Hydrogen peroxide stimulates rat colonic prostaglandin production and alters electrolyte transport.

The changes in short circuit current (electrogenic Cl- secretion) of rat colon brought about by xanthine/xanthine oxidase in the Ussing chamber were inhibited by catalase and diethyldithiocarbamate, but not by superoxide dismutase. These results, the reproduction of the response with glucose/glucose oxidase and with exogenous H2O2, and the lack of effect of preincubation with deferoxamine or thiourea implicate H2O2, and not O2- or OH., as the important reactive oxygen metabolite altering intestinal electrolyte transport. 1 mM H2O2 stimulated colonic PGE2 and PGI2 production 8- and 15-fold, respectively, inhibited neutral NaCl absorption, and stimulated biphasic electrogenic Cl secretion with little effect on enterocyte lactic dehydrogenase release, epithelial conductance, or histology. Cl- secretion was reduced by cyclooxygenase inhibition. Also, the Cl- secretion, but not the increase in prostaglandin production, was reduced by enteric nervous system blockade with tetrodotoxin, hexamethonium, or atropine. Thus, H2O2 appears to alter electrolyte transport by releasing prostaglandins that activate the enteric nervous system. The change in short circuit current in response to Iloprost, but not PGE2, was blocked by tetrodotoxin. Therefore, PGI2 may be the mediator of the H2O2 response. H2O2 produced in nontoxic concentrations in the inflamed gut could have significant physiologic effects on intestinal water and electrolyte transport

Dose-Reduced Busulfan, Cyclophosphamide, and Autologous Stem Cell Transplantation for Human Immunodeficiency Virus–Associated Lymphoma: AIDS Malignancy Consortium Study 020

AbstractIntensive chemotherapy for human immunodeficiency virus (HIV)-associated non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) has resulted in durable remissions in a substantial proportion of patients. High-dose chemotherapy and autologous stem cell transplantation (AuSCT), moreover, has resulted in sustained complete remissions in selected patients with recurrent chemosensitive disease. Based on a favorable experience with dose-reduced high-dose busulfan, cyclophosphamide, and AuSCT for older patients with non-HIV–associated aggressive lymphomas, an AIDS Malignancy Consortium multicenter trial was undertaken using the same dose-reduced busulfan and cyclophosphamide preparative regimen with AuSCT for recurrent HIV-associated NHL and HL. Of the 27 patients in the study, 20 received an AuSCT. The median time to achievement of an absolute neutrophil count (ANC) of ≥ 0.5×109/L was 11 days (range, 9-16 days). The median time to achievement of an unsupported platelet count of ≥ 20×109/L was 13 days (range, 6-57 days). One patient died on day +33 posttransplantation from hepatic veno-occlusive disease (VOD) and multiorgan failure. No other fatal regimen-related toxicity occurred. Ten of 19 patients (53%) were in complete remission at the time of their day +100 post-AuSCT evaluation. Of the 20 patients, 10 were alive and event-free at a median of 23 weeks post-AuSCT. Median overall survival (OS) was not reached by 13 of the 20 patients alive at the time of last follow-up. This multi-institutional trial demonstrates that a regimen of dose-reduced high-dose busulfan, cyclophosphamide, and AuSCT is well tolerated and is associated with favorable disease-free survival (DFS) and OS probabilities for selected patients with HIV-associated NHL and HL

Immune system control of rat and rabbit colonic electrolyte transport. Role of prostaglandins and enteric nervous system.

Le système immunitaire comme le système nerveux et endocrinien intestinal, peut être un système régulateur important du transport intestinal de l'eau et des électrolytes à l'état normal et dans les états pathologiques

A family of oxide ion conductors based on the ferroelectric perovskite Na0.5Bi0.5TiO3

Oxide ion conductors find important technical applications in electrochemical devices such as solid-oxide fuel cells (SOFCs), oxygen separation membranes and sensors1, 2, 3, 4, 5, 6, 7, 8, 9. Na0.5Bi0.5TiO3 (NBT) is a well-known lead-free piezoelectric material; however, it is often reported to possess high leakage conductivity that is problematic for its piezo- and ferroelectric applications10, 11, 12, 13, 14, 15. Here we report this high leakage to be oxide ion conduction due to Bi-deficiency and oxygen vacancies induced during materials processing. Mg-doping on the Ti-site increases the ionic conductivity to ~0.01 S cm−1 at 600 °C, improves the electrolyte stability in reducing atmospheres and lowers the sintering temperature. This study not only demonstrates how to adjust the nominal NBT composition for dielectric-based applications, but also, more importantly, gives NBT-based materials an unexpected role as a completely new family of oxide ion conductors with potential applications in intermediate-temperature SOFCs and opens up a new direction to design oxide ion conductors in perovskite oxides