Cross-Sectional Structure and its Histological Features of the Nasal Cavity and Paranasal Sinuses in the Rat

BACKGROUND AND OBJECTIVES: An understanding of the cross-sectional structures and histological features of experimental animals is necessary for conducting the research of rhinosinusitis in experimental animals. The aim of this study is to determine the most suitable cross-sectional level of rhinosinusitis in a rat model. MATERIALS AND METHODS: The study examined the histological features of the mucosal epithelium, gland, lymphoid tissue, and vomeronasal organs using 4 week-old male rats weighing 60-70 g as test subjects. Whole mounted sinus-nose complexes were divided into four levels of areas which were sectioned according to the coronal plane and each section was stained with hematoxylin-eosin and observed under light microscopy. RESULTS: Level I revealed the nasal turbinate, maxilloturbinale, and nasolacrimal duct. Level II revealed the nasal turbinate, maxilloturbinale, vomeronasal organ, and nasolacrimal duct. Level III revealed the ectoturbinale I, II, endoturbinale II, III, maxillary sinus, Steno's gland, maxillary sinus gland, and nasal associated lymphoid tissue (NALT). Level IV revealed the ectoturbinale II, endoturbinale III, IV, pharyx respiratorius, and NALT. The lining epithelia were squamous, respiratory and olfactory. However, the squamous epithelium was not observed in level III and IV. CONCLUSION: The Level III appears to be the most suitable for the rhinosinusitis animal rat model since we can observe the respiratory epithelium lined sinonasal airspace including the maxillary sinus and NALT.

Clinical Analysis of Isolated Sphenoid Sinus Leision

BACKGROUND AND OBJECTIVES: Isolated sphenoid lesion (ISL) is rare due to its anatomic location in the nasal cavity. The recent advances in the diagnosis with CT and MRI make it easier to diagnose ISL. We experienced 15 cases of ISL and reviewed their clinical characteristics. MATERIALS AND METHODS: Patients with ISL admitted from January 1998 through April 2004 were retrospectively reviewed. Patients' clinical symptoms, endoscopic and radiologic findings, treatment modalities, postoperative diagnosis, and the outcomes were analyzed. RESULTS: The most common symptom was headache presented in 9 patients, followed by nasal symptoms in 4 patients. Five of 15 cases were acute sphenoiditis which was improved with antibiotic trials. The other 10 cases were treated by endoscopic sphenoidotomy. Postoperative pathology showed 4 cases of fungal ball, and 3 cases of mucocele, 3 cases of chronic sphenoiditis. CONCLUSION: Headache and orbital symptom were the most common presentation in patients with ISL. Endoscopic and radiologic findings were not pathognomonic to diagnose ISL in most cases. Antibiotic trials should be preceded, and then followed by endoscopic sphenoidotomy in the refractory cases. Loss of vision or light reflex may predict a poor rognosis.

A Rat Model of Acute Bacterial Rhinosinusitis Induced by Staphylococcus Aureus / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: An experimental model of bacterial rhinosinusitis is essential to study the pathogenesis of rhinosinusitis. To our knowledge, there hasn't been an experimental model using rats for bacterial rhinosinusitis, where Staphylococcus aureus is directly inoculated to the rat nose. Staphylococcus aureus is also a predominantly isolated bacterial pathogen in the episode of acute rhinosinusitis. The aim of this study was to develop a rat model of rhinosinusitis induced by Staphylococcus aureus, ATCC 25923. SUBJECTS AND METHOD: The infected Sprague-Dawley rats (4-6 week-old male) were applied intranasally with 40 microliter of Staphylococcus aureus, ATCC 25923, which corresponds to 108 colony-forming units per milliliter, which in turn corresponds to a No. 1 McFarland turbidity by spectrophotometer (VITEK, USA). After the 2nd, 5th, and 14th day, the rats were killed respectively. RESULTS: Nasal sinuses were then observed at low power field (x40) for changes in the amount of inflammatory cell clusters in the sinus cavity. There were significant differences in the number of inflammatory cell clusters between the infected and control rats (p<0.05). The infected rats killed at the 5th day had significantly more inflammatory cell clusters within the sinus cavities (p<0.05). CONCLUSION: Staphylococcus aureus induces acute bacterial rhinosinusitis in rats as measured by increased inflammatory cell clusters. This study demonstrates the efficacy of a rat model of acute bacterial rhinosinusitis.

A Case of Carcinoma Showing Thymus-Like Differentiation / 대한이비인후과학회지

Carcinoma showing tymus-like differentiation (CASTLE) was defined by Chan et al in 1991, which occurs in the thyroid gland and surrounding soft tissue, or soft tissue of the neck. It originates from ectopic thymus or branchial pouch remnants. The histologic finding shows that the tumor is divided into lobules of variable size and shape, cord with thin and thick fibrous septa, which are infiltrated by lymphocytes and plasma cells. Tumor cells consist of large vesicular nuclei, prominent nucleoli, and abundant cytoplasm. Treatment is surgical excision and prognosis is good. Differential diagnosis is squamous cell carcinoma of thyroid and lymphoepithelioma of thymus. We report a case of CASTLE that we treated by surgery and radiation therapy.

The Role of Inducible Nitric Oxide Synthase in the Development of Nasal Hyper-responsiveness of the Rhinosinusitis Rat Model / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Hyper-responsiveness to nonspecific stimuli is a characteristic finding of all allergic diseases. It is probably due to eosinophil infiltration, release of cytotoxic proteins, and epithelial damage in the airway mucosa. However, the whole mechanism has not been clearly established. We aimed to understand the role of inducible nitric oxide synthase (iNOS) expression in nasal hyper-responsiveness of rhinosinusitis. MATERIALS AND METHOD: 1) To develop a platelet activating factor (PAF)-induced rhinosinusitis rat model, 50 micro liter of 16 micro gram/ml PAF was applied into the nose of rats. At days 1, 3 and 5, the rats were killed. 2) To demonstrate the hyper-responsiveness to topically applied capsaicin, 30 micro liter of 10 micro M capsaicin was applied intranasally and the amount of microvascular leakage in the nasal mucosa was measured with Evans blue assay at days 1, 3 and 5 in the rhinosinusitis model and the control rats. 3) To examine the effect of iNOS, 75 mg/kg of aminoguanidine was pretreated systemically 1 hour before the application of capsaicin. 4) To localize the expression of iNOS, immunohistochemical staining was performed using the avidin-biotin-peroxidase method with an anti-iNOS antibody. RESULTS: Induction of rhinosinusitis by application of PAF was confirmed with histology. A significant infiltration of eosinophils and loss of the epithelium, varied according to the time interval, were observed. A significant enhancement of microvascular leakage was clearly demonstrated by topically applied capsaicin, which was completely blocked by aminoguanidine, the iNOS inhibitor in the PAF-induced rhinosinusitis. The expression of iNOS was localized in the inflammatory cells infiltrated in the mucosa. CONCLUSION: The expression of iNOS in the inflammatory cells as well as epithelial damage related to eosinophil infiltration may cause nasal hyper-responsiveness.