Insights into pathogenic events of HIV-associated Kaposi sarcoma and immune reconstitution syndrome related Kaposi sarcoma

A decrease in the incidence of human immune deficiency virus-associated Kaposi sarcoma (HIV-KS) and regression of some established HIV-KS lesions is evident after the introduction of highly active anti-retroviral treatment (HAART), and is attributed to generalized immune restoration, to the reconstitution of human herpesvirus (HHV)-8 specific cellular immune responses, and to the decrease in HIV Tat protein and HHV-8 loads following HAART. However, a small subset of HIV-seropositive subjects with a low CD4+ T cell count at the time of introduction of HAART, may develop HIV-KS as immune reconstitution inflammatory syndrome (IRIS) within 8 weeks thereafter

Myc-regulated microRNAs attenuate embryonic stem cell differentiation

Myc proteins are known to have an important function in stem cell maintenance. As Myc has been shown earlier to regulate microRNAs (miRNAs) involved in proliferation, we sought to determine whether c-Myc also affects embryonic stem (ES) cell maintenance and differentiation through miRNAs. Using a quantitative primer-extension PCR assay we identified miRNAs, including, miR-141, miR-200, and miR-429 whose expression is regulated by c-Myc in ES cells, but not in the differentiated and tumourigenic derivatives of ES cells. Chromatin immunoprecipitation analyses indicate that in ES cells c-Myc binds proximal to genomic regions encoding the induced miRNAs. We used expression profiling and seed homology to identify genes specifically downregulated both by these miRNAs and by c-Myc. We further show that the introduction of c-Myc-induced miRNAs into murine ES cells significantly attenuates the downregulation of pluripotency markers on induction of differentiation after withdrawal of the ES cell maintenance factor LIF. In contrast, knockdown of the endogenous miRNAs accelerate differentiation. Our data show that in ES cells c-Myc acts, in part, through a subset of miRNAs to attenuate differentiation

Use of Polyamide-6 Type Engineering Polymer as Grouted Rock Bolt Material

In this study, usability of Polyamide-6 type engineering polymer as a new rock bolt material was investigated carrying out a series of laboratory and field scale experiments. The Polyamide-6 type polymer tested as a grouted rock bolt material was assessed to have a good body strength, large elastic deformation limit and high energy absorbing capacity. The load bearing capacity of Polyamide-6 rock bolts was found to dominantly depend on the mechanical anchorage in front of the shank as a result of having low adhesion to the cement grout values. In this study, polyamide rock bolts have been designed with different mechanical anchors. It was suggested to start the systematical use of polyamide rock bolts having ideal support reactions under both static and dynamic load conditions in rock engineering. Especially, Polyamide-6 rock bolts were assessed to be economically usable in rock masses with squeezing, swelling or bursting problem, which need for non-decreasing support pressure while being higly deformed and good energy absorption capacity