Tumour necrosis factor-alpha uncouples respiration in isolated rat mitochondria

Recent studies have demonstrated the existence of an intracellular (associated with mitochondria) tumour necrosis factor-alpha (TNF) binding protein. In an attempt to elucidate if this receptor could be involved in TNF action, we have incubated liver isolated mitochondria in the presence of recombinant murine TNF. The results show that the addition of TNF at concentrations as low as 10(-6) U/microl resulted in a clear uncoupling respiration of liver isolated mitochondria, therefore suggesting that TNF can indeed exert intracellular effects, which are possibly linked with its cytotoxic mechanism.     

Sepsis induces DNA fragmentation in rat skeletal muscle

Recent studies have demonstrated the activation of skeletal muscle DNA fragmentation in some catabolic conditions. In an attempt to elucidate if sepsis (a catabolic state) was also associated with muscle apoptosis, sepsis was induced by cecal ligation and puncture, and the results clearly show an induction of DNA fragmentation in gastrocnemius muscle following the induction of the septic state. Administration of rolipram (an inhibitor of tumour necrosis factor-a (TNF-alpha) synthesis) to septic rats clearly prevented the increased DNA fragmentation, suggesting that TNF-alpha is involved in the activation of the apoptotic events in septic rat skeletal muscle.     

Divergent role of ceramide generated by exogenous sphingomyelinases on NF-kappa B activation and apoptosis in human colon HT-29 cells

A novel branch of the Ras family, Rit, was recently identified. Rit exhibits a distinct C-terminus and effector domain, and does not activate mitogen-activated protein kinase (MAPK) but can cooperate with Raf to transform fibroblasts. Here, we found that when overexpressed, activated mutants of Rit transform NIH 3T3 cells efficiently, and stimulate p38gamma but not MAPK, p38alpha, p38gamma, p38delta, or ERK5. Furthermore, we provide evidence that p38gamma activation is required for the ability of Rit to stimulate gene expression and cellular transformation. These findings suggest that this unique GTPase stimulates proliferative pathways distinct from those regulated by other Ras family members.     

A simple method for N-15 labelling of exocyclic amino groups in synthetic oligodeoxynucleotides

The use of the ammonia deprotection step to introduce ¹⁵N labels at specific exocyclic amino positions of adenine, cytosine, guanine or 2-aminopurine of oligodeoxynucleotides is described.     

Relevance of CD6-mediated interactions in T cell activation and proliferation

CD6 is a cell surface receptor expressed on immature thymocytes and mature T and B1a lymphocytes. The ultimate function of CD6 has not been deciphered yet, but much evidence supports a role for CD6 in T cell activation and differentiation. In this study, we show that a fraction of CD6 molecules physically associates with the TCR/CD3 complex by coimmunoprecipitation, cocapping, and fluorescence resonance energy transfer experiments. Image analysis of Ag-specific T-APC conjugates demonstrated that CD6 and its ligand, activated leukocyte cell adhesion molecule (CD166), colocalize with TCR/CD3 at the center of the immunological synapse, the so-called central supramolecular activation cluster. The addition of a soluble rCD6 form significantly reduced the number of mature Ag-specific T-APC conjugates, indicating that CD6 mediates early cell-cell interactions needed for immunological synapse maturation to proceed. This was in agreement with the dose-dependent inhibition of CD3-mediated T cell proliferation induced by soluble rCD6. Taken together, our data illustrate the important role played by the intra- and intercellular molecular interactions mediated by CD6 during T cell activation and proliferation processes.     

Regulation of iNOS expression and glutathione levels in rat liver by oxygen tension

SNI-2011 induces the long-lasting increase in the amount of aquaporin-5 (AQP5) in apical plasma membranes (APMs) of rat parotid acini in a concentration-dependent manner. This induction was inhibited by p-F-HHSiD, U73122, TMB-8, or dantrolene but not by bisindolmaleimide or H-7, indicating that SNI-2011 acting at M(3) muscarinic receptors induced translocation of AQP5 via [Ca(2+)](i) elevation but not via the activation of protein kinase C. In contrast, acetylcholine induced a transient translocation of AQP5 to APMs. SNI-2011 induces long-lasting oscillations of [Ca(2+)](i) in the presence of extracellular Ca(2+). Thus, SNI-2011 induces a long-lasting translocation of AQP5 to APMs coupled with persistent [Ca(2+)](i) oscillations.     

Identification of culturable bacteria present in haemodialysis water and fluid

Water used to prepare haemodialysis fluid is not sterile, and its microbiological control is important for the prevention of haemodialysis-associated illness. Bacterial populations inhabiting a distribution system for haemodialysis water were studied over an 18-month period. 203 planktonic bacteria isolated on R2A medium were identified by restriction analysis and sequencing of 16S rRNA gene. A diverse bacterial community was detected, containing predominantly Gram-negative members of the Alphaproteobacteria and Betaproteobacteria, as well as representatives of the genus Mycobacterium. Ecological and clinical consequences are discussed: bacteria from the genera Novosphingobium, Pseudomonas and Sphingomonas have been described in the build-up of biofilms, and others like Acinetobacter, Mycobacterium or Brevibacterium may represent a health risk to patients under haemodialysis treatment.     

Synthesis and structure-activity relationships of piperidinylpyrrolopyridine derivatives as potent and selective H1 antagonists

The synthesis and structure-activity relationships of piperidinylpyrrolopyridines as potent and selective H(1) antagonists are discussed. It was found that the nature of the acid chain bonded to piperidine was a key feature for maintaining both the duration of action in vivo and lack of sedative properties.