990 resultados para Destruction Bay Formation
Resumo:
Percutaneous transluminal angioplasty is frequently used in patients with severe arterial narrowing due to atherosclerosis. However, it induces severe arterial injury and an inflammatory response leading to restenosis. Here, we studied a potential activation of the endocannabinoid system and the effect of FA amide hydrolase (FAAH) deficiency, the major enzyme responsible for endocannabinoid anandamide degradation, in arterial injury. We performed carotid balloon injury in atherosclerosis-prone apoE knockout (apoE(-/-)) and apoE(-/-)FAAH(-/-) mice. Anandamide levels were systemically elevated in apoE(-/-) mice after balloon injury. ApoE(-/-)FAAH(-/-) mice had significantly higher baseline anandamide levels and enhanced neointima formation compared with apoE(-/-) controls. The latter effect was inhibited by treatment with CB1 antagonist AM281. Similarly, apoE(-/-) mice treated with AM281 had reduced neointimal areas, reduced lesional vascular smooth-muscle cell (SMC) content, and proliferating cell counts. The lesional macrophage content was unchanged. In vitro proliferation rates were significantly reduced in CB1(-/-) SMCs or when treating apoE(-/-) or apoE(-/-)FAAH(-/-) SMCs with AM281. Macrophage in vitro adhesion and migration were marginally affected by CB1 deficiency. Reendothelialization was not inhibited by treatment with AM281. In conclusion, endogenous CB1 activation contributes to vascular SMC proliferation and neointima formation in response to arterial injury.
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Gout is an inflammatory arthritis caused by monosodium urate (MSU) crystal deposits in and around the joint. The formation of urinary calculi can also occur in gout, but are less common than arthritis. Gout usually presents with recurrent episodes of joint inflammation, which over time lead to tophus formation and joint destruction. In the last decade, significant advances have been made regarding not only the epidemiology and genetics of gout and hyperuricemia but also the mechanisms of inflammation and treatment of gout. In addition, knowledge concerning the key role of interleukin 1 (IL-1) has provided new therapeutic perspectives. However, the current management of gout is often suboptimal, with many Patienten either not receiving adequate treatment or being unable to tolerate existing treatments. New therapeutic agents provide interesting new options for Patienten with difficult-to-treat gouty arthritis.The English full-text version of this is available at SpringerLink (under "Supplemental").
Resumo:
Previous studies in Caenorhabditis elegans showed that RPM-1 (Regulator of Presynaptic Morphology-1) regulates axon termination and synapse formation. To understand the mechanism of how rpm-1 functions, we have used mass spectrometry to identify RPM-1 binding proteins, and have identified RAE-1 (RNA Export protein-1) as an evolutionarily conserved binding partner. We define a RAE-1 binding region in RPM-1, and show that this binding interaction is conserved and also occurs between Rae1 and the human ortholog of RPM-1 called Pam (protein associated with Myc). rae-1 loss of function causes similar axon and synapse defects, and synergizes genetically with two other RPM-1 binding proteins, GLO-4 and FSN-1. Further, we show that RAE-1 colocalizes with RPM-1 in neurons, and that rae-1 functions downstream of rpm-1. These studies establish a novel postmitotic function for rae-1 in neuronal development.
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The Gronnedal-Ika complex is dominated by layered nepheline syenites which were intruded by a xenolithic syenite and a central plug of calcite to calcite-siderite carbonatite. Aegirine-augite, alkali feldspar and nepheline are the major mineral phases in the syenites, along with rare calcite. Temperatures of 680-910degreesC and silica activities of 0.28-0.43 were determined for the crystallization of the syenites on the basis of mineral equilibria. Oxygen fugacities, estimated using titanomagnetite compositions, were between 2 and 5 log units above the fayalite-magnetite-quartz buffer during the magmatic stage. Chondrite-normalized REE patterns of magmatic calcite in both carbonatites and syenites are characterized by REE enrichment (La-CN-Yb-CN = 10-70). Calcite from the carbonatites has higher Ba (similar to5490 ppm) and lower HREE concentrations than calcite from the syenites (54-106 ppm Ba). This is consistent with the behavior of these elements during separation of immiscible silicate-carbonate liquid pairs. epsilon(Nd)(T = 1.30 Ga) values of clinopyroxenes from the syenites vary between +1.8 and +2.8, and epsilon(Nd)(T) values of whole-rock carbonatites range from +2.4 to +2.8. Calcite from the carbonatites has delta(18)O values of 7.8 to 8.6parts per thousand and delta(13)C values of -3.9 to -4.6parts per thousand. delta(18)O values of clinopyroxene separates from the nepheline syenites range between 4.2 and 4.9parts per thousand. The average oxygen isotopic composition of the nepheline syenitic melt was calculated based on known rock-water and mineral-water isotope fractionation to be 5.7 +/- 0.4parts per thousand. Nd and C-O isotope compositions are typical for mantle-derived rocks and do not indicate significant crustal assimilation for either syenite or carbonatite magmas. The difference in delta(18)O between calculated syenitic melts and carbonatites, and the overlap in epsilon(Nd) values between carbonatites and syenites, are consistent with derivation of the carbonatites from the syenites via liquid immiscibility.
Resumo:
Sediment-water exchanges of oxygen, ammonium, nitrate, total dissolved nitrogen, phosphate and total dissolved phosphorus were measured by means of an in situ incubator of 7 1 volume and 700 cm2 base area. The incubations lasted for three hours and were done over a whole season on different kinds of sediments in Alfaques Bay. We present some preliminary results on: i) methodological aspects, ii) spatial and temporal variability of fluxes, and iii) estimates of contribution of benthic nutrient regeneration relative to total nutrient loading of the Bay. Oxygen uptake averaged 1700 mmo1 m-2 h-1 (range 200-3500); no differences were found between sandy and muddy sediments. The release of ammonia from the sediment averaged 70 mmo1 m-2 h-1 and was higher in muddy sediments than in sandy ones. Very low to null nitrate and nitrite fluxes and only small fluxes of organic nitrogen were detected. We conclude that ammonium release from sediment is the major path of nitrogen regeneration. Some sediments removed dissolved reactive phosphorus (DRP) from the water and released dissolved organic phosphorus (DOP). Additional manipulative experiments revealed DRP release under particular conditions (turbulence, anoxia). From these data, we estimate that at least 50% of the nitrogen requirements of phytoplankton in the area may be supplied by benthic remineralization.
Resumo:
The diverse vertebrate remains from the Upper Cretaceous freshwater settings at Iharkut, Hungary, contain two fossil groups, Pycnodontiformes fish and Mosasauridae that are almost exclusively known from marine palaeo-environments. Hence, their appearance in alluvial sediments is very unusual. Trace element and isotope compositions of the remains have been analyzed to investigate the taphonomy and the ecological differences among the different fossil groups present at Iharkut. All examined fossils have undergone post-depositional diagenetic alteration, which resulted in high concentrations of REE, U, and Fe, together with almost complete homogenization of delta(18)O(CO3) values. Similar REE patterns in different fossils suggest a common origin for all remains, hence the discovered species most likely lived in the same local ecosystem. Despite partial diagenetic overprinting, the delta(18)O(PO4) values of the fossils indicate sufficient taxon-specific isotopic diversity to permit some broad conclusions on the palaeo-environment of the fossils. In particular, it is apparent that the isotopic composition of the Pycnodontiformes fish and Mosasauridae remains is most compatible with a freshwater palaeo-habitat and incompatible with a marine palaeo-environment. In addition, the Sr concentration and isotope data indicate that the Pycnodontiformes and Mosasauridae likely lived predominantly in a freshwater environment and were not simply occasional visitors to the Iharkut river ecosystem. Regarding other fossil groups, high delta(18)O(PO4) values of Alligatoroidea and Iharkutosuchus teeth suggest that these small crocodile species might have inhabited swamps and ponds where the water was relatively rich in (18)O due to evaporation. (c) 2009 Elsevier B.V. All rights reserved.
Resumo:
La littérature indique que parmi les différents moyens de promotion de l'activité physique, le conseil par le médecin constitue une voie efficace. La formation PAPRICA, suivie à ce jour par env. 200 médecins, a pour but de promouvoir l'activité physique des patients par les médecins de premier recours. La présente recherche étudie la mise en oeuvre par les médecins des acquis de cette formation. Les données ont été recueillies grâce à un questionnaire à tous les participants, ainsi qu'à des entretiens téléphoniques auprès d'un échantillon plus restreint. Les principaux thèmes abordés concernent les apports de la formation, la pratique effective au cabinet et la satisfaction du médecin. [Auteurs, p. 7]
Resumo:
Authigenic phosphorites from the Miocene Monterey Formation (California) including an autochthonous phosphatic laminite were analyzed for molecular biomarkers, element content, and sulfur isotopic composition of associated pyrite and sulfate to evaluate the role of bacterial activity in the precipitation of phosphate minerals. The phosphorites formed in a depositional environment typified by upwelling with dynamic bottom currents and hardground formation. Pyrite enclosed in the phosphorites shows delta S-34 values as low as -36.5 parts per thousand VCDT, which is consistent with bacterial sulfate reduction. In a three-step extraction phosphorite dissolution extraction procedure, molecular fossils of sulfate-reducing bacteria (di-O-alkyl glycerol ethers and short-chain branched fatty acids i- and ai-C-15:0, i- and ai-C-17:0, and 10MeC(16:0)) were preferentially released from the mineral lattice. This suggests that the molecular fossils were tightly bound to carbonate fluorapatite, indicating that sulfate-reducing bacteria were involved in mineral formation. A close association of sulfate-reducing bacteria with large sulfide-oxidizing bacteria, which was previously suggested to favor carbonate fluorapatite precipitation, could neither be confirmed nor excluded for the Miocene Monterey Formation phosphorites. (C) 2012 Elsevier B.V. All rights reserved.
Resumo:
The late Early Cretaceous greenhouse climate has been studied intensively based on proxy data derived essentially from open marine archives. In contrast, information on continental climatic conditions and on the accompanying response of vegetation is relatively scarce, most notably owing to the stratigraphic uncertainties associated with many Lower Cretaceous terrestrial deposits. Here, we present a palynological record from Albian near-shore deposits of the Lusitanian Basin of W Portugal, which have been independently dated using Sr-isotope signals derived from low-Mg oyster shell calcite. Sr-87/Sr-86 values fluctuate between 0.707373 +/- 0.00002 and 0.707456 +/- 0.00003; absolute values and the overall stratigraphic trend match well with the global open marine seawater signature during Albian times. Based on the new Sr-isotope data, existing biostratigraphic assignments of the succession are corroborated and partly revised. Spore-pollen data provide information on the vegetation community structure and are flanked by sedimentological and clay mineralogical data used to infer the overall climatic conditions prevailing on the adjacent continent. Variations in the distribution of climate-sensitive pollen and spores indicate distinct changes in moisture availability across the studied succession with a pronounced increase in hygrophilous spores in late Early Albian times. Comparison with time-equivalent palynofloras from the Algarve Basin of southern Portugal shows pronounced differences in the xerophyte/hygrophyte ratio, interpreted to reflect the effect of a broad arid climate belt covering southern and southeastern Iberia during Early Albian times.
Resumo:
Steady state viscosity and thixotropy of hydrophobically modified hydroxyethyl cellulose HMHEC and nonassociative cellulose water solutions are studied. Although all the samples are shear thinning, only the HMHEC is thixotropic, since the migration of hydrophobes to micelles is controlled by diffusion. The Cross model fits steady state curves. The Mewis model, a phenomenological model that proposes that the rate of change of viscosity when the shear rate is suddenly changed is related to the difference between the steady state and current values of viscosity raised to an exponent, fits structure construction experiments when the exponent, n, is estimated to be around 2. The Newtonian assumption used by Mewis cannot be used here, however. This seems to be related to the fact that the thickening is due to bridged micelle formation, which is a slow process, and also to topological constraints and entanglements, which are rapid processes. The kinetic parameter was redefined to kn in order to make it independent of initial conditions. So, kn depends only on how the shear affects the structure. kn reaches a plateau at shear rates too low to produce structure destruction and decreases at higher shear rates.
Resumo:
We report that, in the rat hippocampus, learning leads to a significant increase in extracellular lactate levels that derive from glycogen, an energy reserve selectively localized in astrocytes. Astrocytic glycogen breakdown and lactate release are essential for long-term but not short-term memory formation, and for the maintenance of long-term potentiation (LTP) of synaptic strength elicited in vivo. Disrupting the expression of the astrocytic lactate transporters monocarboxylate transporter 4 (MCT4) or MCT1 causes amnesia, which, like LTP impairment, is rescued by L-lactate but not equicaloric glucose. Disrupting the expression of the neuronal lactate transporter MCT2 also leads to amnesia that is unaffected by either L-lactate or glucose, suggesting that lactate import into neurons is necessary for long-term memory. Glycogenolysis and astrocytic lactate transporters are also critical for the induction of molecular changes required for memory formation, including the induction of phospho-CREB, Arc, and phospho-cofilin. We conclude that astrocyte-neuron lactate transport is required for long-term memory formation.