The mitochondrion is a key organelle in the control of cell death. Nitric oxide (NO) inhibits complex IV in the respiratory chain and is reported to possess both proapoptotic and antiapoptotic actions. We investigated the effects of continuous inhibition of respiration by NO on mitochondrial energy status and cell viability. Serum-deprived human T cell leukemia (Jurkat) cells were exposed to NO at a concentration that caused continuous and complete (∼85%) inhibition of respiration. Serum deprivation caused progressive loss of mitochondrial membrane potential (Δψ_m) and apoptotic cell death. In the presence of NO, Δψ_mwas maintained compared to controls, and cells were protected from apoptosis. Similar results were obtained by using staurosporin as the apoptotic stimulus. As exposure of serum-deprived cells to NO progressed (>5 h), however, Δψ_mfell, correlating with the appearance of early apoptotic features and a decrease in cell viability. Glucose deprivation or iodoacetate treatment of cells in the presence of NO resulted in a collapse of Δψ_m, demonstrating involvement of glycolytic ATP in its maintenance. Under these conditions cell viability also was decreased. Treatment with oligomycin and/or bongkrekic acid indicated that the maintenance of Δψ_mduring exposure to NO is caused by reversal of the ATP synthase and other electrogenic pumps. Thus, blockade of complex IV by NO initiates a protective action in the mitochondrion to maintain Δψ_m; this results in prevention of apoptosis. It is likely that during cellular stress involving increased generation of NO this compound will trigger a similar sequence of events, depending on its concentration and duration of release.

The safety of thiopurines and anti-tumor necrosis factor-α (TNF-α) drugs during pregnancy remains controversial, as the experience with these drugs in this situation is limited. Our aim is to assess the safety of thiopurines and anti-TNF-α drugs for the treatment of inflammatory bowel disease (IBD) during pregnancy. Retrospective, multicenter study in IBD patients. Pregnancies were classified according to the therapeutic regimens during pregnancy or during the 3 months before the conception: non-exposed group, pregnancies exposed to thiopurines alone (group A), and pregnancies exposed to anti-TNF-α drugs (group B). An unfavorable Global Pregnancy Outcome (GPO) was considered if pregnancy developed with obstetric complications in the mother and in the newborn. A total of 187 pregnancies in the group A, 66 pregnancies in the group B, and 318 pregnancies in the non-exposed group were included. The rate of unfavorable GPO was different among the three groups (31.8% in non-exposed group, 21.9% in group A, and 34.8% in group B), being lower in pregnancies under thiopurines than among non-exposed (P=0.01). The rate of pregnancy complications was similar among the three groups (27.7% in non-exposed, 20.9% in group A, and 30.3% in group B). The rate of neonatal complications was different among the three groups (23.3% in non-exposed group, 13.9% in group A, and 21.2% in group B), being lower in pregnancies under thiopurines than among non-exposed (P=0.01). In the multivariate analysis, the treatment with thiopurines (odds ratio=0.6; 95% confidence interval=0.4–0.9, P=0.02) was the only predictor of favorable GPO, whereas maternal age >35 years at conception was the only predictor of unfavorable GPO. The treatment with anti-TNF-α drugs was not associated with an unfavorable GPO. The treatment with thiopurines and anti-TNF-α drugs does not seem to increase the risk of complications during pregnancy and does seem to be safe for the newborn.

The effect of prolonged exposure to nitric oxide on enzymes involved in cell metabolism was investigated in T lymphocyte‐derived Jurkat and L929 fibroblast human cell lines using a constant concentration of nitric oxide (1.5 μM) released by the nitric oxide donor DETA‐NO (0.5 mM). Nitric oxide inhibited immediately the respiration of the cells acting reversibly at complex IV. With time, the inhibition became progressively persistent, i.e. not reversed by trapping of nitric oxide with oxyhaemoglobin, and was preceded by a decrease in the concentration of the intracellular reduced glutathione. This persistent effect of nitric oxide on respiration was due to inhibition of complex I activity which could be reversed by addition of reduced glutathione or by cold light, suggesting that it was due to S‐nitrosylation of thiols necessary for the activity of the enzyme. The activity of other enzymes also known to be susceptible to inhibition by S‐nitrosylation, i.e. glyceraldehyde‐3‐phosphate dehydrogenase and glutathione reductase, was progressively decreased by exposure to nitric oxide with a similar time course to that observed for the inhibition of complex I. Furthermore, inhibition of these enzymes only occurred when the concentrations of reduced glutathione had previously fallen and could be prevented by increasing the intracellular concentrations of reduced glutathione. Our results suggest that S‐nitrosylation of different enzymes by nitric oxide may occur only if the reducing potential of the cells is impaired. British Journal of Pharmacology (2000) 129, 953–960; doi:10.1038/sj.bjp.0703147

Primary culture rat astrocytes exposed to the long acting nitric oxide donor (Z)‐1‐[2‐aminoethyl)‐N‐(2‐ammonioethyl)amino]diazen‐1‐ium‐1,2‐diolate (DETA‐NO) for 24 h approximately double their concentration of glutathione (GSH) and show no sign of cell death. In contrast, GSH was depleted by 48%, and significant loss of mitochondrial respiratory chain complex activity and cell death were observed in primary culture rat neurones subjected to DETA‐NO for 18 h. Northern blot analysis suggested that mRNA amounts of both subunits of glutamate‐cysteine ligase (GCL), the rate‐limiting enzyme in GSH synthesis, were elevated in astrocytes following nitric oxide (NO) exposure. This correlated with an increase in astrocytic GCL activity. Neurones on the other hand did not exhibit increased GCL activity when exposed to NO. In addition, the rate of GSH efflux was doubled and γ‐glutamyltranspeptidase (γ‐GT) activity was increased by 42% in astrocytes treated with NO for 24 h. These results suggest that astrocytes, but not neurones, up‐regulate GSH synthesis as a defence mechanism against excess NO. It is possible that the increased rate of GSH release and activity of γ‐GT in astrocytes may have important implications for neuroprotection in vivo by optimizing the supply of GSH precursors to neurones in close proximity.

Y ileocolic CD (n=11) were examined for the viral and microbial communities in their feces and, in one additional case, in the intestinal tissue. Using two different approaches, we compared the viral and microbial communities in several ways: by group (patients vs. controls), entity (viruses vs. bacteria), read assembly (unassembled vs. assembled reads), and methodology (our approach vs. an existing pipeline). Differences in the viral and microbial composition, and abundance between the two groups were analyzed to identify taxa that are under- or over-represented. RESULTS: A lower diversity but more variability between the CD samples in both virome and microbiome was found, with a clear distinction between groups based on the microbiome. Only ≈5% of the differential viral biomarkers are more represented in the CD group (Synechococcus phageS CBS1 andRetroviridaefamily viruses), compared with 95% in the control group. Unrelated patterns of bacteria and bacteriophages were observed. CONCLUSIONS: Our use of an extensive database is critical to retrieve more viral hits than in previous approaches. Unrelated patterns of bacteria and bacteriophages may be due to uneven representation of certain viruses in databases, among other factors. Further characterization ofRetroviridaeviruses in the CD group could be of interest, given their links with immunodeficiency and the immune responses. To conclude, some methodological considerations underlying the analysis of the viral community composition and abundance are discussed. *Correspondence: Andrés Moya, PhD, Departamento de Genética, Cavanilles Institute on Biodiversity and Evolutionary Biology, University of València, c/ José Beltrán 2, 46980 Paterna, Valencia, Spain or Genomics and Health Area, Centro Superior de Investigación en Salud Pública—Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana (CSISP-FISABIO), Avenida de Cataluña 21, 46020 Valencia, Spain. E-mail: andres.moya@uv.es or moya_and@gva.es Received 30 November 2012; accepted 6 May 2013 published online 13 June 2013 © 2013 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology...