Inhibition of Rho-kinase protects cerebral barrier from ischaemia-evoked injury through modulations of endothelial cell oxidative stress and tight junctions

Ischaemic strokes evoke blood-brain barrier (BBB) disruption and oedema formation through a series of mechanisms involving Rho-kinase activation. Using an animal model of human focal cerebral ischaemia, this study assessed and confirmed the therapeutic potential of Rho-kinase inhibition during the acute phase of stroke by displaying significantly improved functional outcome and reduced cerebral lesion and oedema volumes in fasudil- versus vehicle-treated animals. Analyses of ipsilateral and contralateral brain samples obtained from mice treated with vehicle or fasudil at the onset of reperfusion plus 4 h post-ischaemia or 4 h post-ischaemia alone revealed these benefits to be independent of changes in the activity and expressions of oxidative stress- and tight junction-related parameters. However, closer scrutiny of the same parameters in brain microvascular endothelial cells subjected to oxygen-glucose deprivation ± reperfusion revealed marked increases in prooxidant NADPH oxidase enzyme activity, superoxide anion release and in expressions of antioxidant enzyme catalase and tight junction protein claudin-5. Cotreatment of cells with Y-27632 prevented all of these changes and protected in vitro barrier integrity and function. These findings suggest that inhibition of Rho-kinase after acute ischaemic attacks improves cerebral integrity and function through regulation of endothelial cell oxidative stress and reorganization of intercellular junctions. Inhibition of Rho-kinase (ROCK) activity in a mouse model of human ischaemic stroke significantly improved functional outcome while reducing cerebral lesion and oedema volumes compared to vehicle-treated counterparts. Studies conducted with brain microvascular endothelial cells exposed to OGD ± R in the presence of Y-27632 revealed restoration of intercellular junctions and suppression of prooxidant NADPH oxidase activity as important factors in ROCK inhibition-mediated BBB protection.

Transfusion and Treatment of severe anaemia in African children (TRACT): a study protocol for a randomised controlled trial

BACKGROUND: In sub-Saharan Africa, where infectious diseases and nutritional deficiencies are common, severe anaemia is a common cause of paediatric hospital admission, yet the evidence to support current treatment recommendations is limited. To avert overuse of blood products, the World Health Organisation advocates a conservative transfusion policy and recommends iron, folate and anti-helminthics at discharge. Outcomes are unsatisfactory with high rates of in-hospital mortality (9-10 %), 6-month mortality and relapse (6 %). A definitive trial to establish best transfusion and treatment strategies to prevent both early and delayed mortality and relapse is warranted.

METHODS/DESIGN: TRACT is a multicentre randomised controlled trial of 3954 children aged 2 months to 12 years admitted to hospital with severe anaemia (haemoglobin < 6 g/dl). Children will be enrolled over 2 years in 4 centres in Uganda and Malawi and followed for 6 months. The trial will simultaneously evaluate (in a factorial trial with a 3 x 2 x 2 design) 3 ways to reduce short-term and longer-term mortality and morbidity following admission to hospital with severe anaemia in African children. The trial will compare: (i) R1: liberal transfusion (30 ml/kg whole blood) versus conservative transfusion (20 ml/kg) versus no transfusion (control). The control is only for children with uncomplicated severe anaemia (haemoglobin 4-6 g/dl); (ii) R2: post-discharge multi-vitamin multi-mineral supplementation (including folate and iron) versus routine care (folate and iron) for 3 months; (iii) R3: post-discharge cotrimoxazole prophylaxis for 3 months versus no prophylaxis. All randomisations are open. Enrolment to the trial started September 2014 and is currently ongoing. Primary outcome is cumulative mortality to 4 weeks for the transfusion strategy comparisons, and to 6 months for the nutritional support/antibiotic prophylaxis comparisons. Secondary outcomes include mortality, morbidity (haematological correction, nutritional and infectious), safety and cost-effectiveness.

DISCUSSION: If confirmed by the trial, a cheap and widely available 'bundle' of effective interventions, directed at immediate and downstream consequences of severe anaemia, could lead to substantial reductions in mortality in a substantial number of African children hospitalised with severe anaemia every year, if widely implemented.

Contribuição da ecografia cerebral transfontanelar para a avaliação do crescimento cerebral do recém-nascido pré-termo

Tese de doutoramento, Medicina (Pediatria), Universidade de Lisboa, Faculdade de Medicina, 2013

Neuro-glia-vascular alterations by common neonatal clinical conditions

Tese de doutoramento, Farmácia (Biologia Celular e Molecular), Universidade de Lisboa, Faculdade de Farmácia, 2014

Embolization for multicompartmental bleeding in patients in hemodynamically unstable condition: prognostic factors and outcome.

PURPOSE: To determine prognostic factors and evaluate outcomes of transcatheter arterial embolization in severely injured patients in hemodynamically unstable condition with multicompartmental bleeding.¦MATERIALS AND METHODS: Between June 2000 and May 2008, 36 consecutive patients treated with transcatheter arterial embolization for major retroperitoneal bleeding associated with at least one additional source of bleeding were retrospectively reviewed. Mean Injury Severity Score (ISS) was 49.4 ± 15.8. Univariate and multivariate analyses were performed to identify parameters associated with failure of embolization, need for additional surgery to control bleeding, and fatal outcome at 30 d.¦RESULTS: Embolization was technically successful in 35 of 36 patients (97.2%) and resulted in immediate and sustained (> 24 h) hemodynamic improvement in 29 (80.5%). Additional hemostatic surgery was necessary after embolization in six patients (16.6%). Fifteen patients (41.6%) died within 30 d. Failure to restore hemodynamic stability was correlated with the rate of administration of packed red blood cells (P = .014), rate of administration of fresh frozen plasma (FFP; P = .031), and systolic blood pressure (SBP) immediately before embolization (P = .002). The need for additional surgery was correlated with FFP administration rate before embolization (P = .0002) and hemodynamic success (P = .003). Death was correlated with Glasgow Coma Scale score at admission (P = .001), ISS (P = .014), New Injury Severity Score (P = .016), number of injured sites (P = .012), SBP before embolization (P = .042), need for vasopressive drugs before embolization (P = .037), and hemodynamic success (P = .0004).¦CONCLUSIONS: In patients in hemodynamically unstable condition, transcatheter arterial embolization effectively controls bleeding and improves hemodynamic stability. Immediate survival is related to hemodynamic condition before embolization, and 30-d mortality is mainly related to associated brain trauma.

Head-to-head comparison of length of stay, patients' outcome and satisfaction in Switzerland before and after SwissDRG-Implementation in 2012 in 2012: an observational study in two tertiary university centers.

On 1 January 2012 Swiss Diagnosis Related Groups (DRG), a new uniform payment system for in-patients was introduced in Switzerland with the intention to replace a "cost-based" with a "case-based" reimbursement system to increase efficiency. With the introduction of the new payment system we aim to answer questions raised regarding length of stay as well as patients' outcome and satisfaction. This is a prospective, two-centre observational cohort study with data from University Hospital Basel and the Cantonal Hospital Aarau, Switzerland, from January to June 2011 and 2012, respectively. Consecutive in-patients with the main diagnosis of either community-acquired pneumonia, exacerbation of COPD, acute heart failure or hip fracture were included. A questionnaire survey was sent out after discharge investigating changes before and after SwissDRG implementation. Our primary endpoint was LOS. Of 1,983 eligible patients 841 returned the questionnaire and were included into the analysis (429 in 2011, 412 in 2012). The median age was 76.7 years (50.8% male). Patients in the two years were well balanced in regard to main diagnoses and co-morbidities. Mean LOS in the overall patient population was 10.0 days and comparable between the 2011 cohort and the 2012 cohort (9.7 vs 10.3; p = 0.43). Overall satisfaction with care changed only slightly after introduction of SwissDRG and remained high (89.0% vs 87.8%; p = 0.429). Investigating the influence of the implementation of SwissDRG in 2012 regarding LOS patients' outcome and satisfaction, we found no significant changes. However, we observed some noteworthy trends, which should be monitored closely.

Effect of hormone replacement therapy on retinal and optic nerve head blood flow and topography in postmenopausal women, and retinal tissue perfusion in ovariectomized rats

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

Factores de riesgo para convulsiones tras cirugía cardiaca con acido tranexamico: estudio de casos y controles, FCI

La cirugía cardiaca con circulación extracorpórea tiene riesgo de lesión del sistema nervioso central que impacta negativamente el desenlace postoperatorio. Su espectro es variable siendo lo más frecuente la lesión isquémica. Sin embargo esta no es la única complicación neurológica, las convulsiones también tienen un impacto significativo sobre la morbimortalidad y se asocian a un incremento de la estancia hospitalaria. Mientras que los eventos isquémicos tras cirugía cardiaca están bien caracterizados, existen pocos datos acerca de las convulsiones postoperatorias de origen no isquémico. Dentro de las teorías postuladas para explicar estos fenómenos llama la atención el potencial epileptogénico de los medicamentos antifibrinolíticos, ampliamente utilizados con el objetivo de minimizar el sangrado y reducir la exposición a hemoderivados. Numerosos reportes sugieren que el ácido tranexámico puede inducir actividad convulsiva en el postoperatorio. El objetivo de este estudio retrospectivo de casos y controles fue examinar los factores asociados con convulsiones postoperatorias en pacientes sometidos a cirugía cardiaca con circulación extracorpórea que recibieron ácido tranexámico. Todos los pacientes sometidos a cirugía cardiaca con circulación extracorpórea entre Enero de 2008 y Diciembre de 2009 fueron identificados. Los casos se definieron como aquellos pacientes que convulsionaron y requirieron inicio de anticonvulsivantes dentro de las 48 horas post-quirúrgicas. Los criterios de exclusión incluyeron epilepsia preexistente y pacientes con alguna lesión isquémica nueva en neuroimágen. Los controles fueron seleccionados aleatoriamente a partir de la cohorte inicial. Se analizaron un total de 28 casos y 112 controles. Se evidenció una asociación entre disfunción renal, valores elevados de creatinina preoperatoria y convulsiones postoperatorias.

Intestinal injury and endotoxemia in children undergoing surgery for congenital heart disease

RATIONALE: Children with congenital heart disease are at risk of gut barrier dysfunction and translocation of gut bacterial antigens into the bloodstream. This may contribute to inflammatory activation and organ dysfunction postoperatively. OBJECTIVES: To investigate the role of intestinal injury and endotoxemia in the pathogenesis of organ dysfunction after surgery for congenital heart disease. METHODS: We analyzed blood levels of intestinal fatty acid binding protein and endotoxin (endotoxin activity assay) alongside global transcriptomic profiling and assays of monocyte endotoxin receptor expression in children undergoing surgery for congenital heart disease. MEASUREMENTS AND MAIN RESULTS: Levels of intestinal fatty acid binding protein and endotoxin were greater in children with duct-dependent cardiac lesions. Endotoxemia was associated with severity of vital organ dysfunction and intensive care stay. We identified activation of pathogen-sensing, antigen-processing, and immune-suppressing pathways at the genomic level postoperatively and down-regulation of pathogen-sensing receptors on circulating immune cells. CONCLUSIONS: Children undergoing surgery for congenital heart disease are at increased risk of intestinal mucosal injury and endotoxemia. Endotoxin activity correlates with a number of outcome variables in this population, and may be used to guide the use of gut-protective strategies.

Tempol ameliorates murine viral encephalomyelitis by preserving the blood-brain barrier, reducing viral load, and lessening inflammation

Multiple sclerosis (MS) is a progressive inflammatory and/or demyelinating disease of the human central nervous system (CNS). Most of the knowledge about the pathogenesis of MS has been derived from murine models, such as experimental autoimmune encephalomyelitis and vital encephalomyelitis. Here, we infected female C57BL/6 mice with a neurotropic strain of the mouse hepatitis virus (MHV-59A) to evaluate whether treatment with the multifunctional antioxidant tempol (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy) affects the ensuing encephalomyelitis. In untreated animals, neurological symptoms developed quickly: 90% of infected mice died 10 days after virus inoculation and the few survivors presented neurological deficits. Treatment with tempol (24 mg/kg, ip, two doses on the first day and daily doses for 7 days plus 2 mM tempol in the drinking water ad libitum) profoundly altered the disease outcome: neurological symptoms were attenuated, mouse survival increased up to 70%, and half of the survivors behaved as normal mice. Not Surprisingly, tempol substantially preserved the integrity of the CNS, including the blood-brain barrier. Furthermore, treatment with tempol decreased CNS vital titers, macrophage and T lymphocyte infiltration, and levels of markers of inflammation, such as expression of inducible nitric oxide synthase, transcription of tumor necrosis factor-alpha and interferon-gamma, and protein nitration. The results indicate that tempol ameliorates murine viral encephalomyelitis by altering the redox status of the infectious environment that contributes to an attenuated CNS inflammatory response. overall, our study supports the development of therapeutic strategies based on nitroxides to manage neuroinflammatory diseases, including MS. (C) 2009 Elsevier Inc. All rights reserved.

Early nephrology consultation can have an impact on outcome of acute kidney injury patients

Background. Patients who develop acute kidney injury (AKI) in the intensive care unit (ICU) have extremely high rates of mortality and morbidity. The objectives of this study were to compare clinical and laboratory characteristics of AKI patients evaluated and not evaluated by nephrologists in ICU and generate the hypothesis of the relationship between timing of nephrology consultation and outcome.Methods. We explored associations among presence and timing of nephrology consultation with ICU stay and in-ICU mortality in 148 ICU patients with AKI at a Brazilian teaching hospital from July 2008 to May 2010. Multivariable logistic regression was used to adjust confounding and selection bias.Results. AKI incidence was 30% and 52% of these AKI patients were evaluated by nephrologists. At multivariable analysis, AKI patients evaluated by nephrologists showed higher Acute Tubular Necrosis-Index Specific Score and creatinine level, more dialysis indications, lower urine output and longer ICU stay. The mortality rate was similar to AKI patients who were not evaluated. Nephrology consultation was delayed (>= 48 h) in 62.3% (median time to consultation, 4.7 days). Lower serum creatinine levels (P - 0.009) and higher urine output (P = 0.002) were associated with delayed consultation. Delayed consultation was associated with increased ICU mortality (65.4 versus 88.2%, P < 0.001).Conclusions. In AKI, patients evaluated by nephrologists seem to be more seriously ill than those not evaluated and present similar mortality rate. The delayed nephrology consultation can be associated with increased ICU mortality.

CYP1A2*1C, CYP2E1*5B, and GSTM1 polymorphisms are predictors of risk and poor outcome in head and neck squamous cell carcinoma patients

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