A new model for investigating hair cell degeneration in the guinea pig following damage of the stria vascularis using a photochemical reaction.

We have established a new model for investigating the relationship between cochlear lateral wall damage and sensory cell degeneration in guinea pigs by using a photochemical reaction between the systemic injection of Rose Bengal (RB) and controlled green light irradiation to the cochlea. The photochemical reaction produced a reactive oxygen species, which then damaged the endothelium. This triggered platelet adhesion and aggregation at the site of endothelial injury to produce thrombi and affect microcirculation in the lateral wall at the site of irradiation. Changes were studied under a scanning electron microscope (SEM), and compound action potentials (CAP) were measured. SEM observations after tangential illumination of the cochlear wall revealed degeneration of the stria vascularis (SV). Specific morphological findings at 24 h included delayed degeneration of the outer hair cells concurrent with a significant increase in the CAP. Based on these findings, we suggest that degeneration of the SV was a direct result of the photochemical reaction, but CAP changes and sensory hair cell damage were secondarily caused by SV degeneration.

Hereditary sensorineural hearing loss of unknown cause involving mitochondrial DNA 1555 mutation.

We report on a family with maternally inherited sensorineural hearing loss, in which no history of aminoglycoside injection and no other specific etiology could be identified in any member. A 1555 A-to-G mutation of mitochondrial DNA was found in all members demonstrating hearing loss. The hearing in the propositus and his sister was severely impaired at a younger age than that in the mother. This case suggests that the 1555 point mutation of mitochondrial DNA has potential to promote inherited nonsyndromic hearing loss without any known etiology.

Facial nerve stimulation by a cochlear implant in a hemodialysis patient with bone of low mineral density.

Facial nerve stimulation by an activated cochlear implant was noted in a 56-year-old patient who had undergone cochlear implant with a Nucleus 22 implant 2 years previously as treatment for total sensorineural hearing loss following meningitis at age 54. Past history was complicated by total renal failure for which hemodialysis had been required during the past 13 years. Facial spasm occurred 5 months postoperatively with activation of the basal electrodes (channels 13 and 15 of the implant). The facial stimulation was eliminated by deprogramming these electrodes. High-resolusion computed tomography (CT) scanning was unable to demonstrate lucency of the otic capsule and cochlear ossification, but basal electrodes of the implant could be identified near the labyrinthine segment of the facial nerve. To further evaluate bone changes in the patient, the total and regional bone mineral density (BMD) of the head and radius was measured by dual energy X-ray absorptiometry. All BMD values of the patient were markedly low when compared to those of 62 other hemodialysis patient. These findings demonstrate that facial nerve stimulation can occur in the presence of low impedance due to cortical bone changes induced by long-term hemodialysis.

[Clinical issues of tuberculous cervical lymphadenitis: evaluation of 5 cases with packet formation].

Cervical lymphadenopathy with packet formation as the sole presentation of tuberculosis is very rarely seen in modern Japan. During the four years from 1987 to 1990, 5 cases of cervical scrofula with packet formation were treated with selective neck dissection followed by antituberculous chemotherapy at the ENT-department of Haibara General Hospital. Clinical evaluation of these cases suggested the following: 1) The physician must keep in mind that cervical scrofula should be included in the differential diagnosis of any neck masses, and malignant neck tumors particularly should be differentiated from cervical scrofula. 2) The treatment of cervical scrofula should be appropriate to the clinical stage diagnosed by CT or MRI. Recommended therapy for cervical scrofula with packet formation is selective neck dissection followed by antituberculous chemotherapy, which can shorten the period of treatment. 3) We present here a 22-year-old female from the Philippines with cervical scrofula and suggest that, in the future in Japan, tuberculosis may frequently be encountered in the immigrant population from the countries with high incidences of tuberculosis.

[Evaluation of myringotomy in the treatment of acute otitis media with effusion in infants and children].

In January 1990, the clinical features of acute otitis media (AOM) were retrospectively evaluated in 94 infants and children. These cases with AOM were treated with myringotomy under an operative microscope at their initial visit to our hospital during the five-month period from January to May of 1989. These results were as follows; 1) AOM in infants and children should be called "acute otitis media with effusion", because AOM can occur at the same phase as otitis media with effusion (OME) and OME can occur after AOM, both otitis media have the continuum of the pathological condition in the middle ear. 2) For the treatment of recurrent "acute otitis media with effusion", myringotomy as well as reasonable chemotherapy should be performed even with the recent advent of the newer antibiotics. 3) We suggest that the number of chronic otitis media will be reduced at some future time, if all of "acute otitis media with effusion" can be appropriately treated.