Archives of oto-rhino-laryngology最新文献

The volumes of the auditory brainstem nuclei and age-related auditory brainstem response (ABR) thresholds were analyzed in homozygote (je/je) and heterozygote (je/+) jerker mutant mice. Altogether 97 mice were used in the study. Je/je mice never develop any hearing. The dorsal (DCN) and ventral (VCN) cochlear nuclei were found to have stopped their growth at 56 days after birth. In je/+ mutants, ABR thresholds remained normal or near-normal for 3-6 months, whereas VCN and DCN volumes remained unchanged at least after 56 days after birth. There is no significant difference in DCN volume in je/je and je/+ mice. However, the VCN volume and the cross-sectional area of globular cells were both significantly larger in je/+ than in je/je mice (P less than 0.01). These findings show that auditory deprivation during the maturation of hearing in je/je mutants causes an incomplete maturation of only the ventral cochlear nucleus.

Various conservative and surgical procedures are available for the management of aggressive hemangiomas in infancy and childhood. One of them is magnesium seeding, a treatment modality developed more than 90 years ago but neglected for a long time. The technique consists of implanting 0.5- to 1-mm-thick wires of 99.8% pure magnesium into the tumor mass. During repeated courses oxidation of the metal results in fibrosis and cicatricial transformation of the tumor. Indications, technique and results are discussed.

In children, cholesteatoma is closely related to dysfunction of the eustachian tube and evolves inside a malleable temporal bone. The importance of auditory and speech functions in such patients has caused us to use a very particular clinical philosophy. At the present time we have studied 154 cases of cholesteatomas in children under 15 years old. The following three points have been shown: the pathogenesis of a cholesteatoma can be of the primary type, secondary (due to an unfavorable extension of retraction pocket or to squamous cell migration) or even be iatrogenic; anatomical and clinical findings (with X-ray studies) predicate the treatment used; surgical treatment frequently requires a "second-look" operation.

The authors report their surgical experiences with 55 extensive tumours of the pharyngoesophageal junction. Thirty-three of these cases were managed by circular pharyngolaryngectomy, total oesophagectomy with stripping and left coloplasty, and 22 were treated with circular pharyngolaryngectomy with free intestinal transplants. A comparative study of the post-operative courses of the patients and their oncological and functional outcomes shows the advantages, disadvantages and indications of these two techniques.

The records of 14 patients who have benefited from intralaryngeal injections of ZCI collagen for at least 3-4 years were reviewed. All patients still living were evaluated. Qualitative phonatory measurements included laryngostroboscopy and frequency voice analysis, while quantitative studies included maximum phonation times and phonatory quotients. The absence of both local and general inflammatory reactions was observed in these patients, confirming the excellent host tolerance of ZCI collagen and the stability of the functional results achieved.

The olivocochlear innervation has been postulated to regulate active mechanical processes in the mammalian cochlea. Histochemical studies led to the suggestion that a subpopulation of these efferent nerves, which predominantly terminate on outer hair cells (OHCs), are gamma-aminobutyric acid (GABA)-ergic. By means of two monoclonal antibodies, we were able to visualize GABAA-receptor immunoreactivity at the basal pole of isolated sensory cells. Both subunits of the GABAA receptor, the alpha- and beta-subunit, are known to form the transmembranous GABA/benzodiazepine-receptor complex and were present on OHCs. In addition, these inhibitory receptors were more numerous in the apical turns of the cochlea, indicating another criterion for distinguishing the apical from basal turns of the cochlea. These results support the concept that a subpopulation of axosomatic synapses at the basal pole of OHCs liberate the inhibitory neurotransmitter GABA into the synaptic cleft. Binding of the transmitter to these newly observed subsynaptic receptors is possibly followed by a change in OHC motility and a subsequent modulation of the movement of the basilar membrane.

Tympanoplasty can cause a sensorineural hearing loss by a mechanism of acoustic trauma. Although this lesion appears to be relatively infrequent in clinical practice, we believe that its low apparent incidence is caused when clinicians fail to assess the auditory frequencies above 8000 Hz. Twenty-four patients with normal bone-conduction audiometric thresholds scheduled for tympanoplasty were assessed with an electro-stimulation, bone-conduction high-frequency audiometer which can measure hearing frequencies up to 20 kHz before and after surgery. A measurable hearing loss was found in the upper limits of the audible frequencies in 9 patients (37.5%), and was considered important in 4 of them (16.7%). This hearing loss was recorded above the upper frequency limit of conventional audiometers. The findings in this study indicate that drilling of the temporal bone can impair the hearing level in the high frequencies in a significant number of patients. High-frequency audiometry is a very sensitive tool to assess any damage caused to the inner ear by surgical procedures carried out in the middle ear and temporal bone.

The necessity for direct observation of the pharyngeal outlet of the normal or pathological eustachian tube has always stimulated research for suitable diagnostic instruments. As the result of various investigation procedures currently available, we performed a series of endoscopic screenings using both the Hopkins telescope and the fiberoptic rhinopharyngolaryngoscope. The present study aimed at evaluating and demonstrating the morphological and dynamic functional condition of the pharyngeal outlet of the tube. The present investigation was carried out on 60 males and females, ranging in age from 4 to 70 years. Inspection of the pharyngeal outlet of the tube and its adjoining region enabled us to document some of the various causes for tubal dysfunction. By visualizing tubal movements, endoscopy also made it possible to perform a dynamic study of tubal functions. However, the investigation procedure utilized did not allow us to record any significant differences between the two diagnostic instruments used, except that the fiberscope can be more easily handled, whereas the photographs taken with the telescope are of better quality.

Groups of pigmented guinea pigs were exposed unilaterally to a 15 kHz pure tone at 133 dB SPL for 7.5 min. The inner ears of one group were examined by light microscopy to count damaged hair cells 3 weeks after exposure. Four other groups were investigated using scanning electron microscopy to assess the progression of initial surface changes after sound exposure. Hair cells were examined at 0, 10 and 30 min and compared with those seen at 3 weeks. Drastic stereociliary disturbances were present immediately after this short sound stimulation. Changes initially affected the first row of outer hair cells, followed by the inner hair cell row, and then spread to all rows at the centre of a damaged area. These changes appeared more advanced in specimens from the later groups. At 3 weeks, primarily phalangeal scars were seen at the main damaged area, with partially degenerating cells at the periphery. The latter still showed stereociliary disturbances, but the types predominating were different from those seen initially. However, no differences were found in the extens of damage when the various exposure groups were compared. No changes due to overstimulation were present in the contralateral ears.

Photodynamic therapy is based on the production of a cytotoxic factor by porphyrins, particularly hematoporphyrin (HP), when exposed to light of a suitable wavelength and intensity. The uptake of HP is notably large in tissues with a high mitotic index. Although cholesteatomas are not malignant tumors, our working hypothesis was that their high lipid content might result in their exhibiting a remarkable affinity to HP, which is normally carried in the blood by lipoproteins. Cholesteatomas were induced in rabbits using the Tübingen procedure (closure of the auditory canal by sutures). Animals were killed 30-40 days later at intervals of 1, 3, 6, 12, and 24 h following intravenous HP administration (5 mg/kg). Specimens were divided into two portions, one for histological examination and the other for biochemical study. The latter revealed that HP accumulates in experimental cholesteatomas, with a maximum uptake after 3 h. The level then gradually decreases, although at a lower rate than in the liver, but remains considerably high even after 24 h. These results suggest that the photodynamic treatment of cholesteatomas should be feasible in our animal model, although such treatment is still speculative in man.