721 research outputs found
Recommended from our members
Magnetic Resonance Lymphangiography: Establishing Normal.
BACKGROUND: Despite an increased interest in visualising the lymphatic vessels (lymphatics) with Magnetic Resonance Lymphangiography (MRL), there remains little literature describing their appearance in non-lymphoedematous individuals. To determine lymphatic abnormalities, an understanding of how healthy lymphatics appear and behave needs to be established. In this study, MRL of individuals without a history of lymphatic disease was therefore performed. METHODS: A total of 25 individuals (15 female) underwent MRL of their lower limbs using a 3.0T Philips MRI scanner. The first 9 cases were recruited to establish the concentration of Gadolinium-based contrast agent (GBCA) to administer, with the remainder imaged pre- and post-inter-digital forefoot GBCA injections at the optimised dose. Outcomes including lymphatic vessel diameter, tortuosity and the frequency of drainage via particular drainage routes were recorded. RESULTS: Healthy lymphatics following the anteromedial pathway were routinely observed in post-contrast T1 weighted images (average tortuosity = 1.09 ±0.03), with an average of 2.16 ± 0.93 lymphatic vessels, of diameter 2.47 ± 0.50 mm, crossing the anterior ankle. In six limbs, vessels following the anterolateral pathways were observed. No vessels traversing the posterior of the legs were seen. In a subset of ten vessels lymphatic signal, measured at the ankle, peaked 29:50 ± 09:29 mm:ss after GBCA administration. No lymphatic vessels were observed in T2 weighted images. CONCLUSIONS: Contrast-enhanced MRL reliably depicts the lymphatics in the legs of healthy controls. Following inter-digital contrast injection, anteromedial drainage appears dominant. Quantitative measures related to lymphatic vessel size, tortuosity and drainage rate are readily obtainable, and could be beneficial for detecting even subtle lymphatic impairment
Socio-economic variation in CT scanning in Northern England, 1990-2002
<p>Abstract</p> <p>Background</p> <p>Socio-economic status is known to influence health throughout life. In childhood, studies have shown increased injury rates in more deprived settings. Socio-economic status may therefore be related to rates of certain medical procedures, such as computed tomography (CT) scans. This study aimed to assess socio-economic variation among young people having CT scans in Northern England between 1990 and 2002 inclusive.</p> <p>Methods</p> <p>Electronic data were obtained from Radiology Information Systems of all nine National Health Service hospital Trusts in the region. CT scan data, including sex, date of scan, age at scan, number and type of scans were assessed in relation to quintiles of Townsend deprivation scores, obtained from linkage of postcodes with census data, using Ï<sup>2 </sup>tests and Spearman rank correlations.</p> <p>Results</p> <p>During the study period, 39,676 scans were recorded on 21,089 patients, with 38,007 scans and 19,485 patients (11344 male and 8132 female) linkable to Townsend scores. The overall distributions of both scans and patients by quintile of Townsend deprivation scores were significantly different to the distributions of Townsend scores from the census wards included in the study (p < 0.0001). There was a significant association between type of scan and deprivation quintile (p < 0.0001), primarily due to the higher proportions of head scans in the three most deprived quintiles, and slightly higher proportions of chest scans and abdomen and pelvis scans in the least deprived groups. There was also a significant association (p < 0.0001) between the patient's age at the time of the CT scan and Townsend deprivation quintiles, with slightly increasing proportions of younger children with increasing deprivation. A similar association with age (p < 0.0001) was seen when restricting the data to include only the first scan of each patient. The number of scans per patient was also associated with Townsend deprivation quintiles (p = 0.014).</p> <p>Conclusions</p> <p>Social inequalities exist in the numbers of young people undergoing CT scans with those from deprived areas more likely to do so. This may reflect the rates of injuries in these individuals and implies that certain groups within the population may receive higher radiation doses than others due to medical procedures.</p
A âquiet revolutionâ? The impact of Training Schools on initial teacher training partnerships
This paper discusses the impact on initial teacher training of a new policy initiative in England: the introduction of Training Schools. First, the Training School project is set in context by exploring the evolution of a partnership approach to initial teacher training in England. Ways in which Training Schools represent a break with established practice are considered together with their implications for the dominant mode of partnership led by higher education institutions (HEIs). The capacity of Training Schools to achieve their own policy objectives is examined, especially their efficacy as a strategy for managing innovation and the dissemination of innovation. The paper
ends by focusing on a particular Training School project which has adopted an unusual approach to its work and enquires whether this alternative approach could offer a more profitable way forward. During the course of the paper, five different models of partnership are considered:
collaborative, complementary, HEI-led, school-led and partnership within a partnership
Rituximab for maintenance of remission in ANCA-associated vasculitis: expert consensus guidelinesâExecutive summary
[This is the executive summary of Rituximab for maintenance of remission in ANCA-associated vasculitis: expert consensus guidelines: full guideline, doi: 10.1093/rheumatology/kez640
Rituximab for maintenance of remission in ANCA-associated vasculitis: expert consensus guidelines
A 2017 Horizon Scan of Emerging Issues for Global Conservation and Biological Diversity
We present the results of our eighth annual horizon scan of emerging issues likely to affect global biological diversity, the environment, and conservation efforts in the future. The potential effects of these novel issues might not yet be fully recognized or understood by the global conservation community, and the issues can be regarded as both opportunities and risks. A diverse international team with collective expertise in horizon scanning, science communication, and conservation research, practice, and policy reviewed 100 potential issues and identified 15 that qualified as emerging, with potential substantial global effects. These issues include new developments in energy storage and fuel production, sand extraction, potential solutions to combat coral bleaching and invasive marine species, and blockchain technology.Cambridge Conservation Initiative, funded by the Natural Environment Research Council and the Royal Society for the Protection of Birds, Arcadia, Natural Environment Research Council (Grant ID: NE/N014472/1
Mutations in linker for activation of TÂ cells (LAT) lead to a novel form of severe combined immunodeficiency
BACKGROUND: Signaling through the T-cell receptor (TCR) is critical for T-cell development and function. Linker for activation of T cells (LAT) is a transmembrane adaptor signaling molecule that is part of the TCR complex and essential for T-cell development, as demonstrated by LAT-deficient mice, which show a complete lack of peripheral T cells. OBJECTIVE: We describe a pedigree affected by a severe combined immunodeficiency phenotype with absent T cells and normal B-cell and natural killer cell numbers. A novel homozygous frameshift mutation in the gene encoding for LAT was identified in this kindred. METHODS: Genetic, molecular, and functional analyses were used to identify and characterize the LAT defect. Clinical and immunologic analysis of patients was also performed and reported. RESULTS: Homozygosity mapping was used to identify potential defective genes. Sanger sequencing of the LAT gene showed a mutation that resulted in a premature stop codon and protein truncation leading to complete loss of function and loss of expression of LAT in the affected family members. We also demonstrate loss of LAT expression and lack of TCR signaling restoration in LAT-deficient cell lines reconstituted with a synthetic LAT gene bearing this severe combined immunodeficiency mutation. CONCLUSION: For the first time, the results of this study show that inherited LAT deficiency should be considered in patients with combined immunodeficiency with T-cell abnormalities
Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans
BACKGROUND: It is estimated that 60 million computed tomography (CT) scans were performed during 2006, with approximately 11% of those performed on children age 0â15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice. METHODS: The dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm(3 )ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA) was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume. RESULTS: The use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts. CONCLUSION: Images in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans
Physics, Astrophysics and Cosmology with Gravitational Waves
Gravitational wave detectors are already operating at interesting sensitivity
levels, and they have an upgrade path that should result in secure detections
by 2014. We review the physics of gravitational waves, how they interact with
detectors (bars and interferometers), and how these detectors operate. We study
the most likely sources of gravitational waves and review the data analysis
methods that are used to extract their signals from detector noise. Then we
consider the consequences of gravitational wave detections and observations for
physics, astrophysics, and cosmology.Comment: 137 pages, 16 figures, Published version
<http://www.livingreviews.org/lrr-2009-2
Trends and patterns in the use of computed tomography in children and young adults in Catalonia â results from the EPI-CT study
- âŠ