Imaging Hypoxia in Glioblastoma Multiforme with PET

Imaging Hypoxia in Glioblastoma Multiforme with PET Hypoxia plays a crucial role in the progression of glioblastoma multiforme (GBM) promoting angiogenesis, genetic mutations, switch to a more aggressive behaviour and ote important consequences. Many diagnostic methods have been investigated and today PET and MRI appear to be the more attractive for the evaluation of the heterogeneous hypoxia in GBM.(Mendichovszky and Jackson 2011, Vartanian, Singh et al. 2014) Hirata first documented the utility of hypoxic tracers ([18F]FMISO in this study) in patients with differentiating GBM from lower grade gliomas based on the level of tumour hypoxia.(Hirata, Terasaka et al. 2012) Hypoxia assessment by PET imaging seems to provide complementary information to MRI within the complex relationship existing between hypoxia and angiogenesis in GBM. This was confirmed in a study of Swanson et al, where the authors documented a strong correlation between the hypoxic burden, determined with [18F]FMISO, and altered vasculature documented on gadolinium-enhanced T1-weighted MRI sequences.(Swanson, Chakraborty et al. 2009) As for other tumours, the prognostic capability of [18F]FMISO has been confirmed also in GBM, in a study evaluating the correlation between hypoxic volume, intensity of hypoxia an survival in 22 patients with GBM who underwent PET scan before biopsy or between resection and radiation therapy (RT).(Spence, Muzi et al. 2008) The heterogeneous distribution of hypoxia within GBM cannot be fully investigated by [18F]FMISO PET imaging, but the tumour–blood ratio provide acceptable data on the different levels of hypoxia within the tumour.(Padhani, Krohn et al. 2007) [18F]FAZA is another radiotracer tracer, which has showed promising results. The biggest study ever published, evaluating the utility of [18F]FAZA in 50 patients with different types of tumours, documented increased uptake of the tracer in all gliomas, with a tumour-to-background (T/B) ratio range of 1.9-15.6, which is higher compared to that of [18F]FMISO.(Postema, McEwan et al. 2009) However, as already said most of literature on the use of [18F]FAZA in the brain is based in preclinical setting (see Tab.X) According to the group of Wiebe, one important point in favour of [18F]FAZA for the evaluation of hypoxia in brain tumours is the absence of uptake in normal brain tissue, while [18F]FMISO shows, although limited, non-specific uptake in the brain.(Wiebe 2004) Recently, also Belloli and colleagues investigated the combined use of [18F]FAZA and [18F]FDG PET and MRI to follow the biological modification of specific line of glioma cells during the tumour progression in animal models of GBM (rats with implanted glioma F98 cells). The authors observed that [18F]FAZA and [18F]FDG were taken up respectively in the core and in external areas of the tumoyr, with partial overlap and remodelling during disease progression, suggesting that necrotic regions, defined on the basis of [18F]FDG uptake reduction, may include hypoxic clusters of vital tumour tissue identified with 18F]FAZA.(Belloli, Brioschi et al. 2013) BOLD-MRI is an advance MRI technique, particulary suitable for the evaluation of hypoxia, which evaluate the changes in oxygen concentration and ratio between oxyhemoglobin and deoxyhemoglobin within vessels. In contrast to oxyhaemoglobin, deoxyhaemoglobin is paramagnetic and determines an increase of transverse relaxation rate (R2*) of water in blood and surrounding tissues.(Mendichovszky and Jackson 2011) Unfortunately BOLD-MRI signal is sensible also to other tissue factors, such as blood flow, carbon dioxide tension, haematocrit, pH. Decoupling the effects of flow from deoxyhaemoglobin and static components it is essential to measure R2* and be obtained using multi-echo GRE sequences.(Padhani, Krohn et al. 2007) T1-weighted oxygen-enhanced MRI (OE-MRI) has been proposed as an alternative imaging technique for the evaluation of hypoxia.(Zaharchuk, Busse et al. 2006) Dissolved oxygen in blood and plasma influences MRI signal by increasing the longitudinal relaxation rate of protons (R1). OE-MRI has already been employed in the evaluation of oxygen in healthy tissues and in tumours, but not in the evaluation of hypoxia in GBM, except in a preclinical study by Linnik et al. (Linnik, Scott et al. 2014) In an animal study, Wu et al. used a mechanically ventilation with 100% oxygen at the rate of 8 l/min to investigate hypoxia in brain of rats and showed close agreement between R2* and R1 changes in white and grey matter in response to oxygen inhalation.(Wu, Gao et al. 2012) In the study of Wu and colleagues, the T1 values decreased prominently in the cortical grey matter but also, with a lower extent, in the subcortical gray matter and in white matter, where the decrease was the least significant. Instead the T2 values showed an increase in response to the oxygen inhalation in all the regions examined in the following order: white matter>subcortical gray matter>cortical gray matter. Similarly, the T2* values increased with more evident change in the cortical gray matte and white matter and with a less extent in subcortical gray matter.(Wu, Gao et al. 2012) These observations support the use of oxygen-enhanced imaging as a biomarker for tumour oxygenation, although the relationship between the signal changes resulting from variations in dissolved oxygen pressure and true tumour hypoxaemia remain to be elucidated. DCE-MRI, using contrast agents of low molecular weight, has been proposed as an additional MRI method for identification and quantification of hypoxia in some types of tumour and some authors successfully demonstrated a correlation between perfusion parameters to oxygen tension. (Ceelen, Smeets et al. 2006) DCE-MRI parameters have been demonstrated also to indicate preoperatively areas with high hypoxia in glioma patients.In particularly Jensen et al. demonstrated that capillary transit time (tc) correlated with HIF-1 expression and VEGF expression in the histopathological examination of corresponding of active tumour regions. Other parameters, blood volume (Vb), capillary heterogeneity (a-1) and kep (washout rate) also showed a correlation with biomarkers of hypoxia.(Jensen, Mumert et al. 2014) O’ Connor, in a study evaluating ten patients with solid tumours, proposed that DCE may provide complementary information to OE-MRI regarding the tumour microenvironment, estimating lo cal perfusion and extracellular–extravascular volume,(OConnor, Naish et al. 2009) Subsequently, Linnik et al. validated the measurement of hypoxia validated OE-MRI using a murine glioma xenograft with histopathological confirmation. The study involved 5 patients, who underwent the same imaging protocol of the rats: OE-MRI and DCE-MRI and histological confirmation with reduced pimonidazole adducts and CD31 staining. Furthermore, the area under the curve (AUC) was also calculated for the R1 curve for OE-MRI and the gadolinium concentration curve for DCE-MRI. Whereas DCE-MRI did not relate to hypoxia in the xenograft model, the authors found a strong correlation between estimation of hypoxia by means OE-MRI and histology results, supporting further research to validate also the utility of OE-MRI in the evaluation of response to therapy and prediction of prognosis (Fig.).(Linnik, Scott et al. 2014) DWI-MRI instead has been used to clarify the mechanism of action of bevacizumab role, scanning patients with recurrent GBM before and after treatment with bevacizumab.(Rieger, Bahr et al. 2010) The mechanism of action of bevacizumab is still matter of debate. It is thought to produce damage to the endothelial cells, decreasing transport of nutrients and oxygen to the tumour cells,(Field, Jordan et al. 2014) but recently, it has been postulated an alternative theory: antiangiogenic therapy could stimulate a â€Å"vascular normalization†, which would allow improved chemotherapy delivery and radiation effects through enhanced oxygen delivery.(Jain 2005) The study showed that bevacizumab induced stroke-like lesions with diffusion restriction and corresponding ADC decrease in 13 out of 18 patients enrolled in the study. A biopsy, performed in ADC-decreased lesion in one patient, demonstrated and nuclear hypoxia with HIF-1ÃŽ ± up-regulation atypical necrosis but no tumour recurrence , supporting the hypothesis that bevacizumab-increases hypoxia in the tumour bed, expecially in case of prolonged treatment. Furthermore the imaging analysis revealed that regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) were decreased in responders with diffusion restricted lesions.(Rieger, Bahr et al. 2010) Recently the effect of anti-angiogenic therapy has been investigated by a new technique, called vessel architectural imaging (VAI) which analyses the temporal shift in the MR signal estimating the vessel calibre and provides additional information about the microcirculation and oxygen saturation levels. From preliminary investigations, VAI seems to be a reliable MRI method to demonstrate the effect of anti-angiogenic therapy.(Emblem, Mouridsen et al. 2013) Other authors suggested AVOL, a measure of arteriovenous overlap (voxels with both arteriosus and venous perfusion characteristics), as index of abnormal tumour microvasculature and as indicator o f bevacizumab therapy efficacy.(LaViolette, Cohen et al. 2013) Barajas and colleagues (Barajas, Phillips et al. 2012) investigated histopathological and physiologic MRI features using diffusion-weighted imaging (DWI), dynamic susceptibility–weighted, and contrast enhanced perfusion imaging (DSC). Image-guided tissue specimens were taken from contrast enhanced (CE) and non-enhancing (NE) regions in GBM (93 CE and 26 NE regions from 51 patients with newly diagnosed GBM). The authors analysed variables of anatomic, imaging, and histopathological features (tumour score, cell density, proliferation, architectural disruption, hypoxia, and microvascular hyperplasia). Tissue samples from CE regions were found to have increased tumour score, cellular density, proliferation, and architectural disruption compared with NE regions.(Barajas, Phillips et al. 2012) MRI in the evaluation of perfusion Perfusion measurement of regional cerebral blood flow (rCBF) has been proposed as a method for identifying angiogenically active tumours. Increased angiogenesis in high-grade gliomas is correlated with higher cerebral blood volume (CBV) after contrast administration with dynamic MRI, relative to contralateral normal white matter rCBF and tumour aggressiveness. (Provenzale, York et al. 2006, Gruner, Paamand et al. 2012) Also microvascular density (MVD) of tumour tissue has been shown to relate to tumour behaviour and prognosis. Furthermore it has been demonstrated that abnormalities in contrast agent recirculation provide independent information concerning the microcirculation and may be of value as surrogate markers in trials of antiangiogenic therapy.(Alan Jackson 2002) Early changes of rCBV, evaluated by MRI before and at weeks 1-2 and 3-4 during radiotherapy, can indicate response to treatment and correlate with survival [Cao]. Also Galban investigated the predictive impact of MRI in this setting, suggesting the use of voxel-by-voxel parametric response maps at 3 weeks after radiotherapy to predict overall survival.(Galban, Chenevert et al. 2009) Another MRI technique which has shown promises in the assessment of the tumour microvascular environment is susceptibility weighted imaging (SWI), which aims to underline the susceptibility differences between tissues. Liu et al. demonstrated that R2*values are significantly different between high-grade gliomas, low-grade gliomas, postulating that these differences may be related to the different content of deoxyhaemoglobin.(Liu, Liao et al. 2014)

English Composition Essay

There are mixed reviews on online studying. During my research for articles on this subject, I found that more people are choosing online education instead of being in the traditional classroom setting. This appears to be a trend that in the eyes of some people will gain ground on classroom learning. Earning a college degree online will benefit mainly people with full time jobs. As Jessica Groach-Santina views it, â€Å"This form of education, will allow you to learn on your own schedule, put the skills you need directly into practice on the job and give you the valuable technical knowledge that employers are seeking†. Steve Lohr wrote in one of his many articles, â€Å"online education is providing learning experiences that are more tailored to individual students than is possible in the classroom. † The Department of Education performed a study last year and found students that did some or all of their courses online ranked higher in test performance than average classroom students. Steve Lohr wrote in his article, Online Education Beats the Classroom that â€Å"over the next few years, online education will expand sharply as evidence mounts of its value†. Philip R. Regier, the Dean of Arizona State University, also feels within the next three to five years the online studies will triple. Bill Gates, founder of Microsoft, also feels more people will be taking classes online. In one of Steve Lohr’s most recent articles titled â€Å"Second Thoughts on Online Education† he back- tracked on some of the earlier statements he made, â€Å"A rush to online education may come at more of a cost than educators may suspect. † After more research concerning online education was conducted by the National Science Foundation and the Education Department, one study showed Hispanics and males did notably worse online. David Figlio, an economist at Northwestern University believes, the reason for the poor grades by these groups, was that males were more than likely waiting until the last minute to do their assignments. They were also putting off viewing lectures and cramming their studies before a test. Another issue could be that English is a second language for some Hispanic men. I understand there are positives and negatives with almost everything one sets out to accomplish. The key to success is, no matter what you set out to achieve, it will take hard work. This is my first time taking courses online and I know it will be as challenging as sitting in a classroom. However, it’s more convenient than going to a class at a certain time and I also get to work at my own pace, to a certain extent. Work Cited MLA: Groach-Santina Jessica. â€Å"The Value Of An Online Degree. † 10 September 2010. 29 September 2010 http://www. online-education. net/articles/general/securing-a-better-future. html MLA: Lohr Steven. â€Å"Study Finds That Online Education Beats The Classroom†. 19 August 2009. 29 September 2010 http://www. bits. blogs. nytimes. com/2009/08/19/study-finds-that-online-education-beats-the-class†¦ MLA: Lohr Steven. â€Å"Second Thoughts On Online Education†. 8 September 2010. 29 September 2010 http://www. bits. blogs. nytimes. com/2010/09/08/second-thoughts-on-online-education/? scp+1&sq

The Unexpected Truth About Socilogoy of Sports Essay Topics

The Unexpected Truth About Socilogoy of Sports Essay Topics Practicing team sports can effectively teach you an extremely important lesson so you are aware of how to work with each other to reach the very same objective. Sportsmanship is not just to be showcased on the area but it needs to be also carried throughout the life. Practicing a sport team will certainly help you acquire these skills which are likely to assist you throughout life. Perhaps the qualities necessary to be a very good basketball player as well as the skills necessary to command a boardroom. Facts, Fiction and Socilogoy of Sports Essay Topics Sport is the ideal stress buster. Sports are the best method to burn calories. They are necessary for maintaining our health and physical fitness. Sports additionally help to fight stress that's very common nowadays in every area. Swimming can be quite a handy activity since it would help your child to come up with a strong body together with powerful muscles. Injuries can create a negative effect on the mind of players that needs to be eliminated with the support of appropriate therapy. Recreational sports ought to be made must in offices to relieve extra stress. Sports and great education both together turn into the best way to attain success in the life span of a kid. Different types of Sports Sports can be broadly categorized dependent on the location or area where it's being played. ABSTRACT Sports play a critical part in modern contemporary society. Introduction Sports are termed as any bodily or mental activity that is mostly done during leisure time and includes a high degree of entertainment involving an awareness of competition. Individuals always love to play sports no matter what it is that you're into whether it's football or tennis it's always a great time to play sports. Children ought never to be demoted for playing the sports instead they ought to be promoted. Sports play a critical part in modern contemporary society. They are the physical activities with different names according to the ways of playing them. It is an integral part of everyday life. They are an important part of just about every society lives. Top Choices of Socilogoy of Sports Essay Topics Since you can see there are a lot of topics that may be related to sports research papers, and that means you can pick the direction and make your own paper on a narrowed topic. Most times, the introduction is easily the most complex section of an essay because it influences the remainder of the paper. Here you could look for articles in the area of sports science that will enable you to create a great paper. Sports research paper topics cover a wide selection of fields. There are some who are great in writing essays about realities and not about abstracts while some are somewhat more proficient in inventing works of fiction. All it requires is a little creativity and a great, solid argument. It can help to boost the total personality of somebody and makes him more productive and alert. Below you will discover an assortment of general topic suggestions for your sociology essay. Now, when you pick the incorrect subject, you will wind up with lots of evaluations which are baffling. If you still don't understand what essay topics to write about, have a look at this thought-provoking list there are lots of suggestions to consider and choose. Don't forget to select only topics associated with your personal interests. Getting the Best Socilogoy of Sports Essay Topics The results are extremely weak. It also provides you with the ability to create split second decisions, as soon as you must achieve that. There are quite a lot of sources of information and receiving accurate report is easy. There are lots of things that make us different from the other entire sites which claim to provide the form of services we offer.

Practices in another Culture - Free Essay Example

Sample details Pages: 6 Words: 1669 Downloads: 5 Date added: 2018/12/30 Category Sociology Essay Type Report Level High school Tags: Communication Essay Did you like this example? At one point or another, each one of us has encountered various instances which are intertwined with cultural differences. Cultural differences or practices in another different culture have often led to the rise of misunderstandings and difficulties in personal relations. Culture is one strong perspective which has a lot of impact towards our day to day life since it determines how we partake our activities. Don’t waste time! Our writers will create an original "Practices in another Culture" essay for you Create order Our views towards life, our loyalties, as well as our emotions are highly attached to our culture. However, it is so that building and generating relationships will always enable us to understand and interpret other cultures apart from those which we uphold. Differences in culture occur due to various aspects, for instance, the background at which one is raised and brought up in will determine his or her cultural practices. Individual experiences, family, and other attached practices are among those which lead to there being of differences in our cultural practices. Such differences will always affect our understanding, our beliefs, as well as our ways of relating to those surrounding us. Despite the fact that difference in cultures may end up causing harm to the society, it is also one of the most preferred means which gives us recognition in any area where one may inhabit. Ones culture is one significant characteristic since it assists us in building a firm foundation in determinin g the kind of a person to be since it covers the entire life of ones existence. It is so that if culture is not well understood, there may erupt great differences between humanity. In orders to interpret practices in others culture, one should be in a position to understand the individual, national, and structural culture of the specific group you intend to interact with. In order to mingle or understand practices in other peoples culture, one must identify the most vital key factors of the same culture (Cranmer, 1995, p. 60-67). The high, as well as the low context culture, was once introduced by Edward T. Hall who was an anthropologist. Such a theory assists us in understanding the great impact which culture holds towards communication. The critical cultural dimensions are entailed in this particular theory; Hall explains context as the circumstances which surround a particular message or event. Therefore the low or high context involves the external factors which surround a particular culture and may differ depending on the area or background of the participa nts. For the low context ideas are always outspoken, and in most cases, they are always straightforward, explanations should also come along with explanation and taking issues for granted rarely occurs. On the other hand, the high context culture, interpersonal cultures will be emphasized. People belonging to such cultures are less administered by either their institutions as well as their feelings. Practices among others cultures are also determined by the attitude we hold towards our personal space. Some people or societies will be specific in maintaining the distance between themselves and others while as others will easily interact and relate despite there being differences in cultures. Some will demand greater space to solve their cultural issues, and others will be open and free to share information with whomever they come into contact with. Such groups can be identified as high territory and the other as the low territory. The high territory group of people is specific in mai ntaining their cultural ideas and norms whereas the low territory ones are less considerate and do not believe in ownership or privacy towards their cultural practices. Those with low territorial characteristics tend to have context. To pursue and realize more about this particular subject, many have applied a lot of inputs to realize the solution behind the mystery of understanding others cultural practices. After many years of research conducted by well-known research specialists through interviews and other means of data collection, various cultural dimensions are identified which tend to act as the tool in differentiating one particular cultural practice that differs from the rest. Among these dimensions, the primary ones are discussed below. Power distance is one aspect which will determine the recognition of practices in another culture. Power distance is recognized as the degree to which power will be distributed within the society and the response of the members of the society after the distribution. In the high power distance the cultural practices tends to identify the hierarchical mode of governance. Strong individuals who hold and own a large number of properties are likely to be offered and opportuni ty to govern the rest of the society. On the other hand, low power distance implies that personal responsibility is the cultural norm within the society. Risk avoidance is another aspect which will determine the difference in cultural practices. Some culture will accept and support the change of things and activities to avoid severe consequences. For instance, some will adapt to the changes taking place while as other will ignore and deny to accept the same. With the high indecision cultural practices, individuals are in a position to the changes and innovations taking place within their surrounding ready to benefit from these upcoming changes. However, the low indecision cultural practices will deny the adaptation and will work towards maintaining their normality. For instance, they will deny acceptance of innovations such as technology or any other modern discoveries. Instead, these low indecision cultural practices tend to emphasize on upgrading standardization and securing or pr omising job security. Individualism and collectiveness is also another primary aspect which will assist one in understanding the practices in other cultures. These are the degree to which one will recognize the interest of others regardless of his or her interests. Some will hold individualism cultures, the free will and independency are highly appreciated (Preliminary Material, n.d., p. 124-139). Here, the cultures do support self-interests and neglect to mind about a group or a large mass of people. On the other hand, collective cultural practice is one character that neglects and minds less about the personal necessities and major on the needs of an entire society or group. Such aspect which varies as far as the subject of culture is under consideration will assist one to capture the deep understanding of practices in others cultures. However, despite the fact that there are these differences in cultures, it is also clear that there occur some periodic patterns which tend to be similar across various cultures. Such patterns are developed in peoples mind and are temporary. Hence, the cultural patterns can be identified as shared practices, and in most cases, there will be determined by the external factors. Cultural relativism is the view that no culture is better than whatever other culture when looking at frameworks of ethical quality, law, governmental issues, and so on. Its the philosophical idea that every cultural conviction is similarly substantial and that fact itself is relative, contingent upon the social condition. The individuals who hold to social relativism hold that all religious, moral, tasteful, and political convictions are totally in respect to the person inside a social character. Relativism frequently incorporates moral relativism morals rely upon a social development, situational relativism right or wrong depends on the specific circumstance, and intellectual relativism truth itself has no goal standard. However, the world is one wide place, brimming with a wide range of diverse individuals, each with a special viewpoint on the most proficient method to survive and flourish. The greater part of a gatherings center convictions, ceremonies, conventions, and different traditions make up its particular culture. Some portion of makes the world intriguing that every human progress has thought of a one of a kind culture and esteem framework, which prompts individuals seeing life and ways of life in an unexpected way. Social relativism implies that activities ought to be measured by the models of a persons own special culture, not by the benchmarks of others. This clarifies why a few things are flawlessly worthy in one society, however thoroughly unthinkable in another. To abstain from judging the social practices of gatherings that are distinctive to yours, we can utilize the social relativism approach. Social relativism alludes to not judging a culture to our particular principles of what is correct or wrong, interesting or ordinary. Rather, we should attempt to comprehend social practices of the different group of people and learn to understand more about them. It is not ethical to judge and make conclusions on someone out of his or her cultural practices or appearance. For instance, concluding that one is a group of gangs due to body tattoos or piercings which may be part of their culture. We are supposed to learn and embrace other cultural activities and neglect identifying the negativity which we might identify. However, we must also consider maintaining the law and orders which must keep the society on track even as we recognize each other social practices. There should not occur any superior culture than the other; such recommendation will ensure the smooth running of our lives avoiding unnecessary conflicts among ourselves. Cultures resemble a stream that streams through steady an area, and correspondence is the thing that scaffolds these regions to each other. We are individuals who were made to cover through social means and bound to live inside interpersonal exercises. The judgment of an individual is never an individual judgment when generalizations are utilized by the jury. Individuals utilize the few negative perspectives to dissect the entire, yet just a little percent of negative substances we attempt to pass by and large. We should live to cooperate, we should cooperate to live, and we should utilize correspondence to effectively cooperate. References Koester, J., Lustig, M.W. (2010). Intercultural competence. Interpersonal communication across cultures (6th ed.). Retrieved from The University of Phoenix eBook Collection database Proven Models.? (n.d.).? Retrieved from https://www.provenmodels.com/11/five-dimensions-of- culture/hofstedehttps://www.provenmodels.com/11/five-dimensions-of-culture/hofstede Preliminary Material. (n.d.).? Cultural Heritage, Cultural Rights, Cultural Diversity, i-xx. doi:10.1163/9789004228382_001 Changing minds.? (2002-2015).? Retrieved from https://changingminds.org/explanations/culture/hall_culture.htm