RESUMO
Two cases of spinal tuberculosis in atypical regions are presented; in the lumbosacral hinge and cranio-cervical regions respectively; focusing on the radiological appearance using Computed Tomography (CT) and Magnetic Resonance. With regard to these atypical presentations, the clinical history, epidemiology and radiology of spinal tuberculosis are reviewed.
Se presentan dos casos de tuberculosis espinal en localizaciones atípicas; la charnela lumbo-sacra y cráneo-cervical respectivamente; centrándonos en su aspecto radiológico por tomografía computarizada (TC) y resonancia magnética. A propósito de estas atípicas presentaciones se revisa la clínica, epidemiología y radiología de la tuberculosis en la columna vertebral.
Assuntos
Humanos , Masculino , Adulto , Feminino , Idoso de 80 Anos ou mais , Imageamento por Ressonância Magnética , Tomografia Computadorizada por Raios X , Tuberculose da Coluna Vertebral/diagnósticoRESUMO
Ion channel gating kinetics can be described using Kramers' diffusion theory of reaction rates between several closed and open states, where transition rates between states depend exponentially on the membrane potential V. It has been suggested that transition rates have a more complex dependence on V at voltage extremes, but this has never been quantified. We measured the rate constant of the last closed to open transition in a voltage-gated ion channel and show that it does not depend exponentially on membrane potential at values of V greater than ≈150 mV. To explain this behavior, we estimate the effects of electrical polarization of the water contained in crevices within the channel protein, using an electrostatic model of the approximate three-dimensional geometry and the nonlinear effects of charges on the polarization of water.