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Accurate Risk Assessment (accurate + risk_assessment)
Selected AbstractsThe von Hippel-Lindau tumor suppressor gene expression level has prognostic value in neuroblastomaINTERNATIONAL JOURNAL OF CANCER, Issue 3 2006Jasmien Hoebeeck Abstract Deletions of the short arm of chromosome 3 are often observed in a specific subset of aggressive neuroblastomas (NBs) with loss of distal 11q and without MYCN amplification. The critical deleted region encompasses the locus of the von Hippel-Lindau gene (VHL, 3p25). Constitutional loss of function mutations in the VHL gene are responsible for the VHL syndrome, a dominantly inherited familial cancer syndrome predisposing to a variety of neoplasms, including pheochromocytoma. Pheochromocytomas are, like NB, derived from neural crest cells, but, unlike NB, consist of more mature chromaffin cells instead of immature neuroblasts. Further arguments for a putative role of VHL in NB are its function as oxygen sensitizer and the reported relation between hypoxia and dedifferentiation of NB cells, leading to a more aggressive phenotype. To test the possible involvement of VHL in NB, we did mRNA expression analysis and sought evidence for VHL gene inactivation. Although no evidence for a classic tumor suppressor role for VHL in NB could be obtained, a strong correlation was observed between reduced levels of VHL mRNA and low patient survival probability (p = 0.013). Furthermore, VHL appears to have predictive power in NTRK1 (TRKA) positive tumor samples with presumed favorable prognosis, which makes it a potentially valuable marker for more accurate risk assessment in this subgroup of patients. The significance of the reduced VHL expression levels in relation to NB tumor biology remains unexplained, as functional analysis demonstrated no clear effect of the reduction in VHL mRNA expression on protein stability of its downstream target hypoxia-inducible factor ,. © 2006 Wiley-Liss, Inc. [source] Decubitus ulcers: A review of the literatureINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 10 2005Cheryl Bansal BA Decubitus ulcers are a worldwide health care concern affecting tens of thousands of patients and costing over a billion dollars a year. Susceptibility to pressure ulcers comes from a combination of external factors (pressure, friction, shear force, and moisture), and internal factors (e.g. fever, malnutrition, anaemia, and endothelial dysfunction). Often, enough damage is done to create the basis for a decubitus ulcer after as little as 2 h of immobility, a situation which may be difficult to avoid if the patient must undergo prolonged surgery or remain bedridden. Damage owing to pressure may also occur hours before the patient receives medical attention, especially if the patient falls or becomes immobilized owing to a vascular event. Several classification systems for decubitus ulcers have been described, based on where injury first occurs. The histologic progression of decubitus ulcers is a dynamic process involving several stages, each having characteristic histologic features. A team-focused approach integrating all aspects of care, including pressure relief, infection control, nutrition, and surgery, may improve healing rates. With accurate risk assessment and preventative care, we can hope to minimize complications and mortality owing to decubitus ulcers. [source] Jet fires: An experimental study of the main geometrical features of the flame in subsonic and sonic regimesAICHE JOURNAL, Issue 1 2009A. Palacios Abstract Although jet fires are usually smaller than other fires, they may lead to a destructive chain of events that can increase the scale of an accident. Therefore, their size should be predicted for accurate risk assessment. In the literature, most of the proposals for estimating jet fire size concern small jet fires (up to 2.5 m in length) or subsonic flames. In this study, experiments on relatively large propane jet fires in still air were performed. Vertical turbulent diffusion flames up to 10 m in length, with sonic and subsonic mass flow rates, were obtained using six different orifice exit diameters. The experiments were filmed with video and thermographic cameras and the resulting visible and infrared images were used to determine flame length and lift-off distance. Expressions for estimating jet length as a function of several variables (mass flow rate, orifice exit diameter, Froude and Reynolds numbers) are also proposed. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source] Northern Environment Predisposes Birches to Ozone DamagePLANT BIOLOGY, Issue 2 2007E. Oksanen Abstract: Ozone sensitivity of silver birch (Betula pendula Roth) has been thoroughly investigated since early 1990,s in Finland. In our long-term open-field experiments the annual percentage reduction in basal diameter and stem volume increment were the best non-destructive growth indicators for ozone impact when plotted against AOTX. Remarkable differences in defence strategies, stomatal conductance, and defence compounds (phenolics), clearly indicate that external exposure indices are ineffective for accurate risk assessment for birch. For flux-based approaches, site-specific values for gmax and gdark are necessary, and determinants for detoxification capacity, ageing of leaves, and cumulative ozone impact would be needed for further model development. Increasing CO2 seems to counteract negative ozone responses in birch, whereas exposure to springtime frost may seriously exacerbate ozone damage in northern conditions. Therefore, we need to proceed towards incorporating the most important climate change factors in any attempts for ozone risk assessment. [source] | ||||||||||