Isometric muscle training of the spine musculature in patients with spinal bony metastases under radiation therapy

<p/> <p>Background</p> <p>Osseous metastatic involvement of the spinal column affects many patients with a primary tumour disease of all entities. The consequences are pain both at rest and under exertion, impairments in going about day-to-day activities, diminished performance, the risk of pathological fractures, and neurological deficits. Palliative percutaneous radiotherapy is one of the therapeutical options available in this connection. The aim of this explorative study is to investigate the feasibility of muscle-training exercises and to evaluate the progression- and fracture-free survival time and the improvement of bone density, as well as to assess other clinical parameters such as pain, quality of life, and fatigue as secondary endpoints.</p> <p>Methods/Design</p> <p>This study is a prospective, randomized, monocentre, controlled explorative intervention study in the parallel-group design to determine the multidimensional effects of a course of exercises at first under physiotherapeutic instruction and subsequently performed by the patients independently for strengthening the paravertebral muscles of patients with metastases of the vertebral column parallel to their percutaneous radiotherapy. On the days of radiation treatment the patients in the control group shall be given physical treatment in the form of respiratory therapy and the so-called "hot roll". The patients will be randomized into one of the two groups: differentiated muscle training or physiotherapy with thirty patients in each group.</p> <p>Discussion</p> <p>The aim of the study is to evaluate the feasibility of the training programme described here. Progression-free and fracture-free survival, improved response to radiotherapy by means of bone density, and clinical parameters such as pain, quality of life, and fatigue constitute secondary study objectives.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01409720">NCT01409720</a></p

The gating mechanism in cyclic nucleotide-gated ion channels

Cyclic nucleotide-gated (CNG) channels mediate transduction in several sensory neurons. These channels use the free energy of CNs' binding to open the pore, a process referred to as gating. CNG channels belong to the superfamily of voltage-gated channels, where the motion of the \uce\ub1-helix S6 controls gating in most of its members. To date, only the open, cGMP-bound, structure of a CNG channel has been determined at atomic resolution, which is inadequate to determine the molecular events underlying gating. By using electrophysiology, site-directed mutagenesis, chemical modification, and Single Molecule Force Spectroscopy, we demonstrate that opening of CNGA1 channels is initiated by the formation of salt bridges between residues in the C-linker and S5 helix. These events trigger conformational changes of the \uce\ub1-helix S5, transmitted to the P-helix and leading to channel opening. Therefore, the superfamily of voltage-gated channels shares a similar molecular architecture but has evolved divergent gating mechanisms

Conformational rearrangements in the transmembrane domain of CNGA1 channels revealed by single-molecule force spectroscopy

Cyclic nucleotide-gated (CNG) channels are activated by binding of cyclic nucleotides. Although structural studies have identified the channel pore and selectivity filter, conformation changes associated with gating remain poorly understood. Here we combine single-molecule force spectroscopy (SMFS) with mutagenesis, bioinformatics and electrophysiology to study conformational changes associated with gating. By expressing functional channels with SMFS fingerprints in Xenopus laevis oocytes, we were able to investigate gating of CNGA1 in a physiological-like membrane. Force spectra determined that the S4 transmembrane domain is mechanically coupled to S5 in the closed state, but S3 in the open state. We also show there are multiple pathways for the unfolding of the transmembrane domains, probably caused by a different degree of \u3b1-helix folding. This approach demonstrates that CNG transmembrane domains have dynamic structure and establishes SMFS as a tool for probing conformational change in ion channels

Magnetic microspheres (MMS) coupled to selective lectins: a new tool for large-scale extraction and purification of human pancreatic islets

No abstract availabl

Resonance assignments of the nucleotide-free wildtype MloK1 cyclic nucleotide-binding domain

Cyclic nucleotide-sensitive ion channels, known as HCN and CNG channels play crucial roles in neuronal excitability and signal transduction of sensory cells. These channels are activated by binding of cyclic nucleotides to their intracellular cyclic nucleotide-binding domain (CNBD). A comparison of the structures of wildtype ligand-free and ligand-bound CNBD is essential to elucidate the mechanism underlying nucleotide-dependent activation of CNBDs. We recently reported the solution structure of the Mesorhizobium loti K1 (MloK1) channel CNBD in complex with cAMP. We have now extended these studies and achieved nearly complete assignments of H-1, C-13 and N-15 resonances of the nucleotide-free CNBD. A completely new assignment of the nucleotide-free wildtype CNBD was necessary due to the sizable chemical shift differences as compared to the cAMP bound CNBD and the slow exchange behaviour between both forms. Scattering of these chemical shift differences over the complete CNBD suggests that nucleotide binding induces significant overall conformational change