Dynamic estimation of three-dimensional cerebrovascular deformation from rotational angiography

Purpose: The objective of this study is to investigate the feasibility of detecting and quantifying 3D cerebrovascular wall motion from a single 3D rotational x-ray angiography (3DRA) acquisition within a clinically acceptable time and computing from the estimated motion field for the further biomechanical modeling of the cerebrovascular wall. Methods: The whole motion cycle of the cerebral vasculature is modeled using a 4D B-spline transformation, which is estimated from a 4D to 2D + t image registration framework. The registration is performed by optimizing a single similarity metric between the entire 2D + t measured projection sequence and the corresponding forward projections of the deformed volume at their exact time instants. The joint use of two acceleration strategies, together with their implementation on graphics processing units, is also proposed so as to reach computation times close to clinical requirements. For further characterizing vessel wall properties, an approximation of the wall thickness changes is obtained through a strain calculation. Results: Evaluation on in silico and in vitro pulsating phantom aneurysms demonstrated an accurate estimation of wall motion curves. In general, the error was below 10% of the maximum pulsation, even in the situation when substantial inhomogeneous intensity pattern was present. Experiments on in vivo data provided realistic aneurysm and vessel wall motion estimates, whereas in regions where motion was neither visible nor anatomically possible, no motion was detected. The use of the acceleration strategies enabled completing the estimation process for one entire cycle in 5-10 min without degrading the overall performance. The strain map extracted from our motion estimation provided a realistic deformation measure of the vessel wall. Conclusions: The authors' technique has demonstrated that it can provide accurate and robust 4D estimates of cerebrovascular wall motion within a clinically acceptable time, although it has to be applied to a larger patient population prior to possible wide application to routine endovascular procedures. In particular, for the first time, this feasibility study has shown that in vivo cerebrovascular motion can be obtained intraprocedurally from a 3DRA acquisition. Results have also shown the potential of performing strain analysis using this imaging modality, thus making possible for the future modeling of biomechanical properties of the vascular wall.

Communication Strategies Of The Nursing Team In The Aphasia After Cerebrovascular Accident

This is an exploratory, cross-sectional study of quantitative design that aimed to identify the communication strategies used and reported by the nursing staff in the care of aphasic patients after a stroke. The techniques used were the participant observation and interviews with 27 subjects of the nursing staff of neurological units in a general hospital. The most frequently mentioned strategies were gestures (100%), verbal communication (33.3%), written communication (29.6%) and the touch (18.5 %). Among the observed strategies, the gestures reached 40.7% and the touch was present in all situations, given its instrumental character essential to care. The findings show lack of knowledge of nonverbal, proxemics , kinesics and tacesics communication. No significant differences were observed among the professional categories depending on the length of experience with respect to the strategies reported by members of the nursing staff in the care for aphasic patients.


Quality of life of caregivers for patients of cerebrovascular accidents: association of (socio-demographic) characteristics and burden

OBJECTIVE Investigating the association between quality of life with socio-demographic characteristics and the burden of caregivers for individuals with cerebrovascular accident sequelae. METHOD A descriptive, cross-sectional study with a sample composed of 136 caregivers. For data collection, a semi-structured questionnaire, the Barthel, Burden Interview and Short-Form-36 scales were used. Correlation analysis, t-Student test and F-test were used for the analysis in order to compare averages. RESULTS Significant averages in quality of life were demonstrated in association with female caregivers and those over 60 years in the field 'functional capacity,' and in the domains of 'mental health' and 'vitality' for those with higher income. Regarding burden association, the highlighted areas were 'functional capacity,' 'physical aspects,' 'emotional aspects' and 'pain.' CONCLUSION The creation of public policies and social support to effectively reduce the burden on caregivers is a necessity.

Effect of age on intraoperative cerebrovascular autoregulation and near-infrared spectroscopy-derived cerebral oxygenation.

Background. Age is an important risk factor for perioperative cerebral complications such as stroke, postoperative cognitive dysfunction, and delirium. We explored the hypothesis that intraoperative cerebrovascular autoregulation is less efficient and brain tissue oxygenation lower in elderly patients, thus, increasing the vulnerability of elderly brains to systemic insults such as hypotension.Methods. We monitored intraoperative cerebral perfusion in 50 patients aged 18-40 and 77 patients >65 yr at two Swiss university hospitals. Mean arterial pressure (MAP) was measured continuously using a plethysmographic method. An index of cerebrovascular autoregulation (Mx) was calculated based on changes in transcranial Doppler flow velocity due to changes in MAP. Cerebral oxygenation was assessed by the tissue oxygenation index (TOI) using near-infrared spectroscopy. End-tidal CO(2), O(2), and sevoflurane concentrations and peripheral oxygen saturation were recorded continuously. Standardized anaesthesia was administered in all patients (thiopental, sevoflurane, fentanyl, atracurium).Results. Autoregulation was less efficient in patients aged >65 yr [by 0.10 (SE 0.04; P=0.020)] in a multivariable linear regression analysis. This difference was not attributable to differences in MAP, end-tidal CO2, or higher doses of sevoflurane. TOI was not significantly associated with age, sevoflurane dose, or Mx but increased with increasing flow velocity [by 0.09 (SE 0.04; P=0.028)] and increasing MAP [by 0.11 (SE 0.05; P=0.043)].Conclusions. Our results do not support the hypothesis that older patients' brains are more vulnerable to systemic insults. The difference of autoregulation between the two groups was small and most likely clinically insignificant.

Floating arterial thrombus related stroke treated by intravenous thrombolysis.

BACKGROUND: The effects of intravenous thrombolysis on floating thrombi in cervical and intracranial arteries of acute ischemic stroke patients are unknown. Similarly, the best prevention methods of early recurrences remain controversial. This study aimed to describe the clinical and radiological outcome of thrombolyzed strokes with floating thrombi. METHODS: We retrospectively analyzed all thrombolyzed stroke patients in our institution between 2003 and 2010 with floating thrombi on acute CT-angiography before the intravenous thrombolysis. The floating thrombus was diagnosed if an elongated thrombus of at least 5 mm length, completely surrounded by contrast on supra-aortic neck or intracerebral arteries, was present on CT-angiography. Demographics, vascular risk factors, and comorbidities were recorded and stroke etiology was determined after a standardized workup. Repeat arterial imaging was performed by CTA at 24 h or before if clinical worsening was noted and then by Doppler and MRA during the first week and at four months. RESULTS: Of 409 thrombolyzed stroke patients undergoing acute CT Angiography, seven (1.7%) had a floating thrombus; of these seven, six had it in the anterior circulation. Demographics, risk factors and stroke severity of these patients were comparable to the other thrombolyzed patients. After intravenous thrombolysis, the floating thrombi resolved completely at 24 h in four of the patients, whereas one had an early recurrent stroke and one developed progressive worsening. One patient developed early occlusion of the carotid artery with floating thrombus and subsequently a TIA. The two patients with a stable floating thrombus had no clinical recurrences. In the literature, only one of four reported cases were found to have a thrombolysis-related early recurrence. CONCLUSIONS: Long-term outcome seemed similar in thrombolyzed patients with floating thrombus, despite a possible increase of very early recurrence. It remains to be established whether acute mechanical thrombectomy could be a safer and more effective treatment to prevent early recurrence. However, intravenous thrombolysis should not be withheld in eligible stroke patients.

Circulation of private notes during a currency shortage

This paper provides a search theoretical model that captures two phenomena that have characterized several episodes of monetary history: currency shortages and the circulation of privately issued notes. As usual in these models, the media of exchange are determined as part of the equilibrium. We characterize all the different equilibria and specify the conditions under which there is a currency shortage and/or privately issued notes are used as means of payment. There is multiplicity of equilibria for the entire parameter space, but there always exist an equilibrium in which notes circulate, either alone or together with coins. Hence, credit is a self-fulfilling phenomenon that depends on the beliefs of agents about the acceptability and future repayment of notes. The degree of circulation of coins depends on two crucial parameters, the intrinsic utility of holding coins and the extent with which it is possible to find exchange opportunities in the market.

Anomalous rainfall and associated atmospheric circulation in the northeast Spanish Mediterranean area and its relationship to sediment fluidization events in a lake

Changes in the dynamics of sediment transport in a Mediterranean lake (sediment fluidization events) are linked to atmospheric circulations patterns (trough monthly precipitation). In the basins of Lake Banyoles, located in the northeast of Spain, water enters mainly through subterranean springs, and associated fluctuations in the vertical migration of sediment distribution (fluidization events) present episodic behavior as a result of episodic rainfall in the area. The initiation of the fluidization events takes place when the monthly rainfall is ∼2.7 times greater than the mean monthly rainfall of the rainiest months in the area, especially in spring (April and May), October, and December. The duration of these events is found to be well correlated with the accumulated rainfall of the preceding 10 months before the process initiation. The rainfall, in turn, is mainly associated with six atmospheric circulation patterns among the 19 fundamental circulations that emerged in an earlier study focused on significant rainfall days in Mediterranean Spain. Among them, accentuated surface lows over the northeast of Spain, general northeasterly winds by low pressure centered to the east of Balearic Islands and short baroclinic waves over the Iberian Peninsula, with easterly flows over the northeastern coast of Spain, are found the most relevant atmospheric circulations that drive heavy rainfall events

L'interdiction de discrimination en raison de la nationalité au sens de l'Accord sur la libre circulation des personnes

Introduction : 6 décembre 1992: le peuple suisse rejette l'Accord sur l'Espace économique européen (EEE). Le Conseil fédéral décide alors de privilégier la voie bilatérale pour réglementer ses relations avec l'Union européenne (UE). Près de sept ans plus tard, le 21 juin 1999, un premier paquet de sept accords bilatéraux sont signés à Luxembourg. L'Accord sur la libre circulation des personnes (ALCP ou Accord) en constitue certainement « la partie la plus importante ». L'ALCP a pour objectif de garantir la libre circulation des travailleurs salariés, des travailleurs indépendants ainsi que de certaines catégories de non-actifs, et de faciliter la prestation de services sur le territoire des parties contractantes. Or la réalisation de ces objectifs dépend directement de la mise en oeuvre de l'interdiction de discrimination en raison de la nationalité. Au coeur même du principe de libre circulation, l'interdiction de discrimination en raison de la nationalité constitue, sans aucun doute, la clé de voûte de l'Accords. Partant de ce constat, il conviendra d'étudier dans un premier temps le principe de libre circulation (Partie I), puis de nous pencher dans un second temps sur l'interdiction de discrimination en raison de la nationalité (Partie II). La première partie de notre étude (consacrée à la libre circulation des personnes en vertu de l'ALCP) débutera par un survol des dispositions essentielles à l'appréhension d'un droit fondamental à la libre circulation, ainsi que par une présentation succincte du régime communautaire de libre circulation. Après avoir rappelé les étapes du cheminement ayant conduit à l'adoption de l'ALCP, et après avoir défini les différentes sources régissant la libre circulation entre la Suisse et les Etats membres de l'UE, nous analyserons ensuite l'ALCP lui-même, en procédant à la détermination de son champ d'application ainsi qu'à l'examen des principes généraux qui le régissent. Cet examen nous amènera alors à déterminer le rôle que devrait jouer la jurisprudence de la Cour de justice des Communautés européennes (CJCE) dans le cadre de l'Accord. Fort de cette analyse, nous conclurons cette première partie par une présentation du régime de libre circulation tel qu'institué par l'ALCP, sans oublier bien sûr d'évoquer, finalement, la portée du concept d'entrave et de la notion de citoyenneté européenne dans le cadre de ce régime. La seconde partie de notre étude (consacrée à l'interdiction de discrimination en raison de la nationalité selon l'ALCP) identifiera, à titre liminaire, les différentes dispositions de l'Accord visant à prohiber les discriminations en raison de la nationalité. Ces dispositions mises en lumière, nous détaillerons alors les étapes de l'examen permettant de relever la présence d'une discrimination en raison de la nationalité, en nous appuyant sur la jurisprudence de la Cour de justice et celle du Tribunal fédéral d'une part, et sur la doctrine développée en matière d'interdiction de discrimination d'autre part. Dans la foulée, nous pourrons ainsi présenter les différentes formes que peut revêtir une discrimination. Nous examinerons, en particulier, le régime prévu par la jurisprudence de la Cour de justice et celle du Tribunal fédéral en matière de discriminations à rebours présentant un élément transfrontalier. Suite de quoi nous serons en mesure - après examen des jurisprudences allemande et autrichienne relatives aux situations internes de discriminations à rebours - de procéder à une appréciation critique de la solution adoptée par le Tribunal fédéral en pareilles situations. A la suite de ces deux chapitres portant sur la notion et sur les formes de discriminations, il y aura lieu de définir le champ d'application matériel et personnel des différentes dispositions de l'Accord visant à interdire les discriminations en raison de la nationalité. Lors de la définition du champ d'application personnel en particulier, il conviendra, en premier lieu, d'identifier les personnes susceptibles d'invoquer ces différentes dispositions (les bénéficiaires). Cet examen débutera par l'identification des conditions générales communes à l'ensemble des dispositions étudiées. Il se poursuivra par l'analyse des conditions spécifiques de chaque norme, et se terminera par une présentation du régime particulier réservé aux membres de la famille et aux travailleurs détachés. En second lieu, il s'agira de déterminer les sujets de droit à l'encontre desquels ces dispositions sont opposables (les destinataires). Plus précisément, il s'agira d'examiner dans quelle mesure les particuliers, en sus des Etats, peuvent être destinataires des différentes obligations de l'ALCP en matière de libre circulation et d'interdiction de discrimination. Les champs d'application ayant été définis, il nous restera alors à examiner les différentes dispositions de l'Accord susceptibles de limiter la portée du principe de non-discrimination. Pour ce faire, nous analyserons en détail l'article 5 Annexe I-ALCP qui permet de limiter les droits consacrés par l'Accord pour des raisons d'ordre public, de sécurité publique ou de santé publique. Nous nous pencherons aussi sur les limitations liées à l'exercice de la puissance publique, consacrées par les articles 10, 16 et 22 al. 1 Annexe I-ALCP. Après un passage en revue des dernières dispositions de l'Accord prévoyant des limitations, nous examinerons ensuite dans quelle mesure certains principes non expressément prévus par l'Accord sont également susceptibles de justifier une différence de traitement en raison de la nationalité. Nous conclurons cette étude en analysant les implications juridiques d'une violation de l'interdiction de discrimination, ceci non seulement dans les relations liant l'Etat à un particulier, mais aussi dans celles liant deux particuliers entre eux. Dans le premier cas de figure nous verrons qu'il y a lieu de différencier l'analyse en fonction du type d'acte en question - les implications d'une violation n'étant pas les mêmes selon que l'on se trouve en présence d'une norme, d'une décision ou d'un contrat (de droit administratif ou de droit privé) présentant un caractère discriminatoire. Dans le second cas de figure, il s'agira cette fois-ci de distinguer les implications des conditions discriminatoires en fonction des différentes phases d'une relation contractuelle - aux stades de la conclusion d'un contrat, de son exécution et de sa résiliation.

New generation vaccine induces effective melanoma-specific CD8+ T cells in the circulation but not in the tumor site.

Although increasing evidence suggests that CTL are important to fight the development of some cancers, the frequency of detectable tumor-specific T cells is low in cancer patients, and these cells have generally poor functional capacities, compared with virus-specific CD8(+) T cells. The generation with a vaccine of potent CTL responses against tumor Ags therefore remains a major challenge. In the present study, ex vivo analyses of Melan-A-specific CD8(+) T cells following vaccination with Melan-A peptide and CpG oligodeoxynucleotides revealed the successful induction in the circulation of effective melanoma-specific T cells, i.e., with phenotypic and functional characteristics similar to those of CTL specific for immunodominant viral Ags. Nonetheless, the eventual impact on tumor development in vaccinated melanoma donors remained limited. The comprehensive study of vaccinated patient metastasis shows that vaccine-driven tumor-infiltrating lymphocytes, although activated, still differed in functional capacities compared with blood counterparts. This coincided with a significant increase of FoxP3(+) regulatory T cell activity within the tumor. The consistent induction of effective tumor-specific CD8(+) T cells in the circulation with a vaccine represents a major achievement; however, clinical benefit may not be achieved unless the tumor environment can be altered to enable CD8(+) T cell efficacy.