502 research outputs found
Towards an Evaluation-Based Framework of Collaborative Archaeology
Collaborative archaeology is a growing field within the discipline, albeit one that is rarely analyzed. Although collaborative approaches are varied and diverse, we argue that they can all share a single methodological framework. Moreover, we suggest that collaborative archaeology projects can be evaluated to determine the variety among projects and to identify the elements of engaged research. We provide two case studies emphasizing project evaluation: (1) inter-project evaluation of community-engagement in British Columbia archaeology and (2) intra-project evaluation of co-management archaeology projects in Western Australia. The two case studies highlight that project evaluation is possible and that a single framework can be applied to many different types of projects. Collaborative archaeology requires analysis and evaluation to determine what facilitates engagement to further the discipline and to create better connections between archaeologists and community members. The discussed case studies illustrate two shared methods for accomplishing this. The paper argues that collaborative approaches are necessary for advancing archaeological practice
Principal component analysis of the cytokine and chemokine response to human traumatic brain injury.
There is a growing realisation that neuro-inflammation plays a fundamental role in the pathology of Traumatic Brain Injury (TBI). This has led to the search for biomarkers that reflect these underlying inflammatory processes using techniques such as cerebral microdialysis. The interpretation of such biomarker data has been limited by the statistical methods used. When analysing data of this sort the multiple putative interactions between mediators need to be considered as well as the timing of production and high degree of statistical co-variance in levels of these mediators. Here we present a cytokine and chemokine dataset from human brain following human traumatic brain injury and use principal component analysis and partial least squares discriminant analysis to demonstrate the pattern of production following TBI, distinct phases of the humoral inflammatory response and the differing patterns of response in brain and in peripheral blood. This technique has the added advantage of making no assumptions about the Relative Recovery (RR) of microdialysis derived parameters. Taken together these techniques can be used in complex microdialysis datasets to summarise the data succinctly and generate hypotheses for future study
Cerebral microdialysis in clinical studies of drugs: pharmacokinetic applications.
The ability to deliver drug molecules effectively across the blood-brain barrier into the brain is important in the development of central nervous system (CNS) therapies. Cerebral microdialysis is the only existing technique for sampling molecules from the brain extracellular fluid (ECF; also termed interstitial fluid), the compartment to which the astrocytes and neurones are directly exposed. Plasma levels of drugs are often poor predictors of CNS activity. While cerebrospinal fluid (CSF) levels of drugs are often used as evidence of delivery of drug to brain, the CSF is a different compartment to the ECF. The continuous nature of microdialysis sampling of the ECF is ideal for pharmacokinetic (PK) studies, and can give valuable PK information of variations with time in drug concentrations of brain ECF versus plasma. The microdialysis technique needs careful calibration for relative recovery (extraction efficiency) of the drug if absolute quantification is required. Besides the drug, other molecules can be analysed in the microdialysates for information on downstream targets and/or energy metabolism in the brain. Cerebral microdialysis is an invasive technique, so is only useable in patients requiring neurocritical care, neurosurgery or brain biopsy. Application of results to wider patient populations, and to those with different pathologies or degrees of pathology, obviously demands caution. Nevertheless, microdialysis data can provide valuable guidelines for designing CNS therapies, and play an important role in small phase II clinical trials. In this review, we focus on the role of cerebral microdialysis in recent clinical studies of antimicrobial agents, drugs for tumour therapy, neuroprotective agents and anticonvulsants
Volumetric growth rates of meningioma and its correlation with histological diagnosis and clinical outcome: a systematic review.
INTRODUCTION: Tumour growth has been used to successfully predict progression-free survival in low-grade glioma. This systematic review sought to establish the evidence base regarding the correlation of volumetric growth rates with histological diagnosis and potential to predict clinical outcome in patients with meningioma. METHODS: This systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Databases were searched for full text English articles analysing volumetric growth rates in patients with a meningioma. RESULTS: Four retrospective cohort studies were accepted, demonstrating limited evidence of significantly different tumour doubling rates and shapes of growth curves between benign and atypical meningiomas. Heterogeneity of patient characteristics and timing of volumetric assessment, both pre- and post-operatively, limited pooled analysis of the data. No studies performed statistical analysis to demonstrate the clinical utility of growth rates in predicting clinical outcome. CONCLUSION: This systematic review provides limited evidence in support of the use of volumetric growth rates in meningioma to predict histological diagnosis and clinical outcome to guide future monitoring and treatment
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Dyspnea affective response: comparing COPD patients with healthy volunteers and laboratory model with activities of daily living
Background: Laboratory-induced dyspnea (breathing discomfort) in healthy subjects is widely used to study perceptual mechanisms, yet the relationship between laboratory-induced dyspnea in healthy volunteers and spontaneous dyspnea in patients with chronic lung disease is not well established. We compared affective responses to dyspnea 1) in COPD patients vs. healthy volunteers (HV) undergoing the same laboratory stimulus; 2) in COPD during laboratory dyspnea vs. during activities of daily living (ADL). Methods: We induced moderate and high dyspnea levels in 13 COPD patients and 12 HV by increasing end-tidal CO2 (PETCO2) during restricted ventilation, evoking air hunger. We used the multidimensional dyspnea profile (MDP) to measure intensity of sensory qualities (e.g., air hunger (AH) and work/effort (W/E)) as well as immediate discomfort (A1) and secondary emotions (A2). Ten of the COPD subjects also completed the MDP outside the laboratory following dyspnea evoked by ADL. Results: COPD patients and HV reported similar levels of immediate discomfort relative to sensory intensity. COPD patients and HV reported anxiety and frustration during laboratory-induced dyspnea; variation among individuals far outweighed the small differences between subject groups. COPD patients reported similar intensities of sensory qualities, discomfort, and emotions during ADL vs. during moderate laboratory dyspnea. Patients with COPD described limiting ADL to avoid greater dyspnea. Conclusions: In this pilot study, we found no evidence that a history of COPD alters the affective response to laboratory-induced dyspnea, and no difference in affective response between dyspnea evoked by this laboratory model and dyspnea evoked by ADL
Matrix Metalloproteinase Expression in Contusional Traumatic Brain Injury: A Paired Microdialysis Study.
Matrix metalloproteinases (MMPs) are extracellular enzymes that have been implicated in the pathophysiology of blood-brain barrier (BBB) breakdown, contusion expansion, and vasogenic edema after traumatic brain injury (TBI). Specifically, in focal injury models, increased MMP-9 expression has been observed in pericontusional brain, and MMP-9 inhibitors reduce brain swelling and final lesion volume. The aim of this study was to examine whether there is a similarly localized increase of MMP concentrations in patients with contusional TBI. Paired microdialysis catheters were inserted into 12 patients with contusional TBI (with or without associated mass lesion) targeting pericontusional and radiologically normal brain defined on admission computed tomography scan. Microdialysate was pooled every 8 h and analyzed for MMP-1, -2, -7, -9, and -10 using a multiplex immunoassay. Concentrations of MMP-1, -2, and -10 were similar at both monitoring sites and did not show discernible temporal trends. Overall, there was a gradual increase in MMP-7 concentrations in both normal and injured brain over the monitoring period, although this was not consistent in every patient. MMP-9 concentrations were elevated in pericontusional, compared to normal, brain, with the maximal difference at the earliest monitoring times (i.e., <24 h postinjury). Repeated-measures analysis of variance showed that MMP-9 concentrations were significantly higher in pericontusional brain (p=0.03) and within the first 72 h of injury, compared with later in the monitoring period (p=0.04). No significant differences were found for the other MMPs assayed. MMP-9 concentrations are increased in pericontusional brain early post-TBI and may represent a potential therapeutic target to reduce hemorrhagic progression and vasogenic edema.M.R.G. was supported by a National Institute for Health Research
(NIHR) Academic Clinical Fellowship, a Royal College of
Surgeons/Philip King Research Fellowship, and a Beverley and
Raymond Sackler Fellowship. A.H. was supported by a joint
Medical Research Council/ Royal College of Surgeons of England
Clinical Research Training Fellowship. K.L.H.C. is supported by
the NIHR Biomedical Research Center, Cambridge (Neuroscience
Theme; Brain Injury and Repair Theme). J.D.P. is supported by the
Traumatic Brain Injury NIHR Health Technology Cooperative.
D.K.M. is supported by an NIHR Senior Investigator Award.
P.J.A.H. is supported by the Cambridge NIHR BRC and an NIHR
Research Professorship.This is the final published version. It was first made available by Mary Ann Liebert at http://dx.doi.org/10.1089/neu.2014.376
(In)finite extent of stationary perfect fluids in Newtonian theory
For stationary, barotropic fluids in Newtonian gravity we give simple
criteria on the equation of state and the "law of motion" which guarantee
finite or infinite extent of the fluid region (providing a priori estimates for
the corresponding stationary Newton-Euler system). Under more restrictive
conditions, we can also exclude the presence of "hollow" configurations. Our
main result, which does not assume axial symmetry, uses the virial theorem as
the key ingredient and generalises a known result in the static case. In the
axially symmetric case stronger results are obtained and examples are
discussed.Comment: Corrections according to the version accepted by Ann. Henri Poincar
Systemic inflammation alters the neuroinflammatory response: a prospective clinical trial in traumatic brain injury.
BACKGROUND: Neuroinflammation following traumatic brain injury (TBI) has been shown to be associated with secondary injury development; however, how systemic inflammatory mediators affect this is not fully understood. The aim of this study was to see how systemic inflammation affects markers of neuroinflammation, if this inflammatory response had a temporal correlation between compartments and how different compartments differ in cytokine composition. METHODS: TBI patients recruited to a previous randomised controlled trial studying the effects of the drug anakinra (Kineret®), a human recombinant interleukin-1 receptor antagonist (rhIL1ra), were used (n = 10 treatment arm, n = 10 control arm). Cytokine concentrations were measured in arterial and jugular venous samples twice a day, as well as in microdialysis-extracted brain extracellular fluid (ECF) following pooling every 6 h. C-reactive protein level (CRP), white blood cell count (WBC), temperature and confirmed systemic clinical infection were used as systemic markers of inflammation. Principal component analyses, linear mixed-effect models, cross-correlations and multiple factor analyses were used. RESULTS: Jugular and arterial blood held similar cytokine information content, but brain-ECF was markedly different. No clear arterial to jugular gradient could be seen. No substantial delayed temporal associations between blood and brain compartments were detected. The development of a systemic clinical infection resulted in a significant decrease of IL1-ra, G-CSF, PDGF-ABBB, MIP-1b and RANTES (p < 0.05, respectively) in brain-ECF, even if adjusting for injury severity and demographic factors, while an increase in several cytokines could be seen in arterial blood. CONCLUSIONS: Systemic inflammation, and infection in particular, alters cytokine levels with different patterns seen in brain and in blood. Cerebral inflammatory monitoring provides independent information from arterial and jugular samples, which both demonstrate similar information content. These findings could present potential new treatment options in severe TBI patients, but novel prospective trials are warranted to confirm these associations
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