Archives of oto-rhino-laryngology最新文献

Vancomycin has been successfully used clinically for many years. Although early reports found ototoxicity to be a side effect of this antibiotic, later studies could not confirm this. For this reason we have started an experimental study in an animal model on the ototoxic effects of vancomycin. We now report the results of this study. Fourteen healthy Mongolian gerbils were treated with intraperitoneal injections of vancomycin (80 mg/kg per day) for a 2-week period. Before and after treatment each animal's hearing was evaluated by evoked response audiometry. Post mortem the cochleae were investigated by scanning electron microscopy in Amsterdam and by microdissection with surface preparations (hair cell counting) in Stockholm. The results of this study show that there is no clear evidence for the existence of ototoxicity due to vancomycin in this dosage.

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.

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.

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.

In view of recent controversies concerning the preservation of hearing in acoustic neurinoma surgery, we examined the courses of the vestibular and cochlear nerve fibers in 12 intact acoustic neurinomas studied in our department. Due to its lack of specificity, the Luxol fast blue stain was found to be inadequate for our study of the nerve fibers. In contrast, Verhoeff's stain proved to be satisfactory when combined with a highly specific immunohistochemical technique. There were macroscopically visible adherences between the tumor and the cochlear nerve in 9 out of the 12 specimens. From those specimens, histological sections were obtained in which both the cochlear nerve and tumor could be clearly identified. In these specimens the cochlear nerve was involved in the tumoral process and there was no clear cleavage plane between the nerve and the tumor. However, all these patients suffered only from minimal losses of hearing as a result of their tumors.

Over the last 40 years sporadic reports have appeared in the otolaryngological and neurological literature describing techniques and applications of laryngeal electromyography. Despite considerable refinements in methodology and instrumentation over that time laryngeal electromyography has not been widely adopted in routine clinical practice. This paper describes a simple, reliable and reproducible technique which has been employed by the author over a 15-year period. The indications for laryngeal electromyography are reviewed and the technique currently used is briefly described with reference to alternative techniques. The usefulness of the information obtained by this examination is discussed.

In about 10% of patients who are operated on for chronic sinusitis, an aspergilloma is found in the affected paranasal sinus. In order to detect possible underlying immune defects, 25 patients with aspergillomas were subjected to an immunological screening program. The data obtained were compared with those of patients with non-mycotic chronic sinusitis and healthy controls. Total lymphocyte counts and immunoglobulin levels were normal in both groups with sinusitis. However, leukocyte subset analyses using membrane fluorescence revealed a significant decrease of CD11+ cells (macrophages, monocytes and natural killer-cells) in both types of sinusitis. Furthermore, a markedly enhanced frequency of CD25+ cells (interleukin 2-receptor-bearing cells), was observed in patients with the aspergillomas. Additionally, peripheral blood lymphocytes in both groups of patients showed a significant reduction in the proliferative response to both T- and B-cell mitogens, with the values for the mitogens ConA and PHA being significantly lower in the aspergilloma patients as compared to those with non-mycotic sinusitis. This lack of lymphocyte stimulation in the aspergilloma group was also manifest in skin tests to recall antigens. These first data suggest that there is an immune deficiency in patients with chronic sinusitis caused by Aspergillus fumigatus. Further studies are needed to clarify if this defect is the cause or the result of the mycotic infection.

Experience with antibody-dependent, cell-mediated cytotoxicity (ADCC) has shown that antibody can increase the localization and killing capacity of lymphocytes. We tested the possibility of improving the activity of lymphokine-activated killer cells (LAK) on human tumor using the subrenal capsule assay in nude mice. The tumors were first grown in the renal capsule space and the effector cells injected later. In the model experiment we used M21 melanoma and monoclonal antibody against melanoma-associated antigen GD3. This antibody increases the tumor inhibitory activity of LAK cells from healthy donors in comparison to LAK alone. We have been able to prove the clinical relevance of such an approach. Tumor bioptic material from five tumor patients was tested with various monoclonal antibodies, following which the highly reactive antibodies were selected and incubated with the patient's LAK cells. Such pretreated LAK cells have a high growth-inhibitory effect on autologous tumor growing in the renal capsule space of the test mice.

We measured the pure-tone air and bone conduction hearing of 359 randomly selected otologically normal urban preschool children in Finland at the average age of 5.2 years. Children with otoscopically verified middle ear pathology or abnormal impedance audiometry were not included in this sample. The mean air conduction thresholds varied from 16.6 dB at 0.125 kHz to 6.6 dB at 2 kHz, and the mean bone conduction thresholds from 6.0 dB at 0.25 kHz to 0.7 dB at 4 kHz. The pure-tone average (of air conduction thresholds at 0.5, 1 and 2 kHz) of all the ears was 7.6 dB. The distribution of single air conduction hearing thresholds at the frequencies from 0.25 kHz to 4 kHz showed that 66%-75% were at the 5-10 dB level.

Chemically induced esthesioneuroepitheliomas (ENE) in rats were subjected to tissue culture experiments, biochemical evaluations for catecholamines and chromosomal analyses. The most conspicuous cytogenetic finding was a C1 marker chromosome in addition to numerical and structural chromosomal aberrations. Regarding the overwhelming similarity between human ENE and experimentally induced ENE, similar cytogenetic aberrations in its human counterpart are postulated. Biochemically, no catecholamines or their metabolic precursors could be identified, thus distinguishing ENE from sympathetic neuroblastomas. No keratin-positive cells could be found in the primary tumor or in the cell cultures studied, thus showing that immunohistology can be a valuable tool for differentiating ENE from anaplastic carcinomas.