Dynamics of the content of reactive oxygen species and the state of the glutathione system in the oral cavity during subchronic intoxication wuth the fungicide thiram and its antioxidant correction.

Thiram is a dithiocarbamate derivative, which is used as a fungicide for seed dressing and spraying during the vegetation period of plants, and also as an active vulcanization accelerator in the production of rubber-based rubber products. In this study the content of reactive oxygen species (ROS) and the state of the glutathione system have been investigated in the oral fluid and gum tissues of adult male Wistar rats treated with thiram for 28 days during its administration with food at a dose of 1/50 LD50. Thiram induced formation of ROS in the oral cavity; this was accompanied by an imbalance in the ratio of reduced and oxidized forms of glutathione due to a decrease in glutathione and an increase in its oxidized form as compared to the control.

[Specific aspects of the reflection of signal frequency structure in the peripheral compartment of acoustic analyzer in health state and disease].

How frequency structure of the signals is reflected at the exit of the model of acoustic system peripheral compartment was investigated. The system incorporated mechanisms of local feedback by microphone and overall potentials. Defects in the work of the feedback mechanisms lead to substantial deformation of sound reflection at the model exit.

[Ways of using digital signal processing for expanding the potentials of hearing aids].

Compared to analog hearing aids (HA), digital HA provide not only signal transformation but also adaptive filtration and reconstruction of the signals. This allows better speech perception in noisy surroundings for patients with neurosensory hypoacusis and recovery of speech perception in persons with partial frequency deafness. The design of digital hearing aids requires utilization of effective signal processors with signal memory.

[Effect of microphone potential feedback on formation of adjusted curves of the hearing periphery].

The model of the formation of the exiting factor on the neuron endings of the cochlear nerve taking into consideration the feedback mechanisms described in recent experimental investigations is proposed. It is shown that the functioning of the feedback in the model give the possibility to explain the principle of action of the mechanism of enhancement of mechanical duct tuning which produce exquisite tuning, reflected in the tuning properties of cochlear nerve fibers. At the same time the utilisation in the model the mechanism of the lateral inhibition provide it the property similar to the effect of inhibition of the neurone response to a given tone signal when another tone signal arises in a nearby frequency region.