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Principal Determinant (principal + determinant)
Selected AbstractsCritical roles for thrombin in acute and chronic inflammationJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 2009D. CHEN Summary., Thrombin can amplify inflammation induced by other stimuli, either through ischemia (consequent upon thrombosis), indirectly through generation of downstream mediators such as activated protein C, or directly via signals through protease activated receptors (PAR). This paper will summarize recent data from our laboratory indicating that thrombin is required to initiate CCR2-dependent leukocyte recruitment and that it is the principal determinant of the outcome after vascular injury, via PAR-1 activation of a distinct subset of smooth muscle cell progenitors. In both, tissue factor (TF) initiates thrombin generation and the thrombin acts locally, exemplifying that the initiation phase can generate autocrine or paracrine signalling molecules. Thrombin is an important constituent of innate immunity, able to amplify and modify responses to invading pathogens or tissue damage. With novel anti-thrombin therapeutics and agents to target PAR, a new understanding of the importance of thrombin may allow the development of innovative anti-inflammatory strategies. [source] Good, bad or ,necessary evil'?THE GEOGRAPHICAL JOURNAL, Issue 4 2006Reinterpreting the colonial burning experiments in the savanna landscapes of West Africa A simple ecological model underlies contemporary fire policy in many West African countries. The model holds that the timing (or seasonality) of annual savanna fires is a principal determinant of vegetation cover. The model's origin can be traced to the ideas held by influential colonial scientists who viewed anthropogenic fire as a prime force of regional environmental degradation. The main evidence in support of the model derives from the results of a series of long-term burning experiments carried out during last century. The experimental results have been repeatedly mapped onto fire policy often taking the form of a three-tiered model in which fire exclusion is considered the ultimate management objective, late dry-season fire is discouraged and early dry-season fire is allowed but only under specific, often state-controlled circumstances. This paper provides a critique of contemporary fire policy in the region and the fire ecology model on which it is based. Through an analysis of burn scars for the 2002,3 fire season generated from ETM+ imagery, the study documents the spatiotemporal pattern of burning for an area in southern Mali. It argues that current policy, which is informed by an a-spatial model, cannot adequately account for the critical pattern of burning that is characteristic of the region. A reinterpretation of the burning experiments is presented in light of four factors: empirical data; recent developments in patch-mosaic theory; historical evidence on the effects of fire suppression; and data on indigenous burning strategies, all of which suggest a need to reconsider current fire policy. [source] Genetic characterization of specific pathogen-free rhesus macaque (Macaca mulatta) populations at the California National Primate Research Center (CNPRC)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 7 2010Sree Kanthaswamy Abstract A study based on 14 STRs was conducted to understand intergenerational genetic changes that have occurred within the California National Primate Research Center's (CNPRC) regular specific pathogen-free (SPF) and super-SPF captive rhesus macaque populations relative to their conventional founders. Intergenerational genetic drift has caused age cohorts of each study population, especially within the conventional population, to become increasingly differentiated from each other and from their founders. Although there is still only minimal stratification between the conventional population and either of the two SPF populations, separate derivation of the regular and super-SPF animals from their conventional founders has caused the two SPF populations to remain marginally different from each other. The regular SPF and, especially, the super-SPF populations have been influenced by the effects of differential ancestry, sampling, and lost rare alleles, causing a substantial degree of genetic divergence between these subpopulations. The country of origin of founders is the principal determinant of the MHC haplotype composition of the SPF stocks at the CNPRC. Selection of SPF colony breeders bearing desired genotypes of Mamu-A*01 or -B*01 has not affected the overall genetic heterogeneity of the conventional and the SPF research stocks. Because misclassifying the ancestry of research stocks can undermine experimental outcomes by excluding animals with regional-specific genotypes or phenotypes of importance, understanding founder/descendent genetic relationships is crucial for investigating candidate genes with distinct geographic origins. Together with demographic management, population genetic assessments of SPF colonies can curtail excessive phenotypic variation among the study stocks and facilitate successful production goals. Am. J. Primatol. 72:587,599, 2010. © 2010 Wiley-Liss, Inc. [source] Relative impacts of cattle grazing and feral animals on an Australian arid zone reptile and small mammal assemblageAUSTRAL ECOLOGY, Issue 3 2010JOHN L. READ Abstract The effect of different levels of cattle grazing on an arid Australian small terrestrial mammal and lizard assemblage was assessed in a long-tem series of cross-fence comparisons. Cross-fenced sites were closely matched for edaphic and vegetation characteristics and experienced near identical weather patterns, to ensure that cattle grazing pressure was the principal determinant of any differences in fauna assemblages. In addition, the effects of removal of cattle, cats, foxes and rabbits from three of these long-term monitoring sites were assessed to determine the relative impacts of cattle grazing and feral animals. Small mammal captures, with the exception of Mus musculus, revealed a significant negative response to cattle grazing pressure but this response was of a considerably lower magnitude than the dramatic increase in rodent captures and species richness within the feral animal-proof Arid Recovery Reserve. Higher kangaroo numbers in ungrazed controls, compared with treatments grazed by cattle, possibly negated the benefits to small mammals of removing cattle grazing. No reptile species responded significantly to the grazing treatments although reptile richness and captures of geckos and skinks were the lowest and agamid captures were the highest at heavily grazed sites. Nephrurus levis was the only reptile species to increase significantly, while captures of some smaller geckoes declined, within the feral-proof treatment. Feral predation exerted a more significant effect on most small mammal species than the levels of cattle grazing assessed in this study, yet reptile responses to grazing or feral animals were less apparent and were likely primarily driven by changes in vegetation cover or secondary trophic impacts. [source] Adhesion of Pseudomonas aeruginosa ocular isolates to mucinCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 3 2001Lina Panayiota Aristoteli BSc(Hons) ABSTRACT The purpose of this study was to compare the adhesion of Pseudomonas aeruginosa ocular isolates to mucin. An adhesion assay was developed using biotin-labelled P. aeruginosa strains (two corneal ulcer, two acute red eye, one asymptomatic and one standard strains) incubated with porcine gastric mucin immobilized on a nitrocellulose membrane. The adhesion was semiquantified using densitometry. The results showed that all P. aeruginosa strains tested were able to adhere to mucin to various extents with three strains (one corneal ulcer, one acute red eye, one asymptomatic) binding significantly greater than the negative control (P < 0.1). Results suggest that ocular strains of P. aeruginosa strains differ in their adhesion to mucin but this did not correlate with the pathogenic origin of the strain. It is concluded that the adhesion of P. aeruginosa strains to mucin alone may not be a principal determinant of pathogenesis but may be a contributing factor along with other bacterial virulence traits. [source] The origin of fibroblasts and mechanism of cardiac fibrosisJOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2010Guido Krenning Fibroblasts are at the heart of cardiac function and are the principal determinants of cardiac fibrosis. Nevertheless, cardiac fibroblasts remain poorly characterized in molecular terms. Evidence is evolving that the cardiac fibroblast is a highly heterogenic cell population, and that such heterogeneity is caused by the distinct origins of fibroblasts in the heart. Cardiac fibroblasts can derive either from resident fibroblasts, from endothelial cells via an endothelial,mesenchynmal transition or from bone marrow-derived circulating progenitor cells, monocytes and fibrocytes. Here, we review the function and origin of fibroblasts in cardiac fibrosis.NB. The information given is correct. J. Cell. Physiol. 225: 631,637, 2010. © 2010 Wiley-Liss, Inc. [source] Organisational susceptibility to fraud and theft, organizational size and the effectiveness of management controls: some UK evidenceMANAGERIAL AND DECISION ECONOMICS, Issue 3 2007Paul Barnes This paper examines the principal determinants of an organization's susceptibility to theft and fraud in the context of a rational economic framework in which the level of protection is determined by the minimization of cost. The empirical study shows that, adjusting for differences in organizational type and industrial sector, both organizational susceptibility and the size of a typical theft or fraud increase with organizational size. Access to resources and the manner in which the theft or fraud is perpetrated are also important determinants of the money lost. However, they are unaffected by management controls or the nature of their violation. Copyright © 2007 John Wiley & Sons, Ltd. [source] Classification of reproductive performance of ten winegrape varietiesAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2010P.R. DRY Abstract Background and Aims:, Flowering and fruitset are principal determinants of grapevine yield. Poor fruitset is said to limit the yield of many varieties in most regions in Australia; however, there is a lack of knowledge of the reproductive performance of most varieties under Australian conditions. Methods and Results:, The reproductive performance of Vitis vinifera winegrape varieties , Cabernet Sauvignon, Chardonnay, Merlot, Nebbiolo, Pinot Noir, Sangiovese, Sauvignon Blanc, Shiraz, Tempranillo, and Zinfandel , was studied in four consecutive growing seasons (commencing in 2004/05) across a range of climatic regions from cool (Adelaide Hills) to warm (Adelaide Plains). Measures of reproductive performance included flower number per inflorescence, fruitset (%), berry number per bunch, coulure index (CI), and millerandage index (MI). Principal component analysis and agglomerative hierarchical classification were used to group the varieties into three classes of reproductive performance. Conclusions:, Certain varieties have a reputation of having ,poor fruitset' that has been inferred from relatively low berry number per bunch; however, for some of these varieties, it is ,low flower number per inflorescence' rather than ,poor fruitset' that is the cause of low berry number. Significance of the Study:, An improved understanding of the reproductive performance of winegrape varieties has been achieved. [source] Modification of Vegetative Phenology in a Tropical Semi-deciduous Forest by Abnormal Drought and Rain,BIOTROPICA, Issue 1 2002R. Borchert ABSTRACT The control of vegetative phenology in tropical trees is not well understood. In dry forest trees, leaf abscission may be enhanced by advanced leaf age, increasing water stress, or declining photoperiod. Normally, it is impossible to dissect the effects of each of these variables because most leaves are shed during the early dry season when day length is near its minimum and leaves are relatively old. The 1997 El-Niño Southern Oscillation caused a ten-week long, severe abnormal drought from June to August in the semi-deciduous forests of Guanacaste, Costa Rica. We monitored the effect of this drought on phenology and water status of trees with young leaves and compared modifications of phenology in trees of different functional types with the pattern observed during the regular dry season. Although deciduous trees at dry sites were severely water stressed (,stem < -7MPa) and their mesic leaves remained wilted for more than two months, these and all other trees retained all leaves during the abnormal drought. Many trees exchanged leaves three to four months earlier than normal during the wet period after the abnormal drought and shed leaves again during the regular dry season. Irrigation and an exceptional 70 mm rainfall during the mid-dry season 1998/1999 caused bud break and flushing in all leafless trees except dormant stem succulents. The complex interactions between leaf age and water stress, the principal determinants of leaf abscission, were found to vary widely among trees of different functional types. [source] In-Hospital mortality of elderly patients with acute myocardial infarction: Data from the mitra (maximal individual therapy in acute myocardial infarction) registryCLINICAL CARDIOLOGY, Issue 11 2000K. K. Haase M.D. Abstract Background: Advanced age remains one of the principal determinants of mortality in patients with acute myocardial infarction (AMI). Hypothesis: The aim of this study was to determine the in-hospital outcome of elderly (>75 years) patients with AMI who were admitted to hospitals participating in the national MITRA (Maximal Individual Therapy in Acute Myocardial Infarction) registry. Methods: MITRA is a prospective, observational German multicenter registry investigating current treatment modalities for patients presenting with AMI. All patients with AMI admitted within 96 h of onset of symptoms were included in the MITRA registry. MITRA was started in June 1994 and ended in January 1997. This registry comprises 6,067 consecutive patients with a mean age of 65 ± 12 years, of whom 1,430 (17%) were aged > 75 years. Patients were compared with respect to patient characteristics, prehospital delays, early treatment strategies, and clinical outcome. Results: In the elderly patient population, the prehospital delay was 210 min, which was significantly longer than that for younger patients (155 min, p = 0.001). Although the incidence of potential contraindications for the initiation of thrombolysis was almost equally distributed between the two age groups (8.7 vs. 8.2%, p = NS), elderly patients (> 75 years) received reperfusion therapy less frequently (35.9 vs. 64.6%) than younger patients. Mortality increased with advanced age and was 26.4% for all patients aged > 75 years. If reperfusion therapy was initiated, in-hospital mortality was 21.8 versus 28.9% in patients aged > 75 years (p = 0.001) and 29.4 versus 38.5% in patients aged > 85 years (p = 0.001). Conclusion: In this registry, elderly patients with AMI had a much higher in-hospital mortality than that expected from randomized trials. In MITRA, the mortality reduction with reperfusion therapy was found to be highest in the very elderly patient population. [source] | |||||||||||||