Anesthesiology
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Comparative Study
Comparison of thoracic epidural pressure in the sitting and lateral decubitus positions.
The hanging drop technique identifies the epidural space using the negative pressure of this space. Although the hanging drop technique is popular at the thoracic level, there is still controversy on the negative epidural pressure at this level. The authors hypothesized that the epidural pressure is more consistently negative in the sitting position than in the lateral decubitus position at the thoracic level. ⋯ The thoracic epidural pressure is more negative in the sitting position than in the lateral decubitus position. These results suggest that the patient should be sitting when the hanging drop technique is used to identify the epidural space.
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Comparative Study
Cholinesterase inhibitor donepezil dilates cerebral parenchymal arterioles via the activation of neuronal nitric oxide synthase.
An acetylcholinesterase inhibitor donepezil currently is used to treat patients with Alzheimer disease. However, its direct effect on cerebral blood vessels has not been evaluated. The present study was designed to examine whether donepezil induces acute cerebral arteriolar dilation and whether neuronal nitric oxide synthase contributes to this vasodilator response. ⋯ Donepezil produces acute vasodilation induced by a selective activation of neuronal nitric oxide synthase in the cerebral parenchymal arterioles. This agent may be capable of enhancing this enzymatic activity directly or via acetylcholinesterase existing on the arteriolar wall.
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The advent of oxygenic photosynthesis and the accumulation of oxygen in our atmosphere opened up new possibilities for the development of life on Earth. The availability of oxygen, the most capable electron acceptor on our planet, allowed the development of highly efficient energy production from oxidative phosphorylation, which shaped the evolutionary development of aerobic life forms from the first multicellular organisms to the vertebrates.