Synthesis of 2',3'-dideoxy-2',3'-didehydro nucleosides via a serendipitous route

This paper describes a "green" synthesis of 2',3'-unsaturated 2',3'-dideoxynucleosides via an electrochemical reaction. Using this approach d4T, d4U, ddA and ddI can be synthesized in high yields.     

An analysis of turbulent shear stresses in leakage flow through a bileaflet mechanical prostheses

In this work, estimates of turbulence were made from pulsatile flow laser Doppler velocimetry measurements using traditional phase averaging and averaging after the removal of cyclic variation. These estimates were compared with estimates obtained from steady leakage flow LDV measurements and an analytical method. The results of these studies indicate that leakage jets which are free and planar in shape may be more unstable than other leakage jets, and that cyclic variation does not cause a gross overestimation of the Reynolds stresses at large distances from the leakage jet orifice.     

Mechanism of incomplete mitral leaflet coaptation--interaction of chordal restraint and changes in mitral leaflet coaptation geometry. Insight from in vitro validation of the premise of force equilibrium

Clinically observed incomplete mitral leaflet coaptation was reproduced in vitro by altering the balance of the chordal tethering and chordal coapting force components. Mitral leaflet coaptation geometry was distorted by changes of the spatial relations between the papillary muscles and the mitral valve as well as hemodynamics. Mitral leaflet malalignment was accentuated by a redistribution of the chordal tethering and coapting force components. For the overall assessment of systolic mitral leaflet configuration in functional mitral regurgitation it is important to consider the interaction between chordal restraint and an altered mitral leaflet coaptation geometry.     

Two acyl sucroses from Petunia nyctaginiflora

Two new acyl sucroses were isolated from the epigeal parts of Petunia nyctaginiflora Juss. (Solanaceae). Their structures were determined to be 2, 3, 4-tri (5-methylhexanoyl)-alpha-D-glucopyranosyl-beta-D-fructofuranoside (2) and 2, 3, 4-tri (6-methylheptanoyl)-alpha-D-glucopyranosyl-beta-D-fructofuranoside (4) on the basis of chemical and spectroscopic evidence.     

Novel synthesis of 2'-O-methylguanosine

An efficient and chemoselective synthesis of 2'-O-methylguanosine (6) has been accomplished in high yield without protection of the guanine base. The salient feature of the synthesis of 6 lies in the application of methylene-bis-(diisopropylsilyl chloride), (MDPSCl(2), 2) as a new 3',5'-O-protecting group for nucleosides. Use of CH(3)Cl as a weak electrophile and NaHMDS as a mild base was crucial to the success of the 2'-O-methylation of 3',5'-O-protected guanosine.     

Surfactant Protein D Inhibits HIV-1 Infection of Target Cells via Interference with gp120-CD4 Interaction and Modulates Pro-Inflammatory Cytokine Production

Surfactant Protein SP-D, a member of the collectin family, is a pattern recognition protein, secreted by mucosal epithelial cells and has an important role in innate immunity against various pathogens. In this study, we confirm that native human SP-D and a recombinant fragment of human SP-D (rhSP-D) bind to gp120 of HIV-1 and significantly inhibit viral replication in vitro in a calcium and dose-dependent manner. We show, for the first time, that SP-D and rhSP-D act as potent inhibitors of HIV-1 entry in to target cells and block the interaction between CD4 and gp120 in a dose-dependent manner. The rhSP-D-mediated inhibition of viral replication was examined using three clinical isolates of HIV-1 and three target cells: Jurkat T cells, U937 monocytic cells and PBMCs. HIV-1 induced cytokine storm in the three target cells was significantly suppressed by rhSP-D. Phosphorylation of key kinases p38, Erk1/2 and AKT, which contribute to HIV-1 induced immune activation, was significantly reduced in vitro in the presence of rhSP-D. Notably, anti-HIV-1 activity of rhSP-D was retained in the presence of biological fluids such as cervico-vaginal lavage and seminal plasma. Our study illustrates the multi-faceted role of human SP-D against HIV-1 and potential of rhSP-D for immunotherapy to inhibit viral entry and immune activation in acute HIV infection.