1,779 research outputs found

    Radiation exposure in cardiac multislice spiral computed tomography (MSCT)

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    Computed tomographic (CT) imaging involves exposure to ionizing radiation, with a consequent potential risk to the patient. Here we review the technical factors that affect the radiation dose in cardiac CT diagnostic procedures, the parameters that are used to measure and compare radiation doses, the magnitude of radiation exposure, and how to efficiently reduce it

    The cerebellar (para)flocculus:A review on its auditory function and a possible role in tinnitus

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    The cerebellum is historically considered to be involved in motor control and motor learning. However, it is also a site of multimodal sensory and sensory-motor integration, implicated in auditory processing. The flocculus and paraflocculus are small lobes of the cerebellum, in humans located in the cerebellopontine angle. The last two decades, both structures have been a subject of interest in hearing loss and tinnitus research. The current review summarizes insights on the auditory function of the (para)flocculus and its contribution to hearing loss and tinnitus. This leads to the hypothesis of a feedback loop between the paraflocculus and the auditory cortex. Disruption of this loop may be instrumental in both maintaining tinnitus and reducing tinnitus. Although the research mostly has been performed in animals, the implications in humans are also discussed. If the (para)flocculus indeed comprises an auditory function and is part of a tinnitus-mechanism, this would potentially open up new treatment options that involve direct intervention at the (para)flocculus

    Clumps into Voids

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    We consider a spherically symmetric distribution of dust and show that it is possible, under general physically reasonable conditions, for an overdensity to evolve to an underdensity (and vice versa). We find the conditions under which this occurs and illustrate it on a class of regular Lemaitre-Tolman-Bondi solutions. The existence of this phenomenon, if verified, would have the result that the topology of density contours, assumed fixed in standard structure formation theories, would have to change and that luminous matter would not trace the dark matter distribution so well.Comment: LaTeX, 17 pages, 4 figures. Submitted to GRG 20/4/200

    The Role of Inflammation in Tinnitus:A Systematic Review and Meta-Analysis

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    Subjective tinnitus is the perception of sound without the presence of an external source. Increasing evidence suggests that tinnitus is associated with inflammation. In this systematic review, the role of inflammation in subjective tinnitus was studied. Nine animal and twenty human studies reporting inflammatory markers in both humans and animals with tinnitus were included. It was established that TNF-α and IL-1β are increased in tinnitus, and that microglia and astrocytes are activated as well. Moreover, platelet activation may also play a role in tinnitus. In addition, we elaborate on mechanisms of inflammation in tinnitus, and discuss potential treatment options targeting inflammatory pathways

    Evolution of European prostate cancer screening protocols and summary of ongoing trials

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    Population-based organised repeated screening for prostate cancer has been found to reduce disease-specific mortality, but with substantial overdiagnosis leading to overtreatment. Although only very few countries have implemented a screening programme on a national level, individual prostate-specific antigen (PSA) testing is common. This opportunistic testing may have little favourable impact, while stressing the side-effects. The classic early detection protocols as were state-of-the-art in the 1990s applied a PSA and digital rectal examination threshold for sextant systematic prostate biopsy, with a fixed interval for re-testing, and limited indication for expectant management. In the three decades since these trials were started, different important improvements have become available in the cascade of screening, indication for biopsy, and treatment. The main developed aspects include: better identification of individuals at risk (using early/baseline PSA, family history, and/or genetic profile), individualised re-testing interval, optimised and individualised starting and stopping age, with gradual invitation at a fixed age rather than invitation of a wider range of age groups, risk stratification for biopsy (using PSA density, risk calculator, magnetic resonance imaging, serum and urine biomarkers, or combinations/sequences), targeted biopsy, transperineal biopsy approach, active surveillance for low-risk prostate cancer, and improved staging of disease. All these developments are suggested to decrease the side-effects of screening, while at least maintaining the advantages, but Level 1 evidence is lacking. The knowledge gained and new developments on early detection are being tested in different prospective screening trials throughout Europe. In addition, the European Union-funded PRostate cancer Awareness and Initiative for Screening in the European Union (PRAISE-U) project will compare and evaluate different screening pilots throughout Europe. Implementation and sustainability will also be addressed. Modern screening approaches may reduce the burden of the second most frequent cause of cancer-related death in European males, while minimising side-effects. Also, less efficacious opportunistic early detection may be indirectly reduced.</p

    An auditory brainstem implant for treatment of unilateral tinnitus:protocol for an interventional pilot study

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    INTRODUCTION: Tinnitus may have a very severe impact on the quality of life. Unfortunately, for many patients, a satisfactory treatment modality is lacking. The auditory brainstem implant (ABI) was originally indicated for hearing restoration in patients with non-functional cochlear nerves, for example, in neurofibromatosis type II. In analogy to a cochlear implant (CI), it has been demonstrated that an ABI may reduce tinnitus as a beneficial side effect. For tinnitus treatment, an ABI may have an advantage over a CI, as cochlear implantation can harm inner ear structures due to its invasiveness, while an ABI is presumed to not damage anatomical structures. This is the first study to implant an ABI to investigate its effect on intractable tinnitus. METHODS AND ANALYSIS: In this pilot study, 10 adults having incapacitating unilateral intractable tinnitus and ipsilateral severe hearing loss will have an ABI implanted. The ABI is switched on 6 weeks after implantation, followed by several fitting sessions aimed at finding an optimal stimulation strategy. The primary outcome will be the change in Tinnitus Functioning Index. Secondary outcomes will be tinnitus burden and quality of life (using Tinnitus Handicap Inventory and Hospital Anxiety and Depression Scale questionnaires), tinnitus characteristics (using Visual Analogue Scale, a tinnitus analysis), safety, audiometric and vestibular function. The end point is set at 1 year after implantation. Follow-up will continue until 5 years after implantation. ETHICS AND DISSEMINATION: The protocol was reviewed and approved by the Institutional Review Board of the University Medical Centre Groningen, The Netherlands (METc 2015/479). The trial is registered at www.clinicialtrials.gov and will be updated if amendments are made. Results of this study will be disseminated in peer-reviewed journals and at scientific conferences. TRIAL REGISTRATION NUMBER: NCT02630589. TRIAL STATUS: Inclusion of first patient in November 2017. Data collection is in progress. Trial is open for further inclusion. The trial ends at 5 years after inclusion of the last patient
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