Adenosine Triphosphate (ATP) can be released as a signal between cells in an autocrine and paracrine manner that binds purinergic receptors. Highly conserved, purinergic receptors expressed on the cell surface of neurons and astrocytes are capable of being activated across eight orders of magnitude from hundreds of nanomolar ATP to millimolar. Genetically encoded fluorescent protein biosensors have been used to detect ATP outside the cell, but a high affinity extracellular ATP sensor is required to study the ATP signaling dynamics from nanomolar to micromolar magnitudes. Previously, our lab developed a first generation sensor of extracellular ATP called ECATS1 (Conley et al.). To develop an improved sensor, we caried out site-directed mutagenesis of the sensor's ATP binding site and identified a mutant that exhibited a 4-fold increase in ATP binding affinity in solution. We then optimized the membrane-tethering of the sensor to achieve the 4-fold increase in extracellular ATP binding affinity when measured on live cell.s This second-generation sensor was dubbed ECATS2. As a proof-of-concept application, we sought to detect ATP release from cells using <i>in vitro</i> models of edema. We subjected HEK293A cells to hypo-osmotic shock (HOS), revealing ATP release at micromolar levels. Then we tested HOS in cultured cortical astrocytes, also revealing micromolar ATP release. However, when we tested neuron-astrocyte co-cultures, we no longer observed ATP release in response to HOS. Interestingly, this implies that co-culture either entirely prevented ATP release from astrocytes or dampened it into the nanomolar range below the limit of ECATS2 detection. Thus, we have validated the development of a higher affinity, second-generation sensor and used it to discover that ATP release from astrocytes after HOS can be affected by the presence of neurons. <br>

Os venenos do gênero Bothrops induzem efeitos locais caracterizados por hemorragia, necrose, edema e dor intensa. Apesar da importância clínica do fenômeno de dor, os estudos sobre os mecanismos envolvidos na gênese deste fenômeno são ainda escassos. Além disso, não existem dados sobre a capacidade do antiveneno em neutralizar este fenômeno. Neste trabalho foi investigada, a capacidade dos venenos de Bothrops jararaca, Bothrops asper e da miotoxina III (Fosfolipase A2, variante Asp 49), uma toxina isolada do veneno de Bothrops asper, em induzir hiperalgesia em ratos, a mediação química deste fenômeno e a capacidade dos antivenenos em neutralizar esta ação dos venenos. A possível correlação entre a hiperalgesia e a resposta edematogênica causada pelos venenos ou miotoxina foi também avaliada. O limiar de dor foi determinado antes e em diferentes tempos após a administração dos venenos ou toxina, empregando o teste de pressão de pata de rato. Para o estudo da resposta edematogênica, o aumento do volume das patas posteriores foi determinado por pletismografia. Os venenos e a toxina, administrados por via intraplantar, nas doses de 5µg (VBj), 15µg (VBa) ou 10µg (MIII), induziram hiperalgesia e edema, com respostas máxima na 1a (VBj, MIII) ou 2a (VBa) hora, não sendo mais detectadas na 24a hora. Para o estudo da neutralização, foram utilizados o antiveneno botrópico produzido no Instituto Butantan e o antiveneno polivalente produzido no Instituto Clodomiro Picado da Costa Rica, administrados por via endovenosa, 15 min. ou imediatamente antes ou 15 min. após a injeção dos venenos. O AVIB, quando injetado 15 min. antes do VBj, foi capaz de reverter a hiperalgesia induzida pelo veneno. Em relação ao edema, esta inibição foi observada quando o antiveneno foi administrado 15 min. ou imediatamente antes do VBj. Por outro lado, o AVCP não interferiu com a dor e o edema acarretados pelo VBa. Quando o VBj e o VBa foram incubados, in vitro, por 30 min., a 370C com os AV correspondentes, a hiperalgesia e o edema foram abolidos. Estes resultados indicam que a incapacidade do AVCP, quando administrado in vivo, de bloquear a hiperalgesia e o edema induzidos pelo VBa, não é consequência da ausência de anticorpos específicos no antiveneno, uma vez que estes efeitos foram inibidos quando o veneno foi pré-incubado com o antiveneno. Para avaliação da mediação química da hiperalgesia e do edema, os animais foram submetidos a tratamentos com inibidores de síntese, antagonistas de receptores, anticorpos ou drogas depletoras destes mediadores. Os resultados mostraram que o Hoe-140, dexametasona e NDGA inibem a hiperalgesia induzida pelo VBa, enquanto que apenas a prometazina interferiu com o edema causado pelo veneno. A hiperalgesia induzida pela MIII foi revertida pelo tratamento com prometazina, metisergida, Hoe-140, dexametasona e por NDGA, enquanto que o edema foi inibido apenas por prometazina e dexametasona. Estes dados sugerem que: a) a MIII é um importante componente do veneno para a geração de hiperalgesia, b) a bradicinina e os derivados da lipoxigenase são mediadores da dor acarretada pelo VBa e pela MIII, c) histamina e serotonina participam também da hiperalgesia induzida pela miotoxina e d) a histamina é mediador do edema induzido pelo VBa e pela MIII. Com relação à hiperalgesia induzida pelo VBj, somente o tratamento com Hoe-140 diminuiu este fenômeno, indicando a participação da bradicinina. Por outro lado, este tratamento não foi capaz de interferir com o edema induzido por este veneno. Cabe ressaltar que TEIXEIRA et al. (1994) demonstraram a participação de eicosanóides e PAF na hiperalgesia induzida pelo VBj. Os dados em conjunto sugerem ainda, dissociação entre os fenômenos de dor e edema acarretados por ambos os venenos e pela miotoxina. / Bothrops venoms cause pronounced local tissue-damage characterized by hemorrhage, myonecrosis, edema and pain. Venom-induced pain has been poorly investigated, despite its clinical relevance. Furthermore, the ability of antivenom to neutralize hyperalgesia induced by these venoms is not known. In the present study the hyperalgesia and edema induced by Bothrops jararaca (BjV) and Bothrops asper (BaV) venom and by myotoxin III-MIII (Asp49- phospholipase A2), a toxin isolated from BaV, were investigated. The chemical mediators involved in these phenomena and the ability of the antivenom to neutralize the hyperalgesia and edema induced by these venoms were also investigated. Pain threshold was assessed before and at several intervals after venom injection, using the rat paw pressure test. Edema of paw was measured phethysmographically at the same periods of time. The intraplantar injection of BjV (5µg/paw), BaV (15µg/paw) or MIII (10µg/paw) caused hyperalgesia and edema, whose peak were observed at the 1st (BjV, MIII) or 2nd (BaV) hours after venom/toxin administration, decreasing thereafter. For neutralization studies, the antivenoms produced either at Instituto Butantan from Brazil (AVIB) or Instituto Clodomiro Picado from Costa Rica (AVCP) were administered intravenously 15 min prior to, or immediately before, or 15 min after venoms injection. When the antivenom from Instituto Butantan was injected 15 min. before BjV, the hyperalgesia and edema were abolished. Furthermore, partial inhibition of edema was also observed when the antivenom was injected together with BjV. On the other hand, hyperalgesia and edema induced by BaV were not modified by AVCP. Incubation of BjV and BaV, for 30 min. at 37oC, with the antivenoms in vitro, abolished the hyperalgesia and edema. The inability of the in vivo treatment with antivenom in abolishing hyperalgesia and edema induced by BaV seems not to be related to the lack of neutralizing antibodies in antivenom, because neutralization was achieved in pre-incubation experiments. In order to investigate the chemical mediation of hyperalgesia and edema induced by the venoms or toxin, animals were treated with several drugs. Pretreatment with Hoe-140, dexamethasone and NDGA blocked the hyperalgesia induced by BaV, whereas only promethazine reduced the edema induced by this venom. The MIII-induced hyperalgesia was blocked by promethazine, methysergide, Hoe-140, dexamethasone and NDGA, whereas the edema was reduced only by promethazine and dexamethasone. These results suggest that: a) MIII may contribute to the BaV-induced hyperalgesia, b) bradykinin and leukotrienes mediate the BaV- and MIII-induced pain and MIII; c) histamine and serotonin also participate in the myotoxin-induced hyperalgesia and d) the edema induced by BaV and MIII is mediated by histamine. Pre-treatment of the animals with Hoe-140 abolished BjV-induced hyperalgesia, suggesting that bradykinin may mediate the venom-induced hyperalgesia. However, this treatment did not modify the BjV-induced edema. It is important to stress that previous studies have shown that BjV-induced hyperalgesia is mediated, at least partially, by eicosanoids and PAF (TEIXEIRA et al.,1994). The data presented herein also suggest that distinct mechanisms may be involved in the development of hyperalgesia and edema induced by both venoms and myotoxin III.

Fragestellung: Das von Dixon 1991 beschriebene tierexperimentelle Modell der 'controlled cortical impact injury'(CCII) wurde zur Untersuchung pathophysiologischer und pathomorphologischer Veränderungen nach traumatischer Hirnkontusion angewandt. Magnetresonanztomographische Techniken (MRT) einschließlich der diffusionswichtenden Bildgebung (DWI) wurden genutzt, um den Zeitverlauf der Hirnödementwicklung zu erfassen, eine Differenzierung unterschiedlicher Ödemformen zu ermöglichen und einen Blut-Hirn-Schrankenschaden zu detektieren. Desweiteren wurde die MRT genutzt, um den neuroprotektiven Effekt des NO-Synthase-Pathway-Modulators Lubeluzol, der bereits im Modell der zerebralen Ischämie nachgewiesen werden konnte, zu untersuchen. Material und Methoden: An 46 Sprague Dawley Ratten wurde eine links parieto-temporale Kontusion appliziert. Die Tiere wurden bis zu 7 Tage nach Trauma magnetresonanztomographisch untersucht. 36 Tiere erhielten Lubeluzol resp. Plazebo. Ergebnisse: Die T2-gewichtete Bildgebung zeigte eine maximale Ödemausbreitung 24 - 48 Stunden nach Trauma. Es ließ sich mithilfe der DWI ein Kontusionskern von einem Kontusionsrand differenzieren. Der Kontusionskern zeichnete sich bis 48 Stunden nach Trauma durch eine Abfall des apparenten Diffusionskoeffizienten (ADC) aus, einem zytotoxischem Ödem entsprechend, der Kontusionsrand wies während des gesamten Untersuchungszeitraums einen ADC-Anstieg auf, als Ausdruck eines vasogenen Ödems. Die T1-gewichtete Bildgebung konnte nach Kontrastmittel (KM)-Applikation durch die KM-Extravasation eine über 7 Tage anhaltende Störung der Blut-Hirnschranke detektieren. In der Lubeluzol-Studie ließ sich anhand der ADC-Veränderungen, des Ödemausmasses oder physiologischer Parameter wie Blutdruck, intrakranieller Druck oder Hirnschwellung kein signifikanter Unterschied zwischen den Tieren der Substanz- bzw. Plazebo-Gruppe aufzeigen. Schlußfolgerung: Die in dem Modell der CCII induzierte traumatische Hirnkontusion zeichnet sich bis 48 Stunden nach Trauma durch einen zytotoxischen Kontusionskern und einen diesen umgebenen vasogenen Kontusionrand aus. Desweiteren konnte ein anhaltender Blut-Hirnschrankendefekt nachgewiesen werden. Ein neuroprotektiver Effekt des Lubeluzols konnte in diesem Traumamodell in der hier applizierten Dosierung nicht nachgewiesen werden. / Objective: The controlled cortical impact injury (CCII) device, as described by Dixon 1991, was used to investigate the brain tissue damage in an animal model of severe traumatic brain injury. Magnetic resonance imaging (MRI) techniques including diffusion weighted imaging (DWI) have been applied to analyse the time course and the characteristics of edema formation and to detect blood-brain-barrier disruption. Furthermore MRI has been used to investigate a neuroprotective effect of the NO-synthase pathway modulator lubeluzole, which has proved markedly beneficial in a model of cerebral ischemia in rats. Material and Methods: a left parieto-temporal cortical contusion was inflicted upon 46 Sprague Dawley rats. Animals have been examined up to 7 days following trauma by MRI. 36 animals have been administered lubeluzole resp. placebo. Results: The most pronounced edema formation has been shown in T2-weighed imaging at 24 - 48 hours post trauma. DWI was able to distinguish between a contusion core and a contusion rim. The contusion core was marked by a decrease in the apparent diffusion coefficient (ADC) up to 48 hours post trauma, indicating cytotoxic edema, whereas the contusion rim has been characterised by vasogenic edema, as indicated by ADC-increase over the entire investigation period. In T1-weighted imaging contrast agent extravasation indicated a sustained blood brain barrier disruption up to 7 days after trauma. Compared to placebo administered rats in lubeluzole-treated animals no significant differences in ADC-changes, edema-extension or physiological parameters as blood pressure, intracranial pressure or brain swelling could be demonstrated. Conclusion: CCII induced traumatic brain injury is characterised by a cytotoxic edema up to 48 hours encircled by a vasogenic contusion rim accompanied by a sustained blood brain barrier disruption. In the model of CCII lubeluzole did not reveal a neuroprotective effect in the applied dosage.

A cirurgia ortognática é o procedimento cirúrgico que visa a correção das deformidades dentofaciais esqueléticas e pode levar a diminuição dos movimentos mandibulares, dor e edema. Uma possibilidade de tratamento para essas consequências é a fototerapia com laser de baixa potência. O objetivo deste estudo foi realizar uma avaliação longitudinal dos movimentos mandibulares, dor e edema em pacientes submetidos à cirurgia ortognática bimaxilar, após fototerapia com laser de baixa potência (LLLT). Foram avaliados 30 pacientes, divididos em grupo laser (n=15) e grupo controle (n=15) de modo aleatório. O grupo laser recebeu laserterapia pós-operatória por 19 sessões. O grupo controle recebeu placebo de laserterapia. Os grupos foram comparados quanto aos movimentos mandibulares - abertura máxima, lateralidade e protrusão máxima, dor - escala visual analógica, edema - medidas entre pontos cefalométricos, em um período de 60 dias após a cirurgia. Foram aplicados testes estatísticos para comparação entre os grupos (p<0,05). Houve diferença significante para abertura máxima, lateralidade e protrusão máxima nos períodos de 14 a 60 dias para a maioria das comparações. Foi verificada diferença significante para dor pós-operatória na maioria das comparações, nos períodos 24 h a 5 semanas, sendo que grupo laser atingiu o valor 0, 2 semanas antes. Ocorreu redução do edema, sem diferença estatisticamente significante para maioria das mensurações. Com base neste estudo, foi possível concluir que após a fototerapia com laser de baixa potência (LLLT) houve um ganho nos valores de todos os movimentos mandibulares, não houve diferença significante para ocorrência de edema e houve uma diminuição da ocorrência de dor. / The orthognathic surgery is the surgical procedure that aims to correct skeletal dentofacial deformities and can lead to decrease in jaw movements, pain and edema. A possible treatment for these consequences is the low-power laser phototherapy. The aim of this study was a longitudinal evaluation of jaw movements, pain and edema in patients undergoing orthognathic surgery bimaxillary after lowlevel laser light therapy (LLLT). We evaluated 30 patients divided into laser group (n=15) and control group (n=15) randomly. The laser group received postoperative laser therapy for 19 sessions. The control group received laser therapy placebo. The groups were compared regarding jaw movements - maximum aperture, laterality and maximum protrusion, pain - visual analog scale, edema - measured between cephalometric points in a period of 60 days after surgery. Statistical tests were applied to compare the groups (p <0.05). There was a significant difference for maximum aperture, laterality and maximum protrusion in periods of 14 to 60 days for most comparisons. There was a significant difference in postoperative pain in most comparisons, in the periods 24 h to 5 weeks, and laser group reached the value 0 a 2 weeks before. There was a reduction of edema, with no statistically significant difference for most measurements. Based on this study, it was concluded that after phototherapy with low power laser (LLLT) there was a gain in the amount of all mandibular movements, there was no significant difference in the occurrence of edema and there was a decrease in the occurrence of pain.

A infestação de pastagens por populações de Pteridium arachnoideum é um problema que afeta a pecuária, em diversas partes do mundo. Os efeitos deletérios da infestação pela planta sobre a bovinocultura são manifestados na forma de mortalidades e de redução das áreas de pastagens, assim como de perdas produtivas. Devido à importância dessas perdas na produção de bovinos, foi proposto o acompanhamento de uma propriedade do Rio Grande do Sul com problemas decorrentes da infestação pela planta em sua casuística e métodos de controle empregados. Adicionalmente, realizou-se teste da viabilidade de ovinos como ferramenta de controle biológico. Dos casos de intoxicação naturais acompanhados na propriedade, observou-se a ocorrência de quadro agudo de diátese hemorrágica e de quadro crônico de carcinomas do trato digestório superior. Observou-se que quando expostos a fatores predisponentes, como a introdução em áreas recentemente roçadas, os bovinos podem consumir altas doses da planta e assim desenvolver a enfermidade aguda em forma de surtos. Em diversos bovinos jovens com quadro de diátese hemorrágica, além das hemorragias disseminadas e infartos múltiplos, observou-se acentuado edema laríngeo, que cursava clinicamente com dispneia e estertores respiratórios característicos. Os carcinomas do trato digestório superior, apesar de menos frequentes, causaram expressivas perdas devido a mortalidades anuais de matrizes. A tentativa de controle pelo pastejo por ovinos não foi eficiente, devido ao consumo pouco expressivo na lotação praticada. Mortalidade de ovinos, no entanto, decorrente do consumo da planta não foi registrada. O método de combate à planta aplicado na propriedade combinava ou associava a roçagem em áreas densamente povoadas com o uso de herbicidas, nomeadamente metilsulfuron-metil e picloram, em todos os piquetes. A redução da cobertura da P. arachnoideum foi variada em diferentes piquetes; entretanto, possibilitou a recuperação de algumas áreas de pastejo. / The infestation of pastured areas by Pteridium arachnoideum populations has been a considerable and global problem to the livestock production. The deleterious effects of the plant infestation on cattle are manifested as animal mortality and pasture coverage reduction. Given the importance of P. arachnoideum in cattle production, it has been proposed to monitor a beef cattle farm in Rio Grande do Sul, to assess some of the losses associated with the plant consumption apart of the methods employed for controlling the plant. In addition, the viability of sheep’s grazing as a biological control tool was tested. Cases of natural poisoning observed in the farm included the acute form, known as hemorrhagic diathesis as well as the chronic form, consisting in digestive carcinomas. When cattle were exposed to any predisposing factor, such as being moved to newly mowed areas, it was noted that the amount of plant consumed can readily lead to an outbreak of acute poisoning. Several cases of hemorrhagic diathesis in young cattle went along with marked laryngeal edema, which was clinically manifested as dyspnea and roaring, in addition to the classic pathological changes of widespread hemorrhages and infarcts. Even though less frequent, carcinomas of the upper digestive tract caused significant losses, due to annual mortality of mature cows. The attempt through grazing by sheep wasn’t efficient to control P. aquilinum, due to the low consumption of the plant seen in the actual stocking. However, sheep mortality, by P. arachnoideum consumption was not recorded. The plant control method applied at the farm combined mowing of densely populated areas with herbicide applications, namely metilsulfuron-methyl and picloram, in all paddocks. The reduction of P. arachnoideum coverage was varied in different paddocks; however, allowed the recovery of some grazing areas.

Made available in DSpace on 2015-04-14T13:32:49Z (GMT). No. of bitstreams: 1 431587.pdf: 7377364 bytes, checksum: 67d08844621d0e31f41d7413cc729269 (MD5) Previous issue date: 2011-03-02 / Artigo 1: OBJETIVO: O joelho ? a articula??o mais frequentemente lesada durante a pr?tica de futebol por jovens atletas com idade entre 12 e 15 anos. A resson?ncia magn?tica (RM), por sua vez, ? um m?todo de imagem bastante acurado no diagn?stico de les?es relacionadas ao esporte. O objetivo deste estudo transversal de casos e controles foi avaliar os joelhos de jogadores de futebol adolescentes assintom?ticos utilizando uma resson?ncia magn?tica de campo aberto.M?TODOS: Foram avaliados 56 joelhos de 28 adolescentes assintom?ticos do sexo masculino com idade entre 14 e 15 anos. Os participantes foram divididos em dois grupos pareados por idade e peso: jogadores de futebol (28 joelhos) e controles (28 joelhos). Todos os exames foram realizados em uma RM de campo aberto com 0.35 tesla e avaliados por dois radiologistas experientes, cegados para os 2 grupos em estudo. As seguintes anormalidades forma acessadas: derrame articular; edema ?sseo medular; e anormalidades meniscais, ligamentares, tend?neas e cartilaginosas.RESULTADOS: No grupo de jogadores de futebol, 18 joelhos (64,2%) tinham uma ou mais altera??es ? RM, sendo que, no grupo controle, apenas nove joelhos (32,1%) tiveram uma ou mais anormalidade (p = 0,003). A preval?ncia de edema ?sseo medular foi maior no grupo de jogadores de futebol (14 joelhos, 50%), sendo detectada em apenas um joelho (3,5%) do grupo controle (p = 0,0001). Outras altera??es de imagem sem diferen?a estat?stica significativa foram encontradas nos dois grupos: edema coxim adiposo infrapatelar, cistos popl?teos e cistos gangli?nicos.CONCLUS?O: Edema ?sseo medular ? uma anormalidade prevalente encontrada na RM de joelho de jovens atletas jogadores de futebol. Os achados de RM devem ser interpretados com cautela e com estreita correla??o cl?nica.Artigo 2: OBJETIVO: A nata??o ? uma atividade esportiva amplamente difundida, sendo considerada uma forma ideal de exerc?cio, com pouco ou nenhum impacto sobre os joelhos. No entanto, les?es por microtrauma repetitivo ou uso excessivo podem frequentemente afetar a articula??o do joelho de jovens atletas nadadores de n?vel competitivo. As les?es iniciais geralmente s?o assintom?ticos por um per?odo de tempo consider?vel antes de causarem desconforto ou dor articular. O objetivo do presente estudo foi avaliar por resson?ncia magn?tica (RM) os joelhos de jovens atletas assintom?ticos nadadores de elite e compar?-los com um grupo controle pareado por idade e peso, que n?o pratica nenhum esporte de impacto regularmente.M?TODOS: Realizamos um estudo transversal controlado para avaliar 54 joelhos de 27 adolescentes assintom?ticos com 14 a 15 anos de idade, pareados por idade e peso. Os participantes foram divididos em dois grupos: 13 atletas nadadores de elite e 14 controles. Todos os exames foram realizados em uma RM de campo aberto com 0.35 tesla e avaliados por dois radiologistas experientes, cegados para os 2 grupos em estudo. As seguintes anormalidades forma acessadas: derrame articular; edema ?sseo medular; e anormalidades meniscais, ligamentares, tend?neas e cartilaginosas.RESULTADOS: Um ou mais achados de imagem anormais foram detectados em 18 joelhos do grupo de nadadores (69,2%, p = 0,013). Os achados mais prevalentes nos atletas de nata??o foram edema do coxim gorduroso infrapatelar (53,8%, p = 0,049), seguido de edema da medula ?ssea (26,9%, p = 0,022), edema da gordura pre-femoral (19%, p = 0,022) e derrame articular (15,3%, p = 0,047).CONCLUS?O: A preval?ncia de anormalidades de imagem detectadas pela RM foi significativamente maior nos joelhos dos adolescentes nadadores de elite. Esta alta preval?ncia de achados de imagem positivos em nadadores de elite assintom?ticos pode corresponder a altera??es benignas ou les?es pr?cl?nicas, que devem ser melhor avaliadas em um estudo longitudinal de seguimento.

Made available in DSpace on 2015-04-14T13:35:30Z (GMT). No. of bitstreams: 1 438181.pdf: 3961885 bytes, checksum: 1a2e9a9bcf3838013c6755da613f5eb7 (MD5) Previous issue date: 2012-03-30 / INTRODUCTION : Posterior Reversible Encephalopathy Syndrome (PRES) is a clinico-radiological entity that presents with headache, altered mental status, seizure and visual disturbance and is associated with a reversible probably vasogenic edema, predominantly in occipital and parietal lobes. The precise physiopathology remains unclear and there isn t an experimental model of this disorder. OBJECTIVES : The objectives of this paper were (1) the clinical and radiological evaluation of patients with PRES in the Hospital S?o Lucas-PUCRS and (2) the development of a translational model based on clinical features that mimetize this syndrome in pregnants Wistar rats. METHODS : It was performed a review of clinical data, neuroimage and blood basic test of 25 patients with PRES, that were followed in Hospital S?o Lucas-PUCRS in the period from March 15 of 2007 to September 15 of 2011. Based on clinical features and neuroimagem findings, we developed a rat model of PRES using pregnant Wistar rats, which were submitted to a reduction of uterine pressure perfusion (RUPP), measurement of arterial blood pressure with an invasive catheter and a brain anatomo-pathologic study, after Evans s blue venous infusion to verify the permeability of the blood-brain-barrier. RESULTS : Our clinical sample consisted of 25 patients (4 men and 21 women) with mean age of 27,84 years old (range from 2 to 74 years old). The most common causes of PRES reported in this series were associated with pregnant situations that occurred in 11 cases (44%). The symptom more commonly reported was headache in 18 patients (72%). The occipital lobe was the most common topography of the magnetic ressonance abnormality (edema) and occurred in 23 cases (92%). The highest value of the systolic blood pressure presented the mean of 176 mmHg and the highest value of the diastolic blood pressure presented the mean of 95,2 mmHg. Animals submitted to RUPP to simulate the PRES presented increase of the blood-brain-barrier permeability and elevation of blood pressure, when compared with the control animals. CONCLUSION : In our series, PRES occurred predominantly in women and the most frequent triggers were obstetric causes; headache was the most common symptom and the neuroimage findings showed a predominance of posterior alteration suggesting a vasogenic edema due a breakdown of blood brain barrier. The experimental rat model was developed based on these clinical observations, so, we used pregnant rats submitted to reduction of uterine pressure perfusion. We identified in these animals increase of blood pressure and a breakdown of blood brain barrier corroborating to establish an experimental model of PRES. We believe that an experimental model of PRES could be important for future studies allowing a better comprehension of this syndrome. / INTRODU??O : A S?ndrome Encefalopatia Revers?vel Posterior (Posterior Reversible Encephalopathy Syndrome PRES) ? uma entidade clinico-radiol?gica caracterizada por cefal?ia, altera??o do n?vel de consci?ncia, crises convulsivas e altera??o visual e est? associado a um edema provavelmente vasog?nico na subst?ncia branca encef?lica, predominantemente afetando os lobos occipitais e parietais. A fisiopatogenia do PRES permanece desconhecida e n?o existe um modelo experimental de tal dist?rbio. OBJETIVOS : O objetivo desse trabalho ? avaliar apresenta??o cl?nica juntamente com os exames de neuroimagem realizados por pacientes com S?ndrome da Encefalopatia Revers?vel Posterior no Hospital S?o Lucas-PUCRS e baseado nos achados cl?nicos desenvolver um modelo translacional que mimetize essa s?ndrome em ratos Wistar. M?TODOS : Foram revisados os prontu?rio juntamente com os exames de neuroimagem e laboratoriais de 25 pacientes portadores da s?ndrome da encefalopatia revers?vel posterior, os quais foram atendidos no Hospital S?o Lucas-PUCRS no per?odo de 15 de mar?o de 2007 ? 15 de setembro de 2011. A partir das caracter?sticas cl?nicas e de neuroimagem analisadas nesta pesquisa desenvolvemos modelo experimental de PRES com o uso de ratas Wistar gestantes, as quais foram submetidas ? redu??o da press?o de perfus?o uterina (RUPP do ingl?s Reduction of Uterine Pressure Perfusion), medida de press?o arterial invasiva e estudo anatomopatol?gico dos enc?falos dos animais, ap?s infus?o venosa de azul de Evans para avalia??o da permeabilidade da barreira hemato-encef?lica. RESULTADOS : Dos 25 pacientes com PRES analisados com idade m?dia de 27,84 anos (variando de 2 anos a 74 anos), 4 eram homens e 21 mulheres. As causas e/ou desencadeadores mais comumente encontrados foram de origem obst?tricas em 11 casos (44%). O sintoma mais freq?entemente referido foi cefal?ia em 18 pacientes (72%). A topografia mais comumente acometida pelo edema gerado pelo PRES foi occipital em 23 pacientes (92%). O valor da press?o arterial sist?lica m?xima em m?dia foi de 176 mmHg e a press?o arterial diast?lica m?xima em m?dia foi de 95,2 mmHg. Os animais submetidos ao modelo experimental proposto atrav?s do procedimento RUPP para mimetizar o PRES apresentaram altera??es de permeabilidade da barreira hematoencef?lica e eleva??o da press?o arterial quando comparado aos animais controles. CONCLUS?O : Na nossa casu?stica o PRES foi nitidamente predominante em mulheres, os fatores desencadeantes/causais mais frequentes foram os de origem obst?trica, predominando a cefaleia como sintoma; os exames de neuro-imagem confirmaram o predom?nio posterior das altera??es estruturais e sugerem serem decorrentes de edema vasog?nico com quebra da barreira hematoencef?lica. O modelo experimental em ratos Wistar foi desenvolvido baseado nestas observa??es cl?nicas motivo pelo qual utilizamos ratas gestante submetidas a redu??o da press?o de perfus?o uterina. Identificamos nestes animais a quebra da barreira hematoencef?lica corroborando para o estabelecimento do modelo experimental do PRES, o qual pensamos que possa ser de fundamental import?ncia para estudos posteriores que permitam uma melhor compreens?o desta s?ndrome.

Our brain, perhaps the most sophisticated and mysterious part of the human body, to some extent, determines who we are. However, it’s a vulnerable organ. When subjected to an impact, such as a traffic accident or sport, it may lead to traumatic brain injury (TBI) which can have devastating effects for those who suffer the injury. Despite lots of efforts have been put into primary injury prevention, the number of TBIs is still on an unacceptable high level in a global perspective. Brain edema is a major neurological complication of moderate and severe TBI, which consists of an abnormal accumulation of fluid within the brain parenchyma. Clinically, local and minor edema may be treated conservatively only by observation, where the treatment of choice usually follows evidence-based practice. In the first study, the gravitational force is suggested to have a significant impact on the pressure of the edema zone in the brain tissue. Thus, the objective of the study was to investigate the significance of head position on edema at the posterior part of the brain using a Finite Element (FE) model. The model revealed that water content (WC) increment at the edema zone remained nearly identical for both supine and prone positions. However, the interstitial fluid pressure (IFP) inside the edema zone decreased around 15% by having the head in a prone position compared with a supine position. The decrease of IFP inside the edema zone by changing patient position from supine to prone has the potential to alleviate the damage to axonal fibers of the central nervous system. These observations suggest that considering the patient’s head position during intensive care and at rehabilitation should be of importance to the treatment of edematous regions in TBI patients. In TBI patients with diffuse brain edema, for most severe cases with refractory intracranial hypertension, decompressive craniotomy (DC) is performed as an ultimate therapy. However, a complete consensus on its effectiveness has not been achieved due to the high levels of severe disability and persistent vegetative state found in the patients treated with DC. DC allows expansion of the swollen brain outside the skull, thereby having the potential in reducing the Intracranial Pressure (ICP). However, the treatment causes stretching of the axons and may contribute to the unfavorable outcome of the patients. The second study aimed at quantifying the stretching and WC in the brain tissue due to the neurosurgical intervention to provide more insight into the effects upon such a treatment. A nonlinear registration method was used to quantify the strain. Our analysis showed a substantial increase of the strain level in the brain tissue close to the treated side of DC compared to before the treatment. Also, the WC was related to specific gravity (SG), which in turn was related to the Hounsfield unit (HU) value in the Computerized Tomography (CT) images by a photoelectric correction according to the chemical composition of the brain tissue. The overall WC of brain tissue presented a significant increase after the treatment compared to the condition seen before the treatment. It is suggested that a quantitative model, which characterizes the stretching and WC of the brain tissue both before as well as after DC, may clarify some of the potential problems with such a treatment. Diffusion Weighted (DW) Imaging technology provides a noninvasive way to extract axonal fiber tracts in the brain. The aim of the third study, as an extension to the second study was to assess and quantify the axonal deformation (i.e. stretching and shearing)at both the pre- and post-craniotomy periods in order to provide more insight into the mechanical effects on the axonal fibers due to DC. Subarachnoid injection of artificial cerebrospinal fluid (CSF) into the CSF system is widely used in neurological practice to gain information on CSF dynamics. Mathematical models are important for a better understanding of the underlying mechanisms. Despite the critical importance of the parameters for accurate modeling, there is a substantial variation in the poroelastic constants used in the literature due to the difficulties in determining material properties of brain tissue. In the fourth study, we developed a Finite Element (FE) model including the whole brain-CSF-skull system to study the CSF dynamics during constant-rate infusion. We investigated the capacity of the current model to predict the steady state of the mean ICP. For transient analysis, rather than accurately fit the infusion curve to the experimental data, we placed more emphasis on studying the influences of each of the poroelastic parameters due to the aforementioned inconsistency in the poroelastic constants for brain tissue. It was found that the value of the specific storage term S_epsilon is the dominant factor that influences the infusion curve, and the drained Young’s modulus E was identified as the dominant parameter second to S_epsilon. Based on the simulated infusion curves from the FE model, Artificial Neural Network (ANN) was used to find an optimized parameter set that best fit the experimental curve. The infusion curves from both the FE simulations and using ANN confirmed the limitation of linear poroelasticity in modeling the transient constant-rate infusion. To summarize, the work done in this thesis is to introduce FE Modeling and imaging technologiesincluding CT, DW imaging, and image registration method as a complementarytechnique for clinical diagnosis and treatment of TBI patients. Hopefully, the result mayto some extent improve the understanding of these clinical problems and improve theirmedical treatments. / QC 20120201

Multiple modulating genes and environmental factors have been implicated in the pathogenesis of high-altitude pulmonary edema (HAPE). However, at the present time, there exists an incomplete understanding of the molecular mechanisms and pathways which underlie constitutional susceptibility. Genome-wide measurements of gene expression in peripheral blood mononuclear cells (PBMCs) were performed using microarray technology. Comparison of gene expression profiles of HAPE-susceptible and resistant individuals resulted in the identification of several previously undescribed candidate genes. RhoA and Rho-kinase (ROCK), regulators of vascular smooth muscle contraction, were differentially regulated in the HAPE-susceptible cohort, as compared to both HAPE-resistant patients with acute mountain sickness (AMS+) and healthy controls (p=0.0014; p=0.0020). Furthermore, biological pathways involving RhoA and Rho-kinase were strongly upregulated in subjects with HAPE. These findings represent the first description of the RhoA/Rho-kinase signaling pathway in HAPE. Currently, few pharmacologic therapies have been demonstrated to be effective in the prevention and treatment of HAPE. The results of this study provide early evidence that Fasudil, a selective Rho-kinase inhibitor, may represent a novel therapeutic intervention effective in the prevention and/or treatment of high-altitude pulmonary edema.

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