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Unreliable Indicator (unreliable + indicator)
Selected AbstractsMeasurement of body size and abundance in tests of macroecological and food web theoryJOURNAL OF ANIMAL ECOLOGY, Issue 1 2007SIMON JENNINGS Summary 1Mean body mass (W) and mean numerical (N) or biomass (B) abundance are frequently used as variables to describe populations and species in macroecological and food web studies. 2We investigate how the use of mean W and mean N or B, rather than other measures of W and/or accounting for the properties of all individuals, can affect the outcome of tests of macroecological and food web theory. 3Theoretical and empirical analyses demonstrate that mean W, W at maximum biomass (Wmb), W when energy requirements are greatest (Wme) and the W when a species uses the greatest proportion of the energy available to all species in a W class (Wmpe) are not consistently related. 4For a population at equilibrium, relationships between mean W and Wme depend on the slope b of the relationship between trophic level and W. For marine fishes, data show that b varies widely among species and thus mean W is an unreliable indicator of the role of a species in the food web. 5Two different approaches, ,cross-species' and ,all individuals' have been used to estimate slopes of abundance,body mass relationships and to test the energetic equivalence hypothesis and related theory. The approaches, based on relationships between (1) log10 mean W and log10 mean N or B, and (2) log10 W and log10 N or B of all individuals binned into log10 W classes (size spectra), give different slopes and confidence intervals with the same data. 6Our results show that the ,all individuals' approach has the potential to provide more powerful tests of the energetic equivalence hypothesis and role of energy availability in determining slopes, but new theory and empirical analysis are needed to explain distributions of species relative abundance at W. 7Biases introduced when working with mean W in macroecological and food web studies are greatest when species have indeterminate growth, when relationships between W and trophic level are strong and when the range of species'W is narrow. [source] Treatment of acute otitis media in patients with a reported penicillin allergyJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 3 2000Falconer Otitis media occurs commonly in children, and is usually treated with an antibiotic. In this case report, amoxicillin was prescribed for a 6-year-old boy suffering from acute otitis media. As he had previously experienced a rash after the administration of a penicillin, the medication order was switched from amoxicillin to trimethoprim/sulfamethoxazole (TMP/SMX). In an effort to determine whether or not this intervention was appropriate, references were found using Medline, International Pharmaceutical Abstracts and the Cochrane Library. Issues to be addressed included the need for antibiotics in acute otitis media, the comparative efficacy and tolerability of antimicrobial agents and the reliability of reported penicillin allergies. Amoxicillin and TMP/SMX were found to be first-line agents in the treatment of acute otitis media owing to their efficacy, safety and cost, with neither drug being significantly better than the other. The need to treat otitis media with antibiotics remains controversial. Reported penicillin allergies were found to be an unreliable indicator of a potentially serious reaction. In conclusion, it was found that treatment with TMP/SMX was an appropriate intervention. [source] Quantitative measurement of serotonin synthesis and sequestration in individual live neuronal cellsJOURNAL OF NEUROCHEMISTRY, Issue 5 2005J. Balaji Abstract Synthesis and subsequent sequestration into vesicles are essential steps that precede neurotransmitter exocytosis, but neither the total neurotransmitter content nor the fraction sequestered into vesicles have been measured in individual live neurons. We use multiphoton microscopy to directly observe intracellular and intravesicular serotonin in the serotonergic neuronal cell line RN46A. We focus on how the relationship between synthesis and sequestration changes as synthesis is up-regulated by differentiation or down-regulated by chemical inhibition. Temperature-induced differentiation causes an increase of about 60% in the total serotonin content of individual cells, which goes up to about 10 fmol. However, the number of vesicles per cell increases by a factor of four and the proportion of serotonin sequestered inside the vesicles increases by a factor of five. When serotonin synthesis is inhibited in differentiated cells and the serotonin content goes down to the level present in undifferentiated cells, the sequestered proportion still remains at this high level. The total neurotransmitter content of a cell is, thus, an unreliable indicator of the sequestered amount. [source] Review: Neutrophil gelatinase-associated lipocalin: A troponin-like biomarker for human acute kidney injuryNEPHROLOGY, Issue 4 2010PRASAD DEVARAJAN ABSTRACT Acute kidney injury (AKI) is a common and serious condition, the diagnosis of which currently depends on functional markers such as serum creatinine measurements. Unfortunately, creatinine is a delayed and unreliable indicator of AKI. The lack of early biomarkers of structural kidney injury (akin to troponin in acute myocardial injury) has hampered our ability to translate promising experimental therapies to human AKI. Fortunately, understanding the early stress response of the kidney to acute injuries has revealed a number of potential biomarkers. The discovery, translation and validation of neutrophil gelatinase-associated lipocalin (NGAL), possibly the most promising novel AKI biomarker, is reviewed. NGAL is emerging as an excellent stand-alone troponin-like structural biomarker in the plasma and urine for the early diagnosis of AKI, and for the prediction of clinical outcomes such as dialysis requirement and mortality in several common clinical scenarios. The approach of using NGAL as a trigger to initiate and monitor therapies for AKI, and as a safety biomarker when using potentially nephrotoxic agents, is also promising. In addition, it is hoped that the use of sensitive and specific biomarkers such as NGAL as endpoints in clinical trials will result in a reduction in required sample sizes, and hence the cost incurred. Furthermore, predictive biomarkers like NGAL may play a critical role in expediting the drug development process. However, given the complexity of AKI, additional biomarkers (perhaps a panel of plasma and urinary biomarkers) may eventually need to be developed and validated for optimal progress to occur. [source] Double-masked randomised placebo-controlled trial of the effect of prismatic corrections on rate of reading and the relationship with symptomsOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 6 2006Claire I. O'Leary Abstract Practitioners' decisions on when to intervene in decompensated heterophoria are often based on symptoms, which are in some cases an unreliable indicator of whether an intervention will be helpful. The aim of our study was to determine when prismatic corrections improve performance at a measure of dynamic visual function: the Wilkins Rate of Reading Test (WRRT). All participants manifested an aligning prism (associated heterophoria) on the near Mallett Unit of 0.5, or greater. There were 80 participants, of whom 58 had exophoria, 15 esophoria, and seven hyperphoria. The effect of the aligning prism on the WRRT was compared with a control lens using a double-masked randomised design. For exophoria, an aligning prism of 2, and above has a sensitivity of 67% and a specificity of 79% for improving performance at the WRRT by 5% or more. It is not possible from our data to achieve a good compromise between sensitivity and specificity for the other types of heterophoria. Patients in the horizontal (but not vertical) heterophoria groups had significantly more symptoms than a control group. The patients whose visual performance is improved by prismatic correction are not necessarily those who report the most symptoms. Our data suggest that exophoric patients of any age are likely to have improved visual performance with an intervention if they have an aligning prism of 2, or more, even in the absence of symptoms. We stress that although the Mallett Unit Fixation Disparity test provides useful information, its results need to be considered in the overall context of the patient's symptoms, lifestyle, and the results of other optometric tests. Although this study evaluated prismatic corrections, we note that interventions for decompensated heterophoria include not only prismatic corrections, but also eye exercises and refractive modification. [source] | |||||||||||||