Characterization of conducting polymers by inverse gas chromatography

The surface and bulk properties of chemically synthesized conducting polypyrrole doped by Cl- (PPyCl) and its insulating form (PPyR), were studied by Inverse Gas Chromatography (IGC). The dispersive component of the surface tension of both PPyCl and PPyR is in the 30-60 mJ/m2 range at 50°C. Moreover PPyCl and PPyR interact specifically with Lewis acids and bases, thus exhibiting amphoteric behavior. By studying the retention volumes vs temperature we detected a transition around 60-90 °C which might be attributed to the glass transition (Tg) of PPyCl

Interleukin-15 production by monocyte-derived dendritic cells and T cell proliferation in HIV-infected patients with discordant response to highly active antiretroviral therapy

A discordant response to highly active antiretroviral therapy (HAART) occurs when CD4 T cell counts are stable or increased over time despite persistently detectable HIV-RNA levels. In order to identify immunological factors affecting discordant treatment responses, a total of 27 HIV-infected patients were studied: (a) 10 naive patients (mean CD4(+) = 101·5 cells/µl; mean HIV-RNA = 4·8 log(10) copies/ml); (b) seven responder patients (mean CD4(+) = 908·9 cells/µl); and (c) 10 discordant patients (mean CD4(+) = 396·1 cells/µl; mean HIV-RNA = 5·4 log(10) copies/ml). Five healthy blood donors were included as HIV-seronegative controls. The following parameters were evaluated: interleukin (IL)-15 production by monocyte-derived dendritic cells (MDDC) after stimulation with lypopolysaccaride (LPS) and Candida albicans; recall and HIV-1-specific antigen lymphocyte proliferation (LP). Increased levels of IL-15 production by MDDC after stimulation with LPS and C. albicans were found both in discordant patients and responder patients. Conversely, a strong reduction of IL-15 levels was observed in naive patients. Discordant patients developed positive LP responses to C. albicans and HIV-1 p24. LP in response to C. albicans and HIV-1 p24 was also positive in responder patients. Decreased LP response was found in naive patients. In conclusion, HIV-infected patients with discordant viro-immunological responses to HAART present increased levels of IL-15 production by MDDC and enhanced recall and HIV-1-specific antigen LP responses, suggesting an improvement in indices of immune function

Early IL-12 p70, but not p40, production by splenic macrophages correlates with host resistance to blood-stage Plasmodium chabaudi AS malaria

In this study, we compared synthesis of IL-12, a potent Th1-inducing cytokine, by splenic macrophages recovered from resistant C57Bl/6 (B6) mice, which develop predominantly Th1 responses, and susceptible A/J mice that mount primarily Th2 responses during early Plasmodium chabaudi AS infection. Quantitative analysis of IL-12 p40 and p70 release by ELISA revealed significant differences between resistant B6 and susceptible A/J mice in the synthesis of biologically active IL-12 p70, but not p40, by splenic macrophages during early blood-stage P. chabaudi AS infection. Despite up-regulation in p40 and p35 mRNA levels, spontaneous release of p40 in vitro by splenic macrophages was not significantly increased following infection in either mouse strain. In contrast, spontaneous release of p70 by splenic macrophages was increased in cells from B6 mice and levels were significantly higher compared with A/J mice. Furthermore, compared with infected A/J hosts, splenic macrophages recovered from infected B6 mice produced significantly greater quantities of IL-12 p70, but not p40, in vitro, following stimulation with lipopolysaccharide (LPS) or malaria parasite antigen (PRBC). Moreover, we found significant increases in the percentage of macrophages earlier in the spleens of infected B6 mice that could further contribute to differences in total p70 levels in vivo. Taken together, these data suggest that macrophage IL-12 synthesis may contribute to the polarization of Th responses seen in resistant B6 and susceptible A/J mice during acute blood-stage malaria