306 research outputs found

    Subfractionation of human very low density lipoproteins by heparin-Sepharose affinity chromatography.

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    Very low density lipoproteins obtained from normolipidemic subjects were fractionated into subclasses by means of affinity chromatography on a heparin-Sepharose column in the presence of MnCl2. The four subfractions eluted at 0.05, 0.12, 0.20, and 0.38 M NaCl and they differed in chemical composition and apoprotein pattern. The relative amounts of apoB and apoE in subfractions increased with increasing concentrations of the NaCl eluant. Modification of the arginyl residues with 1-2 cyclohexadione demonstrated that arginine plays an important role in determining the elution pattern of VLDL. In vitro studies indicated that only fractions eluted at 0.2 and 0.5 M NaCl compete with LDL for cellular receptors. These data suggest that the various subfractions may represent VLDL at different stages of catabolism

    Sementes como fonte alternativa de substĂąncias quĂ­micas com atividade alelopĂĄtica.

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    Na literatura mundial, observa-se predominĂąncia das folhas como meio preferencial de estudos de compostos quĂ­micos promissores, embora informaçÔes sobre outras fraçÔes da planta tambĂ©m sejam encontradas. Essa tendĂȘncia se deve ao fato de que a maioria dos estudos mostra as folhas com atividade potencialmente alelopĂĄtica de intensidade superior Ă  das demais fraçÔes. Nesta revisĂŁo, procurou-se compilar e analisar as informaçÔes disponĂ­veis sobre a importĂąncia das sementes como fonte alternativa de compostos quĂ­micos com atividade alelopĂĄtica. SĂŁo discutidas as variaçÔes na produção e na alocação de aleloquĂ­micos em função do estĂĄdio ontogenĂ©tico das sementes presentes no banco de sementes. É discutido tambĂ©m o papel dos aleloquĂ­micos produzidos por sementes na repelĂȘncia de insetos, na inibição do desenvolvimento de patĂłgenos nas sementes, na inibição do desenvolvimento inicial de plantas daninhas e como sinalizador positivo para a simbiose com microrganismos do solo. Apresenta-se ainda a atividade alelopĂĄtica de diversas substĂąncias isoladas de sementes, destacando-se os alcaloides, flavonoides, benzoxazinoides e resinas glicosĂ­dicas. Os estudos de aleloquĂ­micos produzidos por sementes podem contribuir expressivamente para o melhor entendimento do papel ecolĂłgico que essas substĂąncias desempenham na ecologia quĂ­mica dos agro e ecossistemas

    The microbiome-gut-brain axis in acute and chronic brain diseases

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    The gut microbiome — the largest reservoir of microorganisms of the human body — is emerging as an important player in neurodevelopment and ageing as well as in brain diseases including stroke, Alzheimer’s disease and Parkinson’s disease. The growing knowledge on mediators and triggered pathways has advanced our understanding of the interactions along the gut-brain axis. Gut bacteria produce neuroactive compounds and can modulate neuronal function, plasticity and behavior. Furthermore, intestinal microorganisms impact the host’s metabolism and immune status which in turn affect neuronal pathways in the enteric and central nervous systems. Here, we discuss the recent insights from human studies and animal models on the bi-directional communication along the microbiome-gut-brain axis in both acute and chronic brain diseases

    pure analgesics in a rheumatological outpatient clinic

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    Objective: Pure analgesics are only rarely used by Italian clinicians and this holds true also for rheumatologists. This work is concerned with an evaluation of the use of analgesics in a rheumatological outpatient clinic during the period 1989-1999. Methods: The records of 1705 patients consecutively seen at the clinic were downloaded on a specifically built website. Results: 4469 visits were considered. In 260 of them (5.8%), analgesics were prescribed to 234 (13.7%) patients. The number of patients with a prescription of analgesics steadily increased during the years 1989-1999. The diagnoses in patients assuming analgesics were: osteoarthritis (47.1%), inflammatory arthritis (24.2%), soft tissue rheumatisms (13.7%), nonspecific arthralgia/myalgia (7.5%), and connective tissue diseases (2.6%). Peripheral analgesics were used in 188 (82.5%) patients and central analgesics were used in the remaining 40 patients (17.5%). Analgesic drugs were used mainly in degenerative joint conditions. The indications for analgesics in the 55 patients with inflammatory arthrits were: (a) partial or total remission of arthritis; for this reason non-steroidal anti-inflammatory drugs were no longer required in 18 patients; (b) to increase the analgesic effect of NSAIDs in 23 patients; (c) contraindications to NSAIDs in 14 patients (renal failure in 2 patients, gastritis in 10, allergy and bleeding in the remaining two). Conclusions: About 14% of our outpatients were treated with analgesics with an increasing trend in the examined period. The main indications for analgesics are degenerative conditions but they can be used also in selected patients with arthritis

    Tracing U mobility in deep groundwater using Ra isotopes

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    The mobility of natural U is compared among four boreholes in a fractured granite using Ra isotopes and geochemical modelling. Rn-222/Ra-226 activity ratios (ARs) spanning an order of magnitude underline differences in reactive surface area. (Ra-224/Ra-228)(ARs) up to 9 indicate recent changes in hydrogeochemistry, and (Ra-226/Ra-228)(ARs) 0.6-30 indicate variable deposition of U. Dissolved U is related to dissolution of a solid U(VI) phase by groundwater with HCO3- > 20 mg.L-1. U reduction is hindered by Ca2UO2(CO3)(3)(0)

    Blood flow characteristics after aortic valve neocuspidization in paediatric patients: a comparison with the Ross procedure.

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    AIMS: The aortic valve (AV) neocuspidization (Ozaki procedure) is a novel surgical technique for AV disease that preserves the natural motion and cardiodynamics of the aortic root. In this study, we sought to evaluate, by 4D-flow magnetic resonance imaging, the aortic blood flow characteristics after AV neocuspidization in paediatric patients. METHODS AND RESULTS: Aortic root and ascending aorta haemodynamics were evaluated in a population of patients treated with the Ozaki procedure; results were compared with those of a group of patients operated with the Ross technique. Cardiovascular magnetic resonance studies were performed at 1.5 T using a 4D flow-sensitive sequence acquired with retrospective electrocardiogram-gating and respiratory navigator. Post-processing of 4D-flow analysis was performed to calculate flow eccentricity and wall shear stress. Twenty children were included in this study, 10 after Ozaki and 10 after Ross procedure. Median age at surgery was 10.7 years (range 3.9-16.5 years). No significant differences were observed in wall shear stress values measured at the level of the proximal ascending aorta between the two groups. The analysis of flow patterns showed no clear association between eccentric flow and the procedure performed. The Ozaki group showed just a slightly increased transvalvular maximum velocity. CONCLUSION: Proximal aorta flow dynamics of children treated with the Ozaki and the Ross procedure are comparable. Similarly to the Ross, Ozaki technique restores a physiological laminar flow pattern in the short-term follow-up, with the advantage of not inducing a bivalvular disease, although further studies are warranted to evaluate its long-term results

    Neutron-induced background by an alpha-beam incident on a deuterium gas target and its implications for the study of the 2H(alpha,gamma)6Li reaction at LUNA

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    The production of the stable isotope Li-6 in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological Li-6 plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of Li-7 abundances and would point to a predominantly primordial origin of Li-6, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang Li-6 production must be revisited. The main production channel for Li-6 in the Big Bang is the 2H(alpha,gamma)6Li reaction. The present work reports on neutron-induced effects in a high-purity germanium detector that were encountered in a new study of this reaction. In the experiment, an {\alpha}-beam from the underground accelerator LUNA in Gran Sasso, Italy, and a windowless deuterium gas target are used. A low neutron flux is induced by energetic deuterons from elastic scattering and, subsequently, the 2H(d,n)3He reaction. Due to the ultra-low laboratory neutron background at LUNA, the effect of this weak flux of 2-3 MeV neutrons on well-shielded high-purity germanium detectors has been studied in detail. Data have been taken at 280 and 400 keV alpha-beam energy and for comparison also using an americium-beryllium neutron source.Comment: Submitted to EPJA; 13 pages, 8 figure

    22q11.2 Deletion Syndrome. Impact of Genetics in the Treatment of Conotruncal Heart Defects

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    Congenital heart diseases represent one of the hallmarks of 22q11.2 deletion syndrome. In particular, conotruncal heart defects are the most frequent cardiac malformations and are often associated with other specific additional cardiovascular anomalies. These findings, together with extracardiac manifestations, may affect perioperative management and influence clinical and surgical outcome. Over the past decades, advances in genetic and clinical diagnosis and surgical treatment have led to increased survival of these patients and to progressive improvements in postoperative outcome. Several studies have investigated long-term follow-up and results of cardiac surgery in this syndrome. The aim of our review is to examine the current literature data regarding cardiac outcome and surgical prognosis of patients with 22q11.2 deletion syndrome. We thoroughly evaluate the most frequent conotruncal heart defects associated with this syndrome, such as tetralogy of Fallot, pulmonary atresia with major aortopulmonary collateral arteries, aortic arch interruption, and truncus arteriosus, highlighting the impact of genetic aspects, comorbidities, and anatomical features on cardiac surgical treatment

    22Ne and 23Na ejecta from intermediate-mass stars: The impact of the new LUNA rate for 22Ne(p,gamma)23Na

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    We investigate the impact of the new LUNA rate for the nuclear reaction 22^{22}Ne(p,γ)23(p,\gamma)^{23}Na on the chemical ejecta of intermediate-mass stars, with particular focus on the thermally-pulsing asymptotic giant branch (TP-AGB) stars that experience hot-bottom burning. To this aim we use the PARSEC and COLIBRI codes to compute the complete evolution, from the pre-main sequence up to the termination of the TP-AGB phase, of a set of stellar models with initial masses in the range 3.0 M⊙−6.0 M⊙3.0\,M_{\odot} - 6.0\,M_{\odot}, and metallicities Zi=0.0005Z_{\rm i}=0.0005, Zi=0.006Z_{\rm i}=0.006, and Zi=0.014Z_{\rm i} = 0.014. We find that the new LUNA measures have much reduced the nuclear uncertainties of the 22^{22}Ne and 23^{23}Na AGB ejecta, which drop from factors of ≃10\simeq 10 to only a factor of few for the lowest metallicity models. Relying on the most recent estimations for the destruction rate of 23^{23}Na, the uncertainties that still affect the 22^{22}Ne and 23^{23}Na AGB ejecta are mainly dominated by evolutionary aspects (efficiency of mass-loss, third dredge-up, convection). Finally, we discuss how the LUNA results impact on the hypothesis that invokes massive AGB stars as the main agents of the observed O-Na anti-correlation in Galactic globular clusters. We derive quantitative indications on the efficiencies of key physical processes (mass loss, third dredge-up, sodium destruction) in order to simultaneously reproduce both the Na-rich, O-poor extreme of the anti-correlation, and the observational constraints on the CNO abundance. Results for the corresponding chemical ejecta are made publicly available
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