A G protein is involved in the angiotensin AT2 receptor inhibition of the T-type calcium current in non-differentiated NG108-15 cells

In non-differentiated NG108-15 cells, both angiotensin II (Ang II) (100 nM) and CGP 42112 (100 nM) decreased the T-type calcium current amplitude by 24 +/- 2% and 21 +/- 3%, respectively. cGMP is not a mediator of the Ang II effect, since loading of cells with 50 microM cGMP did not prevent the inhibitory effects of Ang II. The effects of Ang II involves a non-identified GTPase activity since incubation with GDP beta S (3 mM) completely reversed the inhibitory effect of Ang II while GTP gamma S mimicked its effect. However, Ang II binding was not affected by GTP gamma S, and the effect of Ang II was not modified in pertussis toxin-treated cells. The inhibitory effect of Ang II on the T-type Ca2+ current involves a phosphotyrosine phosphatase activity since sodium orthovanadate prevented the effects of Ang II, although microcystin-LR, a selective Ser/Thr phosphatase 1 and 2A inhibitor, did not modify the effect of Ang II. These results provide the first evidence of a modulation of membrane conductance by Ang II through the AT2 receptor and demonstrate the involvement of a phosphotyrosine phosphatase and a G protein in the AT2 transduction mechanism in NG108-15 cells. Moreover, our data suggest that phosphotyrosine phosphatase activation is proximal to receptor occupation, since sodium orthovanadate inhibits both GTPase activity and T-type current blockage induced by Ang II or CGP 42112, while GTP gamma S inhibition of the T-type calcium current is not impaired.     

1,4-Cyclohexanecarboxylates: potent and selective inhibitors of phosophodiesterase 4 for the treatment of asthma

Evaluation of a variety of PDE4 inhibitors in a series of cellular and in vivo assays suggested a strategy to improve the therapeutic index of PDE4 inhibitors by increasing their selectivity for the ability to inhibit PDE4 catalytic activity versus the ability to compete for high affinity [3H]rolipram-binding sites in the central nervous system. Use of this strategy led ultimately to the identification of cis-4-cyano-4-[3-(cyclopentyloxy)-4-methoxyphenyl]cyclohexane-1-carboxyl ic acid (1, SB 207499, Ariflo), a potent second-generation inhibitor of PDE4 with a decreased potential for side effects versus the archetypic first generation inhibitor, (R)-rolipram.     

Abdominal and thoracoabdominal aortic aneurysm

Most abdominal aortic aneurysms (AAA) and thoracoabdominal aortic aneurysms (TAAA) are asymptomatic and are found on physical exam or incidentally during radiological studies for other indications. These aneurysms are repaired primarily because their risk of rupture increases geometrically as the size exceeds 5 cm. The potential morbidity of intraoperative visceral and spinal ischemia involved with TAAA repair may be reduced with various adjunctive maneuvers.     

Anti-CD4 activity of normal human immunoglobulin G for therapeutic use. (Intravenous immunoglobulin, IVIg)

The effects of intravenously administered normal immunoglobulin G (IVIg) in autoimmune diseases are dependent on the ability of IVIg to interact with surface molecules of lymphocytes. In the present study, we demonstrate the presence of anti-CD4 activity in IVIg by showing the ability of IVIg to bind to CD4 and to inhibit CD4-dependent cellular functions. Binding of IVIg to recombinant soluble human CD4 was assessed by ELISA, immunoblotting and real time analysis of complex formation. Anti-CD4 antibodies isolated from IVIg by affinity-chromatography bound to human CD4+ T cells. These anti-CD4 antibodies inhibited proliferative responses in MLR and infection of CD4+ human T cells with HIV. These results indicate that IVIg contains antibodies reactive with human CD4 and that these anti-CD4 antibodies exhibit biological functions. The presence of anti-CD4 antibodies in IVIg may be relevant to the immunoregulatory effects of normal polyspecific immunoglobulin G.     

Changes in plasma and colonic mucosa fatty acid profiles in rats with ulcerative colitis induced by trinitrobenzene sulfonic acid

Polyunsaturated fatty acids have a key role in the pathogenesis of inflammatory bowel disease since some of the arachidonic acid-derived eicosanoids have been found to be increased in inflamed intestinal mucosa in the acute phase of human disease. The aim of this study was to prospectively assess plasma and colon mucosa fatty acid patterns in rats with experimental ulcerative colitis. Twenty rats were treated with trinitrobenzene sulfonic acid and 20 with NaCl; two groups were killed after one week and two after two weeks to evaluate colon damage. Plasma was obtained by aortic puncture and colonic mucosa was scraped off and the fatty acid pattern was determined by gas-liquid chromatography. Total, saturated, and monounsaturated plasma fatty acids were significantly higher in both periods of ulcerative colitis as compared to controls. Plasma n-6 fatty acids were increased after treatment, but no significant changes were observed concerning to n-3 fatty acids. With regard to colon mucosa, saturated and monounsaturated fatty acids did not change because of the disease; however, n-6 fatty acids decreased in the first week and increased in the second week and n-3 fatty acids were increased. Changes on the fatty acid distribution in plasma did not parallel to those of colonic mucosa except for 22:6(n-3). We have also found that experimental ulcerative colitis induced by trinitrobenzene sulfonic acid reproduces many of the features related to changes in plasma and colon mucosa fatty acids observed in the human disease.     

Synthesis and in vitro antimalarial activity of sulfone endoperoxides

A series of 4,8-dimethyl-4-phenylsulfonylmethyl-2,3-dioxabicyclo[3.3.1]+ ++nonanes, carrying a variety of substituents at position-8 (4) were prepared by a short and efficient method from R-(+)-limonene. Key reactions include thiol oxygen cooxidation, and alkylation and acylation of a sterically hindered tertiary alcohol compatible with the endoperoxy functionality. Some of compounds 4, which are structurally related to yingzhaosu A (2), were found to exhibit in vitro antimalarial activity comparable to that of artemisinin (1) and superior to that of arteflene (3).     

Structural and thermodynamic characterization of the interaction of the SH3 domain from Fyn with the proline-rich binding site on the p85 subunit of PI3-kinase

The interaction of the Fyn SH3 domain with the p85 subunit of PI3-kinase is investigated using structural detail and thermodynamic data. The solution structure complex of the SH3 domain with a proline-rich peptide mimic of the binding site on the p85 subunit is described. This indicates that the peptide binds as a poly(L-proline) type II helix. Circular dichroism spectroscopic studies reveal that in the unbound state the peptide exhibits no structure. Thermodynamic data for the binding of this peptide to the SH3 domain suggest that the weak binding (approximately 31 microM) of this interaction is, in part, due to the entropically unfavorable effect of helix formation (delta S0 = -78 J.mol-1.K-1). Binding of the SH3 domain to the intact p85 subunit (minus its own SH3 domain) is tighter, and the entropic and enthalpic contributions are very different from those given by the peptide interaction (delta S0 = +252 J.mol-1.K-1; delta H0 = +44 kJ.mol-1). From these dramatically different thermodynamic measurements we are able to conclude that the interaction of the proline-rich peptide does not effectively mimic the interaction of the intact p85 subunit with the SH3 domain and suggest that other interactions could be important.