Influence of two different resection techniques (conventional liver resection versus anterior approach) of liver metastases from colorectal cancer on hematogenous tumor cell dissemination – prospective randomized multicenter trial

<p>Abstract</p> <p>Background</p> <p>Surgical hepatic resection remains the treatment of choice for patients with liver metastases from colorectal cancer despite the use of alternative therapeutic strategies. Although this procedure provides long-term survival in a significant number of patients, 50–75% of the patients develop intra- and/or extrahepatic recurrence. One possible reason for tumor recurrence may be intraoperative hematogenous tumor cell dissemination due to mechanical manipulation of the tumor during hepatic resection. Surgical technique may have an influence on hematogenous tumor cell spread. We hypothesize that hematogenous tumor cell dissemination may be reduced by using the anterior approach technique compared to conventional liver resection.</p> <p>Methods/Design</p> <p>This is a multi-centre prospective randomized controlled, superiority trial to compare two liver resection techniques of liver metastases from colorectal cancer. 150 patients will be included and randomized intraoperatively after surgical exploration just prior to resection. The primary objective is to compare the anterior approach with the conventional liver resection technique with regard to intraoperative haematogenous tumor cell dissemination. As secondary objectives we examine five year survival rates (OS and DFS), blood loss, duration of operation, requirement of blood transfusions, morbidity rate, prognostic relevance of tumor cell detection in blood and bone marrow and the comparison of tumor cell detection by different detection methods.</p> <p>Conclusion</p> <p>This trial will answer the question whether there is an advantage for the anterior approach technique compared to the conventional resection group with regard to tumor cell dissemination. It will also add further information about prognostic differences, safety, advantages and disadvantages of each technique.</p> <p>Trial registration</p> <p>Current controlled trials – <b>ISRCTN45066244</b></p

A concept for trial institutions focussing on randomised controlled trials in surgery

<p>Abstract</p> <p>Background</p> <p>Although considered the reference standard for generating valid scientific evidence of a treatment's benefits and harms, the number of Randomised Controlled Trials (RCT) comparing surgical techniques remains low. Much effort has been made in order to overcome methodological issues and improve quality of RCTs in surgery. To the present there has been, however, only little emphasis on development and maintenance of institutions for implementation of adequately designed and conducted surgical RCTs.</p> <p>Mehods/Design</p> <p>Description of the developments in surgical RCT infrastructure in Germany between 2001 and 2006. Cross sectional evaluation of completed and ongoing surgical RCTs within the German Surgical Society and the Clinical Study Centre, Department of Surgery, University of Heidelberg.</p> <p>Results</p> <p>Foundation of a national Clinical Trial Centre (CTC) for the organisation of multi-centre RCTs in the surgical setting (Study Center of the German Surgical Society, SDGC). Establishment of a network of CTCs with affiliated Clinical Sites (CSs) to enhance patient recruitment and shorten the duration of RCTs. Since its foundation four surgical RCTs with a total sample size of 1650 patients (1006 of these randomised) have been supervised by the SDGC with 35 CSs involved in patient recruitment. Five further CTCs were set up in 2006. Together with their affiliated CSs a network has been organised providing improved conditions for the conduction of surgical RCTs.</p> <p>Conclusion</p> <p>Improvement of infrastructure substantially facilitates integration of RCTs into routine surgical practice. A network of collaborating CTCs and CSs can provide an adequate infrastructure for the conduction of multi-centre RCTs.</p

Cell-type specific RNA-Seq reveals novel roles and regulatory programs for terminally differentiated Dictyostelium cells

Abstract Background A major hallmark of multicellular evolution is increasing complexity by the evolution of new specialized cell types. During Dictyostelid evolution novel specialization occurred within taxon group 4. We here aim to retrace the nature and ancestry of the novel “cup” cells by comparing their transcriptome to that of other cell types. Results RNA-Seq was performed on purified mature spore, stalk and cup cells and on vegetative amoebas. Clustering and phylogenetic analyses showed that cup cells were most similar to stalk cells, suggesting that they share a common ancestor. The affinity between cup and stalk cells was also evident from promoter-reporter studies of newly identified cell-type genes, which revealed late expression in cups of many stalk genes. However, GO enrichment analysis reveal the unexpected prominence of GTPase mediated signalling in cup cells, in contrast to enrichment of autophagy and cell wall synthesis related transcripts in stalk cells. Combining the cell type RNA-Seq data with developmental expression profiles revealed complex expression dynamics in each cell type as well as genes exclusively expressed during terminal differentiation. Most notable were nine related hssA-like genes that were highly and exclusively expressed in cup cells. Conclusions This study reveals the unique transcriptomes of the mature cup, stalk and spore cells of D. discoideum and provides insight into the ancestry of cup cells and roles in signalling that were not previously realized. The data presented in this study will serve as an important resource for future studies into the regulation and evolution of cell type specialization

The contribution of fractal nature to BaTiO3-ceramics microstructure analysis

The structure of BaTiO3 based materials can be controlled by using different technological parameters and different additives. In this paper, microstructure and dielectrical properties of Er2O3 doped BaTiO3-ceramics, sintered from 1320 °C to 1380 °C have been investigated. Microstructural investigations were carried out using scanning electron microscope equipped with energy dispersive spectrometer. Grain size distribution was determined by quantitative metallography method.\ud \ud The new correlation between microstructure and dielectric properties of doped BaTiO3-ceramics, based on fractal geometry and contact surface probability, has been developed. Using the fractals and statistics of the grains contact surface, a reconstruction of microstructure configurations, as grains shapes or intergranular contacts, has been successfully done. Obtained results indicated that fractal analysis and statistics model for contact surfaces of different shapes were very important for the prognosis of BaTiO3-ceramics microstructure and dielectric properties.\ud \ud The morphology of ceramics grains pointed out the validity of developing new structure analytical methods, based on different grains’ shape geometries. The grains contact model based on ellipsoidal geometry is presented as new modeling tool for structure research of BaTiO3-ceramics materials. The directions of possible materials properties prognosis are determined according to the correlations synthesis–structure–property.The statistical approach to the investigation of BaTiO3-ceramic grains concerning the relationship between the temperature and the area of the contact surface is also introduced