Role of the Functional Toll-Like Receptor-9 Promoter Polymorphism (-1237T/C) in Increased Risk of End-Stage Renal Disease:A Case-Control Study

Inflammation induced by infectious and noninfectious triggers in the kidney may lead to end stage renal disease (ESRD). Toll-like receptor 9 (TLR-9) a receptor for CpG DNA is involved in activation of immune cells in renal disease and may contribute to chronic inflammatory disease progression through an interleukin-6 (IL-6) dependent pathway. Previous studies indicate that -1237T/C confers regulatory effects on TLR-9 transcription. To date the effect of TLR-9 polymorphisms on ESRD remains unknown. We performed a case-control study and genotyped 630 ESRD patients and 415 controls for -1237T/C, -1486T/C and 1635G/A by real-time PCR assays and assessed plasma concentration of IL-6 by ELISA. Haplotype association analysis was performed using the Haploview package. A luciferase reporter assay and real-time PCR were used to test the function of the -1237T/C promoter polymorphism. A significant association between -1237T/C in TLR-9 and ESRD was identified. The TCA, TTA and CCA haplotype of TLR-9 were associated with ESRD. ESRD patients carrying -1237TC had a higher mean plasma IL-6 level when compared with -1237TT. The TLR-9 transcriptional activity of the variant -1237CC allele is higher than the -1237TT allele. The results indicate that in a Han Chinese population the presence of the C allele of -1237T/C in the TLR-9 gene increases susceptibility towards development of ESRD. In vitro studies demonstrate that -1237T/C may be involved in the development of ESRD through transcriptional modulation of TLR-9

Effects of DNA supercoiling on chromatin architecture

Disruptions in chromatin structure are necessary for the regulation of eukaryotic genomes, from remodelling of nucleosomes at the base pair level through to large-scale chromatin domains that are hundreds of kilobases in size. RNA polymerase is a powerful motor which, prevented from turning with the tight helical pitch of the DNA, generates over-wound DNA ahead of itself and under-wound DNA behind. Mounting evidence supports a central role for transcription-dependent DNA supercoiling in disrupting chromatin structure at all scales. This supercoiling changes the properties of the DNA helix in a manner that substantially alters the binding specificity of DNA binding proteins and complexes, including nucleosomes, polymerases, topoisomerases and transcription factors. For example, transient over-wound DNA destabilises nucleosome core particles ahead of a transcribing polymerase, whereas under-wound DNA facilitates pre-initiation complex formation, transcription factor binding and nucleosome core particle association behind the transcribing polymerase. Importantly, DNA supercoiling can also dissipate through DNA, even in a chromatinised context, to influence both local elements and large chromatin domains. We propose a model in which changes in unconstrained DNA supercoiling influences higher levels of chromatin organisation through the additive effects of DNA supercoiling on both DNA-protein and DNA-nucleosome interactions. This model links small-scale changes in DNA and chromatin to the higher-order fibre and large-scale chromatin structures, providing a mechanism relating gene regulation to chromatin architecture in vivo

Medical programme.

Examination involving students as peer examiner

Training and assessment of technical skill in vascular surgery

Recent media attention on high-profile cases of flawed surgical practice has led to increasing awareness amongst the public and surgical profession of the need for quality control in surgery. Vascular surgery remains a highly technical and unforgiving specialty. These factors together with recent reductions in trainees' work hours have driven surgical educators to develop new methods ofenhancing surgical training and assessing technical perfonnance. Simulation using synthetic models allows for augmentation of training and assessing surgical technique whilst avoiding ethical concerns with animal models and storage and licensing problems associated with cadavers. Hypothesis 1. Vascular surgical training can be enhanced by training on synthetic simulators. 2. Technical skill in vascular surgery can be assessed in a standardised, objective and robust manner with these simulators in an examination setting. Results Three methods were utilised initially, to assess surgical skill: qualitative assessment using rating scales for generic surgical technique (p<O.OOI); quantitative motion analysis using electromagnetic sensors to quantify economy of movement (p<O.OOl); assessment of the surgical end-product (p<O.OOl). Surgical assessment was enhanced by scoring for procedural as well as generic skill and this technique could differentiate between a newly appointed and experienced consultant (p<O.05). The aforementioned techniques were applied before and after workshop training and significant improvements were seen in the generic (p<0.01) as well as procedural skill (p<O.Ol). The end-product improved (p<O.OOl) and operative time was reduced (p<O.05). In an examination setting the models used differentiated between newly appointed and senior consultants (p<O.O 1) and offered a high level of inter-observer reliability (0)0.8). Technical skill did not correlate with the results from an oral examination or log-book training. Conclusion Vascular surgical training can be effectively supplemented by training on simulators. Simulation with the assessment criteria described can be used in a valid and robust examination of technical skill.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Novel device, a temporary guidewire fixator

A novel device for distal fixation of a guidewire was tested in regards to deployment and retrieval, deposition in the blood stream and force of fixation in a pig model. Eleven pigs were subjected to full anaesthesia and heparinized to active clotting time 250-350 s. Uninterrupted blood flow during 4 h deposition was assessed by angiography and inspected for thrombus deposition upon retrieval. The force of fixation was investigated up to the level of loss of fixation (displacement force). The device was successfully deployed and retrieved in over 40 cases. In one case, an alternative method for bailout retrieval was used. Deposition for 4 h was performed, and uninterrupted blood flow was verified by angiography. No instances of arterial occlusion or thrombosis were detected. The median dislocation force was 7.6 N. No arterial rupture or dissection was detected following the loss of fixation. As a conclusion, the device was considered safe and functional in this animal test model

Wear particles generated from studded tires and pavement induces inflammatory reactions in mouse macrophage cells

Health risks associated with exposure to airborne particulate matter (PM) have been shown epidemiologically as well as experimentally, pointing to both respiratory and cardiovascular effects. These health risks are of increasing concern in society, and to protect public health, a clarification of the toxic properties of particles from different sources is of importance. Lately, wear particles generated from traffic have been recognized as a major contributing source to the overall particle load, especially in the Nordic countries where studded tires are used. The aim of this study was to further investigate and compare the ability to induce inflammatory mediators of different traffic-related wear particles collected from an urban street, a subway station, and studded tire-pavement wear. Inflammatory effects were measured as induction of nitric oxide (NO), IL-6, TNF-alpha, arachidonic acid (AA), and lipid peroxidation after exposure of the murine macrophage like cell line RAW 264.7. In addition, the redox potential of the particles was measured in a cell-free system. The results show that all particles tested induce IL-6, TNF-alpha, and NO, and those from the urban street were the most potent ones. In contrast, particles collected from a subway station were most potent to induce lipid peroxidation, AA release, and formation of ROS. Particles from studded tire-pavement wear, generated using a road simulator, were able to induce inflammatory cytokines, NO, lipid peroxidation, and ROS formation. Interestingly, particles generated from pavement containing granite as the main stone material were more potent than those generated from pavement containing quartzite as the main stone material