Submitted on October 27, 2003
Accepted on January 13, 2005
Temporal Nitric Oxide Dynamics in the Paranasal Sinuses during Humming
Lars Menzel1, Alexander Hess2, Wilhelm Bloch3*, Olaf Michel2, Klaus-Dieter Schuster4, Ralph Gabler5, and Wolfgang Urban1
1 Department of Applied Physics, University of Bonn, Bonn, NRW, Germany
2 Department of Oto-Rhino-Laryngology, University of Cologne, Cologne, NRW, Germany
3 Department of Molecular and Cellular Sport Medicine, German Sport University, Cologne, NRW, Germany
4 Institute of Physiology I, University of Bonn, Cologne, NRW, Germany
5 Department of Applied Physics, University of Bonn, Bonn, NRW, Germany; INVIVO GmbH, Adelzhausen, Bayern, Germany
* To whom correspondence should be addressed. E-mail: wilhelm.bloch{at}uni-koeln.de.
In this study the temporal shape of voice-induced NO signals in exhaled air has been investigated on eight healthy individuals by means of laser-magnetic-resonance-spectroscopy (LMRS). The results of the experimental part have been compared with calculated signals obtained by using a simple one-compartment-model of the paranasal sinuses. In the experimental part a rapidly increasing NO concentration has been found when the subjects started humming. After reaching a maximum the emission starts to decrease with the shape of an exponential decay and finally reaches a constant level. The time constant of this decay (NO washout) is 3.0 ±1.2s. The peak height of the NO emission during humming increases when the time between two humming processes increases. When no voice induced NO emission takes place the NO concentration in the paranasal sinuses rebuilds again to a maximum
concentration. The typical time constant for the NO recovery is 4.5±3.2min. A three-compartment-model defining exactly the geometry and anatomy of the paranasal sinuses has been developed which is based on three main assumptions of the NO dynamics: A) Constant NO production of the epithelium in the sinuses. B) The rate of the chemical reaction of NO with the epithelium of the paranasal sinuses is proportional to the NO concentration. C) The emission of NO from the sinuses (volume/sec) is proportional to the NO concentration. It is shown that the three-compartment model under the experimental conditions can be reduced to a one compartment model which describes the complete temporal behaviour of the NO exchange.
