Special delivery from mitochondria to peroxisomes

Inter-organellar communication and interactions are necessary and accepted consequences of the segregation of biochemical functions into subcellular organelles. Recently, Heidi McBride and her collaborators found a novel link between mitochondria and peroxisomes in their discovery of mitochondria-derived vesicles (MDVs), which appear to fuse with a fraction of pre-existing peroxisomes in mammalian cells. We discuss the potential role of this vesicle population in the context of pathways for the exchange of metabolites and/or macromolecules between these compartments.     

Special delivery: vesicle trafficking in prokaryotes

Although the observation that Gram-negative bacteria produce outer membrane vesicles (MVs) was made over 40 years ago, their biological roles have become a focus of study only within the past 10 years. Recent progress in this area has revealed that bacterial MVs are utilized for several processes including delivery of toxins to eukaryotic cells, protein and DNA transfer between bacterial cells, and trafficking of cell-cell signals. Some of these roles appear to be generalized among the Gram-negative bacteria while others are restricted to specific bacterial species/strains. Here we review the known roles of MVs, propose other roles for MVs in mediating interspecies and inter-kingdom communication, and discuss the mechanism of MV formation.     

Special delivery: dynamic targeting via cortical capture of microtubules

Gap junction formation depends on the proper transport of connexin hemichannels to sites of cell-cell contact. Recently in Cell, Shaw et al. implicate microtubule tip tracking proteins in the trafficking of connexin43 to adherens junctions (Shaw et al., 2007). This finding suggests a mechanism for targeted delivery of membrane proteins by microtubule capture at the cortex.     

Special stereotactic radiotherapy techniques: procedures and equipment for treatment simulation and dose delivery

Stereotactic radiotherapy (SRT ) is a multi-step procedure with each step requiring extreme accuracy. Physician-dependent accuracy includes appropriate disease staging, multi-disciplinary discussion with shared decision-making, choice of morphological and functional imaging methods to identify and delineate the tumor target and organs at risk, an image-guided patient set-up, active or passive management of intra-fraction movement, clinical and instrumental follow-up. Medical physicist-dependent accuracy includes use of advanced software for treatment planning and more advanced Quality Assurance procedures than required for conventional radiotherapy. Consequently, all the professionals require appropriate training in skills for high-quality SRT.Thanks to the technological advances, SRT has moved from a “frame-based” technique, i.e. the use of stereotactic coordinates which are identified by means of rigid localization frames, to the modern “frame-less” SRT which localizes the target volume directly, or by means of anatomical surrogates or fiducial markers that have previously been placed within or near the target. This review describes all the SRT steps in depth, from target simulation and delineation procedures to treatment delivery and image-guided radiation therapy. Target movement assessment and management are also described.     

Vaccine delivery: lipid-based delivery systems

Needle-free delivery of vaccines should not only increase compliance, but should also prove to be a safer and less traumatic method of vaccine delivery. One of the potential ways to achieve needle-free delivery is with the use of lipid-based delivery systems. To demonstrate the utility of these systems, we have shown them to be effective with proteins produced by recombinant DNA technology, plasmid-based vaccines, as well as conventional vaccines. Furthermore, these lipid-based delivery systems were shown to be effective in inducing mucosal immunity if delivered to mucosal surfaces or systemic immunity if different transdermally. These approaches have the potential to revolutionize vaccine delivery in humans and animals.