Adrenal Dysfunction in Hemodynamically Unstable Patients in the Emergency Department

Objective: Adrenal failure, a treatable condition, can have catastrophic consequences if unrecognized in critically ill ED patients. The authors' objective was to prospectively study adrenal function in a case series of hemodynamically unstable (high-risk) patients from a large, urban ED over a 12-month period. Methods: In a prospective manner, critically ill adult patients presenting to the ED were enrolled when presenting with a mean arterial blood pressure ≤60 mm Hg requiring vasopressor therapy for more than one hour after receiving fluid resuscitation (central venous pressure of 12-15 mm Hg or a minimum of 40 mL/kg of crystalloid). Patients were excluded if presenting with hemorrhage, trauma, or AIDS, or if steroids were used within the previous six months. An adrenocorticotropic hormone (ACTH) stimulation test was performed and serum cortisol was measured. Treatment for adrenal insufficiency was not instituted. Results: A total of 57 consecutive patients were studied. Of these, eight (14%) had baseline serum cortisol concentrations of <20 Μg/dL (<552 nmol/L), which was considered adrenal insufficiency (AI). Three additional patients (5%) had subnormal 60-minute post-ACTH-stimulation cortisol responses (<30 Μg/dL) and a delta cortisol ≤9 Μg/dL, which is the difference between the baseline and 60-minute levels. This is functional hypoadrenalism (FH). There were no laboratory abnormalities that distinguished patients with AI or FH from those with preserved adrenal function (PAF). Rates of survival to discharge did not differ between the AI group (7 of 8) and PAF patients (21 of 46; p = 0.052). Conclusions: Adrenal dysfunction is common in high-risk ED patients. Overall, it has a frequency of 19% among a homogeneous population of hemodynamically unstable vasopressor-dependent patients. The effect of physiologic glucocorticoid replacement in this setting remains to be determined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71956/1/j.1553-2712.1999.tb00417.x.pd

Information inequalities and Generalized Graph Entropies

In this article, we discuss the problem of establishing relations between information measures assessed for network structures. Two types of entropy based measures namely, the Shannon entropy and its generalization, the R\'{e}nyi entropy have been considered for this study. Our main results involve establishing formal relationship, in the form of implicit inequalities, between these two kinds of measures when defined for graphs. Further, we also state and prove inequalities connecting the classical partition-based graph entropies and the functional-based entropy measures. In addition, several explicit inequalities are derived for special classes of graphs.Comment: A preliminary version. To be submitted to a journa

Phosphoinositide-binding interface proteins involved in shaping cell membranes

The mechanism by which cell and cell membrane shapes are created has long been a subject of great interest. Among the phosphoinositide-binding proteins, a group of proteins that can change the shape of membranes, in addition to the phosphoinositide-binding ability, has been found. These proteins, which contain membrane-deforming domains such as the BAR, EFC/F-BAR, and the IMD/I-BAR domains, led to inward-invaginated tubes or outward protrusions of the membrane, resulting in a variety of membrane shapes. Furthermore, these proteins not only bind to phosphoinositide, but also to the N-WASP/WAVE complex and the actin polymerization machinery, which generates a driving force to shape the membranes

Radio emission from Supernova Remnants

The explosion of a supernova releases almost instantaneously about 10^51 ergs of mechanic energy, changing irreversibly the physical and chemical properties of large regions in the galaxies. The stellar ejecta, the nebula resulting from the powerful shock waves, and sometimes a compact stellar remnant, constitute a supernova remnant (SNR). They can radiate their energy across the whole electromagnetic spectrum, but the great majority are radio sources. Almost 70 years after the first detection of radio emission coming from a SNR, great progress has been achieved in the comprehension of their physical characteristics and evolution. We review the present knowledge of different aspects of radio remnants, focusing on sources of the Milky Way and the Magellanic Clouds, where the SNRs can be spatially resolved. We present a brief overview of theoretical background, analyze morphology and polarization properties, and review and critical discuss different methods applied to determine the radio spectrum and distances. The consequences of the interaction between the SNR shocks and the surrounding medium are examined, including the question of whether SNRs can trigger the formation of new stars. Cases of multispectral comparison are presented. A section is devoted to reviewing recent results of radio SNRs in the Magellanic Clouds, with particular emphasis on the radio properties of SN 1987A, an ideal laboratory to investigate dynamical evolution of an SNR in near real time. The review concludes with a summary of issues on radio SNRs that deserve further study, and analyzing the prospects for future research with the latest generation radio telescopes.Comment: Revised version. 48 pages, 15 figure

Boolean analysis reveals systematic interactions among low-abundance species in the human gut microbiome

The analysis of microbiome compositions in the human gut has gained increasing interest due to the broader availability of data and functional databases and substantial progress in data analysis methods, but also due to the high relevance of the microbiome in human health and disease. While most analyses infer interactions among highly abundant species, the large number of low-abundance species has received less attention. Here we present a novel analysis method based on Boolean operations applied to microbial co-occurrence patterns. We calibrate our approach with simulated data based on a dynamical Boolean network model from which we interpret the statistics of attractor states as a theoretical proxy for microbiome composition. We show that for given fractions of synergistic and competitive interactions in the model our Boolean abundance analysis can reliably detect these interactions. Analyzing a novel data set of 822 microbiome compositions of the human gut, we find a large number of highly significant synergistic interactions among these low-abundance species, forming a connected network, and a few isolated competitive interactions

Systematic Functional Analysis of Bicaudal-D Serine Phosphorylation and Intragenic Suppression of a Female Sterile Allele of BicD

Protein phosphorylation is involved in posttranslational control of essentially all biological processes. Using mass spectrometry, recent analyses of whole phosphoproteomes led to the identification of numerous new phosphorylation sites. However, the function of most of these sites remained unknown. We chose the Drosophila Bicaudal-D protein to estimate the importance of individual phosphorylation events. Being involved in different cellular processes, BicD is required for oocyte determination, for RNA transport during oogenesis and embryogenesis, and for photoreceptor nuclei migration in the developing eye. The numerous roles of BicD and the available evidence for functional importance of BicD phosphorylation led us to identify eight phosphorylation sites of BicD, and we tested a total of 14 identified and suspected phosphoserine residues for their functional importance in vivo in flies. Surprisingly, all these serines turned out to be dispensable for providing sufficient basal BicD activity for normal growth and development. However, in a genetically sensitized background where the BicDA40V protein variant provides only partial activity, serine 103 substitutions are not neutral anymore, but show surprising differences. The S103D substitution completely inactivates the protein, whereas S103A behaves neutral, and the S103F substitution, isolated in a genetic screen, restores BicDA40V function. Our results suggest that many BicD phosphorylation events may either be fortuitous or play a modulating function as shown for Ser103. Remarkably, amongst the Drosophila serines we found phosphorylated, Ser103 is the only one that is fully conserved in mammalian BicD

Influence of opinion dynamics on the evolution of games

Under certain circumstances such as lack of information or bounded rationality, human players can take decisions on which strategy to choose in a game on the basis of simple opinions. These opinions can be modified after each round by observing own or others payoff results but can be also modified after interchanging impressions with other players. In this way, the update of the strategies can become a question that goes beyond simple evolutionary rules based on fitness and become a social issue. In this work, we explore this scenario by coupling a game with an opinion dynamics model. The opinion is represented by a continuous variable that corresponds to the certainty of the agents respect to which strategy is best. The opinions transform into actions by making the selection of an strategy a stochastic event with a probability regulated by the opinion. A certain regard for the previous round payoff is included but the main update rules of the opinion are given by a model inspired in social interchanges. We find that the dynamics fixed points of the coupled model is different from those of the evolutionary game or the opinion models alone. Furthermore, new features emerge such as the resilience of the fraction of cooperators to the topology of the social interaction network or to the presence of a small fraction of extremist players.Comment: 7 pages, 5 figure

Contrast-enhancement cardiac magnetic resonance imaging beyond the scope of viability

The clinical applications of cardiovascular magnetic resonance imaging with contrast enhancement are expanding. Besides the direct visualisation of viable and non-viable myocardium, this technique is increasingly used in a variety of cardiac disorders to determine the exact aetiology, guide proper treatment, and predict outcome and prognosis. In this review, we discuss the value of cardiovascular magnetic resonance imaging with contrast enhancement in a range of cardiac disorders, in which this technique may provide insights beyond the scope of myocardial viability