ABSTRACT
Objective We developed an in vitro model for vasospasm post subarachnoid hemorrhage that was suitable for investigating brain vessel autoregulation. We further investigated the effects of iodinated contrast medium on the vascular tone and the myogenic response of spastic cerebral vessels. Method We isolated and perfused the superior cerebellar arteries of rats. The vessels were pressurized and studied under isobaric conditions. Coagulated blood was used to simulate subarachnoid hemorrhage. The contrast medium iodixanol was applied intraluminally. Results Vessels exposed to blood developed significantly stronger myogenic tone (65.7 ± 2.0% vs 77.1 ± 1.2% of the maximum diameter, for the blood and the control group, respectively) and significantly decreased myogenic response, compared with the control groups. The contrast medium did not worsen the myogenic tone or the myogenic response in any group. Conclusion Our results show that deranged myogenic response may contribute to cerebral blood flow disturbances subsequent to subarachnoid hemorrhage. The contrast medium did not have any negative influence on vessel tone or myogenic response in this experimental setting. .
Objetivo Desenvolvemos um modelo in vitro para vasoespasmo subsequente à hemorragia subaracnóide que foi adequado para investigar a autorregularão dos vasos cerebrais. Em seguida investigamos os efeitos o meio de contraste iodado no tônus vascular e na resposta miogênica dos vasos cerebrais espásticos. Método Isolamos e perfundimos as artérias cerebelares superiores de ratos. Os vasos foram pressurizados e estudados em condições isobáricas. Sangue coagulado foi utilizado para simular hemorragia subaracnóide. O meio de contraste iodixanol foi aplicado intraluminarmente. Resultados Os vasos expostos ao sangue desenvolveram aumento significativo do tônus miogênico (65.7 ± 2.0% vs 77.1 ± 1.2% do maior diâmetro, para o grupo de sangue e o grupo controle, respectivamente) com resposta miogênica significativamente menor do que aquela dos controles. O meio de contraste iodado não piorou o tônus miogênico ou a resposta miogênica em nenhum dos grupos. Conclusão Nossos resultados mostram que uma resposta miogênica pode contribuir para as alterações de fluxo sanguíneo cerebral subsequentes à hemorragia subaracnóide. O meio de contraste iodado não teve nenhuma influência negativa no tônus vascular ou na resposta miogênica neste modelo experimental. .
Subject(s)
Adult , Child , Child, Preschool , Female , Humans , Male , Attention , Language Development , Phonetics , Speech Perception , Reference Values , Sound Spectrography , Speech AcousticsABSTRACT
A microneurografia foi usada para investigar a atividade simpática periférica (ASP) em 25 indivíduos hipertensos, investigados quanto à presença de compressão neurovascular (CNV) no bulbo com a técnica de ressonância magnética (RM). De acordo com a RM, foram formados três grupos: CNV-, sem sinais de CNV (n=9); CNV Tipo I, com imagem vascular junto ao bulbo mas sem deformação anatômica (n=8); e CNV Tipo II, com imagem vascular causando compressão no bulbo (N=8). O grupo CNV Tipo II apresentou ASP mais elevada que os grupos CNV Tipo I e CNV-, tanto no repouso, quanto após estímulos hipotérmico e exercício isométrico. A demonstração de ASP diferenciada dependendo do tipo de CNV é um fato importante, pois pode identificar um subgrupo de hipertensos nos quais a CNV possa ter alguma implicação fisiopatológica.Sympathetic activity in hypertension with neurovascular compression in humans. /Microneurography was used to measure peripheral muscle sympathetic nerve activity (MSNA) in 25 subjects with hypertension, who were submitted to magnetic resonance imaging (MRI) to detect neurovascular compression (NVC) at the medulla. Three groups were formed according to MRI: NVC-, without signs of NVC (N=9); NVC Type I, with a vessel nearby medulla but not compressing it (N=8); NVC Type II, with a vessel compressing the medulla (N=8). Group NVC Type II had higher MSNA than other groups during rest period and after stimuli with cold and isometric exercise. These results show different values of PSA in subjects with different findings of NVC, and are important to the identification of subgroups whose image of NVC really have clinical relevance...
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Hypertension/physiopathology , Sympathetic Nervous System/physiopathology , Case-Control Studies , Magnetic Resonance Imaging/methodsABSTRACT
Plasmacytomas are tumors that may arise in a wide variety of locations, because of the universal distribution of plasma cells. They are rare within the cranial vault and rarely present as extramedullary lesions, arising from the intracranial soft tissues usually without affecting neighboring bony structures. The presentation may resemble a meningioma, both clinically and radiologically. The most commonly recommended therapeutic strategy is complete surgical resection followed by radiotherapy. We report a case of a 47 -years-old man presenting with a median parietal plasmacytoma, submitted to subtotal surgical resection and radiotherapy, with good results