A case of palmoplantar lichen planus in a patient with congenital sensorineural deafness.

We report a case of palmoplantar lichen planus in a 7-year-old Japanese girl with congenital deafness, who presented with erythematous eruptions and hyperkeratosis, with peeling and fissures on her soles, palms and digits. On histological examination of a skin biopsy from the lesion on her wrist, lichen planus was identified. Using computed tomography of the inner ears, bilateral cochlear dysplasia was found. The patient's DNA was sequenced; no sequence variants were detected in the GJB2 gene encoding connexin-26, but she had a missense mutation in SLC26A4 (solute carrier family 26, member 4). Mutations in SLC26A4 are known causes of hearing loss, but this is a novel mutation, which has not been reported previously. In addition, there have been no reports of cutaneous symptoms in previously reported patients with mutations in SLC26A4. To our knowledge, therefore, this is the first report of palmoplantar lichen planus associated with sensorineural deafness accompanied by a mutation in the SLC26A4 gene.

Binocular and monocular measurements of subjective visual vertical in vestibular loss.

The objective of this study was to investigate the possibility to omit the time-consuming monocular vision measurement in the subjective visual vertical (SVV) test by demonstrating that there is no difference in the results between binocular and monocular measurements. Thirty-one patients with unilateral vestibular schwannoma and 20 normal subjects as controls were involved. Both binocular and monocular measurements of SVV were performed. The main outcome of this study was the difference in the results of SVV between binocular and monocular measurements. There were no significant differences in the tilts of the SVV between binocular and monocular measurements in vestibular schwannoma patients as well as in the controls. Abnormal tilts of SVV may be evaluated precisely only by binocular vision instead of monocular vision.

Expression of the osmotically responsive cationic channel TRPV4 in the endolymphatic sac.

The immunohistochemical expression pattern and the physiological role of transient receptor potential vanilloid (TRPV) 4 in the endolymphatic sac were investigated. TRPV4 was expressed predominantly in the apical membrane of mitochondria-rich cells, and cell volume regulation by TRPV4 was observed in a tissue culture of the rat endolymphatic sac. TRPV4 was also present in the endolymphatic sacs of patients with vestibular schwannoma and with Ménière's disease. TRPV4 is assumed to play a role as an osmoreceptor in cell and fluid volume regulation in the human endolymphatic sac.

A case of bilateral middle-ear squamous cell carcinoma.

Only eight cases of bilateral middle-ear squamous cell carcinoma (SCC) have been reported to date. We present the case of a 75-year-old male with bilateral middle-ear SCC and review the previously reported cases. The patient was diagnosed as having moderately-differentiated SCC in the left middle ear in February 1995 and well-differentiated SCC in the right middle ear in September 1997. He initially received radiation therapy with (60)Co pendulum (64 Gy) in the left ear and was subsequently treated by Liniac irradiation (50 Gy) in the right ear. He has now been followed up at our ENT clinic for 29 months without vertigo or facial nerve palsy since the second radiation therapy. Although he has a residual tumour in the right middle ear invading the middle cranial fossa dura, no sign of recurrence has been detected in the left ear.

Expression pattern of adenylyl cyclase isoforms in the inner ear of the rat by RT-PCR and immunochemical localization of calcineurin in the organ of Corti.

Most studies concerning adenylyl cyclases in the inner ear were carried out before the advent of molecular biology. In a PCR approach using cDNAs of six inner ear tissues (stria vascularis, endolymphatic sac, organ of Corti, vestibulum, cochlear and vestibular nerve) we found tissue specific expression of adenylyl cyclase isoforms. Adenylyl cyclases types 2 and 4 are predominant in the fluid controlling tissues, i.e. in the stria vascularis and endolymphatic sac. In the organ of Corti and vestibulum the Ca2+-modulated isoforms types 1, 6 and 9 were expressed. The regulation of adenylyl cyclase 9, which is the major isoform expressed in the organ of Corti, proceeds via the Ca2+-activated protein phosphatase 2B (calcineurin, PPP3). PCR with specific primers for calcineurin demonstrated its abundant expression in the organ of Corti. Using a monoclonal antibody we localized calcineurin immunochemically to the cochlear nerve, the nerve fibers and the inner hair cells. In the cochlear and vestibular nerves a characteristic neuronal expression pattern of adenylyl cyclase isoforms was observed, i.e. adenylyl cyclases types 2, 3 and 8. The functional consequences of the adenylyl cyclase expression pattern in the inner ear are discussed in conjunction with its unique sensory performance.

Expression pattern of aquaporin water channels in the inner ear of the rat. The molecular basis for a water regulation system in the endolymphatic sac.

Mammalian aquaporins constitute a family of so far 10 related water channel proteins which mediate osmotically driven water fluxes across the plasma membrane. Because regulation of the ionic composition and osmolality of inner ear fluids is of great functional significance, we investigated the expression patterns of aquaporins in five defined areas of the rat inner ear by RT-PCR. The tissues used were stria vascularis, endolymphatic sac, Reissner's membrane, vestibulum and organ of Corti. Aquaporin 1 transcripts were detected in all tissues and are probably constitutive. Aquaporin 5 was only expressed in the organ of Corti and in Reissner's membrane. We show that aquaporin 2, so far considered to be specific to the principal cells of the renal collecting duct, is expressed in the endolymphatic sac. Aquaporin 2 expression was not detected in any other inner ear region. The postnatal appearance of aquaporin 2 transcripts in the endolymphatic sac resembled that in the kidney, i.e. it increased postnatally until day 4. The full-length DNA for aquaporin 2 was cloned from cDNA of the endolymphatic sac. It had an irrelevant Ile54Thr mutation because it could be functionally expressed in Xenopus oocytes. Also exclusively in the endolymphatic sac of the inner ear, we detected transcripts for aquaporin isoforms 3 and 4 which are known to be expressed in the renal principal cells. In the kidney, aquaporin 2 regulation involves vasopressin-stimulated, cAMP-dependent phosphorylation of Ser256 of aquaporin 2 which is stored in cytosolic vesicles. These storage vesicles also contain a serpentine calcium/polycation-sensing receptor. Vesicle shuffling to the plasma membrane involves proteins such as vesicle-associated membrane protein VAMP2, syntaxin-4 and the small GTPase Rab3a. Using RT-PCR we were able to demonstrate the expression of all of these components. By analogy the data suggest that in the endolymphatic sac of the inner ear a system for cellular water permeability is in place which may share many similarities with that characterized in the principal cells of the renal collecting duct. These findings may have a number of interesting pharmacological implications which need to be addressed in future studies.

Expression of membrane-bound and cytosolic guanylyl cyclases in the rat inner ear.

Membrane-bound guanylyl cyclases (GCs) are peptide hormone receptors whereas the cytosolic isoforms are receptors for nitric oxide. In the inner ear, the membrane-bound GCs may be involved in the regulation of fluid homeostasis and the cytosolic forms possibly play a role in signal processing and regulation of local blood flow. In this comprehensive study, we examined, qualitatively and quantitatively, the transcription pattern of all known GC isoforms in the inner ear from rat by RT-PCR. The tissues used were endolymphatic sac, stria vascularis, organ of Corti, organ of Corti outer hair cells, cochlear nerve, Reissner's membrane, vestibular dark cells, and vestibular sensory cells. We show that multiple particulate (GC-A, GC-B, GC-D, GC-E, GC-F and GC-G) and several subunits of the heterodimeric cytosolic GCs (alpha1, alpha2, beta1 and beta2) are expressed, albeit at highly different levels. GC-C was not found. GC-A and the soluble subunits alpha1 and beta1 were transcribed ubiquitously. GC-B was present in all tissues except stria vascularis, which contained GC-A and traces of GC-E and GC-G. GC-B was by far the predominant membrane-bound isoform in the organ of Corti (86%), Reissner's membrane (75%) and the vestibulum (80%). Surprisingly, GC-E, a retinal isoform, was detected in significant amounts in the cochlear nerve (8%) and in the organ of Corti (4%). Although the cytosolic GC is a heterodimer composed of an alpha and a beta subunit, the mRNA transcription of these subunits was not stoichiometric. Particularly in the vestibulum, the transcription of the beta1 subunits was at least four-fold higher than of the alpha1 subunit. The data are compatible with earlier suggestions that membrane receptor GCs may be involved in the control of inner ear electrolyte and fluid composition whereas NO-stimulated GC isoforms mainly participate in the regulation of blood flow and supporting cell physiology.

The effect of anti-diuretic hormone on the endolymphatic sac of the inner ear.

The anti-diuretic hormone vasopressin (AVP) regulates water excretion from the kidney by increasing the water permeability of the collecting duct. AVP binds to V2-receptors and induces the translocation of aquaporin-2 water channels (AQP-2) into the apical plasma membrane of principal cells. By this mechanism AVP controls water reabsorption in the kidney. The effects of AVP on the endolymphatic sac (ES) of the inner ear, which is thought to mediate reabsorption of endolymph, were investigated. Both the V2-receptor and the AQP-2 water channel were found to be expressed in the ES epithelium. In the ES AVP binds to receptors most probably of the V2-subtype. Application of AVP to organotypically cultured ES inhibits membrane turnover in ribosomal-rich cells of the ES epithelia, which is thought to mediate translocation of AQP-2 into the surface membrane. This suggests that AVP has contrasting effects in the inner ear and kidney, which may be physiologically useful for maintaining endolymphatic pressure during severe hypovolemia. Animal experiments show that AVP causes endolymphatic hydrops after systemic application to guinea-pigs, which suggests a causal role for the increased AVP levels found in humans suffering from Ménière's disease.

Detection of viral antigen in the endolymphatic sac.

A study was devised to determine whether or not any immune defense mechanism is present when a virus invades the human endolymphatic sac (ES). The ES was removed from 14 fresh autopsy cases having no known pre-mortem diseases in the middle and inner ears. Specimens were then examined for viral antigens including herpes simplex (HSV) type 1 and 2, mumps and cytomegalovirus using immunohistochemical methods. DNA examination by in situ hybridization was also performed for HSV. HSV antigen and DNA were observed in 9 of the 14 cases studied. These findings suggest that the virus invades the ES but is impeded by an immune defense mechanism under normal conditions. Since disease may alter host defenses, further studies are warranted to study the relationship between HSV and patients with Meniere's disease.

Interferon-induced sudden hearing loss.

With the increasing long-term use of interferon (IFN), several new adverse effects have been recognized. Very little attention, however, has been paid to auditory acuity. We encountered 3 cases of sudden hearing loss associated with IFN. We then conducted a prospective study to assess the auditory function of 73 patients receiving IFN. Auditory disability (tinnitus and/or hearing loss) occurred in 32 patients (43.8%) during IFN therapy, among which audiometry documented sensorineural hearing loss in 27 cases (36.9%); 17 (48.6%) of the 35 patients receiving IFN-beta had auditory disability, including hearing loss in 13 cases (37.1%), and 15 (39.5%) of 38 patients receiving IFN-alpha suffered from auditory disability. There was not much difference between the influences of IFN-alpha and -beta. Auditory disability frequently developed in the later stages of treatment, and most patients recovered 7-14 days after the discontinuation of IFN. The results demonstrate that sudden hearing loss can occur as a side effect of treatment with IFN. This may reveal the association between autoimmunity and sudden hearing loss.

Vascular permeability changes associated with experimentally induced facial nerve lesions in the rabbit.

Changes in vascular permeability to sodium fluorescein following experimentally induced nerve lesions were examined in the rabbit facial nerve. Sodium fluorescein was injected intravenously as a permeability tracer and then localized by fluorescence microscopy. In control nerves, endoneurium showed only slight fluorescence while intense fluorescence was observed in the epineurium and perineurium. In nerves demonstrating edema and Wallerian degeneration, endoneurium was found to have an increased accumulation of tracer. This increased endoneurial vascular permeability in facial nerve lesions may explain nerve enhancement seen in gadolinium-enhanced magnetic resonance imaging in patients with facial nerve paralysis.

[Sex hormones in fibrous dysplasia of the facial bone--an immunohistological study].

Fibrous dysplasia of the facial bones frequently occurs in the maxilla around the time of puberty and becomes inactive when skeletal growth is completed. A case of fibrous dysplasia of the maxilla and sphenoidal-temporal bone in a 19 year-old male was studied, in terms of the presence of estradiol, testosterone and dihydrotestosterone, using the peroxidase-antiperoxidase method. This case underwent partial surgical resection, for cosmetic deformity, of the maxillary tumor which, however, relapsed to preoperative size within three weeks. Estradiol and testosterone were strongly positive and dihydrotestosterone was slightly positive in the tumor cells. Sex hormones were apparently present in the tumor cells and exerted a strong influence on the growth of the fibrous dysplasia.

[Immunohistological study of the nasal mucosa in latent allergic patients].

We studied the distribution of T lymphocyte subpopulations and EG2 positive cells in the inferior turbinates of subjects with latent nasal allergy by use of an immunohistochemical procedure. Five patients who had a positive skin test for house dust and one who had a positive skin test for Japanese cedar were studied. The specimens were frozen at -70 degrees C and sliced at 4 microns with a cryostat. The peroxidaseantiperoxidase method with monoclonal antibodies (CD4, CD8, EG2) was used to detect T lymphocyte subpopulations and activated eosinophils. Finally, the specimens were counterstained with Mayer's Hematoxylin. CD4 positive cells and CD8 positive cells were found mainly in the superficial layer of the lamina propria. In every subject, the number of CD4 positive cells dominated that of CD8 positive cells in the lamina propria. The ratio of CD4 positive cells to CD8 positive cells was 1.93, on average. This ratio was lower than the ratio typical of nasal allergy, but higher than the ratio of non-allergic normal controls. Though the number of EG2 positive cells was lower than the number typical of nasal allergy, EG2 positive cells were observed in every case. We speculate that latent nasal allergic reactions may develop in the inferior turbinates.

Vascular permeability to sodium fluorescein in the rabbit cranial nerve root: possible correlation with normal cranial nerve enhancement on gadolinium-enhanced magnetic resonance imaging.

Vascular permeability in cranial nerve roots was examined after intravenous injection of sodium fluorescein in the adult rabbit. Fluorescence was observed in the distal nerves through the following portions: intracavernous portion of the oculomotor nerve, distal internal auditory canal segment of the facial nerve, and ganglionic portions of the trigeminal, glossopharyngeal and vagus nerves. In the acoustic nerve, the vestibular ganglion showed fluorescence. No fluorescence was observed in the olfactory or optic nerves. During in vivo gadolinium-enhanced magnetic resonance imaging (Gd-MRI) of two separate animals, trigeminal nerve enhancement was observed in the region showing fluorescence. Histologically, intense fluorescence was observed in ganglia and external nerve sheaths of the cranial nerves showing macroscopic fluorescence. A slight fluorescence was also seen in endoneurial connective tissue but not observed within the nerve fibers. The results of this study suggest that the physiological enhancement of human cranial nerves seen on Gd-MRI may correlate with vascular permeability.

Sex hormones in the kidney and endolymphatic sac. An immunohistological study.

Autopsy specimens of kidney and endolymphatic sac were studied in terms of progesterone (P), estradiol (E), testosterone (T), dihydrotestosterone (DHT) and aldosterone (A) using the peroxidase-antiperoxidase method. The results obtained were as follows: The epithelial cells of the renal tubules were positive to P, E, T, DHT and A. The epithelial cells of the endolymphatic sac were also positive to these sex hormones though varying in stainability among cases. In view of the immunohistological findings of sex hormones and aldosterone, the resorptive and regulative function of the epithelium in the kidney and endolymphatic sac is discussed.

[Immunohistological study of eosinophilic infiltration of nasal polyps in aspirin-induced asthma].

It is well known that nasal polyps frequently develop in patients with aspirin-induced asthma, which is thought to be a non-atopic disease. We immunohistochemically examined the eosinophils infiltrating the nasal polyps in patients with aspirin-induced asthma. It has also been established that the monoclonal antibody EG1 reacts with both stored and secretion type ECP (eosinophil cationic protein), and that EG2 reacts only with the secretion type of ECP. EG2 positive cells may thus be considered to be activated eosinophils. Seven cases with nasal polyps associated with aspirin-induced asthma participated in our study. Blood eosinophilia was observed in all 7 cases, but 6 showed normal blood values IgE. Two reacted to house dust antigen, on skin tests and RAST. In the nasal polyps, many EG2 positive cells were observed. On serial sections, the number and distribution of EG1 and EG2 positive cells were almost equal. In the superficial lamina propria, extra-cellular release of ECP was noted. However, epithelial damage did not relate to the number of EG2 positive cells or the degree of extra-cellular EG2 release. In the deep lamina propria, slight extra-cellular ECP release was found. From these results, the eosinophils in nasal polyps accompanying aspirin-induced asthma were thought to be activated. Eosinophils seem to play an important role in the development of nasal polyps. However, tissue injury induced by eosinophils, was not be demonstrated in this study.