University of Maine

About: University of Maine is a education organization based out in Orono, Maine, United States. It is known for research contribution in the topics: Population & Ice sheet. The organization has 8637 authors who have published 16932 publications receiving 590124 citations. The organization is also known as: University of Maine at Orono.

Arterial Pulse Wave Velocity and Cognition With Advancing Age

Abstract: We hypothesized that carotid-femoral pulse wave velocity (PWV), a marker of arterial stiffness, interacts with age such that the magnitude of associations between PWV and cognitive performance are greater with increasing age and that this interaction is observed despite adjustments for demographic variables, mean arterial pressure, and cardiovascular risk factors. PWV was estimated using applanation tonometry in 409 dementia- and stroke-free participants of the Maine-Syracuse Longitudinal Study (24 to 92 years of age; 62.3% women). Using linear regression analyses in a cross-sectional design, associations between PWV and age and the interaction of PWV and age were examined in relation to a global composite score, the Wechsler Adult Intelligence Scale Similarities test (abstract reasoning), and 4 cognitive domains indexed by multiple cognitive measures. Adjusting for age, gender, education, height, weight, heart rate, mean arterial pressure, and antihypertensive treatment, PWV-by-age interactions were obtained for the global, visual-spatial organization and memory, scanning and tracking, and verbal episodic memory composites, as well as similarities. The combination of higher PWV and age resulted in progressively lower cognitive performance. This finding was the same with an extended model, which also included adjustment for cardiovascular risk factors and other confounds. PWV interacts with age in a multiplicative way to exert a negative influence on cognitive performance level. Early interventions to prevent an increase in arterial stiffness could possibly play an important role in the preservation of cognitive ability.

Antimicrobial peptide defenses against pathogens associated with global amphibian declines.

Abstract: Global declines of amphibian populations are a source of great concern. Several pathogens that can infect the skin have been implicated in the declines. The pathogen most frequently associated with recent die-offs is a chytrid fungus, Batrachochytrium dendrobatidis. A second fungus, Basidiobolus ranarum, was isolated from declining populations of Wyoming toads. A third pathogen, Aeromonas hydrophila, is an opportunistic bacterium found in healthy frogs, but capable of inducing disease. Among the immune defense mechanisms used by amphibians is the production of antimicrobial peptides in granular glands in the skin. These packets of natural antibiotics can be emptied onto the skin when the amphibian is injured. To determine whether antimicrobial skin peptides defend against these amphibian pathogens, six peptides (magainin I, magainin II, PGLa, CPF, ranalexin, and dermaseptin), from three species, and representing three structurally different families of peptides, were tested in growth inhibition assays. We show here that the peptides can kill or inhibit growth of both fungi but not Aeromonas. Although each peptide varied in its effectiveness, at least one from each species was effective against both fungi at a concentration of about 10-20 microM. This is the first direct evidence that antimicrobial peptides in the skin can operate as a first line of defense against the organisms associated with global amphibian declines. It suggests that this innate defense mechanism may play a role in preventing or limiting infection by these organisms.

Antarctic temperatures over the past two centuries from ice cores

Abstract: [1] We present a reconstruction of Antarctic mean surface temperatures over the past two centuries based on water stable isotope records from high-resolution, precisely dated ice cores. Both instrumental and reconstructed temperatures indicate large interannual to decadal scale variability, with the dominant pattern being anti-phase anomalies between the main Antarctic continent and the Antarctic Peninsula region. Comparative analysis of the instrumental Southern Hemisphere (SH) mean temperature record and the reconstruction suggests that at longer timescales, temperatures over the Antarctic continent vary in phase with the SH mean. Our reconstruction suggests that Antarctic temperatures have increased by about 0.2°C since the late nineteenth century. The variability and the long-term trends are strongly modulated by the SH Annular Mode in the atmospheric circulation.

Factors controlling emission of dimethylsulphide from salt marshes

Abstract: Salt marshes are presently identified as systems exhibiting high area-specific sulfur emission in the form of dimethylsulfide (DMS) and H2S, with the former predominating in vegetated areas of the marshes. Attention is presently given to the distribution of DMS in salt marshes; it is found that this compound primarily arises from physiological processes in the leaves of higher plants, especially the grass species Spartina alterniflora. Uncertainties associated with DMS emission measurements are considered.

Differential Adaptation of Candida albicans In Vivo Modulates Immune Recognition by Dectin-1

Abstract: The β-glucan receptor Dectin-1 is a member of the C-type lectin family and functions as an innate pattern recognition receptor in antifungal immunity. In both mouse and man, Dectin-1 has been found to play an essential role in controlling infections with Candida albicans, a normally commensal fungus in man which can cause superficial mucocutaneous infections as well as life-threatening invasive diseases. Here, using in vivo models of infection, we show that the requirement for Dectin-1 in the control of systemic Candida albicans infections is fungal strain-specific; a phenotype that only becomes apparent during infection and cannot be recapitulated in vitro. Transcript analysis revealed that this differential requirement for Dectin-1 is due to variable adaptation of C. albicans strains in vivo, and that this results in substantial differences in the composition and nature of their cell walls. In particular, we established that differences in the levels of cell-wall chitin influence the role of Dectin-1, and that these effects can be modulated by antifungal drug treatment. Our results therefore provide substantial new insights into the interaction between C. albicans and the immune system and have significant implications for our understanding of susceptibility and treatment of human infections with this pathogen.