O HIPOTÁLAMO DORSOMEDIAL E A ORGANIZAÇÃO DA RESPOSTA CARDIOVASCULAR AO ESTRESSE EMOCIONAL: UMA PERSPECTIVA FUNCIONAL

Emotional stress results in activation of specific pathways into central nervous system, which produces autonomic, behavioral and endocrine responses. It is known that repetitive or continuous exposition to stress situations may result in various pathologic states, for example, arterial hypertension. Classically, the hypothalamus plays an essential role in the integration of physiological responses to emotional stress. Recent studies demonstrate that a specific nucleus from hypothalamus, the dorsomedial hypothalamus (DMH), is an essential component of central pathways that mediate the cardiovascular response to emotional stress. Inhibition of neurons in this area reduces the increases in heart rate and blood pressure in rats submitted to emotional stress paradigms. Conversely, pharmacological activation of DMH neurons evokes increases on heart rate, blood pressure, adrenocorticotrophic hormone, locomotor activity and sympathetic activity. The similarity of this response with that produced during emotional stress suggests that this area is crucial in the integration of the physiological responses to emotional stress. The present review will discuss the central pathways used by DMH in the organization of the cardiovascular response to emotional stress.O estresse emocional resulta em ativação de vias específicas do sistema nervoso central, que produzem respostas autonômicas, comportamentais e endócrinas. Sabe-se que situações de estresse recorrentes ou prolongadas podem resultar em vários estados patológicos, como por exemplo, a hipertensão arterial. O Hipotálamo tem papel fundamental na integração das respostas fisiológicas ao estresse emocional. Particularmente, estudos têm mostrado que um núcleo específico do hipotálamo, o hipotálamo dorsomedial (DMH), é um componente fundamental das vias centrais mediadoras das respostas cardiovasculares ao estresse emocional. A inibição dos neurônios dessa área reduz os aumentos de freqüência cardíaca e de pressão arterial em ratos quando submetidos à situações de estresse emocional. Ao contrário, a ativação farmacológica dos neurônios do DMH produz aumento na frequência cardíaca, pressão arterial, hormônio adrenocorticotrópico (ACTH), atividade locomotora e na atividade simpática para diversos leitos vasculares. A similaridade dessa resposta com aquela produzida durante a situação real de estresse emocional sugere que esta área é fundamental na integração da resposta fisiológica ao estresse. A presente revisão tem como objetivo mostrar, através de resultados de estudos recentes, as vias centrais utilizadas pelo DMH na organização da resposta cardiovascular ao estresse emocional

Pure endoscopic endonasal odontoidectomy: anatomical study

Different disorders may produce irreducible atlanto-axial dislocation with compression of the ventral spinal cord. Among the surgical approaches available for a such condition, the transoral resection of the odontoid process is the most often used. The aim of this anatomical study is to demonstrate the possibility of an anterior cervico-medullary decompression through an endoscopic endonasal approach. Three fresh cadaver heads were used. A modified endonasal endoscopic approach was made in all cases. Endoscopic dissections were performed using a rigid endoscope, 4 mm in diameter, 18 cm in length, with 0 degree lenses. Access to the cranio-vertebral junction was possible using a lower trajectory, when compared to that necessary for the sellar region. The choana is entered and the mucosa of the rhinopharynx is dissected and transposed in the oral cavity in order to expose the cranio-vertebral junction and to obtain a mucosal flap useful for the closure. The anterior arch of the atlas and the odontoid process of C2 are removed, thus exposing the dura mater. The endoscopic endonasal approach could be a valid alternative to the transoral approach for anterior odontoidectomy

Cloning approach and functional analysis of anti-intimin single-chain variable fragment (scFv)

<p>Abstract</p> <p>Background</p> <p>Intimin is an important virulence factor involved in the pathogenesis of enteropathogenic <it>Escherichia coli </it>(EPEC) and enterohemorrhagic <it>Escherichia coli </it>(EHEC). Both pathogens are still important causes of diarrhea in children and adults in many developing and industrialized countries. Considering the fact that antibodies are important tools in the detection of various pathogens, an anti-intimin IgG2b monoclonal antibody was previously raised in immunized mice with the conserved sequence of the intimin molecule (int_388-667). In immunoblotting assays, this monoclonal antibody showed excellent specificity. Despite good performance, the monoclonal antibody failed to detect some EPEC and EHEC isolates harboring variant amino acids within the 338-667 regions of intimin molecules. Consequently, motivated by its use for diagnosis purposes, in this study we aimed to the cloning and expression of the single-chain variable fragment from this monoclonal antibody (scFv).</p> <p>Findings</p> <p>Anti-intimin hybridoma mRNA was extracted and reversely transcripted to cDNA, and the light and heavy chains of the variable fragment of the antibody were amplified using commercial primers. The amplified chains were cloned into <it>pGEM-T Easy </it>vector. Specific primers were designed and used in an amplification and chain linkage strategy, obtaining the scFv, which in turn was cloned into pAE vector. <it>E. coli </it>BL21(DE3)pLys strain was transformed with pAE scFv-intimin plasmid and subjected to induction of protein expression. Anti-intimin scFv, expressed as inclusion bodies (insoluble fraction), was denatured, purified and submitted to refolding. The protein yield was 1 mg protein per 100 mL of bacterial culture. To test the functionality of the scFv, ELISA and immunofluorescence assays were performed, showing that 275 ng of scFv reacted with 2 mg of purified intimin, resulting in an absorbance of 0.75 at 492 nm. The immunofluorescence assay showed a strong reactivity with EPEC E2348/69.</p> <p>Conclusion</p> <p>This study demonstrated that the recombinant anti-intimin antibody obtained is able to recognize the conserved region of intimin (Int_388-667) in purified form and the EPEC isolate.</p