Evaluation of new alternative methods for the identification of estrogenic, androgenic and steroidogenic effects: a comparative in vitro/in silico study.

A suite of in vitro assays and in silico models were evaluated to identify which best detected the endocrine-disrupting (ED) potential of 10 test chemicals according to their estrogenic, androgenic and steroidogenic (EAS) potential compared to the outcomes from ToxCast. In vitro methods included receptor-binding, CALUX transactivation, H295R steroidogenesis, aromatase activity inhibition and the Yeast oestrogen (YES) and Yeast androgen screen (YAS) assays. The impact of metabolism was also evaluated. The YES/YAS assays exhibited a high sensitivity for ER effects and, despite some challenges in predicting AR effects, is a good initial screening assay. Results from receptor-binding and CALUX assays generally correlated and were in accordance with classifications based on ToxCast assays. ER agonism and AR antagonism of benzyl butyl phthalate were abolished when CALUX assays included liver S9. In silico final calls were mostly in agreement with the in vitro assays, and predicted ER and AR effects well. The efficiency of the in silico models (reflecting applicability domains or inconclusive results) was 43-100%. The percentage of correct calls for ER (50-100%), AR (57-100%) and aromatase (33-100%) effects when compared to the final ToxCast call covered a wide range from highly reliable to less reliable models. In conclusion, Danish (Q)SAR, Opera, ADMET Lab LBD and ProToxII models demonstrated the best overall performance for ER and AR effects. These can be combined with the YES/YAS assays in an initial screen of chemicals in the early tiers of an NGRA to inform on the MoA and the design of mechanistic in vitro assays used later in the assessment. Inhibition of aromatase was best predicted by the Vega, AdmetLab and ProToxII models. Other mechanisms and exposure should be considered when making a conclusion with respect to ED effects.

[Diagnosis and treatment of Eustachian tube dysfunction]. / Diagnostik und Therapie von Funktionsstörungen der Tuba auditiva.

The Eustachian tube protects against secretion, germs and sound pressure from the nasopharynx, it acts as a drain, and serves pressure equalization in both directions so that the ear drum and sound-conducting apparatus can vibrate optimally. The incidence of Eustachian tube dysfunction in adults is about 1%, in children almost 40%. Symptoms are often unspecific. For diagnosis, the Eustachian tube score (ETS-5) can be used in patients with a perforated ear drum, and the ETS-7 score in patients with intact ear drum. Adenoid hypertrophy is a frequent cause of obstructive tube dysfunction in children. Treatment of obstructive dysfunction includes steroid nasal sprays and regular performance of the Valsalva maneuver, as well as tube dilation with the Bielefelder balloon catheter. The patulous Eustachian tube is treated with saline nasal irrigation, estrogen-nasal ointment, and craniocervical manual therapy; causal treatments are evaluated.

Balloon Eustachian tuboplasty: a retrospective cohort study.

BACKGROUND: Eustachian tube dysfunction is regarded as a 'black box' term, reflecting a spectrum of dysfunction. The key to its diagnosis and management is in identifying the aetiology and exact pathophysiology of the dysfunction. DESIGN: We present our retrospective 5-year results for the technique of transnasal endoscopic balloon dilatation of the cartilaginous part of the Eustachian tube, balloon Eustachian tuboplasty (BET). The indication for treatment is chronic obstructive Eustachian tube dysfunction. MAIN OUTCOME MEASURES: Preoperatively, the Eustachian tube score (ETS) was obtained by a clinico-objective assessment involving tubomanometry (TMM) and reported patient symptom. The measurements were repeated 1, 2, 3, 4 and 5 years postoperatively. SETTING: Tertiary referral centre. PARTICIPANTS: A total of 622 patients (1076 ears) were treated with BET. RESULTS: One year after treatment, the Eustachian tube score improved from 3.13 (± 2.47 SD) to 5.75 (± 2.76 SD). The Eustachian tube score improved significantly in 73% of ears. The average Eustachian tube score 2 years after treatment improved from 2.65 (± 2.89 SD) to 6.26 (± 3.07 SD). In 82% of patients, the Eustachian tube score improved significantly at 5 years. The subjective satisfaction of the patients was approximately 80%. CONCLUSIONS: Our long-term results suggest that BET is a safe and feasible treatment for chronic obstructive Eustachian tube dysfunction with a success rate of more than 70%. This study has important implications for other Eustachian tube-related clinical entities, such as glue ear management (adults and children), continued grommet insertion and tympanomastoid surgery outcomes.

Evaluation of tubomanometry as a routine diagnostic tool for chronic obstructive Eustachian tube dysfunction.

OBJECTIVE: The objective of this study was to demonstrate the reliability of tubomanometry (TMM) described by Estéve in the diagnosis of chronic obstructive Eustachian tube (ET) dysfunction. STUDY DESIGN: Combined prospective and retrospective clinical study. SETTING: Tertiary referral centre, affiliated to university. METHODS: Two hundred and fifteen healthy subjects were examined once, 25 healthy subjects underwent TMM weekly for 6 weeks, and six healthy subjects were tested three times a day on at least three different days. The results of tubomanometry in healthy subjects were compared to data obtained from 171 patients with chronic obstructive ET dysfunction. RESULTS: In healthy subjects, there was an immediate opening of the ET at 30-50 mbar with an R-value ≤ 1 in at least 94% of the cases. In patients with chronic ET dysfunction, an opening of the ET could be registered in only 42% of patients at 30 mbar and in 58% at 50 mbar. The average of the R-value in these subjects always indicated towards a delayed opening (R > 1). When measurements are repeated in the same subject with a weekly interval, the intraclass correlation (ICC) was 0.49 for the TMM with 30 mbar, 0.51 for the TMM with 40 mbar and 0.52 for the TMM with 50 mbar in healthy people. For the patients with symptoms of ET dysfunction, the ICC for up to four repeated measures was 0.50 for the TMM with 30 mbar, 0.53 for the TMM with 40 mbar and 0.54 for the TMM with 50 mbar. A complete agreement of the results in repeated measurements within seconds was present in 86% for 30 and 40 mbar and in 79% for 50 mbar. The ICC was 0.61 for the TMM with 50 mbar, 0.62 for the TMM with 40 mbar and 0.68 for the TMM with 30 mbar. CONCLUSIONS: Tubomanometry can support the diagnosis of ET dysfunction. An R-value ≤ 1 indicates a regular function of the ET, an R-value >1 indicates a delayed opening of the ET, and no definable R-value means no detectable opening of the ET. TMM is a reliable and valid instrument to support the diagnosis of chronic obstructive ET dysfunction.

[Bacteriologic investigation of the Eustachian tube and the implications of perioperative antibiotics before balloon dilation]. / Bakteriologische Untersuchungen der Tuba auditiva und die Implikation einer perioperativen Antibiotikagabe vor Ballondilatation.

BACKGROUND: Balloon Eustachian Tuboplasty (BET) is a new minimally invasive treatment for chronic Eustachian tube dysfunction (ETD). Initially, perioperative prophylactic antibiotic therapy with ciprofloxacin 2 × 500 mg p.o. for 5 days was administered. This study aimed to characterize the bacterial flora in the ET, nose, and pharynx in patients with chronic obstructive ETD. Additionally, we investigated the necessity of perioperative antibiotic prophylaxis in BET patients. PATIENTS AND METHODS: We examined 40 patients undergoing BET: 20 patients with and 20 patients without perioperative antibiotic prophylaxis. All patients were followed-up for clinical signs and symptoms of local infection for at least 2 weeks after surgery. Following BET, the tips of 35 balloon catheters, as well as swabs from the nose and pharynx were sent for microbiologic analysis. RESULTS: None of these 40 patients had postoperative signs of infection. Of the swabs of the balloon catheters, 46% were sterile and 23% showed standard flora. The remaining 31% of swaps revealed specific bacteria. However, none of the nasal or nasopharyngeal swaps were sterile. CONCLUSION: Due to the lack of signs of postoperative infection in either investigated group, the authors no longer favor use of perioperative antibiotic prophylaxis in patients undergoing BET. The relevance of biofilms and pathogen colonization to ET function has recently been intensively discussed, and should be further investigated in future studies.

[Assessment of chronic obstructive eustachian tube dysfunction : Evaluation of the German version of the Eustachian Tube Dysfunction Questionnaire]. / Beurteilung der chronisch-obstruktiven Tubenfunktionsstörung : Evaluation des "Eustachian Tube Dysfunction Questionnaire" in der deutschen Übersetzung.

BACKGROUND: Eustachian tube dysfunction can cause middle ear diseases and impair quality of life. Sufficient diagnostic tools for chronic obstructive eustachian tube dysfunction are lacking and not reliable enough. PATIENTS AND METHODS: The Eustachian Tube Dysfunction Questionnaire (ETDQ-7) was published by McCoul et al. in 2012 as an instrument to evaluate eustachian tube function. They demonstrated the reliability und validity of their questionnaire. The cut-off point for the diagnosis of eustachian tube dysfunction is ≥ 14.5 at 100 % sensitivity and 100 % specificity. We translated the ETDQ-7 into German and used it on 100 healthy subjects and 43 patients with chronic obstructive eustachian tube dysfunction. RESULTS: The results in the English questionnaire were confirmed by our examinations with the German version of the questionnaire. The mean ETDQ-7 score was 8.67 in the healthy subjects and 24.7 in the patients with chronic obstructive eustachian tube dysfunction. The area under the curve in ROC analysis was 98.8 % (p < 0.0001). CONCLUSION: We recommend the ETDQ-7 as an addition to patient history in the examination of eustachian tube dysfunction. It may as well be valuable in follow-up examinations to monitor treatment success.

A novel three-dimensional Nrf2 reporter epidermis model for skin sensitization assessment.

Skin sensitization assessment has progressed from the use of animal models towards the application of New Approach Methodologies (NAMs). Several skin sensitization NAMs are accepted for regulatory use, but a majority relies on submerged in vitro cell cultures that limit their applicability domain, posing challenges for testing hydrophobic chemicals and mixtures. A newly developed three-dimensional (3D) Nrf2 reporter epidermis model for skin sensitization assessment is reported. This NAM may help to overcome these limitations. The NAM combines the in vivo-like biology and exposure conditions of 3D epidermis models with the reliability, convenience, and cost-effectiveness of secreted reporter gene technology. The Keap1-Nrf2-ARE pathway was chosen as the reporter gene read-out, as it is induced by most skin sensitizers and already adopted in OECD Test guideline 442D. Immortalized human primary keratinocytes (Ker-CT) were stably transfected with the pIGB-Nrf2-SEAP vector to construct a Nrf2 reporter cell line. Ker-CT Nrf2 reporter cells showed negligible basal expression of the Secreted Embryonic Alkaline Phosphatase (SEAP) reporter, which was induced 13.5-fold by exposure to the skin sensitizer cinnamic aldehyde (CA). Co-exposure to CA and the Nrf2 inhibitor glucocorticoid clobetasol propionate significantly suppressed the CA-induced SEAP expression, confirming dependance of the SEAP expression on Nrf2 activation. Using air-liquid interface and animal constituent free culture conditions, the Ker-CT Nrf2 reporter cells differentiated to stratified 3D epidermis models with an in vivo-like skin architecture and functional skin barrier. Evaluation of a Ker-CT Nrf2 reporter cell-based 2D assay by testing 10 conventional reference chemicals showed a predictive accuracy for skin sensitization potential of 80% and 70% compared to LLNA and human data in two independent laboratories and a high intra- and interlaboratory reproducibility. Moreover, the 3D epidermis models predicted 3 sensitizing and 2 non-sensitizing reference chemicals correctly in a first proof-of-concept study. Further investigations foresee the testing of additional chemicals, including hydrophobic compounds and mixtures to confirm the potential of the 3D epidermis models to broaden the applicability domain for NAM-based skin sensitization assessment.

[The patulous eustachian tube-novel surgical approaches]. / Das Syndrom der klaffenden Tube - neue chirurgische Therapieansätze.

A patulous eustachian tube (tuba aperta) may lead to an enormous reduction in quality of life. A patulous eustachian tube can cause symptoms such as autophony, breath synchronous tinnitus, pressure sensation in the ear, and hearing loss. In combination with so-called "sniffing", it can trigger the development of cholesteatoma. Due to the diffuse symptoms the correct diagnosis of this disease can be challenging. A patulous eustachian tube can be best diagnosed through a well-structured examination including patient history, physical examination with thorough observation of movements of the tympanic membrane, and tympanometry with reflex decay. This publication reviews recent literature on the patulous eustachian tube. We focused on the evaluation of the different surgical strategies such as the patulous eustachian tube reconstruction, the Kobayashi plug or the injection of Vox® implants into the torus tubarius.

[Tympanotomy and sealing of the round window membrane in sudden sensorineural hearing loss: a retrospective analysis]. / Tympanoskopie mit Abschottung der Rundfenstermembran beim idiopathischen Hörsturz: Eine retrospektive Analyse.

BACKGROUND: The pathogenesis of idiopathic sudden sensorineural hearing loss (ISSHL) still remains unclear. This retrospective study was performed to evaluate the effectiveness of tympanotomy and sealing of the round window membrane after unilateral idiopathic sudden sensorineural hearing loss. METHODS: A total of 74 patients with idiopathic sudden sensorineural hearing loss were treated with antiphlogistic-rheologic infusion therapy according to Stennert (steroids and pentoxyphylline). In addition, all patients underwent exploratory tympanotomy and sealing of the round window membrane. Pure tone audiometry was performed pre- and postinterventionally. RESULTS: The average hearing loss (four pure tone average) of all patients was 58.9 dB pre-, and 46 dB postinterventionally, which is an average improvement of 12.9 dB. Patients with hearing loss of more than 60% improved significantly compared to patients with hearing loss less than 60% (33.9% vs. +3.3%). Sealing of the round window membrane was found to be more effective when performed within 8 days after ISSHL. A membrane rupture did not lead to better therapy results. No significant correlation was found between therapy outcome and other clinical symptoms. CONCLUSION: Sealing of the window membrane shows equal results to conservative methods. If patients with hearing loss of more than 60% have more benefit in tympanotomy with sealing of the window membrane than patients with less hearing loss--as shown as in this study--has to be proved in randomized examinations. Intraoperatively found ruptures of the round window membrane had no significant effect on the therapy outcome.

[Chronic obstructive eustachian tube dysfunction in adults: long-term results of balloon eustachian tuboplasty]. / Chronisch obstruktive Tubenfunktionsstörung des Erwachsenen: Langzeitergebnisse der Ballondilatation der Tuba Eustachii.

BACKGROUND: Sufficient diagnostic tools and effective therapies for chronic obstructive eustachian tube dysfunction are lacking. PATIENTS AND METHODS: A total of 120 patients (209 ears) with chronic obstructive eustachian tube dysfunction were treated over a 2-year period using transnasal endoscopic balloon dilatation of the cartilaginous part of the eustachian tube (balloon eustachian tuboplasty, BET). A balloon catheter is inserted into the eustachian tube via the pharyngeal opening and dilated with a pressure of 10 bar for 2 min. RESULTS: The first 12 patients (20 dilatations) had a pretreatment average tube score of 1.25 (± 1.83 SD), and 1 year after treatment, the score improved to 6.2 (± 2.61 SD). Furthermore, the pretreatment and 2-month posttreatment data of 66 additional patients (115 dilatations) were analyzed. In these patients, the tube score improved significantly from 2.21 (± 2.02 SD) to 5.4 (± 2.53 SD). CONCLUSION: The initial long-term results suggest that BET is feasible and safe for the treatment of chronic obstructive eustachian tube dysfunction.

[Therapy of chronic obstructive eustachian tube dysfunction: evolution of applied therapies]. / Therapie chronisch obstruktiver Funktionsstörungen der Tuba Eustachii: Konzepte im Wandel der Zeit.

This paper reviews the past and present developments in the treatment of chronic obstructive eustachian tube dysfunction. Alongside tube catheterization and bougie insertion, modern approaches such as laser eustachian tuboplasty and balloon eustachian tuboplasty (BET) are described. In BET, transnasal endoscopic insertion via the pharyngeal ostium places a balloon catheter in the cartilaginous portion of the eustachian tube. This is then dilated to a pressure of 10 bar for 2 min. Up until January 2013, 351 chronic obstructive eustachian tube dysfunction patients had been treated in our department using BET. The average preoperative eustachian tube score was 2.1 (± 1.8 standard deviation, SD); 12 months postoperatively it was 6.1 (± 2.6 SD). Of these patients, 87% expressed satisfaction with the improvement in chronic obstructive dysfunction. These results demonstrate that BET is a safe and effective treatment for improving eustachian tube function and ear ventilation.

[Intralabyrinthine schwannomas]. / Intralabyrinthäre Schwannome.

Schwannomas are benign neurogenic tumors arising from Schwann cells that usually form the myelin sheath of peripheral nerves. The typical localization of vestibular schwannomas is the internal auditory canal or the cerebellopontine angle. Intralabyrinthine lesions are extremely rare. Here we describe a series of four consecutive cases of intralabyrinthine schwannomas that were treated in the Department of Otorhinolaryngology, Head and Neck Surgery, Klinikum Bielefeld in Bielefeld, Germany. Therapeutic options are discussed and the literature is reviewed.

[Acquired postinflammatory stenosis of the external auditory canal]. / Postinflammatorische Gehörgangsstenose.

There are only few publications about acquired postinflammatory stenosis of the auditory canal, its etiology, its progress and an adequate therapy. Chronic inflammatory processes of the ear canal, the tympanic membrane or the middle ear could lead to a replacement of the origin epithelium by fibrotic tissue and ends in a total obliteration of the ear canal. Lateral parts of the canal remain open and have the form of a blind-ending sac. Patients can suffer from severe conductive hearing loss. Treatment implies local therapy in the first stadium of the disease, then in the second one surgical removement of the fibrotic tissue is indicated before ear drum and bony canal are covered with skin graft. This technique results in stable, wide ears with good hearing.

[Superelastic nitinol stapes prostheses]. / Superelastische Nitinol Stapes Prothesen.

UNLABELLED: SUPERELASTIC NITINOL STAPES PROSTHESESINTRODUCTION: Many different prostheses are available for stapes surgery. The newly designed Nitinol piston band-shaped stapes prosthesis could minimize postoperative complications due to its new superelastic characteristic and design. PATIENTS AND METHODS: A stapedectomy and implantation of superelastic Nitinol piston stapes prosthesis was performed in 22 patients with a mean age of 45.2 years. Examination and audiometry was performed pre- and postoperatively. RESULTS: The average observed air-bone-gap in all frequencies was 12.8 dB postoperatively, whereas in the frequencies 0.5-4 kHz ABG was under 10 dB in 68.2% of the patients, between 10 and 15 dB in 18.2% and between 15 and 20 dB in 9.1% of the patients. No patient showed air-bone-gap of more than 20 dB. One patient missed follow-up examination. CONCLUSION: In stapes surgery the step of fixation of the prosthesis onto the incus is critical. Implantation of the new Nitinol piston stapes prosthesis is facilitated due to the superelasticity and the design of the prosthesis. Crimping is not needed anymore. Postoperative hearing results are very good comparable to other Nitinol (shape memory) or titanium prostheses. Long-term results in a larger number of patients will be studied in the future.

[Direct percutaneous embolization of a carotid body tumor with Onyx]. / Perkutane Onyx(R)-Embolisation zur Therapie von Glomus-caroticum-Tumoren.

Carotid body tumors are highly vascularized lesions that require successful preoperative embolization to achieve favorable clinical results in terms of morbidity and complete tumor resection. The procedure of percutaneous embolization was performed using ethylene-vinyl alcohol copolymer (Onyx) in addition to balloon-catheter protection to prevent particle displacement into the internal carotid artery. The procedure resulted in nearly complete tumor embolization and facilitated the uneventful complete surgical resection. Percutaneous angiographic embolization of carotid body tumors in the head and neck was found to be safe and effective. This technique is likely to result in improved surgical outcomes and tumor resectability.

[Clinical and experimental considerations for evaluation of Eustachian tube physiology]. / Klinische und experimentelle Untersuchungen zur Physiologie der Tuba Eustachii.

BACKGROUND: Eustachian tube dysfunction plays a pivotal role in the pathogenesis of otitis media with effusion. Besides the lack of sufficient animal models to investigate the role of gastroesophageal reflux on Eustachian tube function, there is no reliable test that clinically allows the quantification of Eustachian tube function. Therefore, we established a Mongolian gerbil model to trace gastroesophageal reflux into the middle ear. In gerbils with traceable reflux, the refluxate reached the both middle ears through the Eustachian tubes in most cases. METHODS: Clinical studies were performed to analyze the reproducibility of measuring the accuracy of modified tube manometry in healthy Caucasians. RESULTS: Tube manometry was found to be a reliable and reproducible tool for measuring Eustachian tube function. CONCLUSIONS: Both our animal model and the clinical application of tube manometry are likely to be useful for further experimental and clinical studies.

Macroencapsulation of human cartilage implants: pilot study with polyelectrolyte complex membrane encapsulation.

Autogenous cartilage transplantation is a generally accepted method in reconstructive surgery. A promising alternative to this established method could be represented by in vitro engineering of cartilage tissue. In both methods of autogenous transplantation, host response induces reduction of transplant size and transplant instability to an unforeseeable extent. To investigate if polyelectrolyte complex (PEC) membranes were able to avoid host-induced effects on implanted tissues without neglecting the tissue metabolism, human septal cartilage was encapsulated with polyelectrolyte complex membranes and subcutaneously implanted on the back of nude mice. Septal cartilage implants, without encapsulation served as control group. Histochemical and electron microscopic investigations were performed 1, 4, 8 and 16 weeks after implantation. In the case of an intact PEC-membrane no interactions between the host and the implant could be observed. In some implants, the capsule was torn in several areas and signs of chronic inflammation with the cartilage having been affected mildly could be observed. Implanted cartilage protected with PEC-encapsulation showed no signs of degeneration and significantly lower level of after effects of chronic inflammation than implanted cartilage without PEC-encapsulation. Therefore, it could be expected, that PEC membrane encapsulation offers a novel approach to protect cartilage implants from host response after autogenous transplantation.

[Alterations of the basal membrane in middle ear cholesteatoma]. / Alteraciones de la membrana basal en el colesteatoma de oído medio.

Cholesteatoma epithelium is characterized by a keratinocyte disregulation accompanied by destruction of the ossicles and other bony parts of the temporal bone. Immunohistochemical methods using antibodies to fibronectin, tenascin and metalloproteinases were used to assess the alterations of the instrinsic and extrinsic components of the basement membrane. Spatial orientation of the basement membrane was preserved in histological sections. Collagen type IV, tenascin, fibronectin, basic fibroblastic growth factor (bFGF), and matrix metalloproteinases (MMPs) are related to the matrix, perimatrix of normal or pathological tissues. They were studied immunohistologically in twenty cholesteatomas, eight samples of normal auditory canal skin, and six specimens of normal middle ear mucosa. Cholesteatomas displayed alterations of the basal membrane, with presence of MMPs and a linear immunoreactivity for collagen type IV and laminin, disrupted in areas with intense inflammation. The electronic microscope revealed protrusions, duplications, thickening and disruptions of the lamina densa of the basement membrane. Thus, we conclude, that MMPs and bFGF could play an important role maintaining the proliferative activity and the aggressive behaviour of cholesteatoma in the middle ear.

[Comparative analysis of the proliferative capacity of cholesteatomas]. / Análisis comparativo de la capacidad proliferativa del colesteatoma.

Cholesteatomas of the middle ear are frequently aggressive and produce bone destruction. Stimulation of the surrounding inflammatory tissue and autocrine mechanisms could be responsible for the keratinocytic dysregulation of cholesteatomas, as well as for abnormal proliferation patterns. The proliferative capacity of human cholesteatoma of the middle ear was studied through the kinetics of the epithelial cells of cholesteatomas and external ear canal. The APAAP method was used to study the monoclonal antibody MIB-1, which recognizes an antigen of cells in the division phase. Biopsies taken from the outer ear canal (n = 7) revealed an MIB-1 level (the ratio of MIB-1 positive cells to all cells) of 7.6% +/- 2.2%. Cholesteatoma samples (n = 13) showed an MIB-1 level of 17.4% +/- 8.9%, and heterogeneity of the proliferative areas. Epithelial invaginations into the surrounding stroma were characterized by intense mitotic activity. The results confirmed a statistically significant increase in keratinocytes in the cholesteatomas, with an MIB-1 level 2.3 times higher than that of meatal keratinocytes. PCNA, a nuclear proliferation antigen which expresses the growth phase of cells in normal and tumoral tissue, was determined in 15 biopsies of meatal skin and 7 specimens of cholesteatoma in the phase of infection and 8 non-infection. Although the number of proliferative cells changed depending on the site of the cholesteatorna, the amount of PCNA-positive cells was significantly higher in the cholesteatoma (2.5-15, mean 9.3) than in normal skin (1-2.8, mean 1.5) (p < 0.001). Finally, AgNOR (argyrophyllic nucleolar organizer regions), which express proliferative activity, were determined in 12 specimens of meatal skin and in 19 acquired and 2 congenital cholesteatomas. A mean of 3.71 AgNOR dots were counted in the cholesteatomas and 1.54 dots in meatal skin specimens. The immunohistological study with three different markers expressing cellular proliferative capacity showed hyperproliferation associated with keratinocyte dysregulation in cholesteatoma samples, which could explain the clinically aggressive and destructive behavior of these lesions.