ABSTRACT
In the context of cancer surgery, there is always a trade-off between oncological safety and preservation of function. This is especially true in pelvic surgery due to the close relationship to the pelvic floor muscles, blood supply and nerves. Currently, risk models, preoperative imaging, the surgeon's assessment, and the intraoperative frozen section serve as the basis for decision-making. New imaging techniques and standardization in frozen section have significantly improved this in recent years. However, limitations remain due to time delays as well as more difficult correct anatomical assignment in the follow-up. Alternative intraoperative techniques may overcome this limitation in the future. Patient-derived organoids have emerged as an important new research vehicle in recent years. They are based on tumor stem cells that, under special culture conditions, form three-dimensional replicas of the original tissue. This makes them ideally suited for testing individual system therapies but also as a validation technique for new intraoperative diagnostic procedures. The Research Training Group 2543/I, which is funded by the German Research Foundation, is researching the potential of new diagnostic methods in an interdisciplinary team regarding validation in addition to intraoperative frozen sections.
Subject(s)
Frozen Sections , Organoids , Humans , PelvisABSTRACT
The dental follicle is an ectomesenchymally derived connective tissue harboring precursor cells for the tooth supporting apparatus. In this study, we examined gene expression of freshly isolated human dental follicle cells during osteogenic differentiation in vitro. These plastic adherent fibroblastic cells express Notch-1, nestin and vimentin. We differentiated dental follicle cells with dexamethasone or insulin-based protocols into membrane-like structures containing mineralizing foci. An analysis of mineralized tissue with atomic force microscopy illustrated a bone and cementum-like structure. A real-time RT-PCR analysis was developed to investigate expression of typical osteoblast or cementoblast related genes during differentiation. Gene expressions of osteocalcin (OCN), bone morphogenic protein (BMP)-2 and nestin were increased during the both differentiation approaches. Our work demonstrates differentiation of dental follicle cells with an insulin-based protocol for the first time.
Subject(s)
Cell Differentiation/drug effects , Dental Sac/drug effects , Dexamethasone/pharmacology , Insulin/pharmacology , Adult , Bone Morphogenetic Protein 2 , Bone Morphogenetic Proteins/genetics , Bone Morphogenetic Proteins/metabolism , Cell Differentiation/genetics , Cells, Cultured , Dental Cementum , Dental Sac/metabolism , Humans , Immunohistochemistry , Intermediate Filament Proteins/genetics , Intermediate Filament Proteins/metabolism , Microscopy, Atomic Force , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Nestin , Osteogenesis , Phenotype , Receptor, Notch1/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Transforming Growth Factor beta/genetics , Transforming Growth Factor beta/metabolismABSTRACT
The analysis of peptide and protein partitioning in lipid membranes is of high relevance for the understanding of biomembrane function. We used statistical thermodynamics analysis to demonstrate the effect of peptide mixing behavior on heat capacity profiles of lipid membranes with the aim to predict peptide aggregation from c(P)-profiles. This analysis was applied to interpret calorimetric data on the interaction of the antibiotic peptide gramicidin A with lipid membranes. The shape of the heat capacity profiles was found to be consistent with peptide clustering in both gel and fluid phase. Applying atomic force microscopy, we found gramicidin A aggregates and established a close link between thermodynamics data and microscopic imaging. On the basis of these findings we described the effect of proteins on local fluctuations. It is shown that the elastic properties of the membrane are influenced in the peptide environment.
Subject(s)
Gramicidin/chemistry , Hot Temperature , Liposomes/chemistry , Membrane Fluidity , Membrane Lipids/chemistry , Membrane Proteins/chemistry , Models, Molecular , Computer Simulation , Macromolecular Substances , Models, Chemical , Molecular Conformation , Protein Binding , Protein Conformation , Thermal ConductivityABSTRACT
Dynamic interactions of the tumor suppressor protein p53 with a DNA fragment containing a p53-specific recognition sequence were directly observed by time-lapse tapping mode atomic force microscopy (AFM) in liquid. The divalent cation Mg(2+) was used to loosely attach both DNA and p53 to a mica surface so they could be imaged by the AFM while interacting with each other. Various interactions of p53 with DNA were observed, including dissociation/re-association, sliding and possibly direct binding to the specific sequence. Two modes of target recognition of p53 were detected: (a) direct binding, and (b) initial non-specific binding with subsequent translocation by one-dimensional diffusion of the protein along the DNA to the specific site.
