[Exostosis of the internal auditory canal in a patient with myotonic dystrophy]

A 53-year-old patient with myotonic dystrophy presented to our clinic with progressive bilateral hearing loss. The ENT status and particularly the otological examination were without pathological signs. Pure tone audiograms showed a bilateral moderate to severe sensorineural hearing loss. Routinely performed computed tomography of the temporal bones revealed the rare picture of exostosis of the internal auditory canals and the medial surface of the petrous bones. To our knowledge, this is the first report describing exostosis of the internal auditory canal in a patient with myotonic dystrophy, although at present it remains unclear in how far there is a causal connection between these two pathologies.

Expression neurotropher Faktoren im Vestibularisschwannom - eine Übersicht

The vestibular schwannoma is a benign, slow-growing neoplasm that originates from the neurolemmal sheath of the vestibular branch of the VIIIth cranial nerve. This tumor entity accounts for 6 % of all intracranial tumors and the annual incidence of newly diagnosed vestibular schwannoma is reported as 13 per million. The molecular pathogenesis of both sporadic vestibular schwannoma and those occurring in neurofibromatosis type II appears to be associated with an aberration of a tumor suppressor gene on chromosome 22q12. The biological background for the various growth patterns of vestibular schwannoma is, however, largely unknown. This differing clinical and biological behaviour of vestibular schwannoma may be explained by the presence of neurotrophic factors. The results of recent immunohistochemical studies demonstrate the co-expression of transforming growth factor (TGF)-beta 1 and glial cell line-derived neurotrophic factor (GDNF) in vestibular schwannoma and suggest a trophic synergism of both neurotrophic factors in this tumor. Moreover, expression of numerous different neurotrophic factors has been shown in studies of nerve growth factor (NGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), fibroblast growth factor (FGF), neuregulin (NRG) and erythropoietin (EPO) indicating a biological role in development, maintainance or growth of vestibular schwannoma. In this article, we summarize the findings on neurotrophic factor expression and discuss their characteristics and biological role in vestibular schwannoma.

[Peripheral facial palsy as the first symptom of a metastatic bronchogenic carcinoma]

BACKGROUND

We present a case of a facial palsy as the initial symptom of a bronchogenic carcinoma.

METHODS

Case-report. A 56-year-old patient presented with a peripheral facial palsy. The clinical picture as well as the temporal bone CT were without pathological findings. A 10-day rheologic therapy as well as anti-viral medication were not successful. Five days after rheological therapy had been completed, the patient presented a swelling of the neck. In the computer tomography we found a bilateral thrombosis of the internal jugular vein. In addition, the clinical picture of a left-sided glossopharyngeal palsy appeared. The following thorax CT as well as the diagnostic extirpation of an enlarged cervical lymph node lead to the diagnosis of a metastasized smallcell neuro-endocrine bronchogenic carcinoma with a compression of the right primary bronchus and the vena cava superior as well as an upper inflow congestion. In the cMRT we furthermore found a metastasis in the area of the foramen stylomastoideum. The patient underwent emergency radiation and chemotherapy.

RESULTS

According to the present findings, this metastasis lead to the facial palsy as the initial symptom of the bronchogenic carcinoma.

CONCLUSION

Therefore, therapy resistant facial palsy should be further diagnosed in detail, especially examined by imaging procedures.

Parapharyngealabszess und Osteomyelitis im Bereich des Dens axis

We report the case of a 55 year old man with osteomyelitic destruction of the odontoid process and a parapharyngeal abscess. The patient was admitted with diagnosis of meningitis and degenerative cervical spine disease without compression of spinal cord or nerve roots but progressive impairment of cervical spine mobility. Inflammatory parameters in serum and cerebrospinal fluid were detected and antibiotic therapy was initiated resulting in subjective improvement of symptoms. When impairment of cervical spine motility persisted and gait disturbance developed, a parapharyngeal abscess and an osteomyelitic destruction of the odontoid process caused by infection with staphylococcus aureus was diagnosed. After cleavage of the abscess and four months of antibiotic therapy the gait disturbance disappeared and mild impairment of cervical spine motility persisted.

[Neurotrophic factors of the GDNF family and their receptors are detectable in spiral ganglion cells of normal hearing as well as of deafened rats]

BACKGROUND

Recent studies have shown that neurotrophic factors like BDNF, NT-3 and GDNF induce protective effects on spiral ganglion cells after noise- or drug-induced hearing loss. According to these studies it is suggested that deafness leads to a lack of neurotrophic factor or relating receptor expression in spiral ganglion cells, that has to be compensated by local cochlear application of these factors.

METHODS

In the present study we examined the expression pattern of members of the GDNF family (GDNF, Neurturin, Artemin, Persephin) and their relating receptors (Ret, GFRalpha1 - 3) as well as BDNF and trkB on spiral ganglion cells of normal hearing and experimentally deafened rats (10 % neomycine). Indirect immunofluorescence was carried out to determine protein expression of these factors and their receptors 26 days following deafening.

RESULTS

Our results demonstrate neurotrophic factor and receptor expression on spiral ganglion cells of normal hearing as well as experimentally deafened animals.

CONCLUSIONS

Our data indicate that within a period of 26 days after deafening no detectable reduction of the GDNF-family member expression and their receptors was ascertainable on spiral ganglion cells by immunohistochemistry. Thus, a lack of neurotrophic factor expression is unlikely to be the only cause of spiral ganglion cell loss following deafening.

[Embryonal rhabdomyosarcoma of the orbita]

A 2(1/2) year old girl was presented with an acute, painless orbital swelling without signs of local or systemic inflammation. CT and MRT scanning revealed a tumor which by open biopsy disclosed embryonal rhabdomyosarcoma. By means of this case we present the current diagnostic and therapeutic approaches for childhood soft tissue sarcomas. At present our patient receives a poly-chemotherapy which has already shown a good response. For local tumor control, a complete surgical resection as well as radiotherapy may be indicated and have to be considered carefully with respect to the possible late effects. This case demonstrates that in a child with a unilateral, progressive orbital tumor, the differential diagnosis of a soft tissue sarcoma has to be ruled out.

[The interesting case -- case no. 65]

Bilateral Osteomyelitis following frontal sinusitis is a rare complication in the antibiotic era. The main risk of a progredient course is mainly the formation of external subperiostal, epidural, subdural abscesses or brain abscesses with potentially life-threatening complications. This is a report on a patient who presented in our department with progredient cephalgia and swelling in the area around the glabella and frontal sinus. Macroscopical examination revealed septum deviation to the right side and nasal polyposis of the right nasal passage. A computed tomography of the paranasal sinuses showed subtotal soft tissue obstruction of all sinuses with the exception of the sphenoidal sinus. Bilateral osteolysis of the ventral osseous borders of the frontal sinus with accompanying osteosclerosis was also observed. The therapy consisted of radical frontal sinus surgery via Unterberger approach. This case demonstrates a rare case of bilateral frontal osteomyelitis together with the necessary diagnostic and therapeutic measures. The management consisted of the removal of all osteomyelitic bone and antibiotic therapy. Differential diagnostic procedures must be carried out in order to exclude orbital and intracranial complications. Regular follow-up examinations and a CT scan of the paranasal sinuses are part of the standard therapy.

Charakterisierung der Genexpression im Innenohr und der Hörbahn hörender und ertaubter Ratten mittels Gene-Arrays

BACKGROUND

The phenotype of deafness and its mechanisms are morphologically and electrophysiologically well characterised. However, the molecular mechanisms and the consequences of deafness are poorly understood.

METHODS

In this study we investigated changes in gene expression profiles in subfractions of the cochlea and the colliculus inferior, a non-cochlear tissue, of normal and deafened (10 % Neomycin) rats using the gene-array-technology. RNA was prepared from modiolus (Mo) und sensorineural epithel/lateral wall (SnE/Lw) und Colliculus inferior (IC), reverse transcribed with gene specific primers, labeled with (32)P-dATP and hybridised with its complementary sequences of 1200 rat ESTs.

RESULTS

Similar gene expression profiles were detected in Mo- and SnE/Lw in normal as well in deafened rats differing significantly from those found in IC. In deafened animals differences in mRNA levels were determined in IC for 8 genes, in Mo für 17 genes and in SnE/Lw for 25 genes in comparison to those of normal rats. By using gene-arrays many genes described in the literature previously could be detected. Otherwise most of the genes found in the cochlea are unknown.

CONCLUSIONS

The gene-array-technology is a valuable tool in otological research for gene expression analysis and, therefore, for comprehensive understanding of molecular processes in the inner ear. Furthermore gene screening for candidate genes could be a big step ahead in developing therapies of diseases of the inner ear.

[The interesting case -- case number 61]

A 58-year-old patient presented after having undergone radiation therapy, afterloading therapy and chemotherapy of a T4 nasopharynx carcinoma. On the basis of the MRI findings, local tumour recurrence was suspected. The samples taken from the nasopharynx and the left maxillary sinus confirmed this diagnosis. Neuroradiological imaging showed that the tumour extended into the area around the left skull base and also revealed an irregular formation located in the left temporal flap. Therefore not only tumour resection (Fisch approach type C) but also a temporal craniotomy was indicated in order to determine the degree of intracerebral tumour extension. The dura mater, which had been intact, was intraoperatively opened and revealed vital brain tissue, i. e. tumour infiltration had not reached the brain. It was concluded that the radiological findings probably indicated a postradiogenic necrosis of the temporal flap. The presented case illustrates the rare differential diagnostic procedure carried out in a patient with radiogenic necrosis while taking into account the possibility of local tumour infiltration into the brain parenchyma.

Co-expression of Transforming Growth Factor-β1 and Glial Cell Line–Derived Neurotrophic Factor in Vestibular Schwannoma

HYPOTHESIS

Transforming growth factor-beta1, glial cell line-derived neurotrophic factor, and their receptors are expressed in vestibular schwannoma, and the expression data correlate with the proliferation activity (Ki-67 labeling index) and the clinical growth rate of vestibular schwannoma tissue.

BACKGROUND

Glial cell line-derived neurotrophic factor is a potent growth factor for the central and peripheral nervous system. Recent results demonstrate that glial cell line-derived neurotrophic factor requires transforming growth factor-beta to exert its trophic effect on neural tissue. A functional role, including that in Schwann cell proliferation, is discussed for both transforming growth factor-beta1 and glial cell line-derived neurotrophic factor.

METHODS

Immunohistochemical analysis for transforming growth factor-beta1 and glial cell line-derived neurotrophic factor and their receptors TbetaR II, GFRalpha-1, and Ret was performed on formalin-fixed, paraffin-embedded archival surgical specimens. The Ki-67 labeling index (mean Ki-67 labeling index and highest Ki-67 labeling index for Antoni Type A and Type B regions) and the clinical growth rate of vestibular schwannoma were determined and correlated with the expression patterns of the examined neurotrophic factors and their receptors.

RESULTS

Results demonstrate co-expression of transforming growth factor-beta1 and glial cell line-derived neurotrophic factor with higher levels in Antoni Type A than in Antoni Type B regions. Ninety-five percent of vestibular schwannomas exhibited transforming growth factor-beta1 immunoreactivity, and glial cell line-derived neurotrophic factor expression was found in 100% of vestibular schwannoma specimens. Fifty percent of vestibular schwannoma displayed TbetaR II immunostaining, 100% showed positive reactions for GFRalpha-1, and 86% showed positive reactions for Ret. Statistical analysis revealed no significant correlation in neurotrophin expression related to sex, age, tumor size, clinical growth rate, or Ki-67-labeling indices.

CONCLUSIONS

Expression of transforming growth factor-beta1 and glial cell line-derived neurotrophic factor may suggest a biological role for both growth factors in vestibular schwannomas. Trophic transforming growth factor-beta/glial cell line-derived neurotrophic factor synergism seems possible and is underscored by co-expression of both neurotrophic factors and their receptors.

[Cochlear implants in adults: indications and realization. Special cases and technical parameters of the implantation systems]

From the technical point of view, cochlear implant (CI) surgery in adults is a well established procedure. Pre- and postoperative evaluation, surgical approach and rehabilitation programs are standardized, presenting CI as a low risk procedure with rare complications similar to those of middle ear surgery. Part 1 described the diagnostics, surgical procedure and possible complications. The second part will cover the contraindications, special cases as well as the technical parameters of the modern implant system.

[Cochlear implants in adults: indications and realizations. Part I: Diagnosis, operation techniques and results]

From the technical point of view, cochlear implant (CI) surgery in adults is a well established procedure. Pre- and postoperative evaluation, surgical approach and rehabilitation programs are standardized, presenting CI as a low risk procedure with rare complications similar to those of middle ear surgery. Modern advanced CI devices offer technical reliability and multiple speech encoding strategies and recently, even small processors which are worn behind the ear. Further technical advances are continuously available, even for implanted patients. Upgrading is usually easy because the outer parts of the implant are exchangeable and software upgrades can be transmitted transcutaneously to the implant. Assuming that medical and rehabilitation requirements are available, there are only very few indications against CI in adults. Candidate patients should therefore be transferred to CI-centres where a decision can be taken depending on presurgical evaluation results.

Technical report: modification of a cochlear implant electrode for drug delivery to the inner ear

OBJECTIVE

To investigate the possibility of modifying a cochlear implant electrode for the purpose of drug delivery to the cochlea.

BACKGROUND

Animal experiments suggest that local therapy of the inner ear could be a promising new approach to the interventional treatment of inner ear disease, and that pharmacologic intervention could possibly enhance cochlear implant performance. One of the key aspects is the deployment of a means of drug delivery to the human inner ear.

METHODS

The tip of the Contour electrode array was cut to open the lumen of the array, and a connecting piece was developed to connect the electrode to a pump. The feasibility of using the array for drug delivery was tested using both an Alzet mini-osmotic pump and a mechanical pump. The connection was tested for its stability in terms of leakage and resistance to tractive forces. The system was also applied to temporal bones to evaluate its applicability to the human cochlea.

RESULTS

The modified Contour electrode is easy to handle in temporal bones and can be used to simulate drug delivery to the inner ear. The connection to the pump was sealed for all tested pump rates and resisted tractive forces up to 50 N.

CONCLUSIONS

The described modified electrode could provide a safe and easy-to-handle means of combining electrical stimulation with the beneficial effects of a local drug therapy applied to the inner ear.

Telomerase activity, telomere length, and apoptosis: a comparison between acquired cholesteatoma and squamous cell carcinoma

BACKGROUND

Cholesteatoma disease is characterized by accumulation of keratinizing epithelium. Several molecular markers of tumor formation have been found in cholesteatoma (e.g. upregulation of matrix metalloproteinases, c and activation of angiogenesis). Other molecular findings clearly distinguish between cholesteatoma and malignant tumors (e.g., lack of chromosomal instability, intact checkpoint responses). To further distinguish the molecular mechanisms in cholesteatoma from malignant tumors, the authors determined telomerase activity and telomere length in both tissue types.

METHODS

To evaluate the role of telomerase activation and telomere length in cholesteatoma, 29 cholesteatoma samples and 9 squamous cell carcinomas were analyzed for telomerase activity and telomere length. In addition, the rate of apoptosis was determined in both groups, using the TdT-mediated dUTP nick end labeling technique.

RESULTS

As previously described, a high proportion of squamous cell carcinoma exhibited telomerase activity (6/9, 66%). By contrast, a significantly lower rate of telomerase activity was found in cholesteatoma samples (1/29, 3.4%, p = 0.0002). Despite the differences in telomerase activity, the telomere length was similar in cholesteatoma (mean length 7.43 kb) and in squamous cell carcinoma (mean length 7.99 kb; difference not significant, p = 0.1364). The low rate of telomerase activity in cholesteatoma was accompanied by significantly higher rates of apoptosis in cholesteatoma (mean 30%) compared with squamous cell carcinoma tissue (mean 3%, p = 0.0031).

CONCLUSIONS

Taken together, these data show that telomerase activation is a rare event in cholesteatoma and that the absence of telomerase activity is accompanied by high rates of apoptosis in cholesteatoma. It is proposed that the absence of telomerase limits the proliferative capacity of cholesteatoma by induction of apoptosis, whereas the presence of telomerase allows immortal growth of squamous cell carcinoma.

[Feasibility of inner ear gene transfer after middle ear administration of an adenovirus vector]

BACKGROUND

Several groups demonstrated in animal experiments that gene transfer is a feasible tool for inner ear intervention. Various approaches for inoculation of vectors have been successfully used for inner ear gene therapy. One possible way to reduce the risk of hearing loss following the opening of the cochlea for application of the vector into the perilymphatic space is to deliver vectors through the round window. This study was designed to determine whether middle ear application of an adenoviral vector is a feasible approach to inoculate vectors and lead to transduction of cells in the inner ear.

METHODS

A unilateral middle ear application of an adenoviral vector was performed in 4 guinea pigs directly on the round window membrane (RWM) and in 4 additional animals by placing a cotton patch soaked with the vector solution on the RWM. The expression of a reporter gene (lacZ) was used to localize vector-transduced cells.

RESULTS

Only one out of 8 animals showed cochlear expression of the reporter gene, whereas all 8 animals showed strong lacZ expression in the middle ear mucosa, in the RWM and in the mucosa surrounding the stapes.

CONCLUSION

Our results indicate that the RWM presents a close barrier, almost completely preventing the adenovirus to diffuse into the perilymphatic space. Therefore middle ear application of an adenoviral vector cannot be used to induce inner ear gene transfer. However, middle ear application of a viral vector may be useful for developing treatment for diseases of the middle ear mucosa.

Glial cell line-derived neurotrophic factor (GDNF) and its receptor complex are expressed in the auditory nerve of the mature rat cochlea

Glial cell line-derived neurotrophic factor (GDNF) is a survival factor for many neuronal cell types which signals through a heterodimer receptor consisting of GDNF-family receptor alpha 1 (GFRalpha-1) and Ret (rearranged during transformation). GDNF expression has previously been reported in the inner hair cells of the rat cochlea, with expression of GFRalpha-1 but not Ret in the cell bodies of the auditory nerve (spiral ganglion cells), using in situ hybridization. The present study used reverse transcription-polymerase chain reaction (RT-PCR), and immunocytochemistry to examine GDNF, GFRalpha-1 and Ret in the adult rat auditory nerve. Semi-quantitative RT-PCR showed expression of GDNF and the two receptor components, GFRalpha-1 and Ret, in the modiolar subfraction of the cochlea containing spiral ganglion cells. A shorter mRNA splice variant for GDNF was also detected. Immunocytochemistry showed immunostaining in the modiolus for GDNF, GFRalpha-1 and Ret that was confined to spiral ganglion cells. When RT-PCR expression levels were compared to the expression in the substantia nigra, GFRalpha-1 expression levels were similar, Ret mRNA was lower in the modiolus and GDNF expression was higher in the modiolus. However, when GDNF was further assessed using Western blot, while GDNF protein was found in the modiolus it was at lower levels than in substantia nigra tissue. These results demonstrate that GDNF and both of its receptor components are found in spiral ganglion cells of the adult rat cochlea. Along with the previous report of GDNF in inner hair cells, these new results provide a basis for the role of GDNF as a survival factor for the auditory nerve, as suggested by previous studies.

Mastoiditis and acute otitis media in children with cochlear implants: recommendations for medical management

Acute otitis media (OM) or mastoiditis is a very dangerous condition for the ear after cochlear implantation. However, acute OM is very common in childhood and can occasionally occur in an implanted ear. Most cases of acute OM can be successfully treated with intravenous high-dosage antibiotics. In cases of mastoiditis and clinical signs of mastoid abscess, retroauricular drainage is necessary to prevent infection of the implant bed. In a series of 366 children given implants (1 to 14 years), acute OM occurred in 5.6% during a follow-up period of 1 to 8 years. Seven ears had to be opened by means of myringotomy. Five ears were opened by retroauricular incision with mastoid revision on the implanted side. Adenoidectomy and use of ventilation tubes before cochlear implantation, as well as careful subtotal mastoidectomy during the implantation, can reduce the incidence of acute OM in children after implantation. Early and subsequent treatment with operative mastoid drainage can prevent implant loss and should be performed at the implantation center.

Upregulation of glial cell line-derived neurotrophic factor (GDNF) in the rat cochlea following noise

There are endogenous intracellular mechanisms that provide cells with protection from stress, as well as repair from damage. These pathways often involve stress proteins and neurotrophic factors. The present study used Western blot analysis to examine changes in glial cell line-derived neurotrophic factor (GDNF) following noise overstimulation. A noise exposure was utilized which causes a temporary threshold shift and has been previously shown to upregulate heat shock protein 72 in the rat cochlea. This noise exposure also provides protection from a second noise exposure that would otherwise cause a permanent threshold shift. Experimental animals were assessed 2, 4, 8 and 12 h after cessation of noise exposure. Control animals received the same treatment except for the noise exposure and were assessed at the 8 h time point. A moderate expression of GDNF was observed in the normal cochlea. No significant change in GDNF levels was observed at 2 or 4 h following noise overstimulation. However, a significant increase was found at 8 h. At 12 h following noise overstimulation, GDNF levels were no longer significantly elevated from normal. These results suggest that GDNF is involved in the endogenous stress response in the cochlea and are consistent with the protection that exogenously applied GDNF has been shown to provide.

Expression of the GDNF family members and their receptors in the mature rat cochlea

The GDNF family comprises glial cell line-derived neurotrophic factor (GDNF) and the related proteins neurturin, artemin and persephin, which form a subgroup of the TGF-beta superfamily of growth factors. All four neurotrophic factors provide neuronal cell protection and cell survival. GDNF expression was found in the cochlea, and GDNF has been shown to be effective for inner ear protection from drugs and noise-induced insults. As the other members of the GDNF family also provide protective effects on neuronal cells, they may play important roles in the inner ear. We used RT-PCR to examine the expression of GDNF, neurturin, artemin, persephin and their receptors GFRalpha-1, GFRalpha-2, GFRalpha-3 and c-ret in whole rat cochlea as well as in functionally different subfractions (modiolus and sensorineural epithelium/lateral wall) and compared the levels of neurotrophin and receptor mRNAs in the cochlea to those in substantia nigra brain region. Our results demonstrate the expression of all GDNF family members and their receptors in cochlea and substantia nigra. However, the relative levels of mRNA were different for several genes tested in subfractions of the cochlea and/or compared to expression levels in substantia nigra. The presence of mRNA for all four members of the GDNF family and their preferred receptors in the rat cochlea suggests potential functional importance of these neurotrophic factors as protection and survival factors in the inner ear.

Transduction of the contralateral ear after adenovirus-mediated cochlear gene transfer

Cochlear gene transfer is a promising new approach for inner ear therapy. Previous studies have demonstrated hair cell protection with cochlear gene transfer not only in the inoculated, but also in the uninoculated ear. To characterize the kinetics of viral spread, we investigated the extent of transgene expression in the contralateral (uninoculated) cochlea after unilateral adenoviral cochlear gene transfer. We used a lacZ reporter gene vector, and demonstrated spread of the adenovirus into the cerebrospinal fluid (CSF) after cochlear inoculation of 25 microl viral vector. Direct virus application into the CSF resulted in transduction of both cochleae, whereas virus inoculation into the bloodstream did not. The cochlear aqueduct was identified as the most likely route of virus spread to the contralateral cochlea. These data enhance our understanding of the kinetics of virus-mediated transgene expression in the inner ear, and assist in the development of clinical applications for inner ear gene therapy. Our results showed a functional communication between the CSF and the perilymphatic space of the inner ear, that is not only of importance for otological gene transfer, but also for CNS gene transfer. Gene Therapy (2000) 7, 377-383.

[Sonographic diagnosis of metastatic renal cell carcinoma to the head and neck region]

In the area of the head and neck metastases from distant primary tumours are rare in comparison to the common squamous cell carcinomas of the upper respiratory and digestive tract. Thus correct preoperative diagnosis may be difficult. Two cases with distant metastases of renal cell carcinoma to the head and neck region are presented in this report. In a 60-year-old male patient, diagnostic evaluation of unilateral epistaxis revealed a radioopacity of the maxillary sinus, six months after removal of a renal cell carcinoma. In the second case a slowly progressive indolent swelling of the left neck developed in a 56-year-old man six years after resection of a renal cell carcinoma and two years after surgical treatment of a pancreatic carcinoma. Following clinical examination, modern imaging techniques with special emphasis on colour Doppler sonography with a Siemens Quantum 2000 were used for diagnostic evaluation in both patients. Sonography of metastatic renal cell carcinoma to the maxillary sinus revealed complete opacity of the antrum. The cervical mass proved to the inhomogeneous and hypoechogenic and was difficult to distinguish from the lower parotid lobe and the vessel sheath. A common feature of both tumours was a high degree of perfusion which could be confirmed by superselective angiography. The histological examination of the surgical specimen showed an isolated metastasis of a renal cell carcinoma in both cases. In patients with a history of renal cell carcinoma the possibility of distant spread to the head and neck region should be taken into account even after a long period of complete remission. Colour Doppler sonography facilitates the distinction between the normally well perfused secondary tumours and squamous cell carcinomas which usually only have a minimal blood supply. Because of the high risk of profuse bleeding a biopsy should only be performed in the operating theatre.

Cochlear gene transfer: round window versus cochleostomy inoculation

Two possible approaches for cochlear gene transfer have been inoculation via the round window membrane and through a cochleostomy. The aim of this study was to determine which of the two is more effective. Using both approaches, normal-hearing and deafened guinea pigs were inoculated with adenovirus carrying the reporter gene lacZ. After 5 days, the animals were killed and the cochlear tissue was stained with X-gal. The distribution and intensity of staining was estimated by a score system developed to compare gene transfer results between animals. We found that gene transfer via the cochleostomy resulted in a better distribution throughout the cochlea and in higher staining intensity, due to more efficient transfection. Auditory brainstem response (ABR) results showed that neither virus inoculation through a cochleostomy nor through the round window membrane had a significant effect on the click-ABR threshold measured on day 5 following virus injection. Gene transfer via both approaches was also found to be more effective in deafened animals than in hearing animals.