996 resultados para Isolated carbonate platforms
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BACKGROUND: The SCN5A gene encodes for the α-subunit of the cardiac sodium channel NaV1.5, which is responsible for the rapid upstroke of the cardiac action potential. Mutations in this gene may lead to multiple life-threatening disorders of cardiac rhythm or are linked to structural cardiac defects. Here, we characterized a large family with a mutation in SCN5A presenting with an atrioventricular conduction disease and absence of Brugada syndrome. METHOD AND RESULTS: In a large family with a high incidence of sudden cardiac deaths, a heterozygous SCN5A mutation (p.1493delK) with an autosomal dominant inheritance has been identified. Mutation carriers were devoid of any cardiac structural changes. Typical ECG findings were an increased P-wave duration, an AV-block I° and a prolonged QRS duration with an intraventricular conduction delay and no signs for Brugada syndrome. HEK293 cells transfected with 1493delK showed strongly (5-fold) reduced Na(+) currents with altered inactivation kinetics compared to wild-type channels. Immunocytochemical staining demonstrated strongly decreased expression of SCN5A 1493delK in the sarcolemma consistent with an intracellular trafficking defect and thereby a loss-of-function. In addition, SCN5A 1493delK channels that reached cell membrane showed gain-of-function aspects (slowing of the fast inactivation, reduction in the relative fraction of channels that fast inactivate, hastening of the recovery from inactivation). CONCLUSION: In a large family, congregation of a heterozygous SCN5A gene mutation (p.1493delK) predisposes for conduction slowing without evidence for Brugada syndrome due to a predominantly trafficking defect that reduces Na(+) current and depolarization force.
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Isolated nonperfused rabbit renal proximal tubules were used to investigate the basolateral step of transport of the organic cation N1-methylnicotinamide (NMN). NMN accumulation was highest and saturable in S2 and S3 segments, but lowest and nonsaturable in S1 segments. In S1 segments, accumulation of [3H]-NMN (0.5-8 microM in the bath) resulted in an average tubular water/medium concentration ratio (T/M) of 8.2, whereas in S2 and S3 segments T/M averaged 19.5 and 18.6, respectively. At these concentrations, about 30% of the label was attached in all segments to a metabolite comigrating with nicotinamide. KCN (10(-2) M) or ouabain (10(-4) M) reduced T/M to about 8 for all segments. NMN accumulation was inhibited (to a T/M of about 3 with mepiperphenidol) by other organic cations (10(-5)-10(-3) M) with the potency sequence mepiperphenidol greater than tetraethylammonium = quinine greater than morphine, these organic cations having no effect on p-aminohippurate accumulation, except for the highest concentration of quinine (10(-3) M). After correction for metabolism, NMN accumulation could be accounted for by simple electrochemical equilibrium across the basolateral membrane. The basolateral step of NMN transport appears therefore to be a carrier-mediated diffusion, in opposition to the active basolateral accumulation described for tetraethylammonium.
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Acquired isolated accommodation palsy is an uncommon problem which can occur either in patients with an organic lesion, in otherwise healthy patients, or in functional, non-organic patients. We report a healthy 9-year-old girl with an acquired isolated accommodation palsy which was believed to be related to a 10 mm pineal cyst compressing the superior colliculi. A literature search (1932 - 2005) on symptomatic pineal cysts revealed 159 reported cases of symptomatic pineal cysts. Blurred vision was a complaint of 18/ 159 patients, but only three were documented to have an accommodation palsy. Although rarely symptomatic, pineal cysts might be responsible for accommodation palsy.
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The Monte San Giorgio (Southern Alps, Ticino, Switzerland) is the most important locality in the world for vertebrates dating back to the Middle Triassic. For this reason it was registered in 2003 as a UNESCO World Heritage Site. One of the objectives of this doctoral thesis was to fill some of the cognitive gaps regarding the Ladinian succession, including in particular the San Giorgio Dolomite and the Meride Limestone. In order to achieve this, the entire succession, more than 600 metres thick, was measured and sampled. Biostratigraphic research based on new finds of fossil invertebrates and microfossils and on the palynological analysis of the entire section was integrated with single-zircon U-Pb dating of volcanic ash layers intercalated in the carbonate succession. This enabled a redefinition of the bio-chronostratigraphic and geochronologic framework of the succession, which encompasses a significantly shorter time interval than previously held. The Ladinian section extends from the E. curionii Ammonoid Zone (Early Fassanian) to the P. archelaus Ammonoid Zone (Early Longobardian). The age of the classic fossiliferous levels of the Meride Limestone, rich in organic matter and containing vertebrate fossils which are known all over the world, was defined in both biostratigraphic and geochronologic terms. The presumed stratigraphie significance of the pachypleurosaurid reptiles found in such levels is called into question by new finds. These fossiliferous horizons were found to correspond to the main volcanoclastic intervals of the Buchenstein Formation (Middle and Upper Pietra Verde). Thus, a correlation with the Bagolino Section (Italy) containing the GSSP for the base of the Ladinian was proposed. Bulk sedimentation rates in the studied succession average 200 m/Myr and therefore prove to be 20 times higher than those of the South-Alpine pelagic basins. These values express high carbonate productivity from the surrounding platforms on one hand, and on the other a marked subsidence of the basin. Only in the intervals consisting of laminated limestones did the sedimentation rates drop to average values of around 30 m/Myr. The distribution of organic and inorganic facies appears to be the consequence of relative variations in sea-level. The laminated and organic-matter- rich intervals of the Meride Limestone are linked to a relative sea-level drop which favoured dysoxic to anoxic bottom-water conditions, coupled with an increase in runoff, perhaps due to recurrent explosive volcanic activity. The transient development under dysoxic conditions of monospecific benthic meio-/macrofaunas was documented. Organic matter suggests a predominant origin due to benthic bacterial activity, as can be witnessed in alveolar structures typical of exopolymeric substances secreted by bacteria within microbial mats. A microbial contribution to the carbonate (peloidal) precipitation was documented. The protective effect exerted by these microbial mats is also indicated as the main taphonomic factor contributing to the excellent preservation of vertebrate fossils. A radiolarian assemblage discovered in the lower part of the section (earliest Ladinian, E. curionii Zone) suggests the transient existence of open-marine but not deep-water connections with the tethyan pelagic basins. It shows marked similarities to the faunas typical of the late Anisian, suggesting therefore a low resolution power provided by radiolarian biostratigraphy in recognizing the Anisian/Ladinian boundary. The present thesis describes a new species of conifer (Elatocladus cassinae), a new species of insect (Dasyleptus triassicus) and seven new species of radiolarians (Eptingium danieli, Eptingium neriae, Parentactinosphaera eoladinica, Sepsagon ticinensis, Sepsagon? valporinae, Novamuria wirzi and Pessagnollum? hexaspinosum). In addition, following revision of the type material of already existent taxa, four new genera of radiolarians are introduced: Bernoulliella, Eohexastylus, Ticinosphaera and Lahmosphaera.
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Selostus: Näköesteen vaikutus sinikettujen hyllynkäyttöön
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BORIS/CTCFL is a member of cancer testis antigen family normally expressed in germ cells. In tumors, it is aberrantly expressed although its functions are not completely well-defined. To better understand the functions of BORIS in cancer, we selected the embryonic cancer cells as a model. Using a molecular beacon, which specifically targets BORIS mRNA, we demonstrated that BORIS positive cells are a small subpopulation of tumor cells (3-5% of total). The BORIS-positive cells isolated using BORIS-molecular beacon, expressed higher telomerase hTERT, stem cell (NANOG, OCT4, SOX2) and cancer stem cell marker genes (CD44 and ALDH1) compared to the BORIS-negative tumor cells. In order to define the functional role of BORIS, stable BORIS-depleted embryonic cancer cells were generated. BORIS silencing strongly down-regulated the expression of hTERT, stem cell and cancer stem cell marker genes. Moreover, the BORIS knockdown increased cellular senescence in embryonic cancer cells, revealing a putative role of BORIS in the senescence biological program. Our data indicate an association of BORIS expressing cells subpopulation with the expression of stemness genes, highlighting the critical role played by BORIS in embryonic neoplastic disease.
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In this Contribution we show that a suitably defined nonequilibrium entropy of an N-body isolated system is not a constant of the motion, in general, and its variation is bounded, the bounds determined by the thermodynamic entropy, i.e., the equilibrium entropy. We define the nonequilibrium entropy as a convex functional of the set of n-particle reduced distribution functions (n ? N) generalizing the Gibbs fine-grained entropy formula. Additionally, as a consequence of our microscopic analysis we find that this nonequilibrium entropy behaves as a free entropic oscillator. In the approach to the equilibrium regime, we find relaxation equations of the Fokker-Planck type, particularly for the one-particle distribution function.
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The Late Triassic and Jurassic platform and the oceanic complexes in Evvoia, Greece, share a complementary plate-tectonic evolution. Shallow marine carbonate deposition responded to changing rates of subsidence and uplift, whilst the adjacent ocean underwent spreading, and then convergence, collision and finally obduction over the platform complex. Late Triassic ocean spreading correlated with platform subsidence and the formation of a long-persisting peritidal passive-margin platform. Incipient drowning occurred from the Sinemurian to the late Middle Jurassic. This subsidence correlated with intra-oceanic subduction and plate convergence that led to supra-subduction calc-alkaline magmatism and the formation of a primitive volcanic arc. During the Middle Jurassic, plate collision caused arc uplift above the carbonate compensation depth (CCD) in the oceanic realm, and related thrust-faulting, on the platform, led to sub-aerial exposures. Patch-reefs developed there during the Late Oxfordian to Kimmeridgian. Advanced oceanic nappe-loading caused platform drowning below the CCD during the Tithonian, which is documented by intercalations of reefal turbidites with non-carbonate radiolarites. Radiolarites and bypass-turbidites, consisting of siliciclastic greywacke, terminate the platform succession beneath the emplaced oceanic nappe during late Tithonian to Valanginian time.
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ABSTRACT An alternative for recovery of areas degraded by coal mining is revegetation with rapidly growing leguminous trees, which often do not establish in low fertility soils. The objective of this study was to evaluate the efficiency of native rhizobia isolated from coal mining areas in the nodulation and growth of leguminous trees. We isolated 19 strains of rhizobia from a degraded soil near Criciúma, SC, Brazil, and evaluated the nodulation and growth-promoting capacity of the inoculated isolates for bracatinga (Mimosa scabrella), maricá (M. bimucronata) and angico-vermelho (Parapiptadenia rigida). Isolates UFSC-B2, B6, B8, B9, B11 and B16 were able to nodulate bracatinga, providing average increases of 165 % in shoot dry matter, with a significant contribution to N accumulation. Isolates UFSC-B5, B12, and M8 favored nodulation and growth of maricá, especially isolate UFSC-B12, which promoted increases of 370 % in N accumulation compared to treatment with N fertilizer. All strains were inefficient in promoting growth and N uptake by angico-vermelho. In conclusion, isolation and use of selected rhizobia for bracatinga and maricá plant inoculation can contribute to the growth and accumulation of N, with prospects for use in programs for revegetation of degraded soils in coal mining areas.
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Using isolated, in situ, single-pass perfused rat livers, incubations of freshly isolated hepatocytes, and sinusoidal membrane-enriched vesicles, we and others have shown the saturability of transport (efflux) of hepatic glutathione (GSH). These observations have implicated a carrier mechanism. Our present studies were designed to provide further evidence in support of a carrier mechanism for hepatic GSH efflux by demonstrating competition by liver-specific ligands which are taken up by hepatocytes. Perfusing livers with different substances, we found that: (a) sulfobromophthalein-GSH (BSP-GSH) had a dose-dependent and fully reversible inhibitory effect on GSH efflux, while GSH alone did not have any effect; (b) taurocholate had no inhibitory effect; (c) all of the organic anions studied, i.e., BSP, rose bengal, indocyanine green, and unconjugated bilirubin (UCB), manifested potent, dose-dependent inhibitory effects, with absence of toxic effects and complete reversibility of inhibition in the case of UCB. The inhibitory effects of UCB could be overcome partially by raising (CoCl2-induced) hepatic GSH concentration. Because of the physiological importance of UCB, we conducted a detailed study of its inhibitory kinetics in the isolated hepatocyte model in the range of circulating concentrations of UCB. Studies with Cl- -free media, to inhibit the uptake of UCB by hepatocytes, showed that the inhibition of GSH efflux by UCB is apparently from inside the cell. This point was confirmed by showing that the inhibition is overcome only when bilirubin-loaded cells are cleared of bilirubin (incubation with 5% bovine serum albumin). Using Gunn rat hepatocytes and purified bilirubin mono- and diglucuronides, we found that both UCB and glucuronide forms of bilirubin inhibit GSH efflux in a dose-dependent manner. We conclude that the organic anions, although taken up by a mechanism independent of GSH, may competitively inhibit the carrier for GSH efflux from inside the hepatocyte.