Cyclobutenes by Platinum-Catalyzed Cycloisomerization Reactions of Enynes

1,6-Enynes bearing (electron-rich) aryl substituents on their alkyne moiety rearrange to cyclobutene derivatives in the presence of catalytic amounts of PtCl2 in toluene. The reaction is significantly accelerated when performed under an atmosphere of CO (1 atm), most likely by increasing the electrophilicity of the metal template by temporary coordination to this π-acidic ligand. This transformation allows the build up of considerable strain in the products as witnessed by the productive formation of tricyclic skeletons, such as 7 or 9. Moreover, these products provide evidence for the mechanistic scenario of platinum-catalyzed cycloisomerization reactions previously proposed, which are thought to proceed via organo−platinum species that mimic the reactivity of metal-complexed “nonclassical” carbocations

Improving the efficiency of CTDIw annual measurements with established 16 cm: 32 cm phantom ratios

Purpose: To validate the use of the 16 cm CTDI phantom to estimate the 32 cm phantom CTDIw with tabulated data from previous years.Methods: A retrospective analysis of CTDI measurements was performed from the annual physics testing reports of four Siemens Symbia (Emotion) T6, one Siemens Symbia (Emotion) T16, one Siemens Sensation Open, one Siemens Sensation 16, one Siemens Sensation 32, two GE LightSpeed 16 and five GE VCT CT scanners. For each annual report, the ratio of the 16 cm: 32 cm CTDI phantom measurements was calculated from mAs-normalized CTDI100. The ratios from a) the acceptance test, b) one year after the acceptance test or c) an average ratio of all of the previous years (range 4-8 years), were then used to estimate 32 cm CTDI phantom measurements based on active 16 cm CTDI measurements. The average percent difference between measured and calculated CTDIw was determined per scanner for all years.Results: The most accurate results were obtained when using the average ratios of all the previous years, -2% to 3% difference across all scanner models. For the ratios of the year after the acceptance test, the difference ranged from -3% to 7%, while the data estimated from the acceptance testing results yielded the largest percent difference -4% to 8%. The 64-detector row system estimates displayed the greatest variation, followed by the 16-detector row scanners, while the 6-detector row system estimates were the most accurate.Conclusion: Compared to the Siemens and GE specified CTDI limits of ± 15-30% , the variation in the estimated 32 cm phantom CTDIw values was 2-15 times lower, dependent on the scanner model and method of estimation. The variation was considerably less (2-3%) with ratios of all the previous years, perhaps indicative of year to year variations that can result in greater error.------------------------------Cite this article as: Dodge C, Gress D. Improving the efficiency of CTDIw annual measurements with established 16 cm: 32 cm phantom ratios. Int J Cancer Ther Oncol 2014; 2(2):020220. DOI: 10.14319/ijcto.0202.2

Emerging concepts in pancreatic cancer medicine: targeting the tumor stroma

Pancreatic ductal adenocarcinoma is a stroma-rich and highly challenging cancer to treat. Over recent years, it has become increasingly evident that the complex network of soluble cytokines, growth factors, proteases, and components of the extracellular matrix collaboratively interact within the tumor microenvironment, sustaining and driving cancer cell proliferation, invasion, and early metastasis. More recently, the tumor microenvironment has also been appreciated to mediate therapeutic resistance in pancreatic ductal adenocarcinoma, thus opening numerous avenues for novel therapeutic explorations. Inert and soluble components of the tumor stroma have been targeted in order to break down the extracellular matrix scaffold, relieve vessel compression, and increase drug delivery to hypovascular tumors. Moreover, targeting of antiapoptotic, immunosuppressive, and pro-proliferative effects of the tumor stroma provides novel vantage points of attack. This review focuses on current and future developments in pancreatic cancer medicine, with a particular emphasis on biophysical and biochemical approaches that target the tumor microenvironment

Co-ordination and management of chronic conditions in Europe:the role of primary care.

Healthcare systems in Europe struggle with inadequate co-ordination of care for people with chronic conditions. Moreover, there is a considerable evidence gap in the treatment of chronic conditions, lack of self-management, variation in quality of care, lack of preventive care, increasing costs for chronic care, and inefficient use of resources. In order to overcome these problems, several approaches to improve the management and co-ordination of chronic conditions have been developed in European healthcare systems. These approaches endeavour to improve self-management support for patients, develop clinical information systems and change the organisation of health care. Changes in the delivery system design and the development of decision support systems are less common. Almost as a rule, the link between healthcare services and community resources and policies is missing. Most importantly, the integration between the six components of the chronic care model remains an important challenge for the future. We find that the position of primary care in healthcare systems is an important factor for the development and implementation of new approaches to manage and coordinate chronic conditions. Our analysis supports the notion that countries with a strong primary care system tend to develop more comprehensive models to manage and co-ordinate chronic conditions