1,721,031 research outputs found
Comment on "levels of vancomycin in the cerebral interstitial fluid after severe head injury" by Caricato et al. [7]
No full textMy paper 20 years later: cerebral venous oxygen saturation studied with bilateral samples in the internal jugular veins
No full textIntroduction: Jugular oxygen saturation monitoring was introduced in neurointensive care after severe traumatic brain injury (TBI) to explore the adequacy of brain perfusion and guide therapeutic interventions. The brain was considered homogeneous, and oxygen saturation was taken as representative of the whole organ. We investigated whether venous outflow from the brain was homogeneous by measuring oxygen saturation simultaneously from the two jugular veins.Methods: In 32 comatose TBI patients both internal jugular veins (IJs) were simultaneously explored using intermittent samples; hemoglobin saturation was also recorded continuously by fiber-optic catheters in five patients. In five cases long catheters were inserted bilaterally upstream, up to the sigmoid sinuses.Main findings: On average, measurements from the two sides were in agreement (mean and standard deviation of the differences between the saturation of the two IJs were respectively 5.32 and 5.15). However, 15 patients showed differences of more than 15 % in hemoglobin saturation at some point; three others showed differences larger than 10 %. No relationship was found between the computed tomographic scan data and the hemoglobin saturation pattern.Discussion/conclusion: Several groups have confirmed differences between oxygen saturation in the two jugular veins. After years of enthusiasm, interest for jugular saturation has decreased and more modern methods, such as tissue oxygenation monitoring, are now available. Jugular saturation monitoring has low sensitivity, with the risk of missing low saturation, but high specificity; moreover it is cheap, when used with intermittent sampling. Monitoring the adequacy of brain perfusion after severe TBI is essential. However the choice of a specific monitor depends on local resources and expertise
New Perspectives on Amyloid-β Dynamics After Acute Brain Injury
No full textThe links between traumatic brain injury and Alzheimer disease have been of great interest for many years. However, the importance of amyloid-β- related neurodegenerative pathophysiologic processes after traumatic brain injury is still unknown. In this review, we present a brief overview of the scientific evidence regarding traumatic brain injury as a contributor to Alzheimer disease and describe recent results showing significant changes in brain extracellular amyloid-β dynamics in patients with severe brain injury. We then discuss the clinical significance of these findings with their implications for translational neurobiology and conclude with further directions for traumatic brain injury and Alzheimer disease research. ©2010 American Medical Association. All rights reserved
Radon and crustal deformation continuous monitoring in the seismic area of Friuli, North-Eastern Italy
No full text
Low-dimensional chaos is present in radon time variations
No full textAn indoor radon (222Rn) concentration time series registered in a house at Angera (Italy) in 1986 and 1987 was characterised by an important aperiodic component presenting a chaotic-deterministic behaviour. The data were analysed by comparing three algorithms that are used to extract phase-space dynamical information from experimental time series. They show different fractal dimensions. Consequently, the phenomenon is intrinsically unpredictable and a small number of parameters (related to fractal dimension) can be sufficient to describe its attractor dynamics, even when it is influenced by many variables such as micro climatic and geological conditions. Also large, rare concentrations, related to small changes in the above mentioned variables are present in radon time set
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
