824 resultados para Human pancreaqtic ribonuclease
Resumo:
This paper describes the cloning and characterization of a new member of the vascular endothelial growth factor (VEGF) gene family, which we have designated VRF for VEGF-related-factor. Sequencing of cDNAs from a human fetal brain library and RT-PCR products from normal and tumor tissue cDNA pools indicate two alternatively spliced messages with open reading frames of 621 and 564 bp, respectively. The predicted proteins differ at their carboxyl ends resulting from a shift in the open reading frame. Both isoforms show strong homology to VEGF at their amino termini, but only the shorter isoform maintains homology to VEGF at its carboxyl terminus and conserves all 16 cysteine residues of VEGF165. Similarity comparisons of this isoform revealed overall protein identity of 48% and conservative substitution of 69% with VEGF189. VRF is predicted to contain a signal peptide, suggesting that it may be a secreted factor. The VRF gene maps to the D11S750 locus at chromosome band 11q13, and the protein coding region, spanning approximately 5 kb, is comprised of 8 exons that range in size from 36 to 431 bp. Exons 6 and 7 are contiguous and the two isoforms of VRF arise through alternate splicing of exon 6. VRF appears to be ubiquitously expressed as two transcripts of 2.0 and 5.5 kb; the level of expression is similar among normal and malignant tissues.
Resumo:
The CDKN2 gene, encoding the cyclin-dependent kinase inhibitor p16, is a tumour suppressor gene that maps to chromosome band 9p21-p22. The most common mechanism of inactivation of this gene in human cancers is through homozygous deletion; however, in a smaller proportion of tumours and tumour cell lines intragenic mutations occur. In this study we have compiled a database of over 120 published point mutations in the CDKN2 gene from a wide variety of tumour types. A further 50 deletions, insertions, and splice mutations in CDKN2 have also been compiled. Furthermore, we have standardised the numbering of all mutations according to the full-length 156 amino acid form of p16. From this study we are able to define several hot spots, some of which occur at conserved residues within the ankyrin domains of p16. While many of the hotspots are shared by a number of cancers, the relative importance of each position varies, possibly reflecting the role of different carcinogens in the development of certain tumours. As reported previously, the mutational spectrum of CDKN2 in melanomas differs from that of internal malignancies and supports the involvement of UV in melanoma tumorigenesis. Notably, 52% of all substitutions in melanoma-derived samples occurred at just six nucleotide positions. Nonsense mutations comprise a comparatively high proportion of mutations present in the CDKN2 gene, and possible explanations for this are discussed.
Resumo:
CDKN2A, the gene encoding the cell-cycle inhibitor p16CDKN2A, was first identified in 1994. Since then, somatic mutations have been observed in many cancers and germline alterations have been found in kindreds with familial atypical multiple mole/melanoma (FAMMM), also known as atypical mole syndrome. In this review we tabulate the known mutations in this gene and discuss specific aspects, particularly with respect to germline mutations and cancer predisposition.
Resumo:
This workshop is a continuation and extension to the successful past workshops exploring the intersection of food, technology, place, and people, namely 2009 OZCHI workshop, Hungry 24/7? HCI Design for Sustainable Food Culture and Sustainable Interaction with Food, Technology, and the City [1] and 2010 CHI panel Making Food, Producing Sustainability [3]. The workshop aims to bring together experts from diverse backgrounds including academia, government, industry, and non-for-profit organisations. It specifically aims to create a space for discussion and design of innovative approaches to understanding and cultivating sustainable food practices via human-computer-interaction (HCI) as well as addressing the wider opportunities for the HCI community to engage with food as a key issue for sustainability The workshop addresses environmental, health, and social domains of sustainability in particular, by looking at various conceptual and design approaches in orchestrating sustainable interaction of people and food in and through dynamic techno-social networks.
Resumo:
Modelling how a word is activated in human memory is an important requirement for determining the probability of recall of a word in an extra-list cueing experiment. The spreading activation, spooky-action-at-a-distance and entanglement models have all been used to model the activation of a word. Recently a hypothesis was put forward that the mean activation levels of the respective models are as follows: Spreading � Entanglment � Spooking-action-at-a-distance This article investigates this hypothesis by means of a substantial empirical analysis of each model using the University of South Florida word association, rhyme and word norms.
Resumo:
Background and Objective: A number of bone filling materials containing calcium (Ca++) and phosphate (P) ions have been used in the repair of periodontal bone defects; however, the effect that local release of Ca++ and P ions have on biological reactions is not fully understood. In this study, we investigated the effects of various levels of Ca++ and P ions on the proliferation, osteogenic differentiation, and mineralization of human periodontal ligament cells (hPDLCs). Materials and Methods: hPDLCs were obtained using an explant culture method. Defined concentrations and ratios of ionic Ca++ to inorganic P were added to standard culture and osteogenic induction media. The ability of hPDLCs to proliferate in these growth media was assayed using the Cell Counting Kit-8 (CCK-8). Cell apoptosis was evaluated by FITC-Annexin V/PI double staining method. Osteogenic differentiation and mineralization were investigated by morphological observations, alkaline phosphatase (ALP) activity, and Alizarin red S/von Kossa staining. The mRNA expression of osteogenic related markers was analyzed using a reverse transcriptase polymerase chain reaction (RT-PCR). Results: Within the ranges of Ca++ and P ions concentrations tested, we observed that increased concentrations of Ca++ and P ions enhanced cell proliferation and formation of mineralized matrix nodules; whereas ALP activity was reduced. The RT-PCR results showed that elevated concentrations of Ca++ and P ions led to a general increase of Runx2 mRNA expression and decreased ALP mRNA expression, but gave no clear trend on OCN mRNA levels. Conclusion: The concentrations and ratios of Ca++ and P ions could significantly influence proliferation, differentiation, and mineralization of hPDLCs. Within the range of concentrations tested, we found that the combination of 9.0 mM Ca++ ions and 4.5 mM P ions were the optimum concentrations for proliferation, differentiation, and mineralization in hPDLCs.
Resumo:
The relationship between the environment and human rights has long been recognised. It is now largely accepted that a ‘good’ environment is a necessary precondition for the enjoyment of a wide range of human rights, including the right to health, the right to an adequate standard of living, and even the right to life. It has even been suggested that as humans we all possess a right to live in an environment of a certain standard, based on the intrinsic value of the natural world to all human beings. In this context much has been written regarding the important role that the environment plays in human lives. This paper looks at the flip-side of this discussion, and examines what human rights can do for the environment. It is argued that, while there are valid criticisms for linking environmental protection too strongly to human needs, there is nonetheless much to be gained from using human rights law as a framework to achieve environmental protection.
Resumo:
The role of human rights in environmental governance is increasingly gaining attention. This is particularly the case in relation to the challenge of climate change, where there is growing recognition of a real threat to human rights. This chapter argues in favour of greater reference to human rights principles in environmental governance. It refers to the experiences of Torres Strait Islanders to demonstrate the impact of climate change on human rights, and the many benefits which can be gained from a greater consideration of human rights norms in the development of strategies to combat climate change. The chapter also argues that a human rights perspective can help address the underlying injustice of climate change: that it is the people who have contributed least to the problem who will bear the heaviest burden of its effects.
Resumo:
The links between the environment and human rights are well established internationally. It is accepted that environmental problems impact on individuals’ and communities’ enjoyment of rights which are guaranteed to them under international human rights law. Environmental issues also impact on governments’ capacity to protect and fulfil the rights of their citizens. In addition to these links between the environment and human rights, it is argued that human rights principles offer a strategy for addressing environmental injustice. The justice implications of environmental problems are well documented, with many examples where pollution, deforestation or other degradation disproportionately impacts upon poorer neighbourhoods or areas populated by minority groups. On the international level, there are environmental injustices which exist between developed and developing states. Further, there are also potential injustices for future generations. This paper investigates the role of human rights principles in addressing these instances of environmental injustice, and argues that the framework of human rights norms provides an approach to environmental governance which can help to minimise injustice and promote the interests of those groups who are most adversely affected. Further, it suggests that the human rights enforcement mechanisms which exist at international law could be utilised to lend more weight to claims for more equitable environmental policies.
Resumo:
Emotional processes modulate the size of the eyeblink startle reflex in a picture-viewing paradigm, but it is unclear whether emotional processes are responsible for blink modulation in human conditioning. Experiment 1 involved an aversive differential conditioning phase followed by an extinction phase in which acoustic startle probes were presented during CS+, CS-, and intertrial intervals. Valence ratings and affective priming showed the CS+ was unpleasant postacquisition. Blink startle magnitude was larger during CS+ than during CS-. Experiment 2 used the same design in two groups trained with pleasant or unpleasant pictorial USs. Ratings and affective priming indicated that the CS+ had become pleasant or unpleasant in the respective group. Regardless of CS valence, blink startle was larger during CS+ than CS- in both groups. Thus, startle was not modulated by CS valence.
Resumo:
Affect modulates the blink startle reflex in the picture-viewing paradigm, however, the process responsible for reflex modulation during conditional stimuli (CSs) that have acquired valence through affective conditioning remains unclear. In Experiment 1, neutral shapes (CSs) and valenced or neutral pictures (USs) were paired in a forward (CS → US) manner. Pleasantness ratings supported affective learning of positive and negative valence. Post-acquisition, blink reflexes were larger during the pleasant and unpleasant CSs than during the neutral CS. Rather than affect, attention or anticipatory arousal were suggested as sources of startle modulation. Experiment 2 confirmed that affective learning in the picture–picture paradigm was not affected by whether the CS preceded the US. Pleasantness ratings and affective priming revealed similar extents of affective learning following forward, backward or simultaneous pairings of CSs and USs. Experiment 3 utilized a backward conditioning procedure (US → CS) to minimize effects of US anticipation. Again, blink reflexes were larger during CSs paired with valenced USs regardless of US valence implicating attention rather than anticipatory arousal or affect as the process modulating startle in this paradigm.
Resumo:
The 21" century business environment is dominated by unprecedented change across a broad spectrum of social, economic, technological and cultural factors (Nowotny, Scott & Gibbons 2001). Among these, two broad trends -economic globalisation and rising knowledge intensity (Hart 2006)have come to distinguish organisational life. Under the weight of these transformational influences, the developed world, it seems, has arrived at a transformational moment. The far-reaching effects of the global financial crisis and its shadowy twin: the threat of a double dip recession, continue to exert an unsteadying influence on global and corporate finances. Growth in developed economies has slumped, share prices have declined, the market value of corporations has slipped and unemployment rates, in the vast majority of developed economies, have risen. Gross domestic product (GDP) growth has retreated from the strong growth experienced in the late 1990s to negative growth in 2009 and a sluggish and unsteady recovery in 2010. In response, the reach of Government in terms of its participation in markets has been extended, bringing with it the need to transition to new governance and regulatory arrangements. Ongoing concerns regarding the pace and sustainability of the recovery remains a front-of-mind concern with bailouts, buybacks, borrowings and BP dominating news services: 'We are witnessing the reweaving of the social, political and economic fabric that binds our planet, with long-term consequences that are as or more profound than those of the industrial era' (Tapscott & Williams 2006, p. 59).
Resumo:
Eccentric exercise is the conservative treatment of choice for mid-portion Achilles tendinopathy. While there is a growing body of evidence supporting the medium to long term efficacy of eccentric exercise in Achilles tendinopathy treatment, very few studies have investigated the short term response of the tendon to eccentric exercise. Moreover, the mechanisms through which tendinopathy symptom resolution occurs remain to be established. The primary purpose of this thesis was to investigate the acute adaptations of the Achilles tendon to, and the biomechanical characteristics of, the eccentric exercise protocol used for Achilles tendinopathy rehabilitation and a concentric equivalent. The research was conducted with an orientation towards exploring potential mechanisms through which eccentric exercise may bring about a resolution of tendinopathy symptoms. Specifically, the morphology of tendinopathic and normal Achilles tendons was monitored using high resolution sonography prior to and following eccentric and concentric exercise, to facilitate comparison between the treatment of choice and a similar alternative. To date, the only proposed mechanism through which eccentric exercise is thought to result in symptom resolution is the increased variability in motor output force observed during eccentric exercise. This thesis expanded upon prior work by investigating the variability in motor output force recorded during eccentric and concentric exercises, when performed at two different knee joint angles, by limbs with and without symptomatic tendinopathy. The methodological phase of the research focused on establishing the reliability of measures of tendon thickness, tendon echogenicity, electromyography (EMG) of the Triceps Surae and the standard deviation (SD) and power spectral density (PSD) of the vertical ground reaction force (VGRF). These analyses facilitated comparison between the error in the measurements and experimental differences identified as statistically significant, so that the importance and meaning of the experimental differences could be established. One potential limitation of monitoring the morphological response of the Achilles tendon to exercise loading is that the Achilles tendon is continually exposed to additional loading as participants complete the walking required to carry out their necessary daily tasks. The specific purpose of the last experiment in the methodological phase was to evaluate the effect of incidental walking activity on Achilles tendon morphology. The results of this study indicated that walking activity could decrease Achilles tendon thickness (negative diametral strain) and that the decrease in thickness was dependent on both the amount of walking completed and the proximity of walking activity to the sonographic examination. Thus, incidental walking activity was identified as a potentially confounding factor for future experiments which endeavoured to monitor changes in tendon thickness with exercise loading. In the experimental phase of this thesis the thickness of Achilles tendons was monitored prior to and following isolated eccentric and concentric exercise. The initial pilot study demonstrated that eccentric exercise resulted in a greater acute decrease in Achilles tendon thickness (greater diametral strain) compared to an equivalent concentric exercise, in participants with no history of Achilles tendon pain. This experiment was then expanded to incorporate participants with unilateral Achilles tendinopathy. The major finding of this experiment was that the acute decrease in Achilles tendon thickness observed following eccentric exercise was modified by the presence of tendinopathy, with a smaller decrease (less diametral strain) noted for tendinopathic compared to healthy control tendon. Based on in vitro evidence a decrease in tendon thickness is believed to reflect extrusion of fluid from the tendon with loading. This process would appear to be limited by the presence of pathology and is hypothesised to be a result of the changes in tendon structure associated with tendinopathy. Load induced fluid movement may be important to the maintenance of tendon homeostasis and structure as it has the potential to enhance molecular movement and stimulate tendon remodelling. On this basis eccentric exercise may be more beneficial to the tendon than concentric exercise. Finally, EMG and motor output force variability (SD and PSD of VGRF) were investigated while participants with and without tendinopathy performed the eccentric and concentric exercises. Although between condition differences were identified as statistically significant for a number of force variability parameters, the differences were not greater than the limits of agreement for repeated measures. Consequently the meaning and importance of these findings were questioned. Interestingly, the EMG amplitude of all three Triceps Surae muscles did not vary with knee joint angle during the performance of eccentric exercise. This raises questions pertaining to the functional importance of performing the eccentric exercise protocol at each of the two knee joint angles as it is currently prescribed. EMG amplitude was significantly greater during concentric compared to eccentric muscle actions. Differences in the muscle activation patterns may result in different stress distributions within the tendon and be related to the different diametral strain responses observed for eccentric and concentric muscle actions.