36 research outputs found

    In vivo quantification of metabolic activity in aortic aneurysms using PET

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    Objective: To investigate the role of hybrid 18F-FDG PET/CT as a potential risk-stratification tool of aneurysm expansion by measuring metabolic activity on PET and textural analysis on CT in abdominal aortic aneurysm (AAA). Histological markers of AAA wall inflammatory cell infiltrate and enzymatic degradation have been associated with increased 18F-Fluorodeoxyglucose (18F-FDG)-Positron Emission Tomography /Computed Tomography (PET/CT) uptake. Methods: Fifty patients with asymptomatic infrarenal AAA enrolled under surveillance at one of our institutions underwent 18F-FDG-PET/CT. Seventeen subjects were investigated for increased glucolysis in the AAA wall and optimal circulation imaging time for 18F-FDG. In 25 subjects the relationship between aneurysm metabolic activity and expansion was explored. Forty subjects had AAA CT textural analysis (CTTA) parameters performed on the CT component of PET/CT and were studied in relation to aneurysm expansion. Twenty-four subjects had circulating biomarkers analysed. Whole vessel assessment, region of interest analysis and the role of correcting for background blood pool activity were explored. Results: Thirteen of seventeen subjects investigated for increased 18F-FDG uptake had an AAA wall SUVmax > 2.5. In 17 subjects assessed for optimal circulation imaging time for 18F-FDG, no significant advantage in imaging at 3h over 1h after 18F-FDG injection was observed. 18F-FDG uptake correlated inversely with future AAA expansion in the preliminary group of 25 patients and in 40 subjects who also had CTTA. In subjects who had CTTA, coarse texture showed an inverse association with 18F-FDG uptake and medium coarse texture correlated with future AAA expansion. In 24 AAA patients who had serum biomarker assays, significantly higher levels of high sensitivity matrix metalloproteinase-9 (hsMMP-9) and hsMMP-2 compared to healthy controls were found. There was no correlation between AAA 18F-FDG uptake and levels of hsMMP-9, hsMMP-2, hs-interferon-γ and hs-C-reactive protein. Conclusions: In-vivo 18F-FDG PET/CT data indicated that small AAA show increased glucose metabolism. Relationships between AAA 18F-FDG uptake, CTTA and future expansion were identified. AAA18F-FDG PET/CT shows potential to identify subjects at risk of significant expansion. AAA metabolism may not relate to serum levels of certain inflammatory biomarkers

    The conundrum of iron in multiple sclerosis – time for an individualised approach

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    Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

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    The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

    Phosphine-Borane complexes: In situ deprotection and application as ligands in the Rh- or Pd-Catalysed hydroformylation reaction

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    Triarylphosphine-borane complexes are directly useful in the Rh-catalysed hydroformylation reaction of 1-octene (or Pdcatalysed hydroformylation of 1-pentene). Mild reaction conditions provide similar yields and selectivities of the anticipated aldehyde products to reactions making use of the corresponding free phosphines as ligands. The mono- or bidentate P-B adducts undergo in situ CO-mediated deprotection the produce the free phosphine ligands. The results demonstrate that phosphine-borane complexes may be directly applied to carbonylation reactions without a prior deprotection step, with little to no change in the reaction outcome

    Temporal and sex-specific variation in growth rates of Marabou Stork Leptoptilos crumeniferus chicks

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    The nesting success of Marabou StorksLeptoptilos crumeniferus breeding in north-eastern Swaziland is closely associated with rainfall, with nests started late in the season exposed to higher rainfall and showing lower  success. This may be related to lower food intake and slower growth of the chicks. This study set out to determine whether hatching date and sequence of laying affected the growth rate of chicks. Chicks were also sexed, as Marabou Storks show sexual size dimorphism—males are on average 20% larger—and this trait is often associated with differing patterns of growth between sexes. Nestlings were measured weekly from hatching until they either died or fledged. Nestling development is  described in detail and photographs of differentaged chicks are presented. The nestling period was significantly shorter for female chicks, at 94 d, than for male chicks at 104 d. Male and female chicks differed in growth rate and asymptote for both mass and wing length. Unusually, females showed higher instantaneous growth rates for much of the nestling period. Chicks surpassed adult mass before fledging. Date of hatching had an effect on growth rates, with chicks at late nests having slower growth, consistent with a decline in food availability. Marabou Storks appear to be slower growing than expected for the Ciconiidae, the taxonomic family to which they belong. OSTRICH 2010, 81(2): 85–9

    Análise das complicações tardias em operações anorretais: experiência de um serviço de referência em coloproctologia Analysis of late complications of anorectal procedures: experience of a referral coloproctology unit

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    INTRODUÇÃO: as operações anorretais correspondem a 80% do movimento do coloproctologista. O índice de complicações tardias após estas operações é indefinido, e varia de acordo com o tipo de operação e serviço onde estas são realizadas. OBJETIVO: estabelecer a taxa de complicações tardias decorrentes das operações anorretais e fatores de risco que pudessem estar associados a estas complicações. MÉTODO: estudo retrospectivo (série de casos) dos pacientes submetidos a operações anorretais entre janeiro de 2007 e julho de 2009. Variáveis estudadas: sexo, idade, operação, sistema de saúde, técnica de anestesia, complicações tardias, além da taxa de reoperações realizadas. RESULTADOS: foram avaliados 430 pacientes (234 mulheres - 54,4%), submetidos a 453 operações anorretais. A hemorroidectomia foi o mais freqüente procedimento realizado: 50,3% das operações. Encontrou-se 102 complicações tardias pós-operatórias, representando 22,52% dos casos. A fissura anal residual foi a complicação mais freqüente (54%/ n=55). Somente 38 pacientes necessitaram de reintervenção cirúrgica (8,83%). Não houve diferença significativa em relação ao sexo, idade, sistema de saúde e ao tipo de operação realizada com as complicações encontradas. CONCLUSÕES: a taxa de complicações tardias foi de 22,52%, com reintervenções cirúrgicas em 8,83% dos pacientes. Não houve fator de risco para complicações identificado nesta série de casos.<br>INTRODUCTION: anorectal procedures consist 80% of surgical cases in colorectal surgery practice. The exact rate of long-term complications after anorectal surgery is unknown. This number is variable according to the medical centres and the type of procedures. OBJECTIVE: to evaluate the long-term complications secondary to anorectal procedures, as well as the risk factors that might be associated with these complications. METHOD: retrospective analysis, including anorectal procedures performed between January 2007 and July 2009. The characteristics analyzed were: sex, age, type of surgery, health system, long-term complications and reoperations performed. RESULTS: 430 patients submitted to 453 anorectal procedures were studied (54,4% female). Hemorrhoidectomy was the most common procedure (50,3% of all operations). The mean period of follow-up was 164,7 days and 102 long-term complications were identified, occurring in 22,52% of all procedures. Residual fissure in ano was the most frequent complication (54%, n=55). Only 38 patients needed reoperation (8,83% of all cases). There was no statistical significance between sex, age, health system and type of surgery in relation to the complications found. CONCLUSIONS: the long-term complication rate was 22,52%, with reoperations performed in 8,83% of all patients. There was no risk factor for long-term complications identified in this case series
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