was to detect newly diagnosed, false positive and false negative cases of cancer from hospital discharge claims, using four Spanish population-based cancer registries as the gold standard. Prostate cancer was used as a case study. Results. A total of 2286 incident cases of prostate cancer registered in 2000 were used for validation. In the most sensitive algorithm (that using five diagnostic codes), estimates for Sensitivity ranged from 14.5% (CI95% 10.3-19.6) to 45.7% (CI95% 41.4-50.1). In the most predictive algorithm (that using five diagnostic and five surgical codes) Positive Predictive Value estimates ranged from 55.9% (CI95% 42.4-68.8) to 74.3% (CI95% 67.0-80.6). The most frequent reason for false positive cases was the number of prevalent cases inadequately considered as newly diagnosed cancers, ranging from 61.1% to 82.3% of false positive cases. The most frequent reason for false negative cases was related to the number of cases not attended in hospital settings. In this case, figures ranged from 34.4% to 69.7% of false negative cases, in the most predictive algorithm. Conclusions. HDAD might be a helpful tool for cancer registries to reach their goals. The findings suggest that, for automating cancer registries, algorithms combining diagnoses and procedures are the best option. However, for cancer surveillance purposes, in those cancers like prostate cancer in which care is not only hospital-based, combining inpatient and outpatient information will be required.
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La migració internacional contemporània és integrada en un procés d'interconnexió global definit per les revolucions del transport i de les tecnologies de la informació i la comunicació. Una de les conseqüències d'aquesta interconnexió global és que les persones migrants tenen més capacitat per a processar informació tant abans com després de marxar. Aquests canvis podrien tenir implicacions inesperades per a la migració contemporània pel que fa a la capacitat de les persones migrants per a prendre decisions més informades, la reducció de la incertesa en contextos migratoris, el desdibuixament del concepte de distància o la decisió d'emigrar cap a llocs més llunyans. Aquesta recerca és important, ja que la manca de coneixement sobre aquesta qüestió podria contribuir a fer augmentar la distància entre els objectius de les polítiques de migració i els seus resultats. El paper que tenen els agents de la informació en els contextos migratoris també podria canviar. En aquest escenari, perquè les polítiques de migració siguin més efectives, s'haurà de tenir en compte la major capacitat de la població migrant de processar la informació i les fonts d'informació en què es confia. Aquest article demostra que l'equació més informació equival a més ben informat no es compleix sempre. Fins i tot en l'era de la informació, les fonts no fiables, les expectatives falses, la sobreinformació i els rumors encara són presents en els contextos migratoris. Tanmateix, defensem l'argument que aquests efectes no volguts es podrien reduir complint quatre requisits de la informació fiable: que sigui exhaustiva, que sigui rellevant, que s'hi confiï i que sigui actualitzada.
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A new oligochromatographic assay, Speed-Oligo Novel Influenza A H1N1, was designed and optimized for the specific detection of the 2009 influenza A H1N1 virus. The assay is based on a PCR method coupled to detection of PCR products by means of a dipstick device. The target sequence is a 103-bp fragment within the hemagglutinin gene. The analytical sensitivity of the new assay was measured with serial dilutions of a plasmid that contained the target sequence, and we determined that down to one copy per reaction of the plasmid was reliably detected. Diagnostic performance was assessed with 103 RNAs from suspected cases (40 positive and 63 negative results) previously analyzed with a reference real-time PCR technique. All positive cases were confirmed, and no false-positive results were detected with the new assay. No cross-reactions were observed when other viral strains or clinical samples with other respiratory viruses were tested. According to these results, this new assay has 100% sensitivity and specificity. The turnaround time for the whole procedure was 140 min. The assay may be especially useful for the specific detection of 2009 H1N1 virus in laboratories not equipped with real-time PCR instruments
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Observations in daily practice are sometimes registered as positive values larger then a given threshold α. The sample space is in this case the interval (α,+∞), α & 0, which can be structured as a real Euclidean space in different ways. This fact opens the door to alternative statistical models depending not only on the assumed distribution function, but also on the metric which is considered as appropriate, i.e. the way differences are measured, and thus variability
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The aim of this study was to determine the impact of the learning curve on the diagnostic performances of CT colonography. Two blinded teams, each having a radiologist and gastroenterologist, prospectively examined 50 patients using helical CT scan followed by colonoscopy. Intermediate data evaluation was performed after 24 data sets (group 1) and compared with data from 26 subsequent patients (group 2). Parameters evaluated included sensitivity, specificity, false-positive and false-negative findings, time of data acquisition and interpretation. Using colonoscopy as the gold standard, sensitivity for CT colonography was for lesions >5 mm 63% for both teams for group 1 patients; for group 2 patients sensitivity was 45% for team 1 and 64% for team 2. Specificity per patients was for patient group 1 42% for team 1 and 58% for team 2; for patient group 2 it was 79% for both teams ( p=0.04 for team 1; p=0.2 for team 2). Comparing group 1 with group 2, the number of false-positive findings decreased significantly ( p=0.02). Furthermore, the mean time of data evaluation decreased from 45 to 17 min ( p=0.002) and the mean time of data acquisition from 19 to 17 min. With increasing experience, specificity and the time required for data interpretation improved and false positives decreased. There was no significant change of sensitivity, false-negative findings and time of data acquisition. A minimum experience of the readers is required for data interpretation of CT colonography.
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Detecting changes between images of the same scene taken at different times is of great interest for monitoring and understanding the environment. It is widely used for on-land application but suffers from different constraints. Unfortunately, Change detection algorithms require highly accurate geometric and photometric registration. This requirement has precluded their use in underwater imagery in the past. In this paper, the change detection techniques available nowadays for on-land application were analyzed and a method to automatically detect the changes in sequences of underwater images is proposed. Target application scenarios are habitat restoration sites, or area monitoring after sudden impacts from hurricanes or ship groundings. The method is based on the creation of a 3D terrain model from one image sequence over an area of interest. This model allows for synthesizing textured views that correspond to the same viewpoints of a second image sequence. The generated views are photometrically matched and corrected against the corresponding frames from the second sequence. Standard change detection techniques are then applied to find areas of difference. Additionally, the paper shows that it is possible to detect false positives, resulting from non-rigid objects, by applying the same change detection method to the first sequence exclusively. The developed method was able to correctly find the changes between two challenging sequences of images from a coral reef taken one year apart and acquired with two different cameras
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Interpretability and power of genome-wide association studies can be increased by imputing unobserved genotypes, using a reference panel of individuals genotyped at higher marker density. For many markers, genotypes cannot be imputed with complete certainty, and the uncertainty needs to be taken into account when testing for association with a given phenotype. In this paper, we compare currently available methods for testing association between uncertain genotypes and quantitative traits. We show that some previously described methods offer poor control of the false-positive rate (FPR), and that satisfactory performance of these methods is obtained only by using ad hoc filtering rules or by using a harsh transformation of the trait under study. We propose new methods that are based on exact maximum likelihood estimation and use a mixture model to accommodate nonnormal trait distributions when necessary. The new methods adequately control the FPR and also have equal or better power compared to all previously described methods. We provide a fast software implementation of all the methods studied here; our new method requires computation time of less than one computer-day for a typical genome-wide scan, with 2.5 M single nucleotide polymorphisms and 5000 individuals.