Chemical and boron isotopic compositions of volcanics from ODP Sites 135-834 to 135-840

The influence of fluid flux on petrogenesis in the Tonga-Kermadec Arc was investigated using ion microprobe measurements of B/Be and boron isotope ratios (11B/10B) to document the source and relative volumes of the fluids released from the subducting oceanic plate. We analyzed young lavas from eight different islands along the Tonga-Kermadec Arc, as well as glass shards in volcanic sediments from Ocean Drilling Program (ODP) Site 840, which record the variations in the chemistry of Tonga magmatism since 7 Ma. B/Be is variable (5.8-122), in young Tonga-Kermadec Arc lavas. In contrast, glass shards from around 3 to 4 Ma old volcanic sediments at Site 840 have the highest B/Be values yet reported for arc lavas (18-607). These values are too high to be related simply to a sediment influence on petrogenesis. Together with very high d11B values (-11.6 to +37.5) for the same shards and lavas these data indicate that most of the B is derived from fluid escaped from the subducting altered Pacific oceanic crust, rather than from sediment. High d11B values also reflect large degrees of isotopic fractionation in this cold fast subduction zone. Lower d11B values noted in the Kermadec Arc (17 to -4.4) are related to the influence of sediment eroded from New Zealand and slower convergence. High fluid flux (B/Be) is synchronous in Tonga and the Marianas at 3 to 4 Ma and may be related to acceleration of the Pacific Plate just prior to this time. The timing of maximum B/Be at 3 to 4 Ma correlates with maximum light rare earth (LREE) and high field strength element depletion. This suggests maximum degrees of partial melting at this time. Although thinning of the arc lithosphere during rifting to form the Lau Basin is expected to influence the arc geochemistry, variable aqueous fluid flux from the subducting plate alone appears capable of explaining boron and other trace element systematics in the Tonga-Kermadec Arc with no indication of slab melting.

Isotopic composition of rocks from the Lau/Tonga back-arc basin, data of DSDP Leg 21 and ODP Legs 91 an 135

New trace element, Sr-, Nd-, Pb- and Hf isotope data provide insights into the evolution of the Tonga-Lau Basin subduction system. The involvement of two separate mantle domains, namely Pacific MORB mantle in the pre-rift and early stages of back-arc basin formation, and Indian MORB mantle in the later stages, is confirmed by these results. Contrary to models proposed in recent studies on the basis of Pb isotope and other compositional data, this change in mantle wedge character best explains the shift in the isotopic composition, particularly 143Nd/144Nd ratios, of modern Tofua Arc magmas relative to all other arc products from this region. Nevertheless, significant changes in the slab-derived flux during the evolution of the arc system are also required to explain second order variations in magma chemistry. In this region, the slab-derived flux is dominated by fluid; however, these fluids carry Pb with sediment-influenced isotopic signatures, indicating that their source is not restricted to the subducting altered mafic oceanic crust. This has been the case from the earliest magmatic activity in the arc (Eocene) until the present time, with the exception of two periods of magmatic activity recorded in samples from the Lau Islands. Both the Lau Volcanic Group, and Korobasaga Volcanic Group lavas preserve trace element and isotope evidence for a contribution from subducted sediment that was not transported as a fluid, but possibly in the form of a melt. This component shares similarities with that influencing the chemistry of the northern Tofua Arc magmas, suggesting some caution may be required in the adoption of constraints for the latter dependent upon the involvement of sediments from the Louisville Ridge. A key outcome of this study is to demonstrate that the models proposed to explain subduction zone magmatism cannot afford to ignore the small but important contributions made by the mantle wedge to the incompatible trace element inventory of arc magmas.

Coxsackievirus 135 induced apoptosis of HeLa cells: Effects on p53 and SUMO

Coxsackievirus B5 (CVB5), a human enterovirus of the family Picornaviridae, is a frequent cause of acute and chronic human diseases. The pathogenesis of enteroviral infections is not completely understood, and the fate of the CVB5-infected cell has a pivotal role in this process. We have investigated the CVB5-induced apoptosis of HeLa cells and found that it happens by the intrinsic pathway by a mechanism dependent on the ubiquitin-proteasome system, associated with nuclear aggregation of p53. Striking redistribution of both SUMO and UBC9 was noted at 4 h post-infection, simultaneously with a reduction in the levels of the ubiquitin-ligase HDM2. Taken together, these results suggest that CVB5 infection of HeLa cells elicit the intrinsic pathway of apoptosis by MDM2 degradation and p53 activation, destabilizing protein sumoylation, by a mechanism that is dependent on a functional ubiquitin-proteasome system. (C) 2009 Elsevier Inc. All rights reserved.

Effectiveness of primary angioplasty in the treatment of acute myocardial infarction. Analysis of in-hospital and late outcomes in 135 consecutive cases

OBJECTIVE: Evaluate early and late evolution of patients submitted to primary coronary angioplasty for acute myocardial infarction. METHODS: A prospective study of 135 patients with acute myocardial infarction submitted to primary transcutaneous coronary angioplasty (PTCA). Success was defined as TIMI 3 flow and residual lesion <50%. We performed statistical analyses by univariated, multivariated methods and survival analyze by Kaplan-Meier. RESULTS: PTCA success rate was 78% and early mortality 18,5%. Killip classes III and IV was associated to higher mortality, odds ratio 22.9 (95% CI: 5,7 to 91,8) and inversely related to age <75 years (OR = 0,93; 95% CI: 0.88 to 0.98). If we had chosen success flow as TIMI 2 and had excluded patients in Killip III/IV classes, success rate would be 86% and mortality 8%. The survival probability at the end or study, follow-up time 142 ± 114 days, was 80% and event free survival 35%. Greater survival was associated to stenting (OR = 0.09; 0.01 to 0.75) and univessel disease (OR = 0.21; 0.07 to 0.61). CONCLUSION: The success rate was lower and mortality was higher than randomized trials, however similar to that of non randomized studies. This demonstrated the efficacy of primary PTCA in our local conditions.

Asociación del anticuerpo anti-C1q con las manifestaciones clínicas, hematológicas e inmunológicas en el Lupus Eritematoso Sistémico: Estudio observacional retrospectivo de 135 casos.

: Las concentraciones de anticuerpo anti-C1q están elevadas en los pacientes afectados de LES. Según algunos estudios la presencia de este anticuerpo está asociada a la nefropatía lúpica, sin embargo en otros estudios esta relación no se comprobó. En nuestro trabajo relacionamos la positividad del anticuerpo anti-C1q con las manifestaciones clínicas, hematológicas e inmunológicas de la enfermedad. A diferencia de estudios previos sólo pudimos establecer una relación estadísticamente significativa con la vasculitis (p&0.001), la presencia de anti-DNAds (p 0.034), de anti-Sm (p 0.045) y el consumo de C3 (p 0.006). Se observó que los pacientes anti-C1q positivos desarrollan la enfermedad a edades más tempranas que los pacientes anti-C1q negativos. (p &0.005).

Clinical Supervision for Mental Health Nurses in NI (PDF 135 KB)

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