Poliovirus RNA replicative complexes are associated with cytoplasmic membranous structures that accumulate during viral infection. These membranes were immunoisolated by using a monoclonal antibody against the viral nonstructural protein 2C. Biochemical analysis of the isolated membranes revealed that several organelles of the host cell (lysosomes, trans-Golgi stack and trans-Golgi network, and endoplasmic reticulum) contributed to the virus-induced membranous structures. Electron microscopy of infected cells preserved by high-pressure freezing revealed that the virus-induced membranes contain double lipid bilayers that surround apparently cytosolic material. Immunolabeling experiments showed that poliovirus proteins 2C and 3D were localized to the same membranes as the cellular markers tested. The morphological and biochemical data are consistent with the hypothesis that autophagy or a similar host process is involved in the formation of the poliovirus-induced membranes.

Various methods enable the preparation of platelet components and of highly concentrated components for local use according to standard blood banking criteria. The obtained components differ, particularly in their WBC content and in vitro platelet activation. These findings are relevant for planning and evaluating further studies of locally usable autologous platelet components.

Dissolving PC in Triton-X-100 releases maximum quantities of growth factors from platelets. The release of each growth factor by any sample preparation method should be investigated and interpreted separately. The preanalytical sample-preparation method, as well as the platelet and WBC content, influence the measurable levels of growth factors in PCs. The results implicate the need to correct, considerably upwards, previous estimations of the PDGF content of platelets.

A HeLa cDNA expression library was screened for human polypeptides that interacted with the poliovirus RNA-dependent RNA polymerase, 3D, using the two-hybrid system in the yeast Saccharomyces cerevisiae. (6), and a subunit of the translation initiation factor eIF-3 has been shown to be part of the brome mosaic virus template-specific replicase (7).We have used the two-hybrid system in the yeast Saccharomyces cerevisiae to identify human polypeptides that can interact with the poliovirus RNA-dependent RNA polymerase, 3D (8, 9). A library of plasmids that contain HeLa cDNAs fused to sequences that encode a transcriptional activation domain was screened for those encoding polypeptides that interact with a LexA-3D hybrid protein (9). Because poliovirus RNA replicates well in HeLa cells, mRNAs that encode proteins important for replication should be represented in this HeLa cDNA library, which was provided by Roger Brent and Jeno Gyuris (Harvard University). We have identified cDNAs for several host proteins that interact with 3D polymerase, most notably a 68-kDa protein that associates with Src during

Within the limits of the study, we conclude that for bone defects larger than 4 mm in case of peri-implantitis, this single surgical intervention provided a reliable method to reduce bone defects.