Anticorpos bloqueadores dos checkpoints imunes

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

MILK : the Mobile Informal Learning Kit. Collaborating to design successful mobile learning applications

This paper suggests ways for educators and designers to understand and merge priorities in order to inform the development of mobile learning (m-learning) applications that maximise user experiences and hence learning opportunities. It outlines a User Experience Design (UXD) theory and development process that requires designers to conduct a thorough initial contextual inquiry into a particular domain in order to set project priorities and development guidelines. A matrix that identifies the key contextual considerations namely the social, cultural, spatial, technical and temporal constructs of any domain is presented as a vital tool for achieving successful UXD. The frame of reference provided by this matrix ensures that decisions made throughout the design process are attributable to a desired user experience. To illustrate how the proposed UXD theory and development process supports the creation of effective m-learning applications, this paper documents the development process of MILK (Mobile Informal Learning Kit). MILK is a support tool that allows teachers and students to develop event paths that consist of a series SMS question and answer messages that lead players through a series of checkpoints between point A and point B. These event paths can be designed to suit desired learning scenarios and can be used to explore a particular place or subject. They can also be designed to facilitate formal or informal learning experiences.

Innovation and the city : a macromarketing approach to industry development

Purpose – The purpose of this paper is to propose and demonstrate the relevance of marketing systems, notably the process of product management and innovation, to urban development challenges. Design/methodology/approach – A macromarketing perspective is adopted to construe the city as a product and begin the application of the innovation process to urban management, following the steps commonly proposed for successful innovation in product management. An example of the application of the initial new product development steps of idea generation and opportunity identification is presented. Findings – The innovation process provides guidelines and checkpoints that enable corporations to improve the success rate of their development initiatives. Cities, like corporations, need to innovate in order to maintain their image and functionality, to provide a myriad benefits to their stakeholders and, thereby, to survive and grow. The example here shows how the preliminary NPD steps of idea generation and opportunity identification enrich the process of identifying and analysing new industry opportunities for a city. Practical implications – By conceptualising the city as a multifaceted product, the disciplined planning and evaluation processes pertinent to NPD success become relevant and helpful to practitioners responsible for urban planning, urban development and change. Originality/value – The paper shows how pertinent concepts and processes from marketing can be effectively applied to urban planning and economic development initiatives.

Phosphorylation of Exo1 modulates homologous recombination repair of DNA double-strand breaks

DNA double-strand break (DSB) repair via the homologous recombination pathway is a multi-stage process, which results in repair of the DSB without loss of genetic information or fidelity. One essential step in this process is the generation of extended single-stranded DNA (ssDNA) regions at the break site. This ssDNA serves to induce cell cycle checkpoints and is required for Rad51 mediated strand invasion of the sister chromatid. Here, we show that human Exonuclease 1 (Exo1) is required for the normal repair of DSBs by HR. Cells depleted of Exo1 show chromosomal instability and hypersensitivity to ionising radiation (IR) exposure. We find that Exo1 accumulates rapidly at DSBs and is required for the recruitment of RPA and Rad51 to sites of DSBs, suggesting a role for Exo1 in ssDNA generation. Interestingly, the phosphorylation of Exo1 by ATM appears to regulate the activity of Exo1 following resection, allowing optimal Rad51 loading and the completion of HR repair. These data establish a role for Exo1 in resection of DSBs in human cells, highlighting the critical requirement of Exo1 for DSB repair via HR and thus the maintenance of genomic stability.

Real-time detection of concealed chemical hazards under ambient light conditions using Raman spectroscopy

Current concerns regarding terrorism and international crime highlight the need for new techniques for detecting unknown and hazardous substances. A novel Raman spectroscopy-based technique, spatially offset Raman spectroscopy (SORS), was recently devised for non-invasively probing the contents of diffusely scattering and opaque containers. Here, we demonstrate a modified portable SORS sensor for detecting concealed substances in-field under different background lighting conditions. Samples including explosive precursors, drugs and an organophosphate insecticide (chemical warfare agent surrogate) were concealed inside diffusely scattering packaging including plastic, paper and cloth. Measurements were carried out under incandescent and fluorescent light as well as under daylight to assess the suitability of the probe for different real-life conditions. In each case, it was possible to identify the substances against their reference Raman spectra in less than one minute. The developed sensor has potential for rapid detection of concealed hazardous substances in airports, mail distribution centers and customs checkpoints.

ATM is required for the cellular response to thymidine induced replication fork stress

Genetically distinct checkpoints, activated as a consequence of either DNA replication arrest or ionizing radiation-induced DNA damage, integrate DNA repair responses into the cell cycle programme. The ataxia-telangiectasia mutated (ATM) protein kinase blocks cell cycle progression in response to DNA double strand breaks, whereas the related ATR is important in maintaining the integrity of the DNA replication apparatus. Here, we show that thymidine, which slows the progression of replication forks by depleting cellular pools of dCTP, induces a novel DNA damage response that, uniquely, depends on both ATM and ATR. Thymidine induces ATM-mediated phosphorylation of Chk2 and NBS1 and an ATM-independent phosphorylation of Chk1 and SMC1. AT cells exposed to thymidine showed decreased viability and failed to induce homologous recombination repair (HRR). Taken together, our results implicate ATM in the HRR-mediated rescue of replication forks impaired by thymidine treatment.

"My mother would freak out" : understanding the influence of parents on the risky behaviour of their young novice drivers

Purpose Parents can influence the driving behaviour of their young novice drivers in a variety of ways. Research was undertaken to explore and identify the nature and mechanisms of parental influence upon novice drivers (16-25 years) to inform the design of more effective young driver countermeasures. Methods The mechanisms and nature of parental influence on young novice drivers were explored in small group interviews (n = 21) and three surveys (n1 = 761, n2 = 1170, n3 = 390) in a larger Queensland-wide study. Surveys two and three were part of a six-month longitudinal study. Results Parental influence appeared to occur across the pre-Licence, Learner, and Provisional (intermediate) periods. The most risky novice drivers (in terms of pre-Licence driving, unsupervised driving while a Learner, and risky driving behaviours such as speeding) reported that their parents were less likely to punish risky driving, and that their parents – who they were more likely to imitate – were also risky drivers (indicated by crashes and offences). Conclusions Parents appear influential in the risky behaviour of young novice drivers. Interventions enhancing their positive influence may improve road safety outcomes not only for young novice drivers, but for all persons who share the road with them. Among the interventions warranting further development and evaluation are programs to encourage the modelling of safe driving behaviour by parents; continued parental monitoring of driving during the pre-Licence, Learner and Provisional periods (e.g., Checkpoints program); and sharing the family vehicle during the first six months of independent licensure.

Agent-based model of passenger flows in airport terminals

Passenger flow studies in airport terminals have shown consistent statistical relationships between airport spatial layout and pedestrian movement, facilitating prediction of movement from terminal designs. However, these studies are done at an aggregate level and do not incorporate how individual passengers make decisions at a microscopic level. Therefore, they do not explain the formation of complex movement flows. In addition, existing models mostly focus on standard airport processing procedures such as immigration and security, but seldom consider discretionary activities of passengers, and thus are not able to truly describe the full range of passenger flows within airport terminals. As the route-choice decision-making of passengers involves many uncertain factors within the airport terminals, the mechanisms to fulfill the capacity of managing the route-choice have proven difficult to acquire and quantify. Could the study of cognitive factors of passengers (i.e. human mental preferences of deciding which on-airport facility to use) be useful to tackle these issues? Assuming the movement in virtual simulated environments can be analogous to movement in real environments, passenger behaviour dynamics can be similar to those generated in virtual experiments. Three levels of dynamics have been devised for motion control: the localised field, tactical level, and strategic level. A localised field refers to basic motion capabilities, such as walking speed, direction and avoidance of obstacles. The other two fields represent cognitive route-choice decision-making. This research views passenger flow problems via a "bottom-up approach", regarding individual passengers as independent intelligent agents who can behave autonomously and are able to interact with others and the ambient environment. In this regard, passenger flow formation becomes an emergent phenomenon of large numbers of passengers interacting with others. In the thesis, first, the passenger flow in airport terminals was investigated. Discretionary activities of passengers were integrated with standard processing procedures in the research. The localised field for passenger motion dynamics was constructed by a devised force-based model. Next, advanced traits of passengers (such as their desire to shop, their comfort with technology and their willingness to ask for assistance) were formulated to facilitate tactical route-choice decision-making. The traits consist of quantified measures of mental preferences of passengers when they travel through airport terminals. Each category of the traits indicates a decision which passengers may take. They were inferred through a Bayesian network model by analysing the probabilities based on currently available data. Route-choice decision-making was finalised by calculating corresponding utility results based on those probabilities observed. Three sorts of simulation outcomes were generated: namely, queuing length before checkpoints, average dwell time of passengers at service facilities, and instantaneous space utilisation. Queuing length reflects the number of passengers who are in a queue. Long queues no doubt cause significant delay in processing procedures. The dwell time of each passenger agent at the service facilities were recorded. The overall dwell time of passenger agents at typical facility areas were analysed so as to demonstrate portions of utilisation in the temporal aspect. For the spatial aspect, the number of passenger agents who were dwelling within specific terminal areas can be used to estimate service rates. All outcomes demonstrated specific results by typical simulated passenger flows. They directly reflect terminal capacity. The simulation results strongly suggest that integrating discretionary activities of passengers makes the passenger flows more intuitive, observing probabilities of mental preferences by inferring advanced traits make up an approach capable of carrying out tactical route-choice decision-making. On the whole, the research studied passenger flows in airport terminals by an agent-based model, which investigated individual characteristics of passengers and their impact on psychological route-choice decisions of passengers. Finally, intuitive passenger flows in airport terminals were able to be realised in simulation.

Developing a new index for comparing road safety maturity: Case study of the ASEAN community

As part of the development of the ASEAN Regional Road Safety Strategy, a new index for measuring road safety maturity (RSM) was constructed from numerical weightings given to measurable factors presented for each of the pillars that guide national road safety plans and activities in WHO Global Road Safety Report 2013: road safety management, safer road and mobility, safer vehicles, safer road users and post-crash response. The index is based on both a content analysis approach and a binary methodology (report/no report) including measures which have been considered pertinent and not redundant. For instance, the use of random breath testing and/or police checkpoints in the national drink driving law are combined in the enforcement index. The value of the index per pillar ranges from 0 to 100%, taking into account whether there is total, partial or non-implementation of certain actions. In addition, when possible, the self-rated level of enforcement is included. The overall ratings for the I 0 ASEAN countries and the scores for each of the pillars are presented in the paper. The extent to which the RSM index is a valid indicator of road safety performance is also discussed.

p53 and DNA damage checkpoint responses in the human prostate

Prostate cancer is the most common noncutaneous malignancy and the second leading cause of cancer mortality in men. In 2004, 5237 new cases were diagnosed and altogether 25 664 men suffered from prostate cancer in Finland (Suomen Syöpärekisteri). Although extensively investigated, we still have a very rudimentary understanding of the molecular mechanisms leading to the frequent transformation of the prostate epithelium. Prostate cancer is characterized by several unique features including the multifocal origin of tumors and extreme resistance to chemotherapy, and new treatment options are therefore urgently needed. The integrity of genomic DNA is constantly challenged by genotoxic insults. Cellular responses to DNA damage involve elegant checkpoint cascades enforcing cell cycle arrest, thus facilitating damage repair, apoptosis or cellular senescence. Cellular DNA damage triggers the activation of tumor suppressor protein p53 and Wee1 kinase which act as executors of the cellular checkpoint responses. These are essential for genomic integrity, and are activated in early stages of tumorigenesis in order to function as barriers against tumor formation. Our work establishes that the primary human prostatic epithelial cells and prostatic epithelium have unexpectedly indulgent checkpoint surveillance. This is evidenced by the absence of inhibitory Tyr15 phosphorylation on Cdk2, lack of p53 response, radioresistant DNA synthesis, lack of G1/S and G2/M phase arrest, and presence of persistent gammaH2AX damage foci. We ascribe the absence of inhibitory Tyr15 phosphorylation to low levels of Wee1A, a tyrosine kinase and negative regulator of cell cycle progression. Ectopic Wee1A kinase restored Cdk2-Tyr15 phosphorylation and efficiently rescued the ionizing radiation-induced checkpoints in the human prostatic epithelial cells. As variability in the DNA damage responses has been shown to underlie susceptibility to cancer, our results imply that a suboptimal checkpoint arrest may greatly increase the accumulation of genetic lesions in the prostate epithelia. We also show that small molecules can restore p53 function in prostatic epithelial cells and may serve as a paradigm for the development of future therapeutic agents for the treatment of prostate cancer We hypothesize that the prostate has evolved to activate the damage surveillance pathways and molecules involved in these pathways only to certain stresses in extreme circumstances. In doing so, this organ inadvertently made itself vulnerable to genotoxic stress, which may have implications in malignant transformation. Recognition of the limited activity of p53 and Wee1 in the prostate could drive mechanism-based discovery of preventative and therapeutic agents.

CHEK2 in Breast and Colorectal Cancer

Breast and colorectal cancers, are common types of cancer, with over two million newly diagnosed cases annually worldwide. Cancer is a genetic disease and defects in DNA integrity restoring functions make a significant contribution to cancer risk. CHEK2 is a checkpoint kinase functioning as a regulator of cell cycle checkpoints, apoptosis, and DNA repair in response to DNA double-strand breaks. The aim of this study was to evaluate the role of CHEK2 in breast cancer predisposition in Finnish breast cancer families and in breast cancer risk at the population level. We were interested in the clinical and biological characteristics of the breast tumors associated with the CHEK2 germline mutations or aberrant CHEK2 protein expression and the effect on survival of patients with these CHEK2 defects. We also assessed the role of CHEK2 mutations, namely 1100delC and I157T, in colorectal cancer susceptibility in Finland. CHEK2 I157T was found to be a low-penetrance breast cancer susceptibility allele, conferring a 1.4-fold risk for carriers. Reduced or absent CHEK2 protein expression was observed in one-fifth of breast tumors from patients unselected for family history, implying that defective CHEK2 signaling contributes to tumorigenesis. Reduction in CHEK2 expression was more common in tumors with larger diameter and ER expression, but with regard to other tumor characteristics and prognosis of a patient no association was observed. Results from comparison of CHEK2 1100delC carrier tumors with noncarrier tumors were in line with the findings from the CHEK2 expression study. Tumors from CHEK2 1100delC carriers were more often of higher grade than tumors from noncarriers, and they also tended to be ER-positive more often, although generally 1100delC status does not seem to radically affect the tumor characteristics. Our results suggest that CHEK2 1100delC may not be a susceptibility allele for CRC, although a very small effect cannot be excluded. Furthermore, CHEK2 1100delC is equally frequent in HBCC (hereditary breast and colorectal cancer) phenotype families and in breast cancer families. Over 1000 CRC cases were screened for CHEK2 I157T, and a significantly higher frequency of I157T was observed among both familial and sporadic CRC cases. The relation of CHEK2 I157T with familial CRC has not been studied previously. CHEK2 I157T seems to be a susceptibility allele for both familial and sporadic CRC, conferring a 1.5-fold risk for carriers of this variant. CHEK2 I157T has been proposed to have a role as a multiple cancer susceptibility allele, which is supported by our results since we observed a trend towards higher frequency of the variant among cases with multiple primary tumors or those with a family history of cancer. During the last five years CHEK2 has established its role as an important cancer susceptibility gene. It has become apparent that CHEK2 is a low-penetrance susceptibility gene for several cancer types, significantly contributing to familial cancer risk as well as to cancer risk at the population level.

Stimulating immune responses to fight cancer: Basic biology and mechanisms

Chronic inflammation is now recognized as a major cause of malignant disease. In concert with various mechanisms (including DNA instability), hypoxia and activation of inflammatory bioactive lipid pathways and pro-inflammatory cytokines open the doorway to malignant transformation and proliferation, angiogenesis, and metastasis in many cancers. A balance between stimulatory and inhibitory signals regulates the immune response to cancer. These include inhibitory checkpoints that modulate the extent and duration of the immune response and may be activated by tumor cells. This contributes to immune resistance, especially against tumor antigen-specific T-cells. Targeting these checkpoints is an evolving approach to cancer immunotherapy, designed to foster an immune response. The current focus of these trials is on the programmed cell death protein 1 (PD-1) receptor and its ligands (PD-L1, PD-L2) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Researchers have developed anti-PD-1 and anti-PDL-1 antibodies that interfere with the ligands and receptor and allow the tumor cell to be recognized and attacked by tumor-infiltrating T-cells. These are currently being studied in lung cancer. Likewise, CTLA-4 inhibitors, which have had success treating advanced melanoma, are being studied in lung cancer with encouraging results.

An efficient and scalable checkpointing and recovery algorithm for distributed systems

In this paper, we describe an efficient coordinated-checkpointing and recovery algorithm which can work even when the channels are assumed to be non-FIFO, and messages may be lost. Nodes are assumed to be autonomous, and they do not block while taking checkpoints. Based on the local conditions, any process can request the previous coordinator for the 'permission' to initiate a new checkpoint. Allowing multiple initiators of checkpoints avoids the bottleneck associated with a single initiator, but the algorithm permits only a single instance of checkpointing process at any given time, thus reducing much of the overhead associated with multiple initiators of distributed algorithms.