Serpentinite-derived slab fluids control the oxidation state of the subarc mantle.

Recent geochemical evidence confirms the oxidized nature of arc magmas, but the underlying processes that regulate the redox state of the subarc mantle remain yet to be determined. We established a link between deep subduction-related fluids derived from dehydration of serpentinite ± altered oceanic crust (AOC) using B isotopes and B/Nb as fluid proxies, and the oxidized nature of arc magmas as indicated by Cu enrichment during magma evolution and V/Yb. Our results suggest that arc magmas derived from source regions influenced by a greater serpentinite (±AOC) fluid component record higher oxygen fugacity.

Early accretion of water and volatile elements to the inner Solar System: evidence from angrites.

Inner Solar System bodies are depleted in volatile elements relative to chondrite meteorites, yet the source(s) and mechanism(s) of volatile-element depletion and/or enrichment are poorly constrained. The timing, mechanisms and quantities of volatile elements present in the early inner Solar System have vast implications for diverse processes, from planetary differentiation to the emergence of life. We report major, trace and volatile-element contents of a glass bead derived from the D'Orbigny angrite, the hydrogen isotopic composition of this glass bead and that of coexisting olivine and silicophosphates, and the Pb-Pb age of the silicophosphates, 4568 ± 20 Ma.

Experimental constraints on the damp peridotite solidus and oceanic mantle potential temperature.

Decompression of hot mantle rock upwelling beneath oceanic spreading centers causes it to exceed the melting point (solidus), producing magmas that ascend to form basaltic crust ~6 to 7 kilometers thick. The oceanic upper mantle contains ~50 to 200 micrograms per gram of water (HO) dissolved in nominally anhydrous minerals, which-relative to its low concentration-has a disproportionate effect on the solidus that has not been quantified experimentally. Here, we present results from an experimental determination of the peridotite solidus containing known amounts of dissolved hydrogen.

Microtomography of partially molten rocks: three-dimensional melt distribution in mantle peridotite.

The permeability of the upper mantle controls melt segregation beneath spreading centers. Reconciling contradictory geochemical and geophysical observations at ocean ridges requires a better understanding of transport properties in partially molten rocks. Using x-ray synchrotron microtomography, we obtained three-dimensional data on melt distribution for mantle peridotite with various melt fractions.

Accelerated senescence in the kidneys of patients with type 2 diabetic nephropathy.

We examined the hypothesis that senescence represents a proximate mechanism by which the kidney is damaged in type 2 diabetic nephropathy (DN). As a first step, we studied whether the senescence-associated beta-galactosidase (SA-beta-Gal) and the cell cycle inhibitor p16INK4A are induced in renal biopsies from patients with type 2 DN. SA-beta-Gal staining was approximately threefold higher (P < 0.

Mammalian catalase: a venerable enzyme with new mysteries.

Mammalian catalase has been the subject of many classic biochemical studies. Despite our detailed knowledge of its functional mechanisms and its three-dimensional structure, however, several unexpected features of mammalian catalase have been recently discovered. For example, some mammalian catalases seem to have oxidase activity and produce reactive oxygen species when exposed to UVB light.

Clonal granulocytes in polycythaemia vera and essential thrombocythaemia have shortened telomeres.

Summary The purpose of this study was to evaluate telomere length in peripheral blood granulocytes and mononuclear cells collected from 22 women with polycythaemia vera (PV) and essential thrombocythaemia (ET). PV and ET are chronic myeloproliferative diseases whose heterogeneity of stem cell origin and clonal development has been established through analysis of X-chromosome inactivation patterns. The results from clonality assay and determination of telomere length show that only clonal granulocytes have shortened telomeres.

High telomerase activity in granulocytes from clonal polycythemia vera and essential thrombocythemia.

Essential thrombocythemia (ET) and polycythemia vera (PV) are chronic myeloproliferative disorders that share the involvement of a multipotent progenitor cell and dominance of the transformed clone over normal hematopoiesis. On the other hand, the heterogeneity of these diseases with respect to clonal development from a common progenitor has been well established. To identify useful prognostic indicators, we analyzed telomerase activity (TA), a known marker of neoplastic proliferation, in granulocytes (PMNs) and mononuclear cells (MNCs) from 22 female patients with ET and PV.

A novel NADPH:(bound) NADP+ reductase and NADH:(bound) NADP+ transhydrogenase function in bovine liver catalase.

Many catalases have the shared property of containing bound NADPH and being susceptible to inactivation by their own substrate, H2O2. The presence of additional (unbound) NADPH effectively prevents bovine liver and human erythrocytic catalase from becoming compound II, the reversibly inactivated state of catalase, and NADP+ is known to be generated in the process. The function of the bound NADPH, which is tightly bound in bovine liver catalase, has been unknown.

Influenza vaccine in chronic lymphoproliferative disorders and multiple myeloma.

Objective: Vaccination against influenza in patients with chronic lymphoproliferative disorders (CLPD) and multiple myeloma (MM) is still a matter of clinical uncertainty. The aim of this study was to determine the safety, immunogenicity and clinical response to a commercially available vaccine against influenza in a group of such patients.

Methods: Thirty-four patients with CLPD and MM and 34 immunologically normal subjects were vaccinated with the same vaccine against influenza.

Exposure of erythrocytes to methylene blue shows the active role of catalase in removing hydrogen peroxide.

Methylene blue (MB) is a powerful reducing agent that is widely used in clinical practice as well as for metabolic studies of the erythrocyte. We have investigated the role of catalase as a specific enzyme for the removal of hydrogen peroxide by measuring the in vitro effects of MB on human red cells. In the presence of MB, catalase underwent inactivation even with the co-existence of active generation of NADPH, leaving the glutathione concentration unaffected.

Histological subtypes of Hodgkin's disease in the setting of HIV infection.

The relative incidence of Hodgkin's disease (HD) has been found to have increased approximately seven times in HIV-infected patients. We analyzed the histological distribution of HIV-associated HD with the aim of clarifying purported difference(s) from de novo HD. References on HIV/AIDS-associated HD were retrieved from the most complete databases.

Mutations of the HFE gene and the risk of hepatocellular carcinoma.

The discovery of the C282Y and H63D point mutations in the hereditary hemochromatosis-associated HFE gene allows us to study the molecular basis of congenital and acquired iron overload disorders. In hereditary hemochromatosis an increased frequency of the C282Y and, to a lesser extent, of the H63D mutations has been established, but their role in other conditions associated with iron overload and their prevalence in the normal population are still under investigation. We sought to determine the presence of such mutations, and their possible involvement in the multi-step neoplastic transformation of the hepatocytes, in patients diagnosed with hepatocellular carcinoma, a frequent complication of iron-induced liver cirrhosis occurring in untreated hereditary hemochromatosis subjects.

Mechanisms of protection of catalase by NADPH. Kinetics and stoichiometry.

NADPH is known to be tightly bound to mammalian catalase and to offset the ability of the substrate of catalase (H2O2) to convert the enzyme to an inactive state (compound II). In the process, the bound NADPH becomes NADP+ and is replaced by another molecule of NADPH. This protection is believed to occur through electron tunneling between NADPH on the surface of the catalase and the heme group within the enzyme.

Heterogeneity of clonal development in chronic myeloproliferative disorders.

Recent reports have suggested a previously unexpected variability in the expression of the dominant neoplastic clone in myeloproliferative disorders (MPD). We evaluated 49 female patients with MPD and informative at the X-linked androgen receptor (AR) locus to establish the X chromosome inactivation pattern of hemopoietic cells. Whereas in chronic myelogenous leukemia (CML) the granulocytes (PMN) were uniformly of monoclonal origin, a striking heterogeneity of clonal development was found in PMN from patients with other MPD, with up to 50% of them expressing a polyclonal pattern of X inactivation.

X chromosome inactivation patterns in normal females.

Since one of the two X chromosomes is randomly inactivated at an early stage of female embryonic development, X-linked markers have been used to study the origin and development of various neoplastic disorders in affected heterozygous women; clonality assays have provided a useful tool to the understanding of the mechanisms underlying the development of neoplasia. Recently, a technique of clonal analysis has been devised that takes advantage of a highly polymorphic short tandem repeat within the X-linked human androgen receptor (AR) gene, resulting in a heterozygosity rate approaching 90%. The rapid expansion of the number of women now suitable for X inactivation analysis has however given rise to new controversies, one of the more troublesome being the possibility of a modification of the pattern of X- chromosome inactivation pattern in blood cells of elderly women.

Familial Hodgkin's disease: a disease of young adulthood?

Familial Hodgkin's disease (FHD) is estimated to represent approximately 4.5% of all cases of Hodgkin's disease (HD). Shared environmental factors, such as Epstein-Barr virus and other viral agents, and genetic determinants have all been proposed to explain familial aggregation of HD.

Polyclonal origin of medullary carcinoma of the thyroid in multiple endocrine neoplasia type 2.

Multiple endocrine neoplasia type 2 (MEN 2) is a dominantly inherited cancer syndrome characterized by medullary thyroid carcinoma (MTC) and other tumors. Since MTC can also occur in a sporadic form and as familial medullary thyroid carcinoma, this neoplasm offers a unique opportunity to investigate the difference of origin, if any, between the sporadic and the hereditary forms of a tumor. While sporadic malignancies have usually been found to result from a mutational event occurring at the single-cell level and are therefore monoclonal, studies on hereditary neoplasms have been scarce and often produced conflicting results.

[Use of new forms for the evaluation of the clinical apprenticeship of nursing students].

The development of forms oriented to the evaluation of the practical training of nursing students is described. The activities of the nursing students were listed and the relevant activities for each practical training period were identified. The level of difficulty of the activity, the skills needed and the performance level to be reached by the end of the practical training period was agreed on and clearly stated for each activity.

Active involvement of catalase during hemolytic crises of favism.

The endemic occurrence of favism in certain Mediterranean regions provided an investigative opportunity for testing in vivo the validity of claims as to the role of catalase in protecting human erythrocytes against peroxidative injury. Reduced activity of catalase was found in the erythrocytes of six boys who were deficient in erythrocytic glucose-6-phosphate dehydrogenase (G6PD) and who were studied while suffering hemolysis after ingesting fava beans. Activity of catalase was further reduced when their red blood cells were incubated with aminotriazole.

Unusual bone marrow relapse of Hodgkin's disease with typical Pel-Ebstein fever.

We report the unusual case of a 43-year-old man with a diagnosis of clinical stage I A mixed cellularity Hodgkin's disease (HD), who relapsed 4 years after diagnosis with exclusive bone marrow involvement and a cyclic variation in body temperature typical of Pel-Ebstein fever. In the absence of clinical and laboratory signs of infection, a restaging of the lymphoma was performed. Total-body CT scan revealed no parenchymal or lymph node involvement, while a bone-marrow biopsy was positive for the presence of Reed-Sternberg cells.

Predominant role of catalase in the disposal of hydrogen peroxide within human erythrocytes.

Purified enzymes were mixed to form a cell-free system that simulated the conditions for removal of hydrogen peroxide within human erythrocytes. Human glutathione peroxidase disposed of hydrogen peroxide (H2O2) at a rate that was only 17% of the rate at which human catalase simultaneously removed hydrogen peroxide. The relative rates observed were in agreement with the relative rates predicted from the kinetic constants of the two enzymes.