Immunohistochemical localization of phospholipase A2 in the guinea pig nasal mucosa.

OBJECTIVE: Phospholipase A2 (PLA2) is a key enzyme in arachidonic acid metabolism, which is involved in the maintenance of biological homeostasis and the onset of various diseases. The immunohistochemical localization of PLA2 in the nasal mucosa has not been reported, even though the presence of messenger RNA of PLA2 has been demonstrated in the human nasal brush sample. The present study was designed to determine the localization of PLA2s in the nasal cavity. METHODS: The immunohistochemichal localization of secretory PLA2 (sPLA2) and cytosolic PLA2 (cPLA2) in the nasal mucosa was studied using adult guinea pig. RESULTS: Both sPLA2 and cPLA2 were localized in the nasal gland as well as the respiratory epithelium, and not in the surrounding vascular endothelial cells, olfactory gland, olfactory epithelium or submucosal tissue. CONCLUSION: Our data provide the first convincing evidence that both sPLA2 and cPLA2 are significantly expressed in the nasal gland and the respiratory epithelium, and are suggested to regulate the function of the nasal mucosa, such as bactericidal, Na secretion, and allergic response.

Six1 controls patterning of the mouse otic vesicle.

Six1 is a member of the Six family homeobox genes, which function as components of the Pax-Six-Eya-Dach gene network to control organ development. Six1 is expressed in otic vesicles, nasal epithelia, branchial arches/pouches, nephrogenic cords, somites and a limited set of ganglia. In this study, we established Six1-deficient mice and found that development of the inner ear, nose, thymus, kidney and skeletal muscle was severely affected. Six1-deficient embryos were devoid of inner ear structures, including cochlea and vestibule, while their endolymphatic sac was enlarged. The inner ear anomaly began at around E10.5 and Six1 was expressed in the ventral region of the otic vesicle in the wild-type embryos at this stage. In the otic vesicle of Six1-deficient embryos, expressions of Otx1, Otx2, Lfng and Fgf3, which were expressed ventrally in the wild-type otic vesicles, were abolished, while the expression domains of Dlx5, Hmx3, Dach1 and Dach2, which were expressed dorsally in the wild-type otic vesicles, expanded ventrally. Our results indicate that Six1 functions as a key regulator of otic vesicle patterning at early embryogenesis and controls the expression domains of downstream otic genes responsible for respective inner ear structures. In addition, cell proliferation was reduced and apoptotic cell death was enhanced in the ventral region of the otic vesicle, suggesting the involvement of Six1 in cell proliferation and survival. In spite of the similarity of otic phenotypes of Six1- and Shh-deficient mice, expressions of Six1 and Shh were mutually independent.

Argon plasma coagulation for intractable nasal obstruction occurring in patients with allergic rhinitis.

New surgical treatment for the intractable nasal obstruction in patients with nasal allergy by using Argon Plasma Coagulator (APC) was introduced. Of patients with allergic rhinitis treated at our institute, 28 patients complaining nasal obstruction were treated APC surgery. Epithelization of the mucosa of inferior turbinate was almost completely accomplished at 4 weeks after surgery, at which time mucosal swelling was reduced, and nasal obstruction was ameliorated in all cases, though a crust and fibrin membrane adhered to the mucosa between 2 to 4 weeks after surgery, resulting in temporary exacerbation of nasal obstruction. Nasal obstruction was again aggravated in only one patient about 6 months after surgery, but such symptom could be ameliorated by re-coagulation. No bleeding and no smoke occurred in the operation. No morbidity was also noticed after operation. APC is easy to perform safely and effectively compared with another laser surgeries, and is useful for intractable nasal obstruction occurring in patients with allergic rhinitis.

Expression of CLC-KB gene promoter in the mouse cochlea.

SUMMARY: We have investigated the expression of chloride channels by examining the cochlea of mice harboring the enhanced green fluorescence protein (EGFP) gene driven by an 11 kbp human CLC-KB gene promoter. CLC-KB was seen not only on the stria vascularis but on spiral ligament and limbal fibrocytes, interdental cells and satellite cells of spiral ganglion neurons that are known to possess both Na,K-ATPase and the Na-K-Cl co-transporter (NKCC). These results suggest that some fibrocytes possessing both the CLC-KB and the NKCC may be involved in the regulation of cell volume, transport and recycling of Cl- such as is seen in the stria vascularis. Moreover, these fibrocytes may recycle Cl- through CLC that accompany Na+ and K+ into the cell via NKCC.

Late laryngo-tracheal cartilage necrosis with external fistula 44 years after radiotherapy.

Major late complications, following radiotherapy of head and neck carcinomas, such as laryngeal oedema, perichondritis and chondronecrosis usually occur between three and 12 months after treatment. However, the present case displayed necrosis of the laryngo-tracheal cartilage and ulceration of anterior neck skin with a tracheal fistula 44 years after irradiation. The reasons for the long interval between irradiation and late complications may be explained by long-standing hypovascularity and/or infection of the irradiated area. Histological study revealed chondronecrosis without inflammatory cells in the laryngo-tracheal cartilage and bacterial colonization of subcutaneous tissue. Necrotic tissue was removed and tracheostomy was performed. The fistula was almost completely closed using a delto-pectoral cutaneous flap and the clinical course of patient has been good. This paper demonstrates the possibility of laryngo-tracheal necrosis in cases that had received radiation as long ago as 44 years.

Anomalies of the auditory organ in trisomy 18 syndrome: human temporal bone histopathological study.

The purpose of this study was to define the histopathological changes in the temporal bone of a fetus with trisomy 18 syndrome, a stillborn due to perosplanchnia. Several anomalies were found including malformation of the auditory ossicles, residual mesenchyme in the middle ear, aberrant tensor tympani muscle, absence of stapedial tendon, aberrant lateral ampullary nerve and wide endolymphatic sinus. The incus body was deformed and separated from the long process by connective tissue and monocrural stapes was noted in the right ear. Three-dimensional reconstruction images provided a clear view of the auditory ossicle malformation. The abnormal findings in our case indicate that ear anomalies in this syndrome might be derived from the component around the first and second branchial arches.

Rhabdomyoma of the base of the tongue.

The histopathological and imaging findings of a rhabdomyoma of the base of the tongue were studied. An immunohistochemical examination of the tumour cells showed positive immunostaining for myoglobin, desmin, and striated muscle actin, but negative immunostaining for smooth muscle actin. Electron microscopy showed many glycogen granules and mitochondria in the tumour cells. The T2-weighted and contrast-enhanced magnetic resonance images (MRI) clearly delineated morphological features of this tumour, but T1-weighted MRI and computed tomography (CT) images showed no important features. These findings are typical for an adult extracardiac rhabdomyoma located in the head and neck region, and they will be useful for diagnosis of this tumour.

Expression of cyclooxygenase-1 and -2 is limited to the nasal glands in the guinea pig nasal cavity.

OBJECTIVES: To clarify the localization of cyclooxygenase (COX)-1 and -2 in the nasal cavity of guinea pigs and ascertain their physiological roles. MATERIAL AND METHODS: The distribution of the enzymes was investigated using immunohistochemistry. RESULTS: Immunoreactivities for COX-1 and -2 were limited to the nasal glands, and no expression was noted in the surrounding vascular endothelial cells, olfactory glands, respiratory epithelium, olfactory epithelium, submucosal tissue or nerves. To confirm the specificity of the reaction, the kidneys of the same animals were prepared as positive controls. The results demonstrated localization of COX-1 and -2 in uriniferous tubules. CONCLUSION: Our findings suggest that COX is involved in the secretion of nasal discharge from the nasal glands and that prostaglandins in the nasal discharge are probably secreted directly from the nasal glands.

Successful treatment of an extra-abdominal fibromatosis (desmoid tumor) arising from the prevertebral fascia of the neck.

We describe the successful treatment of a fibromatosis (desmoid tumor) arising from the prevertebral fascia of the neck. Total resection with wide margins is reportedly the best treatment for this kind of tumor. However, the anatomy of the head and neck makes such resection difficult. In this case, we were unable to completely remove the tumor because it was large and located close to the cervical vertebrae, common carotid artery and internal jugular vein. Incomplete resection is known to result in higher tumor recurrence than complete resection. In addition, the recurrence or progression of a tumor in the head or neck region is known to cause mortality by compression of the airway or major blood vessels. On the basis of reports that irradiation is effective treatment for this kind of tumor, we administered 30-Gy irradiation to the affected area. This therapy was very effective and no sign of recurrence was seen for 2 years after irradiation. We found that function-sparing resection plus postoperative radiotherapy is an effective treatment for advanced fibromatosis in the head and neck regions with proximity to or involvement with vital structures.

New interdisciplinary approach for removing large clivus and upper cervical spine tumors.

We have developed a new interdisciplinary approach for removing large clivus and upper cervical spine tumors. This approach is a combination of the Le Fort I osteotomy, midfacial degloving, and median labiomandibular glossotomy. Our approach gives an excellent, wide surgical field from the nasopharynx, including the base of the skull, to the base of the tongue and permits sufficiently safe extirpation of clivus and upper cervical spine tumors that may not be removed by transoral or transcervical approaches. Our approach not only incorporates the merits of each approach but also creates a larger surgical field that may be modified or expanded to accommodate the removal of more bulky tumors in this region. This novel approach will facilitate more successful resection of tumors arising between the nasopharynx, including the skull base, and the retropharyngeal area.

Effects of furosemide applied chronically to the round window: a model of metabolic presbyacusis.

Hearing thresholds in elderly humans without a history of noise exposure commonly show a profile of a flat loss at low frequencies coupled with a loss that increases with frequency above approximately 2 kHz. This profile and the relatively robust distortion product otoacoustic emissions that are found in elderly subjects challenge the common belief that age-related hearing loss (presbyacusis) is based primarily on sensory-cell disorders. Here, we examine a model of presbyacusis wherein the endocochlear potential (EP) is reduced by means of furosemide applied chronically to one cochlea of a young gerbil. The model results in an EP that is reduced from 90 to approximately 60 mV, a value often seen in quiet-aged gerbils, with no concomitant loss of hair cells. Resulting measures of cochlear and neural function are quantitatively similar to those seen in aging gerbils and humans, e.g., a flat threshold loss at low frequencies with a high-frequency roll-off of approximately -8.4 dB/octave. The effect of the EP on neural thresholds can be parsimoniously explained by the known gain characteristics of the cochlear amplifier as a function of cochlear location: in the apex, amplification is limited to approximately 20 dB, whereas in the base, the gain can be as high as 60 dB. At high frequencies, amplification is directly proportional to the EP on an approximately 1 dB/mV basis. This model suggests that the primary factor in true age-related hearing loss is an energy-starved cochlear amplifier that results in a specific audiogram profile.

Innervation of supporting cells in the guinea pig cochlea detected in bloc-surface preparations.

We immunohistochemically examined the distribution of nerve fibers among supporting cells of the cochlea by using the bloc-surface preparation. The existence of these nerve fibers was not very clear in the standard avidin-biotin complex (ABC) method. However, the standard ABC method complemented with silver intensification procedure provided very fine details of the nerve fibers. The nerves started to appear at low density about 55% of the distance from the apex, and their density gradually increased toward the upper turn. In each portion, the nerve fibers increased in thickness and length as well as the number of synapses made with the nuclei. Moreover, the distribution of these nerves in the fetal cochlea was similar to that in the adult. However, the functional significance and importance of these nerves remains to be determined. Our study also indicates that the silver intensification procedure combined with the standard ABC method is useful for the detailed observation of stereoscopic innervation in thick tissue preparations like such as the cochlea.

Human CLC-KB gene promoter drives the EGFP expression in the specific distal nephron segments and inner ear.

Human CLC-KB has been identified as a kidney-specific member of the CLC chloride channel family, and mutations of the human CLC-KB gene are known to cause Bartter syndrome type III. A precise understanding of the localization of this channel in the human kidney is imperative to our understanding of the pathophysiology, but this has remained unclear due to the high homology between human CLC-KB and CLC-KA, another kidney-specific member of the same family. The high intraspecies homology also rules out an exact correlation of the human isoforms (CLC-KA and CLC-KB) to the mouse and rat isoforms (CLC-K1 and CLC-K2, respectively). This study created transgenic mice harboring the enhanced green fluorescence protein (EGFP) gene driven by an 11-kbp human CLC-KB gene promoter. Three transgenic lines were generated, and all of them showed EGFP fluorescence in the kidney, with an identical pattern of localization to the thick ascending limb of Henle's loop, distal tubules, connecting tubules, and intercalated cells of the collecting duct. This localization is exactly the same as that of mouse CLC-K2 identified in a previous report (Kobayashi et al. J Am Soc Neph 12: 1327-1334, 2001). EGFP fluorescence was also detected in the inner ear, more specifically in marginal cells of the stria vascularis and dark cells of the vestibular labyrinth, suggesting that human CLC-KB could play an important role in the fluid transport mechanism of the inner ear. The results (1) confirmed that CLC-KB is the true human homologue of rat and mouse CLC-K2 and (2) established that the 11-kbp human CLC-KB gene promoter is sufficient to elicit the precise expression in specific cell types of the kidney and inner ear.

Histopathological examination of ruptured carotid artery after irradiation.

We report 2 cases of carotid artery rupture after irradiation that was performed 1 year and 17 years before the ruptures. When irradiation-induced arterial rupture occurs, it usually does so within a few months following irradiation. However, the histopathological sections obtained in the present cases revealed carotid artery necrosis that was presumably induced by irradiation. Carotid artery rupture is sudden, massive hemorrhage that ranks among the most dreaded complications in the head and neck. However, several patients have been saved by hospital personnel who discovered the rupture in time to take appropriate measures such as cleaning of the wound and protection with myocutaneous or myofascial flaps. Therefore, it is important to be aware of the possibility of rupture or perforation of major vessels after irradiation, even when the radiation therapy was performed a long time ago.