Evaluation of a method to measure long term cortisol levels

IntroductionElevated levels of cortisol are known to induce various symptoms and diseases, e.g. abdominal obesity, type 2 diabetes, osteoporosis and cardiovascular disease. Measuring serum, saliva and urine cortisol is limited to one time point. Measurement of cortisol in scalp hair is a recently developed method to measure long term cortisol levels. The aim of this study was to investigate whether hair cortisol is a feasible parameter to measure cortisol exposure.ExperimentalWe collected hair samples of 195 healthy individuals, 9 hypercortisolemic and one hypocortisolemic patient and measured hair cortisol levels. Cortisol was extracted from scalp hair using methanol and cortisol levels were measured using a salivary ELISA kit. Measurement of waist and hip circumferences and blood pressure was performed in 46 healthy subjects.ResultsWe found a positive correlation between hair cortisol and both waist circumference (r = 0.392, p = 0.007) and waist-to-hip ratio (WHR) (r = 0.425, p = 0.003). No correlations were found between hair cortisol levels and BMI, blood pressure or age. There was no decline in cortisol levels in six consecutive hair segments. Hair cortisol levels were elevated in patients with known hypercortisolism (p < 0.0001).ConclusionsHair cortisol was positively correlated with WHR, suggesting that hair cortisol reflects cortisol exposure at tissue level, which was also supported by elevated hair cortisol levels in hypercortisolemic patients and concordance between hair cortisol levels and clinical disease course. Cortisol levels in hair are slightly influenced by hair treatment but not by natural hair colour, use of hair products, gender or age.     

Evaluation of gene-expression clustering via mutual information distance measure

Background  

The definition of a distance measure plays a key role in the evaluation of different clustering solutions of gene expression profiles. In this empirical study we compare different clustering solutions when using the Mutual Information (MI) measure versus the use of the well known Euclidean distance and Pearson correlation coefficient.     

Evaluation of a fully automated method to measure the critical removal stress of adult barnacles

A computer-controlled force gauge designed to measure the adhesive strength of barnacles on test substrata is described. The instrument was evaluated with adult barnacles grown in situ on Silastic T2(R)-coated microscope slides and epoxy replicas adhered to the same substratum with synthetic adhesive. The force per unit area required to detach the barnacles (critical removal stress) using the new automated system was comparable to that obtained with ASTM D5618 (1994) (0.19 and 0.28 MPa compared with 0.18 and 0.27 MPa for two batches of barnacles). The automated method showed a faster rate of force development compared with the manual spring force gauge used for ASTM D5618 (1994). The new instrument was as accurate and precise at determining surface area as manual delineation used with ASTM D5618 (1994). The method provided significant advantages such as higher throughput speed, the ability to test smaller barnacles (which took less time to grow) and to control the force application angle and speed. The variability in measurements was lower than previously reported, suggesting an improved ability to compare the results obtained by different researchers.     

Coastal eutrophication research: a new awareness

An analysis of the contents and conclusions of the papers contained in this issue (Hydrobiologia Volume xxx) suggests that a new vision is taking shape that may correspond to an emerging new paradigm in the way we understand and manage coastal eutrophication. This new paradigm emphasizes its global dimension and the connections with other global environmental pressures, and re-evaluates the targets of remedial actions and policies. Eutrophication research must evolve toward a more integrative, ecosystem perspective which requires that it be extended to include impacts beyond primary producers and to examine possible cascading effects and feedbacks involving other components of the ecosystem. A quantitative framework that incorporates the interacting top-down and bottom-up effects in eutrophication models must be urgently developed to guide diagnostics and establish targets to mitigate coastal eutrophication. The required macroscopic view must also be extended to the managerial and policy frameworks addressing eutrophication, through the development of policies that examine activities in the environment in an integrative, rather than sectorial, manner. Recent evidence of complex responses of coastal ecosystems to nutrient reduction requires that management targets, and the policies that support them, be reconsidered to recognize the complexities of the responses of coastal ecosystems to reduced nutrient inputs, including non-linear responses and associated thresholds. While a predictive framework for the complex trajectories of coastal ecosystems subject to changes in nutrient inputs is being developed, the assessment of managerial actions should be reconsidered to focus on the consideration of the status achieved as the outcome of nutrient reduction plans against that possibly derived from a ‘do nothing’ scenario. A proper assessment of eutrophication and the efforts to mitigate it also requires that eutrophication be considered as a component of global change, in addressing both its causes and its consequences, and that the feedbacks between other components of global change (e.g., climate change, overfishing, altered biogeochemical cycles, etc.) be explicitly considered in designing eutrophication research and in managing the problem. Guest editors: J. H. Andersen & D. J. Conley Eutrophication in Coastal Ecosystems: Selected papers from the Second International Symposium on Research and Management of Eutrophication in Coastal Ecosystems, 20–23 June 2006, Nyborg, Denmark     

Evaluation of some enzymatic methods to measure the bio-activity of aquatic environments

Methods have been evaluated and standardised to measure the phosphatase, saccharase, amylase and lipase enzymatic activities in aquatic environments. The analytical reproducibility, the ecological applicability and the etiology of these activities have been investigated. The usefulness of the various enzymatic assays for routine analyses and for fundamental research of aquatic environments is discussed.     

Endophenotypes as a measure of suicidality

Suicide is thought to result from the harmful interaction of multiple factors that have social, environmental, neurobiological, and genetic backgrounds. Recent studies have suggested that genetic predisposition to suicidal behavior may be independent of the risk of suicide associated to mental disorders, such as affective disorders, schizophrenia, or alcohol dependence. Given the suicidal behavior heterogeneity and its hereditary complexity, the need to find demonstrable intermediate phenotypes that may make it possible to establish links between genes and suicide behaviors (endophenotypes) seems to be necessary. The main objective of this review was to consider the candidate endophenotypes of suicidal behaviors. Due to the recent advances in neuroimaging, we also characterize brain regions implicated in vulnerability to suicide behavior that are influenced by gene polymorphisms associated with suicidal behavior.     

Spatial awareness

A new method of mapping marine environments and activities is hoped will help better resolve conflicting uses and conservation interests.     

Evaluation of the electro-ultrafiltration technique (EUF) as a measure of the K supplying power of Quebec soils

The electro-ultrafiltration (EUF) method has been used to evaluate the short-term and long-term supplying power of soils for many essential plant nutrients. The objective of this study was to compare the capacity of EUF with other extraction techniques to predict the plant availability of soil K and K fertilizer responsiveness by 10 cuts of alfalfa (Medicago sativa L.) growing over a 366-day period. Increasingly higher average concentrations of soil K were extracted by EUF at 50 V and 20°C (29 mg kg^-1), EUF at 200 V and 20°C (48 mg kg^-1), 0.002 M SrCl₂ (55 mg kg^-1), EUF at 200 V and 80°C (85 mg kg^-1), 0.1 M HCl (105 mg kg^-1), Mehlich 3 (119 mg kg^-1), 1 M NH₄OAc (120 mg kg^-1) and boiling 1 M HNO₃ (601 mg kg^-1). The large content of vermiculitic minerals in the silt and clay fractions is responsible for EUF desorbing more K in 55 minutes than NH₄OAc in 29 out of 30 soils. The total amount of K desorbed by EUF at 80°C was as effective as Mehlich 3-extractable K in predicting K uptake for the first three cuts and was best among the extracting procedures after boiling 1 M HNO₃ in predicting the long-term K supply, the uptake of K from non-exchangeable sources and the relative yield of alfalfa over 10 cuts. The desorption of soil K with EUF provides a better evaluation of the K-supplying power of Quebec soils than the extractants currently used, especially on a long-term basis.Contribution no. 396.     

Secretory IgA as a measure of immunocompetence

The field of psychoimmunology has rapidly expanded in recent years and various parameters of the immune system have been examined in relation to psychological factors. The secretory immune system is one of the more interesting aspects of the entire immune system because it protects mucosal membranes from invading organisms. Stress-produced changes in secretory immunoglobulin A (s-IgA) as measured by radial immunodiffusion assays have been reported in several studies. We present three reasons why total s-IgA protein, the measure derived from radial immunodiffusion assays, may not be a reasonable measure of immune system functioning, and we suggest an alternative method for examining secretory IgA that focuses on s-IgA antibody response to a novel antigen.     

Overt visual attention as a causal factor of perceptual awareness

Our everyday conscious experience of the visual world is fundamentally shaped by the interaction of overt visual attention and object awareness. Although the principal impact of both components is undisputed, it is still unclear how they interact. Here we recorded eye-movements preceding and following conscious object recognition, collected during the free inspection of ambiguous and corresponding unambiguous stimuli. Using this paradigm, we demonstrate that fixations recorded prior to object awareness predict the later recognized object identity, and that subjects accumulate more evidence that is consistent with their later percept than for the alternative. The timing of reached awareness was verified by a reaction-time based correction method and also based on changes in pupil dilation. Control experiments, in which we manipulated the initial locus of visual attention, confirm a causal influence of overt attention on the subsequent result of object perception. The current study thus demonstrates that distinct patterns of overt attentional selection precede object awareness and thereby directly builds on recent electrophysiological findings suggesting two distinct neuronal mechanisms underlying the two phenomena. Our results emphasize the crucial importance of overt visual attention in the formation of our conscious experience of the visual world.     

The dental awareness and needs of a Parkinson's disease population

The dental awareness and needs of a population with Parkinson's disease were assessed by means of postal questionnaires sent to members of Parkinson's disease societies of Belfast and London. A total of 228 valid replies were received representing a response rate of 31%. Results showed that dental problems were reported often, xerostomia and burning sensation being at least twice that of the general population. Satisfaction with dental care was high although it was significantly reduced in those with loose dentures and burning sensation. The results of this study support a greater participation by dentists in the planning and provision of healthcare for sufferer of Parkinson's disease.