Revisiting PLA/PLGA microspheres: an analysis of their potential in parenteral vaccination.

Poly(lactide) and poly(lactide-co-glycolide) microspheres have been studied for controlled antigen delivery and immune response enhancement for more than a decade. Early developments of such vaccines were basically technology-driven, stemming from the well-established biocompatibility of these polymers in concert with their innate properties to tailor rates of bioerosion and release. More recently, other features have become equally or even more appealing, such as the adjuvancy of such microspheres and their ability to elicit cellular effector responses, so-called cytotoxic T-cell responses, in addition to antibody responses observed already in the very early studies. In this review, we intended to revisit microsphere-based vaccines designed for the parenteral route and attempted to outline major developmental issues, as well as to analyze immunological fundamentals and data associated with antigen delivery by microspheres.     

Cf-252 neutron therapy of cervical carcinoma: topometrical radiotherapy planning using an afterloading technic and computerized tomography

The introduction of the afterloading technique with Cf-252 sources of high dose rate into the clinical practice has made necessary a topometrical radiation treatment planning (RTP) with increased accuracy in order to keep the risk of post-irradiation complications as low as possible. The possibilities of computerized tomography (CT) for topometrical RTP have been examined on 20 patients with histologically verified carcinoma of the cervix (stage Ia and Ib). The systematic use of the methods provides comprehensive information on anatomical relations and the localization of the applicator on all levels required for physical RTP. Thus, it was revealed that the cervix is enclosed by the bladder and that the distance from the dorsal wall of the bladder to the applicator in the cervical canal is, as a rule, not or little dependent on the level of bladder filling. By controlling the level of bladder filling it may be possible to reduce radiation load on the ileum, and thus to diminish the risk of radiation damage in case of intracavitary brachytherapy with Cf-252.     

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Ohne Zusammenfassung     

High-resolution, spin-echo BOLD, and CBF fMRI at 4 and 7 T.

With growing interest in noninvasive mapping of columnar organization and other small functional structures in the brain, achieving high spatial resolution and specificity in fMRI is of critical importance. We implemented a simple method for BOLD and perfusion fMRI with high spatial resolution and specificity. Increased spatial resolution was achieved by selectively exciting a slab of interest along the phase-encoding direction for EPI, resulting in a reduced FOV and number of phase-encoding steps. Improved spatial specificity was achieved by using SE EPI acquisition at high fields, where it is predominantly sensitive to signal changes in the microvasculature. Robust SE BOLD and perfusion fMRI were obtained with a nominal in-plane resolution up to 0.5 x 0.5 mm(2) at 7 and 4 Tesla, and were highly reproducible under repeated measures. This methodology enables high-resolution and high-specificity studies of functional topography in the millimeter to submillimeter spatial scales of the human brain.     

Hydrogel nerve conduits produced from alginate/chitosan complexes

Nerve conduits (NCs) represent a promising alternative to conventional treatments for peripheral nerve repair. Materials for NC production should be biodegradable, possess adequate mechanical properties, and allow for exchange of nutrients. To this aim, we developed biodegradable NC made of a hydrogel that consisted of the oppositely charged polysaccharides alginate and chitosan. Swelling and permeation studies, as well as rheological measurements, served to characterize the NC. The alginate/chitosan NC showed high water uptake (84% w/w) and permitted permeation of fluorescent-labeled dextrans in a molecular weight dependent manner. The NC fulfilled the mechanical specifications without further crosslinking. The soft NC can be expected to preclude nerve compression (storage modulus of about 40 kPa), but possess sufficient mechanical strength. In combination with remarkable tear resistance, the NC affords easy surgical handling.     

Control of in vitro tissue-engineered bone-like structures using human mesenchymal stem cells and porous silk scaffolds

Natural bone consists of cortical and trabecular morphologies, the latter having variable pore sizes. This study aims at engineering different bone-like structures using scaffolds with small pores (112-224 microm) in diameter on one side and large pores (400-500 microm) on the other, while keeping scaffold porosities constant among groups. We hypothesized that tissue engineered bone-like structure resulting from silk fibroin (SF) implants is pre-determined by the scaffolds' geometry. To test this hypothesis, SF scaffolds with different pore diameters were prepared and seeded with human mesenchymal stem cells (hMSC). As compared to static seeding, dynamic cell seeding in spinner flasks resulted in equal cell viability and proliferation, and better cell distribution throughout the scaffold as visualized by histology and confocal microscopy, and was, therefore, selected for subsequent differentiation studies. Differentiation of hMSC in osteogenic cell culture medium in spinner flasks for 3 and 5 weeks resulted in increased alkaline phosphatase activity and calcium deposition when compared to control medium. Micro-computed tomography (microCT) detailed the pore structures of the newly formed tissue and suggested that the structure of tissue-engineered bone was controlled by the underlying scaffold geometry.     

Immunoprofile of the adenomatoid odontogenic tumor

This study was focused on the immunohistochemical profile of the adenomatoid odontogenic tumor. A Pub/Medline search revealed a number of immunohistochemical studies including cytokeratin profiles, extracellular matrix proteins, Integrins, ameloblast‐associated proteins resorption regulators (RANK, RANKL), p53, PCNA, MDM2 protein, cyclin D1, Ki‐67, Bcl‐2 metallothionein, metalloproteinases, D56 hepatocyte growth factor, c‐met, DNA methyltransferase, podoplanin, TGF‐βI, Smad‐2/3, Smad‐I‐5/‐8, Smad 4, beta‐ catenin, calretinin, and clonality. Careful interpretation of the findings indicates that the adenomatoid odontogenic tumor may be more of a hamartomatous than neoplastic nature.