The Epstein-Glaser causal approach to the light-front QED(4). II: Vacuum polarization tensor

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Aspects correlates with Scandinavian Stroke Scale for predicting early neurological impairment

Objective: To investigate the correlation between the Alberta Program Early CT Score (ASPECTS) and the Scandinavian Stroke Scale (SSS) for the evaluation of neurological impairment in patients with acute stroke. Method: 59 patients with a first acute ischemic stroke were evaluated. The ASPECTS were evaluated by 2 neurologists at admission and by another neurologist after 48 hours. The NIHSS and SSS was applied to determinate stroke severity. Correlations and agreements were analysed statistically by Spearman and Kappa tests. Results: ASPECTS was correlated with National Institute of Health Stroke Scale (NIHSS) at admission (r = -0.52; p < 0.001) and SSS (r = 0.50; p < 0.001). The ASPECTS and SSS items were most correlated with arm (r = 0.52; p < 0.001) and hand (r = 0.49; p < 0.001) motor power, and speech (r = 0.51; p < 0.001). The SSS of 25.5 shows sensitivity (68%) and specificity (72%) when associated with ASPECTS <= 7. Conclusion: The SSS can predict worst neurological impairment when associated with lower values of ASPECTS.

Electromagnetic gauge field interpolation between the instant form and the front form of the Hamiltonian dynamics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Validation of the Scandinavian stroke scale in a multicultural population in Brazil

Background: The objective of this study was to evaluate the consistency, coherence, and interobserver reliability of the Portuguese version of the Scandinavian Stroke Scale (SSS) in a multicultural population of stroke. Methods: The SSS was translated, culturally adapted, and applied by two independent investigators. This was a randomized transverse study involving two groups: group 1 included 20 patients in the acute phase and group 2 included 20 patients in the subacute phase after stroke was confirmed by computed tomography with a pre-stroke modified Rankin Scale score of 0. Each patient also underwent National Institutes of Health Stroke Scale (NIHSS) evaluation at hospital entry and at the time of the SSS evaluation for correlation with our current standard hospital practice. Consistency and coherence were analyzed by Cronbach’s α and interobserver reliability by ĸ. Results: Forty patients were evaluated with 0.88 consistency and coherence in both stroke phases. Mean interobserver ĸ was 0.76, with reliability considered excellent and good for most scale items, and moderate for only the facial palsy item. Conclusion: The SSS is adequate and validated to study post-stroke patients in a multicultural Brazilian population and in the Portuguese language.

Stroke as the First Clinical Manifestation of Takayasu's Arteritis

Takayasu's arteritis is a chronic inflammatory disease, and neurological symptoms occur in 50% of cases, most commonly including headache, dizziness, visual disturbances, convulsive crisis, transient ischemic attack, stroke and posterior reversible encephalopathy syndrome. The aim of this study was to report the case of a young Brazilian female with a focal neurological deficit. She presented with asymmetry of brachial and radial pulses, aphasia, dysarthria and right hemiplegia. Stroke was investigated extensively in this young patient. Only nonspecific inflammatory markers such as velocity of hemosedimentation and C-reactive protein were elevated. During hospitalization, clinical treatment was performed with pulse therapy showing improvement in neurological recuperation on subsequent days. In the chronic phase, the patient was submitted to medicated angioplasty of the brachiocephalic trunk with paclitaxel, with significant improvement of the stenosis. At the 6-month follow-up, the neurological exam presented mild dysarthria, faciobrachial predominant disproportionate hemiparesis, an NIHSS score of 4 and a modified Rankin Scale score of 3 (moderate incapacity). In conclusion, Takayasu's arteritis must be recognized as a potential cause of ischemic stroke in young females.

Variability of the subtropical shelf front off eastern South America: Winter 2003 and summer 2004

Hydrographic data collected during surveys carried out in austral winter 2003 and summer 2004 are used to analyze the distributions of temperature (T) and salinity (S) over the continental shelf and slope of eastern South America between 27 degrees S and 39 degrees S. The water mass structure and the characteristics of the transition between subantarctic and subtropical shelf water (STSW), referred to as the subtropical shelf front (STSF), as revealed by the vertical structure of temperature and salinity are discussed. During both surveys, the front intensifies downward and extends southwestward from the near coastal zone at 33 degrees S to the shelf break at 36 degrees S. In austral winter subantarctic shelf water (SASW), derived from the northern Patagonia shelf, forms a vertically coherent cold wedge of low salinity waters that locally separate the outer shelf STSW from the fresher inner shelf Plata Plume Water (PPW) derived from the Rio de la Plata. Winter T-S diagrams and cross-shelf T and S distributions indicate that mixtures of PPW and tropical water only occur beyond the northernmost extent of pure SASW, and form STSW and an inverted thermocline characteristic of this region. In summer 2004, dilution of Tropical water (TW) occurs at two distinct levels: a warm near surface layer, associated to PPW-TW mixtures, similar to but significantly warmer than winter STSW, and a colder (T similar to 16 degrees C) salinity minimum layer at 40-50 m depth, created by SASW-STSW mixtures across the STSF. In winter, the salinity distribution controls the density structure creating a cross-shore density gradient, which prevents isopycnal mixing across the STSF. Temperature stratification in summer induces a sharp pycnocline providing cross-shelf isopycnal connections across the STSF. Cooling and freshening of the upper layer observed at stations collected along the western edge of the Brazil Current suggest offshore export of shelf waters. Low T and S filaments, evident along the shelf break in the winter data, suggest that submesoscale eddies may enhance the property exchange across the shelf break. These observations suggest that as the subsurface shelf waters converge at the STSF, they flow southward along the front and are expelled offshore, primarily along the front axis. (C) 2008 Elsevier Ltd. All rights reserved.

Biological, physical and chemical properties at the Subtropical Shelf Front Zone in the SW Atlantic Continental Shelf

The physical aspects of the Subtropical Shelf Front (STSF) for the Southwest Atlantic Continental Shelf were previously described. However, only scarce data on the biology of the front is available in the literature. The main goal of this paper is to describe the physical, chemical and biological properties of the STSF found in winter 2003 and summer 2004. A cross-section was established at the historically determined location of the STSF. Nine stations were sampled in winter and seven in summer. Each section included a series of conductivity-temperature-depth (CTD) stations where water samples from selected depths were filtered for nutrient determination. Surface samples were taken for chlorophyll a (Chl-a) determination and plankton net tows carried out above and below the pycnocline. Results revealed that winter was marked by an inner-shelf salinity front and that the STSF was located on the mid-shelf The low salinity waters in the inner-shelf indicated a strong influence of freshwater, with high silicate (72 mu M), suspended matter (45 mg l(-1)), phosphate (2.70 mu M) and low nitrate (1.0 mu M) levels. Total dissolved nitrogen was relatively high (22.98 mu M), probably due to the elevated levels of organic compound contribution close to the continental margin. Surface Chl-a concentration decreased from coastal well-mixed waters, where values up to 8.0 mg m(-3) were registered, to offshore waters. Towards the open ocean, high subsurface nutrients values were observed, probably associated to South Atlantic Central Waters (SACW). Zooplankton and ichthyoplankton abundance followed the same trend; three different groups associated to the inner-, mid- and outer-shelf region were identified. During summer, diluted waters extended over the shelf to join the STSF in the upper layer; the concentration of inorganic nutrients decreased in shallow waters; however, high values were observed between 40 and 60 m and in deep offshore waters. Surface Chl-a ranged 0.07-1.5 mg m(-3); winter levels were higher. Three groups of zoo and ichthyoplankton, separated by the STSF, were also identified. Results of the study performed suggest that the influence of freshwater was stronger during winter and that abundance distribution of Chl-a, copepods and ichthyoplankton was related to the Plata Plume Waters (PPW), rather than to the presence of the STSF. During summer, when the presence of freshwater decreases, plankton interactions seem to take place in the STSF. (C) 2008 Elsevier Ltd. All rights reserved.

Using the National Institute of Health Stroke Scale to Predict Dysphagia in Acute Ischemic Stroke

Background and Purpose: Oropharyngeal dysphagia is a common manifestation in acute stroke. Aspiration resulting from difficulties in swallowing is a symptom that should be considered due to the frequent occurrence of aspiration pneumonia that could influence the patient's recovery as it causes clinical complications and could even lead to the patient's death. The early clinical evaluation of swallowing disorders can help define approaches and avoid oral feeding, which may be detrimental to the patient. This study aimed to create an algorithm to identify patients at risk of developing dysphagia following acute ischemic stroke in order to be able to decide on the safest way of feeding and minimize the complications of stroke using the National Institutes of Health Stroke Scale (NHISS). Methods: Clinical assessment of swallowing was performed in 50 patients admitted to the emergency unit of the University Hospital, Faculty of Medicine of Ribeirao Preto, Sao Paulo, Brazil, with a diagnosis of ischemic stroke, within 48 h after the beginning of symptoms. Patients, 25 females and 25 males with a mean age of 64.90 years (range 26-91 years), were evaluated consecutively. An anamnesis was taken before the patient's participation in the study in order to exclude a prior history of deglutition difficulties. For the functional assessment of swallowing, three food consistencies were used, i.e. pasty, liquid and solid. After clinical evaluation, we concluded whether there was dysphagia. For statistical analysis we used the Fisher exact test, verifying the association between the variables. To assess whether the NIHSS score characterizes a risk factor for dysphagia, a receiver operational characteristics curve was constructed to obtain characteristics for sensitivity and specificity. Results: Dysphagia was present in 32% of the patients. The clinical evaluation is a reliable method of detection of swallowing difficulties. However, the predictors of risk for the swallowing function must be balanced, and the level of consciousness and the presence of preexisting comorbidities should be considered. Gender, age and cerebral hemisphere involved were not significantly associated with the presence of dysphagia. NIHSS, Glasgow Coma Scale, and speech and language changes had a statistically significant predictive value for the presence of dysphagia. Conclusions: The NIHSS is highly sensitive (88%) and specific (85%) in detecting dysphagia; a score of 12 may be considered as the cutoff value. The creation of an algorithm to detect dysphagia in acute ischemic stroke appears to be useful in selecting the optimal feeding route while awaiting a specialized evaluation. Copyright (C) 2012 S. Karger AG, Basel

Clinical Effects of Scalp Electrical Acupuncture in Stroke: A Sham-Controlled Randomized Clinical Trial

Objectives: The majority of individuals who survive a stroke are disabled because of persisting neurological impairments. The objective of this study was to evaluate the efficacy of subcutaneous electrical stimulation of the scalp in spontaneous functional recovery of patients with chronic ischemic stroke, by evaluating clinical, neurological, and functional findings. Subjects and methods: Sixty-two (62) subjects who were at least 18 months postdiagnosis of ischemic stroke were randomized to receive 10 sessions of placebo or active low-frequency electrical stimulation (2/100 Hz) using subcutaneous acupuncture needles over the scalp. Functional and neurological evaluations were indexed by the Barthel, Rankin, and National Institutes of Health Stroke Scale (NIHSS). Results: Results show that there was a significant difference in functional improvement between the sham and active group as indexed by NIHSS scale. The active group had a larger functional improvement after 10 sessions of scalp electrical acupuncture. The other two functional scales (Rankin and Barthel) failed to show significant differences between the two treatment groups. Conclusions: These results support further testing of scalp electrical acupuncture for the treatment of stroke as well further mechanistic studies to understand mechanisms associated with the observed improvement. Further studies need to consider longer follow-up assessments to investigate potential functional changes associated with electrical acupuncture.

Early stroke case-fatality rates in three hospital registries in the Northeast and Southeast of Brazil

Few studies have addressed early cerebrovascular lethality in Brazil. Objective: To evaluate 10 and 28-day stroke case-fatality rates in three hospitals in three Brazilian cities. Methods: We described the stroke registries in Sao Paulo, Joao Pessoa, and Natal. Results: Out of a total of 962 first-ever events (mean age, 68.1 years-old; 53% men), 83.6% (804 cases) were classified as ischemic and 16.4% (158) as hemorrhagic stroke. Overall, the case-fatality rates and 95% confidence intervals (95% CI) for hemorrhagic stroke events were higher than for ischemic events, both at 10 (12.3%; 95% CI 7.2-17.4 versus 7.0%; 95% CI 5.3-8.8) and at 28 days (19.8%; 95% CI 13.6-26.0 versus 11.1%; 95% CI 8.9-13.3). Conclusions: We did not find any substantial differences in early case-fatality rates according to stroke subtypes, when comparing the three centers.

Correlates of the incidence of disability and mortality among older adult Brazilians with and without diabetes mellitus and stroke

Background: The combined effect of diabetes and stroke on disability and mortality remains largely unexplored in Brazil and Latin America. Previous studies have been based primarily on data from developed countries. This study addresses the empirical gap by evaluating the combined impact of diabetes and stroke on disability and mortality in Brazil. Methods: The sample was drawn from two waves of the Survey on Health and Well-being of the Elderly, which followed 2,143 older adults in Sao Paulo, Brazil, from 2000 to 2006. Disability was assessed via measures of activities of daily living (ADL) limitations, severe ADL limitations, and receiving assistance to perform these activities. Logistic and multinomial regression models controlling for sociodemographic and health conditions were used to address the influence of diabetes and stroke on disability and mortality. Results: By itself, the presence of diabetes did not increase the risk of disability or the need for assistance; however, diabetes was related to increased risks when assessed in combination with stroke. After controlling for demographic, social and health conditions, individuals who had experienced stroke but not diabetes were 3.4 times more likely to have ADL limitations than those with neither condition (95% CI 2.26-5.04). This elevated risk more than doubled for those suffering from a combination of diabetes and stroke (OR 7.34, 95% CI 3.73-14.46). Similar effects from the combination of diabetes and stroke were observed for severe ADL limitations (OR 19.75, 95% CI 9.81-39.76) and receiving ADL assistance (OR 16.57, 95% CI 8.39-32.73). Over time, older adults who had experienced a stroke were at higher risk of remaining disabled (RRR 4.28, 95% CI 1.53, 11.95) and of mortality (RRR 3.42, 95% CI 1.65, 7.09). However, risks were even higher for those who had experienced both diabetes and stroke. Diabetes was associated with higher mortality. Conclusions: Findings indicate that a combined history of stroke and diabetes has a great impact on disability prevalence and mortality among older adults in Sao Paulo, Brazil.

Antiphospholipid syndrome plus rheumatic fever: a higher risk factor for stroke?

To compare clinical and laboratory findings between patients with primary antiphospholipid syndrome (PAPS) versus secondary APS due to rheumatic fever (APS-RF) (according to Jones criteria). Seventy-three APS patients (Sapporo criteria) were enrolled, and demographic, clinical, and laboratory data were collected. Exclusion criteria were heart congenital abnormalities and previous infectious endocarditis. Patients were divided into two groups: PAPS (n = 68) and APS-RF (n = 5). The mean current age, disease duration, frequencies of female gender, and Caucasian race were similar in APS-RF and PAPS patients (P > 0.05). Remarkably, the frequency of stroke was significantly higher in APS-RF compared to PAPS patients (80% vs. 25%, P = 0.02). Of note, echocardiogram of these patients did not show intracardiac thrombus. No significant differences were found in peripheral thromboembolic events (P = 1.0), pulmonary thromboembolism (P = 1.0), miscarriage (P = 0.16), thrombocytopenia (P = 0.36), arterial events (P = 0.58), and thrombosis of small vessels (P = 1.0). There were no differences in the frequencies of comorbidities such as diabetes mellitus, hypertension, smoking, and hyperlipidemia in both groups (P > 0.05). The frequencies of lupus anticoagulant, IgG, and IgM anticardiolipin were similar in two groups. APS patients associated with rheumatic fever without infective endocarditis may imply a high stroke risk as compared with PAPS, and future studies are needed to confirm this finding.

Modified constraint-induced movement therapy and modified forced-use therapy for stroke patients are both effective to promote balance and gait improvements

Background: Previous studies show that chronic hemiparetic patients after stroke, presents inabilities to perform movements in paretic hemibody. This inability is induced by positive reinforcement of unsuccessful attempts, a concept called learned non-use. Forced use therapy (FUT) and constraint induced movement therapy (CIMT) were developed with the goal of reversing the learned non-use. These approaches have been proposed for the rehabilitation of the paretic upper limb (PUL). It is unknown what would be the possible effects of these approaches in the rehabilitation of gait and balance. Objectives: To evaluate the effect of Modified FUT (mFUT) and Modified CIMT (mCIMT) on the gait and balance during four weeks of treatment and 3 months follow-up. Methods: This study included thirty-seven hemiparetic post-stroke subjects that were randomly allocated into two groups based on the treatment protocol. The non-paretic UL was immobilized for a period of 23 hours per day, five days a week. Participants were evaluated at Baseline, 1st, 2nd, 3rd and 4th weeks, and three months after randomization. For the evaluation we used: The Stroke Impact Scale (SIS), Berg Balance Scale (BBS) and Fugl-Meyer Motor Assessment (FM). Gait was analyzed by the 10-meter walk test (T10) and Timed Up & Go test (TUG). Results: Both groups revealed a better health status (SIS), better balance, better use of lower limb (BBS and FM) and greater speed in gait (T10 and TUG), during the weeks of treatment and months of follow-up, compared to the baseline. Conclusion: The results show mFUT and mCIMT are effective in the rehabilitation of balance and gait. Trial Registration ACTRN12611000411943.

Arterial Spin Labeling Measurements of Cerebral Perfusion Territories in Experimental Ischemic Stroke

Collateral circulation, defined as the supplementary vascular network that maintains cerebral blood flow (CBF) when the main vessels fail, constitutes one important defense mechanism of the brain against ischemic stroke. In the present study, continuous arterial spin labeling (CASL) was used to quantify CBF and obtain perfusion territory maps of the major cerebral arteries in spontaneously hypertensive rats (SHRs) and their normotensive Wistar-Kyoto (WKY) controls. Results show that both WKY and SHR have complementary, yet significantly asymmetric perfusion territories. Right or left dominances were observed in territories of the anterior (ACA), middle and posterior cerebral arteries, and the thalamic artery. Magnetic resonance angiography showed that some of the asymmetries were correlated with variations of the ACA. The leptomeningeal circulation perfusing the outer layers of the cortex was observed as well. Significant and permanent changes in perfusion territories were obtained after temporary occlusion of the right middle cerebral artery in both SHR and WKY, regardless of their particular dominance. However, animals with right dominance presented a larger volume change of the left perfusion territory (23 +/- 9%) than animals with left dominance (7 +/- 5%, P<0.002). The data suggest that animals with contralesional dominance primarily safeguard local CBF values with small changes in contralesional perfusion territory, while animals with ipsilesional dominance show a reversal of dominance and a substantial increase in contralesional perfusion territory. These findings show the usefulness of CASL to probe the collateral circulation.