Mobility through Heterogeneous Networks in a 4G Environment

Serving and Managing users in a heterogeneous environment. 17th WWRF Meeting in Heidelberg, Germany, 15 - 17 November 2006. [Proceeding presented at WG3 - Co-operative and Ad-hoc Networks]The increase will of ubiquitous access of the users to the requested services points towards the integration of heterogeneous networks. In this sense, a user shall be able to access its services through different access technologies, such as WLAN, Wimax, UMTS and DVB technologies, from the same or different network operators, and to seamless move between different networks with active communications. In this paper we propose a mobility architecture able to support this users’ ubiquitous access and seamless movement, while simultaneously bringing a large flexibility to access network operators

Extensive intracranial involvement with multiple dissections in a case of giant cell arteritis

A 56-year-old man presented with weight loss, articular pain and minor neurological symptoms progressing over 1 month. Neurosonological evaluation suggested occlusion in intracranial segments of the left vertebral artery (VA) and of both internal carotid arteries (ICA) and hypoechoic halo sign in both superficial temporal arteries. The diagnosis of giant cell arteritis was supported by inflammatory markers and confirmed by biopsy. Despite early steroid initiation, he manifested fluctuant vascular deficits and became lethargic. Brain MRI indicated watershed infarcts and intracranial dissections of left VA and both ICA. The patient was stabilised with the association of prednisolone 2 mg/kg, methotrexate and oral anticoagulation. Since then he has been neurologically asymptomatic and control imaging showed only residual intracranial left VA stenosis, with no signs of temporal artery inflammation or new vascular lesions. This is to the best of our knowledge, the first reported clinical case with such an extensive intracranial involvement with multiple dissections

Permeability of the blood-brain barrier through the phases of ischaemic stroke and relation with clinical outcome: protocol for a systematic review

Introduction: Ischaemic stroke is the most prevalent type of stroke and is characterised by a myriad of pathological events triggered by a vascular arterial occlusion. Disruption of the blood-brain barrier (BBB) is a key pathological event that may lead to fatal outcomes. However, it seems to follow a multiphasic pattern that has been associated with distinct biological substrates and possibly contrasting outcomes. Addressing the BBB permeability (BBBP) along the different phases of stroke through imaging techniques could lead to a better understanding of the disease, improved patient selection for specific treatments and development of new therapeutic modalities and delivery methods. This systematic review will aim to comprehensively summarise the existing evidence regarding the evolution of the BBBP values during the different phases of an acute ischaemic stroke and correlate this event with the clinical outcome of the patient. Methods and analysis: We will conduct a computerised search on Medline, EMBASE, Cochrane Central Register of Controlled Trials, Scopus and Web of Science. In addition, grey literature and ClinicalTrials.gov will be scanned. We will include randomised controlled trials, cohort, cross-sectional and case-controlled studies on humans that quantitatively assess the BBBP in stroke. Retrieved studies will be independently reviewed by two authors and any discrepancies will be resolved by consensus or with a third reviewer. Reviewers will extract the data and assess the risk of bias of the selected studies. If possible, data will be combined in a quantitative meta-analysis following the guidelines provided by Cochrane Handbook for Systematic Reviews of Interventions. We will assess cumulative evidence using the Grading of Recommendations, Assessment, Development and Evaluation approach. Ethics and dissemination: Ethical approval is not needed. All data used for this work are publicly available. The result obtained from this work will be published in a peer-reviewed journal and disseminated in relevant conferences.info:eu-repo/semantics/publishedVersio

Hemorheological effects of sodium fluorescein in rats

© 2001 – IOS Press. All rights reservedSodium fluorescein is widely used in clinical practice for the study of the retinal circulation by angiography. It has been reported several hemorheological and microvascular abnormalities induced by this compound. The aim of this work was to analyse the hemorheological effects of intravenous sodium fluorescein in an animal model. Twenty male 10–16 weeks-old Wistar rats were used, under systemic anaesthesia. The animals were divided in 2 groups of 10 each: (1) intravenous injection of sodium fluorescein (14 mg/kg of body weight) – Group NaF, (2) controls (injection of NaCl 0.9%) – Group CTRL. A blood sample was drawn by aortic puncture after 60 minutes and hemorheological parameters determined: hematocrit, hemoglobin, metahemoglobin, carboxyhemoglobin, plasma viscosity, erythrocyte deformability, membrane fluidity and acetylcholinesterase activity. In the Group NaF there was a 20% reduction of the AChE activity (p < 0.05) and an increase in PV (p < 0.05). Concerning hemoglobin status, a three-fold increase in COHb (p < 0.001) was shown. In conclusion, the NaF injection in the animal model produces hemorheological abnormalities similar to those reported in the human

The effect of sodium fluorescein angiography on erythrocyte properties

© 1998 – IOS Press. All rights reservedSodium fluorescein angiography is a widely used routine ophthalmological diagnostic procedure which enables the study of chorioretinal microcirculation and consists of the injection of sodium fluorescein into the systemic bloodstream. The aim of the present study was to evaluate whether or not fluorescein interferes with erythrocyte properties during the angiographic procedure. In a group of 37 patients, 26 with non-insulin-dependent diabetes mellitus (DM) with and without retinopathy, and 11 without diabetes mellitus (non-DM) although affected by other ophthalmological diseases, all undergoing routine angiography, blood samples were drawn before (T0) and 30 min (T30) after fluorescein injection. The erythrocyte aggregation index (EAI), membrane lipid fluidity and erythrocyte acetylcholinesterase activity were determined in both groups. After fluorescein injection there was no statistical change in EAI and erythrocyte membrane fluidity in either group. Erythrocyte acetylcholinesterase activity, a marker of membrane protein integrity, decreased significantly (p < 0:01) in the DM group. Membrane lipid fluidity did not change with fluorescein injection, however, (i) in the DM group erythrocyte membranes became more rigid than in the non-DM (DPH: p < 0:01); (ii) EAI and membrane lipid fluidity became significantly correlated (r = 0:6263, p < 0:05) in non-DM patients at T30. In conclusion, fluorescein administration for angiographic procedures seems to interact with erythrocyte membrane, namely, in diabetic patients, which may interfere with the blood flow in the microcirculation

Recurrence in intracranial atherosclerotic disease: a stenosis-based analysis

BACKGROUND: Intracranial atherosclerotic disease is a common cause of stroke; its incidence and prevalence vary widely by ethnicity. The aim of our study was to analyze the recurrence rate of cerebrovascular events in patients with symptomatic and asymptomatic intracranial stenosis (IS). METHODS: We conducted a historical cohort study including all patients admitted in our hospital for stroke or transient ischemic attack (TIA) during 2011 and 2012 with information on intracranial circulation (ultrasonography and/or computed tomography angiography). We identified patients with symptomatic and asymptomatic IS and studied the recurrence of cerebrovascular events (TIA or ischemic stroke within the territory of the stenosis) for a minimum follow-up period of 6 months after the diagnosis of IS. For the recurrence rate estimation, patients with other potentially embolic diseases (in cervical arteries or heart) were excluded. We calculated the rate of recurrence of cerebrovascular events and performed Kaplan-Meier survival curves for symptomatic and asymptomatic IS. RESULTS: We investigated 1302 patients, mean age was 72.41 years (standard deviation 12.75). We identified 218 IS in 158 patients, 77 were symptomatic and 141 were asymptomatic. The recurrence rate of cerebrovascular events was 12.32 per 100 patient-years, with a mean time to recurrence of 1.73 months for symptomatic intracranial stenosis (SIS) and .88 per 100 patient-years for asymptomatic IS (P < .001). CONCLUSIONS: These results indicate a high risk of early recurrence of stroke in the territory of a SIS, highlighting the importance of its early diagnosis and aggressive treatment.info:eu-repo/semantics/publishedVersio

Diagnostic accuracy of CT angiography and CT perfusion imaging for detecting distal medium vessel occlusions: Protocol for a systematic review and meta-analysis

Background: Distal medium vessel occlusions (DMVOs) represent 25-40% of all acute ischemic strokes (AIS). DMVO clinical syndromes are heterogenous, but as eloquent brain regions are frequently involved, they are often disabling. Since current intravenous fibrinolytic therapies may fail to recanalize up to two-thirds of DMVOs, endovascular treatment is progressively being considered in this setting. Nevertheless, the optimal imaging method for diagnosis remains to be defined. Stroke centers that use computed tomography as a routine stroke imaging approach rely on either isolated computed tomography angiography (CTA) or combined perfusion (CTP) studies. Despite a simplified non-CTP-dependent approach seeming reasonable for large vessel occlusion AIS diagnosis, CTP may still hold advantages for DMVOs workup. Therefore, this systematic review aims to compare the diagnostic performance of CTA and CTP in detecting DMVOs. Methods: We will perform a systematic search in PubMed, EMBASE, Web of Science Core Collection, and Cochrane Central Register of Controlled Trials. In addition, grey literature and ClinicalTrials.gov will be scanned. We will include any type of study that presents data on the diagnostic accuracy of CTA and/or CTP for detecting DMVOs. Two authors will independently review retrieved studies, and any discrepancies will be resolved by consensus or with a third reviewer. Reviewers will extract the data and assess the risk of bias in the selected studies. Data will be combined in a quantitative meta-analysis following the guidelines provided by the Cochrane Handbook for Systematic Reviews of Interventions. We will assess cumulative evidence using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Discussion: This will be the first systematic review and meta-analysis that compares two different imaging approaches for detecting DMVOs. This study may help to define optimal acute ischemic stroke imaging work-up. Trial registration: PROSPERO registration: CRD42022344006.info:eu-repo/semantics/publishedVersio

Ethanol and erythrocyte membrane interaction : a hemorheologic perspective

© 1999 – IOS Press. All rights reservedPrevious studies have documented structural and functional changes induced by ethanol–erythrocyte membrane interaction. In order to perform an in vitro study on the effect of different ethanol concentrations on erythrocyte hemorheologic properties, blood samples were collected from 21 male donors at the Hospital of Santa Maria. Whole blood aliquots were incubated with ethanol solutions of rising concentrations. The following parameters were measured: erythrocyte aggregation, haemoglobin, carboxyhaemoglobin and methaemoglobin concentrations, hematocrit, plasma osmolality and erythrocyte membrane fluidity (fluorescence polarisation probes TMA-DPH and DPH). With ethanol blood concentrations of 45 mM a rise in plasma osmolality (0.352 Osm/kg H2O vs 0.310 Osm/kg H2O; p < 0.001) was verified. With 67 mM concentration a decrease of erythrocyte aggregation (11.03 vs 12.81; p < 0.05) and an increase in plasma osmolality (0.380 Osm/kg H2O vs 0.310 Osm/kg H2O;p < 0.001) were obtained. In conclusion, ethanol only changes erythrocyte aggregation for a concentration of 67 mM. These data could lead to future changes in therapeutic approaches to situations such as alcoholic coma

CTA and CTP for Detecting Distal Medium Vessel Occlusions: A Systematic Review and Meta-analysis

Background: The optimal imaging method for detecting distal medium vessel occlusions (DMVOs) remains undefined. Purpose: The objective of this study is to compare the diagnostic performance of CTA with CTP in detecting DMVOs. Data sources: We searched PubMed, EMBASE, Web of Science Core Collection, and Cochrane Central Register of Controlled Trials up to March 31, 2023 (PROSPERO: CRD42022344006). Study selection: A total of 12 studies reporting accuracy values of CTA and/or CTP were included, comprising 2607 patients with 479 cases (18.3%) of DMVOs. Data analysis: Pooled sensitivity and specificity of both imaging methods were compared using a random-effects model. Subgroup analyses were performed based on the technique used in CTA (multi or single-phase) and the subtype of DMVOs (M2-only vs. M2 and other DMVOs). We applied Quality Assessment of Diagnostic Accuracy (QUADAS-2) tool and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) quality assessment criteria. Data synthesis: CTA demonstrated significantly lower sensitivity compared to CTP in detecting DMVOs [0.74, 95%CI (0.63-0.82) vs. 0.89, 95% CI (0.82-0.93), P < 0.01]. When subgrouped into single-phase and multi-phase CTA, multi-phase CTA exhibited higher sensitivity for DMVO detection than single-phase CTA [0.91, 95%CI (0.85-0.94) vs. 0.64, 95%CI (0.56-0.71), P < .01], while reaching similar levels to CTP. The sensitivity of single-phase CTA substantially decreased when extending from M2 to other non-M2 DMVOs [0.74, 95%CI (0.63-0.83) vs. 0.61, 0.95%CI (0.53-0.68), P = .02]. Limitations: We identified an overall high risk of bias and low quality of evidence, attributable to the design and reference standards of most studies. Conclusions: Our findings highlight a significantly lower sensitivity of single-phase CTA compared to multi-phase CTA and CTP in diagnosing DMVOs.info:eu-repo/semantics/publishedVersio

Bilateral versus ipsilesional cortico-subcortical activity patterns in stroke show hemispheric dependence

Background Understanding of interhemispheric interactions in stroke patients during motor control is an important clinical neuroscience quest that may provide important clues for neurorehabilitation. In stroke patients, bilateral overactivation in both hemispheres has been interpreted as a poor prognostic indicator of functional recovery. In contrast, ipsilesional patterns have been linked with better motor outcomes. Aim We investigated the pathophysiology of hemispheric interactions during limb movement without and with contralateral restraint, to mimic the effects of constraint-induced movement therapy. We used neuroimaging to probe brain activity with such a movement-dependent interhemispheric modulation paradigm. Methods We used an fMRI block design during which the plegic/paretic upper limb was recruited/mobilized to perform unilateral arm elevation, as a function of presence versus absence of contralateral limb restriction ( n = 20, with balanced left/right lesion sites). Results Analysis of 10 right-hemispheric stroke participants yielded bilateral sensorimotor cortex activation in all movement phases in contrast with the unilateral dominance seen in the 10 left-hemispheric stroke participants. Superimposition of contralateral restriction led to a prominent shift from activation to deactivation response patterns, in particular in cortical and basal ganglia motor areas in right-hemispheric stroke. Left-hemispheric stroke was in general characterized by reduced activation patterns, even in the absence of restriction, which induced additional cortical silencing. Conclusion The observed hemispheric-dependent activation/deactivation shifts are novel and these pathophysiological observations suggest short-term neuroplasticity that may be useful for hemisphere-tailored neurorehabilitation.info:eu-repo/semantics/publishedVersio