Repair of DNA double-strand breaks (DSBs) by homologous recombination requires resection of 5'-termini to generate 3'-single-strand DNA tails. Key components of this reaction are exonuclease 1 and ...the bifunctional endo/exonuclease, Mre11 (refs 2-4). Mre11 endonuclease activity is critical when DSB termini are blocked by bound protein--such as by the DNA end-joining complex, topoisomerases or the meiotic transesterase Spo11 (refs 7-13)--but a specific function for the Mre11 3'-5' exonuclease activity has remained elusive. Here we use Saccharomyces cerevisiae to reveal a role for the Mre11 exonuclease during the resection of Spo11-linked 5'-DNA termini in vivo. We show that the residual resection observed in Exo1-mutant cells is dependent on Mre11, and that both exonuclease activities are required for efficient DSB repair. Previous work has indicated that resection traverses unidirectionally. Using a combination of physical assays for 5'-end processing, our results indicate an alternative mechanism involving bidirectional resection. First, Mre11 nicks the strand to be resected up to 300 nucleotides from the 5'-terminus of the DSB--much further away than previously assumed. Second, this nick enables resection in a bidirectional manner, using Exo1 in the 5'-3' direction away from the DSB, and Mre11 in the 3'-5' direction towards the DSB end. Mre11 exonuclease activity also confers resistance to DNA damage in cycling cells, suggesting that Mre11-catalysed resection may be a general feature of various DNA repair pathways.
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Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Diseases are biological processes, and molecular imaging with positron emission tomography (PET) is sensitive to and informative of these processes. This is illustrated by detection of biological ...abnormalities in neurological disorders with no computed tomography or MRI anatomic changes, as well as even before symptoms are expressed. PET whole body imaging in cancer provides the means to (i) identify early disease, (ii) differentiate benign from malignant lesions, (iii) examine all organs for metastases, and (iv) determine therapeutic effectiveness. Diagnostic accuracy of PET is 8-43% higher than conventional procedures and changes treatment in 20-40% of the patients, depending on the clinical question, in lung and colorectal cancers, melanoma, and lymphoma, with similar findings in breast, ovarian, head and neck, and renal cancers. A microPET scanner for mice, in concert with human PET systems, provides a novel technology for molecular imaging assays of metabolism and signal transduction to gene expression, from mice to patients: e.g., PET reporter gene assays are used to trace the location and temporal level of expression of therapeutic and endogenous genes. PET probes and drugs are being developed together--in low mass amounts, as molecular imaging probes to image the function of targets without disturbing them, and in mass amounts to modify the target's function as a drug. Molecular imaging by PET, optical technologies, magnetic resonance imaging, single photon emission tomography, and other technologies are assisting in moving research findings from in vitro biology to in vivo integrative mammalian biology of disease.
The third section of our Special Task Force report identifies and defines a series of elements that warrant consideration in value assessments of medical technologies. We aim to broaden the view of ...what constitutes value in health care and to spur new research on incorporating additional elements of value into cost-effectiveness analysis (CEA). Twelve potential elements of value are considered. Four of them—quality-adjusted life-years, net costs, productivity, and adherence-improving factors—are conventionally included or considered in value assessments. Eight others, which would be more novel in economic assessments, are defined and discussed: reduction in uncertainty, fear of contagion, insurance value, severity of disease, value of hope, real option value, equity, and scientific spillovers. Most of these are theoretically well understood and available for inclusion in value assessments. The two exceptions are equity and scientific spillover effects, which require more theoretical development and consensus. A number of regulatory authorities around the globe have shown interest in some of these novel elements. Augmenting CEA to consider these additional elements would result in a more comprehensive CEA in line with the “impact inventory” of the Second Panel on Cost-Effectiveness in Health and Medicine. Possible approaches for valuation and inclusion of these elements include integrating them as part of a net monetary benefit calculation, including elements as attributes in health state descriptions, or using them as criteria in a multicriteria decision analysis. Further research is needed on how best to measure and include them in decision making.
Traditional approaches to the study of cognition emphasize an information-processing view that has generally excluded emotion. In contrast, the recent emergence of cognitive neuroscience as an ...inspiration for understanding human cognition has highlighted its interaction with emotion. This review explores insights into the relations between emotion and cognition that have resulted from studies of the human amygdala. Five topics are explored: emotional learning, emotion and memory, emotion's influence on attention and perception, processing emotion in social stimuli, and changing emotional responses. Investigations into the neural systems underlying human behavior demonstrate that the mechanisms of emotion and cognition are intertwined from early perception to reasoning. These findings suggest that the classic division between the study of emotion and cognition may be unrealistic and that an understanding of human cognition requires the consideration of emotion.
Phelps discusses the research reported by James Lomas which makes a useful contribution to a vexing question: how to consider new technology investmests that are acceptable by usual ...cost-effectiveness analysis (CEA) standards but fracture budgets of healthcare-providing organizations such as the British National Health Service (BNHS) that operate with externally imposed budget constraints. The analysis uses the opportunity costs created by budget constrainsts as relevant for measuring value of new technologies.
PET and SPECT are molecular imaging techniques that use radiolabeled molecules to image molecular interactions of biological processes in vivo. PET imaging technologies have been developed to provide ...a pathway to the patient from the experimental paradigms of biological and pharmaceutical sciences in genetically engineered and tissue transplanted mouse models of disease. PET provides a novel way for molecular therapies and molecular diagnostics to come together in the discovery of molecules that can be used in low mass amounts to image the function of a target and, by elevating the mass, to pharmacologically modify the function of the target. In both cases, the molecules are the same or analogs of each other. PET can be used to titrate drugs to their sites of action within organ systems in vivo and to assay biological outcomes of the processes being modified in the mouse and the patient. The goal is to provide a novel way to improve the rates of discovery and approval of radiopharmaceuticals and pharmaceuticals. Extending this relationship into clinical practice can improve drug use by providing molecular diagnostics in concert with molecular therapeutics. Diseases are biological processes, and molecular imaging with PET is sensitive and informative to these processes. This sensitivity is exemplified by the detection of disease with PET without evidence of anatomic changes on CT and MRI. These biological changes are seen early in the course of disease, even in asymptomatic stages, as illustrated by the metabolic abnormalities detected with PET and FDG in Huntington's and familial Alzheimer's diseases 7 and 5 y, respectively, before symptoms appear. Differentiation of viable from nonviable tissue is fundamentally a metabolic question, as shown by the use of PET to differentiate patients with coronary artery disease who will benefit from revascularization from those who will not. Although beginning within a specific organ, cancer is a systemic disease the most devastating consequences of which result from metastases. Whole-body PET imaging with FDG enables inspection of glucose metabolism in all organ systems in a single examination to improve the detection and staging of cancer, selection of therapy, and assessment of therapeutic response. In lung and colorectal cancers, melanoma, and lymphoma, PET FDG improves the accuracy of detection and staging from 8% to 43% over conventional work-ups and results in treatment changes in 20%-40% of the patients, depending on the clinical question. Approximately 65% are upstaged because unsuspected metastases are detected, and 35% are downstaged because a structural diagnosis of lesions is changed from malignant to benign. Similar results are now being shown for other cancers. The main difference between CT, sonography, MRI, and PET or SPECT is not technologic but, rather, a difference between detecting and characterizing a disease by its anatomic features as opposed to its biology. The importance and success of developing new molecular imaging probes is increasing as PET becomes integral to the study of the integrative mammalian biology of disease and as molecular therapies targeting the biological processes of disease are developed.
The amygdala and hippocampal complex, two medial temporal lobe structures, are linked to two independent memory systems, each with unique characteristic functions. In emotional situations, these two ...systems interact in subtle but important ways. Specifically, the amygdala can modulate both the encoding and the storage of hippocampal-dependent memories. The hippocampal complex, by forming episodic representations of the emotional significance and interpretation of events, can influence the amygdala response when emotional stimuli are encountered. Although these are independent memory systems, they act in concert when emotion meets memory.
We examined the impact of autism severity and parental coping strategies on stress in parents of children with ASD. Children’s autism symptoms and parental coping strategies (task-oriented, ...emotion-oriented, social diversion, and distraction) were evaluated as predictors of four types of parental stress (parent and family problems, pessimism, child characteristics, and physical incapacity). In order to examine potential buffering effects of coping strategies on stress associated with the child’s symptom severity, the interactive effects of autism symptoms with coping strategies were also examined. Participants included 77 primary caregivers of a child with ASD. Using multiple regression analyses, emotion-oriented coping scores were associated with more parent and family problems, and task-oriented coping was associated with lower physical incapacity scores. The child’s autism severity was the strongest and most consistent predictor of stress. Further, emotion-oriented coping moderated the relationship between pessimism stress and autism symptomatology, and distraction coping was a moderator between parent and family stress and autism symptoms. Results indicate that increasing our knowledge of the coping strategies that are more or less effective and under what conditions some coping strategies may be either beneficial or harmful for this population of parents has direct implications for treatment and parent education efforts.
Abstract Practitioners of cost-utility analysis know that their models omit several important factors that often affect real-world decisions about health care options. Furthermore, cost-utility ...analyses typically reflect only single perspectives (e.g., individual, business, and societal), further limiting the value for those with different perspectives (patients, providers, payers, producers, and planners—the 5Ps). We discuss how models based on multicriteria analyses, which look at problems from many perspectives, can fill this void. Each of the 5Ps can use multicriteria analyses in different ways to aid their decisions. Each perspective may lead to different value measures and outcomes, whereas no single-metric approach (such as cost-utility analysis) can satisfy all these stakeholders. All stakeholders have unique ways to measure value, even if assessing the same health intervention. We illustrate the benefits of this approach by comparing the value of five different hypothetical treatment choices for five hypothetical patients with cancer, each with different preference structures. Nine attributes describe each treatment option. We add a brief discussion regarding the use of these approaches in group-based decisions. We urge that methods to value health interventions embrace the multicriteria approaches that we discuss, because these approaches 1) increase transparency about the decision process, 2) allow flight simulator-type evaluation of alternative interventions before actual investment or deployment, 3) help focus efforts to improve data in an efficient manner, 4) at least in some cases help facilitate decision convergence among stakeholders with differing perspectives, and 5) help avoid potential cognitive errors known to impair intuitive judgments.
Childhood fractures can have a significant impact on the daily lives of families affecting children's normal activities and parent's work. Wrist fractures are the most common childhood fracture. The ...more serious wrist fractures, that can look visibly bent, are often treated with surgery to realign the bones; but this may not be necessary as bent bones straighten in growing children. The children's radius acute fracture fixation trial (CRAFFT) is a multicentre randomised trial of surgery versus a cast without surgery for displaced wrist fractures. Little is known about how families experience these wrist fractures and how they manage treatment uncertainty. This study aimed to understand families' experience of this injury and what it is like to be asked to include their child in a clinical trial.
Nineteen families (13 mothers, 7 fathers, 2 children) from across the UK participated in telephone interviews. Interviews were audio recorded, transcribed and analysed using reflexive thematic analysis.
Our findings highlight parents' desire to be a good parent through the overarching theme "protecting my injured child". To protect their child after injury, parents endeavoured to make the right decisions about treatment and provide comfort to their child but they experienced ongoing worry about their child's recovery. Our findings show that parents felt responsible for the decision about their child's treatment and their child's recovery. They also reveal the extent to which parents worried about the look of their child's wrist and their need for reassurance that the wrist was healing.
Our findings show that protecting their child after injury can be challenging for parents who need support to make decisions about treatment and confidently facilitate their child's recovery. They also highlight the importance of providing information about treatments, acknowledging parents' concerns and their desire to do the right thing for their child, reassuring parents that their child's wrist will heal and ensuring parents understand what to expect as their child recovers.
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