The intracranial dura mater is a thick meningeal barrier of connective tissue located between the skull and leptomeninges. This meninx can be divided into three layers: the periosteal (external), the meningeal (internal), and the subdural neurothelium. Such layers are well joined, separated only in the venous sinuses and the cerebral falx (Haines, 1991).

http://dx.doi.org/10.5007/2175-7925.2016v29n3p35Dentre os bichos-preguiça, pode-se destacar a espécie Bradypus variegatus, encontrada especialmente no Nordeste brasileiro. Diante da importância e escassez de informações acerca do sistema digestório de animais silvestres, o objetivo deste artigo é descrever a morfologia dos dentes dessa espécie de preguiça. Para tal, foram utilizados quatro animais adultos, pertencentes ao acervo de anatomia do Centro Acadêmico de Vitória de Santo Antão da Universidade Federal de Pernambuco (UFPE). Os dentes das preguiças foram analisados, retirados das arcadas e, em seguida, submetidos a duas técnicas de preparação histológica de tecido duro, desgaste e descalcificação. As lâminas obtidas foram analisadas em microscópio óptico. As preguiças têm 18 dentes molariformes, com cúspides e espaços interdentais. De acordo com a análise histológica, percebeu-se que os dentes não possuem esmalte, sendo compostos por 1 camada espessa de cemento e 2 camadas de dentina, uma externa e outra interna. A polpa apresenta um aspecto semelhante à humana. Pôde-se constatar, ainda, a presença de ligamento periodontal espesso e vascularizado entre o dente e o osso alveolar, este último com ósteons facilmente identificados.

Objective: To identify the electrical parameters of transcranial direct current stimulation (tDCS) that effectively alter cerebral blood flow in rats. Methodology: Six eletronic databases were searched with no time or language restrictions to identify experimental studies with rats using tDCS with anodal and/or cathodal stimulation with or without a comparison group. Internal validity was assessed via the following criteria: housing, lighting, temperature, water/food, groups randomization and ethical aspects. The ‘Laboratory Systematic Review Center for Laboratory animal Experimentation’ (SYRCLE) tool was used to assess risk of bias. The tDCS electrical parameters and cerebral blood flow were considered as primary outcomes and cerebral histological alterations as the secondary outcome. Results: Four articles were included. All four studies were considered to present a high level of scientific bias. The electrical tDCS parameters implemented were heterogeneous but overall, tDCS with anodal stimulation promoted an increase in cerebral blood flow while the cathodal stimulation decreased it. Cerebral histological alterations were assessed in two studies and tissue necrosis was reported in only one animal per study. Conclusion: The identification of tDCS electrical parameters that effectively alter cerebral blood flow in rats was not possible due to the heterogeneity of tDCS protocols being implemented in the literature. Considering the high risk of scientific bias in the included studies, the current available evidence regarding tDCS efficacy is insufficient and inconclusive.

There is a plethora of articles dealing with the use of triptans to treat migraine, but so far no unanimity exists regarding the optimal form of using this group of drugs in a patient with recurrent attacks of migraine. Although all of them may exert their pharmacological effects through a known specific mechanism of action, i.e. agonist effects on serotonin 5-HT (1B/1D) receptors, distinct differences exist. The author comment a few facts on the prescription of triptans and possible adverse effects, depending on the clinical scenario. Thus, even though an enormous amount of information has accumulated over the last few decades on triptans, several questions remain to be answered, and research priorities need to be addressed.

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