Pathomorphological peculiarities of damage to hair cells of the organ of corti in experimental sensorineural hearing loss.

Pathomorphology of the organ of Corti was studied on models of acute and chronic sensorineural damage to the acoustic analyzer. Peculiarities of hair cell degeneration, necrosis, and apoptosis in the organ were studied by light and scanning electron microscopy. The type of pathomorphological substrate in abnormalities of the organ of Corti depends on the intensity of the destructive exposure, but not on the nature of otopathological factors.

Protective effect of carnosine on excitable structures of the auditory apparatus in albino rats with acute acoustic trauma.

We studied the effect of natural antioxidant carnosine on Wistar rats with experimental acoustic trauma of the auditory apparatus. Repeated intraperitoneal injection of carnosine in a dose of 200 mg/kg 12 and 0.5 h before modeling of acute acoustic trauma decreased the severity of degenerative and atrophic changes in the nuclei of hair cells in the cochleae.

[General pathological aspects of the hair cells damage in spiral organ].

The information concerning general pathological changes in hair cells of the spiral organ is reviewed. The conditions for the onset, morphological picture of dystrophy, necrosis, apoptosis typical for hair cells in respect to structural and functional features of the sensory epithelium of the spiral organ are outlined. Nonspecific morphological changes of the spiral organ neuroepithelium after the action of damaging agents of different origin (such ototoxic drugs as aminoglycoside antibiotics and others, intensive acoustic impacts, ageing of the acoustic analyzer) are emphasized.

[The condition of the auditory tube in patients with chronic purulent otitis media as shown by computed tomography].

Computed tomography (CT) was made in 25 patients with otitis media purulenta chronica (OMPC). Of them 17 patients had meso- or mesoepitympanitis and 8 patients had the history of radical operations on the ear. At first, CT was made of the temporal bone without contrast medium, then with instillation of the contrast medium through the external acoustic meatus and tympanic cavity into the auditory tube.

Protective effect of calcium channel blocker verapamil on morphological and functional state of hair cells of the organ of corti in experimental kanamycin-induced ototoxicity.

The protective effect of verapamil against acute ototoxic sensorineural damage produced by intraperitoneal injections of kanamycin (50 mg/kg daily for 14 day) was studied on rats. The functional (otoacoustic emission), histological, and physiological methods proved the protective effect of daily injections of calcium channel blocker verapamil (2 mg/kg) on the state of hair cells of the organ of Corti.

[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.

[Low-intensity laser irradiation in otorhinolaryngology].

Low-intensity laser irradiation is a modality widely practiced in otorhinolaryngology. Basing on extensive personal experience and literature data the authors provide ENT specialists with relevant techniques and parameters of the radiation for different otorhinolaryngological diseases.

[Diagnosis of peripheral diseases of the facial nerve].

Work-up of 120 patients with peripheral facial paresis included evaluation of spontaneous and reflex lacrimal secretion, electrogustometry, impedance, tonal and supraliminal tonal audiometry. Symptom complexes for different by severity nerve lesions are specified. In patients with basilar skull fractures 3 types of postdenervation syndromes were observed: atropine salivary paradox, paradoxical facial hyperemia, crocodile tears.

[Problems of diagnosis and treatment of atypical mastoiditis].

The specific features of the diagnosis and therapy of the dry form of atypical mastoiditis are discussed. Of great diagnostic importance were local changes in the mastoid area, otoscopic signs in the posterior-superior tympanic membrane and bone compartment of the auditory meatus, hearing impairment, thermographic signs of purulent-destructive lesions in the antrum and other cells of the mastoid process, and X-ray symptoms of bone destruction of the mastoid process. It is obvious that the clinical picture and development of atypical mastoiditis are closely related to the age and reactivity of the patient, irrational use of antibiotics and physiotherapy, concomitant diseases, especially endocrine pathologies.

[Device for measuring the acoustic impedance of the middle ear].

There exists a direct proportional relation between the acoustic impedance of the tympanic membrane and static pressure in the external acoustic duct. This relation forms the basis of the UM-01 device which enables the acoustic impedance to be determined and allows it to judge from its magnitude on the condition of the sound-conducting sector of the auditory analyser. The device is simple to handle and does not require any balancing of the measuring portion in the circuit.