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Thyroid tumor is one of the most common diseases encountered by otolaryngologists and head and neck surgeons. Most patients are young and female and have good prognosis. Therefore, surgery for thyroid tumor needs cosmetic consideration. Various approaches have been proposed to minimize or avoid an undesirable scar on the neck. As a result of these studies, enodoscopic thyroid surgery has been introduced. We performed endoscopic thyroid surgery using an optical device for sinus surgery which is familiar and conveniently available to otolaryngologists. The main incision was made below the clavicle on the chest wall. A second incision was placed on the lateral neck for insertion of an endoscope. After dissecting the layer under the platysma, two segments of Kirschner wire were horizontally inserted, then lifted up to obtain a working space. Vessels were incised with an ultrasonically activated scalpel or vessel sealing system. Magnified endoscopic vision permitted easy identification of the reccurent nerve. Use of a short endoscope improved surgical manageability. This method of endoscopic thyroid surgery offers cosmetic advantages to otolaryngologists.

Juzen-taiho-to (JTT) is known as a herbal medicine that improves immune function. We evaluated whether JTT has a beneficial effect in otitis-prone children. Twenty otitis-prone infants took JTT at 0.1-0.14mg/kg/day twice a day for three months. The medication compliance rate was 85%. The frequency of otitis media purulenta significantly decreased (t-test, p=.000, Wilcoxon signed rank test, p=.000) by the oral administration of JTT. The number of days of fever (t, p=.000, Wilcoxon, p=.000), antibiotic administration (t, p=.002, Wilcoxon, p=.001), hospital visits (t, p=.014, Wilcoxon, p=.005), and emergency hospital visits (t, p=.000, Wilcoxon, p=.000) also showed significant decreases after taking JTT as compared with before.The onset and progression of infection depends on the balance between the reproductive power of microbes and host defense. The effects of JTT on otitis-prone individuals have not been investigated before. JTT is thought to be one of the effective treatments for otitis-prone cases, and avoiding the overuse of antibiotics would prevent the increase of drug-resistant bacteria both in terms of their number and level of resistance.

Clinical usefulness of olopatadine hydrochloride was studied in 97 patients with cedar pollinosis in 2005. The subjects were divided into 2 groups based on the time of starting treatment before or after the onset of pollen season. Subjective symptoms, objective findings of nose and quality of life scores using Japanese Rhino-conjunctivitis Quality of Life Questionnaire (JRQLQ No 1) were compared between the two groups. Both the clinical scores and QOL scores remained normal even at the peak of pollen scattering in patients who started medication before pollen season, and showed significant differences in each index compared with those in the patient group starting treatment after the onset of pollen season. The patients who started medication after pollen dispersal were not relieved of their symptoms at the peak of pollen scattering, but they had lower scores at both the beginning and end of pollen season. There were strong correlations between the clinical symptom scores and QOL scores in both groups. In conclusion, olopatadine hydrochloride appeared to be sufficiently effective for cedar pollinosis during the season of peak pollen of scattering by starting medication before the onset of pollen season.

Pulmonary edema following acute upper airway obstruction is called negative pressure pulmonary edema (NPPE). The predominant mechanism is increased negative intrathoratic pressure, although hypoxia, cardiac and neurologic factors may contribute. We encountered a case of pulmonary edema after pharyngeal surgery. A 50-year-old male with peritonsillar abscess underwent incision and drainage under general anesthesia. After extubation of the tracheal tube following successful surgical procedure, upper airway obstruction due to laryngospasm and/or edema of the pharynx ensued. The patient developed respiratory distress with vigorous inspiratory efforts. After reestablishment of the airway, pink frothy sputum flowed from his mouth and nose. Chest X-rays demonstrated bilateral diffuse alveolar infiltration. Diuretics, steroids and mechanical ventilatory support by continuous positive airway pressure were effective. The onset of NPPE is usually rapid, and without prompt recognition and intervention, the outcome can be fatal. NPPE appears more frequently in healthy male patients, particularly patients receiving head and neck surgery with or without concurrent airway obstruction. Prevention, early diagnosis, and prompt treatment facilitate an uncomplicated resolution.

Toxoplasma gondii is a protozoan parasite that infects up to a fourth of the Japanese population. Infection is mainly acquired by ingestion of food or water that is contaminated with oocysts shed by cats or by eating undercooked or raw meat containing tissue cysts. Toxoplasma gondii primary infection is asymptomatic in most patients. The most typical clinical manifestation is isolated cervical lymphadenopathy.We report a case of chronic right neck lymphadenopathy caused by infection with toxoplasma gondii. A 16-year-old previously healthy male visited our department for evaluation of chronic cervical lymphadenopathy. Physical examination revealed multiple painless lymph nodes with a size of approximately 1.5cm in the right submandibular region. The first histological examination revealed stellate granulomas with central necrosis, which is compatible with cat scratch disease (CSD). Sixteen months later, submandibular lymphadenopathy appeared again. The second histological examination was probable toxoplasmosis, which was confirmed with serological tests. Immunoglobulin (Ig) M and IgG antibodies to toxoplasma gondii were detected, which revealed elevated titers of both IgM and IgG, of 20 and 1, 280, respectively. Both of dye test and indirect latex agglutination test for toxoplasma gondii were 1, 024, respectively. The patient was thought to be infected with toxoplasma gondii following CSD. He was successfully treated with Acetylspiramycin (900mg/day) for four weeks without any evidence of recurrence, or side effect.

Chronic progressive radiation myelopathy (CPRM) is a delayed injury to the spinal cord after radiotherapy. A 50 year-old male with hypopharyngeal cancer underwent intra-arterial chemotherapy and radiotherapy. Six months later he developed a pain in the left ankle and progressive weakness in his lower extremities. MR image demonstrated high signal intensity on T2 weighted images extending from C2/3 to Th3/4 and atrophy of the cervical cord. Neurological examination revealed weakness in extremities, parestheisa in extremities and abdomen, hyperreaction of deep tendon reflex and dysuria. Corticosteroid and anticoagulation therapy did not improve the neurological symptoms. The incidence of CPRM is rare, however, we should be aware of this possible complication following radiotherapy for head and neck cancer.

We inserted the ventilation tube into seven children for recurrent acute otitis media (rAOM), who could not recover from rAOM in spite of comprehensive treatments including myringotomies, oral or intravenous administration of antibiotics, and administration of immunoglobulin.In order to select patients for the ventilation tube insertion, we followed the indications for surgery as below.1) Recurring otitis media purulenta more than once a month2) Inability to recover from rAOM in spite of comprehensive treatments including myringotomies and peroral or intravenous administration of adequate antibiotics3) Ability to undergo general anesthesia.The average observation times before and after surgery were 8.05 and 5.10 months. During these periods, the frequency of otitis media purulenta significantly decreased (t test, p

We report 7 cases of acute and recurrent inspiratory dyspnea in which no organic cause could be identified. Patients were from 12 to 68 years old (43.6 in average), consisting of five males and two females. In three of the seven cases, fiberoptic laryngoscopy during an attack of dyspnea revealed laryngospasms following symmetric adduction of the vocal cords. Each patient experienced loud, stridorous noise during inspiration at the beginning of an attack as well as the subsequent inability to inspire. The attacks ranged from several tenths of a second to a few minutes in duration and occurred frequently, several times a day in some cases. Results of physical examinations, lung function tests, roentgenograms of the chest and larynx, and CTs of the lungs and the neck were unremarkable. Laboratory findings including blood gas analysis between attacks were within normal limits. No atopic stigmata were found.Drinking water or swallowing could sometimes relieve the grade of the attack, and the patient could completely prevent attacks once they understood the condition of the dyspnea and mastered a breathing maneuver during the attack. Previous upper respiratory infection, cough, and sleep apnea were suggested to correlate with the episodes. Our patients did not require drastic maneuvers such as tracheostomy or intubation. Administration of Eperisone hydrochloride and Etizolam proved effective in some cases.Laryngospasm as a cause of recurrent inspiratory dyspnea is functional, and we suspect that it is not such a rare occurrence. An awareness of this entity could prevent unnecessary tracheotomies.

We report a case of a maxillary sinus foreign body that was not identified before surgery. A 53-year-old man visited our hospital complaining of nasal obstruction and nasal discharge. X-ray and CT examinations revealed left maxillary sinusitis. We therefore performed endoscopic sinus surgery under the diagnosis of chronic sinusitis. Two foreign bodies were removed from the maxillary sinus, which turned out to be root canal filling agents called gutta-percha point. Because the patient has been free of complaints after removing the root canal points, this sinusitis could be attributable to movement of the root canal point. We should be aware of foreign bodies that go undetected by radiologic examinations.

Recently, a rapid increase in penicillin resistant pneumococci has been reported in most areas of the world. These penicillin resistant bacteria are becoming less susceptible to other commonly prescribed oral antimicrobial drugs, including extended-spectrum cephalosporins. Also, a rapid spread of ampicillin resistant Heamophilus influenzae in children with respiratory tract infections has been reported in Japan. Therefore, we carried out clinical and bacteriological studies on double quantities of cefditoren (CDTR) in patients with pediatric acute otitis media at 5 general hospitals.Between February 1999 and May 1999, 118 strains of Streptococcus pneumoniae and 70 strains of Haemophilus influenzae were isolated from the nasopharynx in 144 children with acute otitis media. Of the 118 Streptococcus pneumoniae, penicillin G resistant S. pneumoniae (PRSP) and penicillin G intermediately resistant S. pneumoniae (PISP) accounted for 29% and 43%, respectively. On the other hand, of the 70 Haemophilus influenzae, the number of j3-lactamase-negative ampicillinresistant (BLNAR) strains was 24%.The bacteriological efficacy of double quantities of CDTR in patients with PRSP, PISP and BLNAR was 20%, 43% and 63%, and the clinical efficacy of CDTR was 65%, 79% and 75%, respectively. These results suggest that the sterilization of pediatric nasopharynxes using oral antimicrobial drugs is difficult, but CDTR is a useful oral antibiotic for clinically acute pediatric otitis media.

In order to investigate the bacteriologic and clinical interpretation of the flora of the nasopharynx from children (n=31) and the staff (n=15) in a nursery school, penicillin resistance (Pcr) of Streptococcus pneumoniae was examined. Chief bacteria from children were S. pneumoniae (27 strains, 87%), Haemophilus influenzae (27 strains, 87%) and Moraxella catarrhalis (24 strains, 80%). Of the 27 strains of S. pneumoniae, 23 strains (85%) were identified as a Pcr S. pneumoniae. Two children had recurrent episodes of acute otitis media, but no children showed the conditions of acute otitis media on the medical examination day. From these data, prevalence of Pcr S. pneumoniae is very high in young children in nursery school in Japan.On the other hand, chief bacteria from the staff were H. influenzae (8 strains, 47%) and M. catarrhalis (2 strains, 12%). S. pneumoniae was not detected in these healthy adults.

We report a case of external carotid—external jugular fistula with clinical, radiological and surgical features. A 12-year-old female's clinical findings included a right neck mass and buzzing noise in the right ear. This patient was successfully treated with endovascular treatment using an interlocking detachable coil. This patient has shown no recurrence for a year after treatment.

Ectasia of the jugular system is unusual in children. We present here a pediatric case with internal jugular vein phlebectasia, and an adult case with a venous aneurysm. These two ectasias were observed as nonpulsatile, elongated or round neck masses that enlarges with the Valsalva maneuver or speaking. Computed tomography (CT), magnetic resonance imaging (MRI), ultrasound and angiography have all been used in the diagnosis of ectasia. However, CT with a contrast agent make it possible to obtain a clear diagnosis, and allows the detection of thrombus formation.In our adult case, a thrombus in the aneurysm was suggested. After CT with a contrast agent, angiography was useful to detect the thrombosis and its connection with the internal jugular vein. Surgical resection of the jugular aneurysm was undertaken to avoid the risk of embolization in this case. In our pediatric case, the phlebectasia has been examined regularly because the lesion was stable in size, and there was no thrombus formation. We recommend surgical resection only if the lesion forms a thrombus, increases in size, or causes cosmetic deformity.

The therapeutic efficacy, safety and usefulness of emedastine difumarate (DAREN) given at doses from 2 to 4 mg/day for 8 weeks to patients with severe perennial allergic rhinitis were investigated.Among a total of 36 patients enrolled, 34 patients were evaluated for efficacy and usefulness, 36 for safety.The results were as follows.1) In the final global improvement rating, 28 of 34 cases (82.4%) were assessed as “moderately improved” or more.2) In 29 of 34 patients (85.3%), the severity of the subjective and objective (nasal) symptoms were ameliorated from “severe” to “slight” or “none”.3) In the overall safety rating, the percentage of cases evaluated as “no adverse reaction and safe” was 88.9%.4) Adverse reactions were observed in 4 cases (11.1%), of which drowsiness was the reaction (3 cases).Administration was, however, continued in all cases throughout the study period, because the side-effects were mild and not clinically serious.5) In the usefulness rating, the treatment was rated as “fairly useful” or better in 76.5% (26/34), of the cases.In conclusion, DAREN is considered to be markedly effective, safe and useful in the treatment of severe perennial allergic rhinitis.

The purpose of this study was to examine the role of angiogenesis and the expression of matrix metalloproteinase 9 (MMP9) on metastasis in primary nasopharyngeal carcinoma (NPC). Intratumoral microvessels were highlighted by immunohistochemical staining of endothelial cells for von Willebrand factor (vWF). The expression of angiogenetic factors, including basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and transforming growth factor-α (TGF-α) was also evaluated in NPC specimens, in addition to the expression of Epstein-Barr virus (EBV) encoded small RNAs. The expression of bFGF, VEGF, TGF-α and LMP-1 increased significantly with the grade of regional lymph node metastases. Multiple regression analysis showed that the expression of latent membrane protein-1 (LMP-1) was the most important factor that affects the microvessel counts in NP.Matrix metalloproteinases (MMPs) are frequently expressed in malignant tumor cells and are thought to play crucial roles in tumor invasion and metastasis. In this study, the expression of MMP9 was found to be increased in EBV-infected type III latency lymphoma cell lines. Type III cell lines express abundant LMP-1, the principal EBV oncoprotein, as well as the other latency proteins including the transcriptional factor EBV nuclear antigen 2 (EBNA2) which is also required for cell immortalization. Transection of an LMP-1 expression plasmid in the C33A cell line increased MMP9 expression, whereas overexpression of EBNA2 did not. Deletional and mutational analysis of the MMP9 promoter region was also carried out with chloramphenicol acetyltransf erase (CAT) assays. We found that binding sites for NF-κB, SP-1 and AP-1 also contributed to induction of the MMP9 promoter by the viral protein, LMP-1, mainly through the NF-κB and, to a lasser extent, the SP-1 and AP-1 sites. These results indicate that expression of MMP9 is induced by LMP-1. In conclusion, these observations suggest that LMP-1 plays a key role in metastasis in NPC.

The clinical efficacy of erythromycin, clarithromycin (CAM) and roxithromycin on chronic paranasal sinusitis has been reported in numerous studies. We investigated the clinical efficacy of low-dose and long-term CAM on sinusitis in children. Each child was given 5-7mg/kg of CAM as two doses daily. The clinical efficacy was assessed by the quality and quantity of nasal discharge, and by the findings on plain X-ray films of the maxillary sinuses after 8 weeks of administration. Twenty-one out of 28 (75%) patients treated with CAM demonstrated an improvement in the quality of nasal discharge. Twenty out of 28 (71%) patients treated with CAM demonstrated an improvement in the quantity of nasal discharge. Twenty-four out of 28 (86%) patients treated with CAM demonstrated an improvement in their findings on plain X-ray films of their maxillary sinuses. Patients who received CAM demonstrated significantly better quality and quantity of nasal discharge, and their findings on plain X-ray films of their maxillary sinuses were better than patients who didn't receive CAM. Clarithromycin was judged to be useful in the treatment of sinusitis in children.

Ceftizoxime and ambroxol were administered in combination to patients with chronic sinusitis, who required surgical treatment. The transfer of ceftizoxime in combination with ambroxol into the ethmoid cell mucosa was compared to that of ceftizoxime alone. Ethmoid cell mucosal concentrations of ceftizoxime 90-120 minutes after intravenous administration of 1g of ceftizoxime alone ranged from 0.21 to 14.3μg/g. Plasma concentrations ranged from 9.51 to 31.6μg/ml, and the tissue distribution rate (ethmoid cell mucosal c./plasma c.) was 31%. When ambroxol was administered in combination with ceftizoxime, ethmoid cell mucosal concentrations of ceftizoxime ranged from 1.04 to 9.66μg/g. Plasma concentrations ranged from 6.7 to 33.5μg/ml, and the tissue distribution rate was 38%. In patients administered ceftizoxime alone, the tissue distribution rates of ceftizoxime were comparatively variable. The mean distribution rates however, were nearly the same in both groups. On the basis of these findings, it was concluded that the concentrations of ceftizoxime in the ethmoid cell mucosa and the plasma were scarcely affected even when ceftizoxime was administered in combination with ambroxol. Ethmoid cell mucosal concentrations and plasma concentrations of ceftizoxime are typically maintained at MIC80 values for period of 4 hours or more, in the treatment of various clinical isolates including organisms causing respiratory infection. This suggests that the therapeutic effects of ceftizoxime can be obtained clinically even when it is used alone. Concomitant use of ambroxol is however, considered to be useful supplemental therapy since the antibacterial activity of ceftizoxime is supported by the improvements in sinusitis induced by ambroxol.

This report describes three cases of juvenile nasopharyngeal angiofibroma and presents appropriate surgical management strategies. Case 1: 22-year-old male (stage III, Sessions' staging classification). Removal of the tumor by a transpalatal approach was attempted however the surgical procedure was not completed due to excessive bleeding. This patient subsequently received radiation a total dose of 40 Gy. Following radiation therapy, the tumor was reduced in size.Case 2: 10-year-old male (stage TEA). The tumor was removed in this patient by the transpalatal approach. After 10 months however, the tumor reappeared. Case 3: 18-year-old male (stage JIB).The tumor in this patient was removed by the transantral approach. The tumor in this case had not relapsed at five months after surgery.All three patients underwent preoperational selective arterial embolization. Surgical approaches and patient prognosis in eight cases, including the three described here, have been reported in the last 10 years. Using the transantral approach, a clearer view of the tumor and maxillary artery could be obtained than by the transpalatal approach. Therefore, the transantral approach was determined to be better than the transpalatal approach for surgical treatment of tumor which had grown into the pterygopalatine fossa. To choose the most appropriate surgical method for the management of juvenile nasopharyngeal angiofibroma however, it is necessary to first obtain a correct diagnosis based on CT findings and MR images.

Thirty-two cases of epiglottic cysts were treated surgically with direct laryngoscopy between January 1984 and December 1994. Nineteen cases were epidermoid cyst, 8 were retention cyst, one was branchial cyst, and 4 were idiopathic. Two or three cysts were found in 8 cases (7 males and 1 famale), among which 6 were epidermoid cyst, one was retention cyst, and one was unconfirmed. The literature regarding epiglottic cysts is reviewed.

At our clinic, we encountered 272 cases of facial bone fracture between 1983 and 1993. These patients were analyzed by age, gender, cause and location of the fracture.There were 202 nasal bone fractures, which comprised 59.3% of all facial bone fractures. Males were significantly predominant (75.2%). These injuries mainly occurred during sports, fighting and automobile accidents.While usually single and rather slight bone fractures such as nasal bone fractures occured during sports, more severe fractures involving many facial bones occured in high speed, such as automobile accidents. Moreover, orbital bone fractures mainly resulted from fightings or sports. Precise otolaryngological knowledge and management is indispensable for ENT clinicians.

It is generally accepted that subacute thyroiditis is a self-limited inflammatory disease of the thyroid gland, characterized by severe pain and tenderness on the thyroid gland, transient thyrotoxicosis, erythrocyte sedimentation rate elevation, systemic manifestations of inflammation such as malaise, fever and fatigue. It recurs in about 10-20% of patients. Some authors have reported cases of subacute thyroiditis with liver dysfunction, such as elevation of transaminase (glutamic oxalacetic transaminase-GOT, glutamic pyruvic transaminase-GPT) and alkaline phosphatase. These abnormalities were all reduced in the course of therapy, and none of patients showed recurrent subacute thyroiditis or liver dysfunction. In this report, we present a case of subacute thyroiditis associated with liver dysfunction which progressed and improved in parallel wite the thyroiditis. The serum antibody titer against Coxsackie A virus was elevated, and Coxsackie A virus was suspected to be the etiological agent.

We usually use 6 frequencies, 250, 500, 1000, 2000, 4000 and 8000 Hz, in conventional pure tone audiometry. When these 6 points do not show hearing loss, our clinical diagnosis is no hearing loss. If the hearing loss is not located in the clinical 6 frequencies, we cannot detect it.The authors diagnosed 6000 Hz-dip type acute hearing loss in a 43-year-old male with tinnitus. We measured the hearing levels at 6 frequencies and found no hearing loss. The pitch of his tinnitus was 6000 Hz, so we measured the hearing levels at 4 other frequencies (800, 1500, 3000 and 6000 Hz) and detected a 6000 Hz-dip.Steroid treatment cured both the tinnitus and the 6000 Hz-dip hearing loss.When hearing loss occurs at a frequency other than the conventional pure tone audiometric frequencies, a mistaken diagnosis of no hearing loss is made. If the patient complains of tinnitus, the clinician should investigate the pitch and measure the hearing level near the frequency of the tinnitus. This is a useful method of discovering narrow diptype acute hearing loss.

Squamous cell carcinoma accounts for approximately 98 per cent of all malignant neoplasms that occur in the nasopharynx. The high incidence of nasopharyngeal carcinoma (NPC) is a characteristic of the Oriental races. Viral and environmental factors appear to have an etiologic impact on this disease. The most common sites are the lateral wall followed by the roof. NPC spreads primarily by local infiltration and regional metastases. Local infiltration of the eustachian tube is evidenced clinically when the patients presents with a unilateral conductive hearing loss secondary to the development of a secretory otitis media. Multiple cranial nerve deficits can develop. The maxillary and mandibular branches of the trigeminal complex (V2 and V3) are the most commonly involved cranial nerves and indicate extension of the tumor through the foramen rotundum and foramen ovale. Lateral rectus deficits cause the patient to complain of diplopia, especially on lateral gaze, indicating tumor involvement along the course of cranial nerve VI. More extensive internal and external ophthalmoplegias suggest orbital or cavernous sinus involvement. Lateral extension or spread into the pterygomaxillary fossa and the infratemporal fossa can easily affect the lower cranial nerves (IX, X, XI, XII), indicating that the tumor has progressed into the area of the jugular foramen. Lack of significant tumor bulk in the nasopharynx or parapharyngeal spaces with paralysis of the lower cranial nerves usually indicates involvement of adjacent lymph nodes surrounding the jugular foramen rather than direct extension from the primary tumor. Lymphatic spread from the nasopharynx may be either unilateral or bilateral. When the tumor has spread into the upper deep cervical lymph nodes, a cervical mass usually first becomes detectable clinically.

The distribution of ofloxacin (OFLX) in the palatal tonsil and maxillary sinus mucosa was quantitatively analyzed. OFLX (100mg), lomefloxacin (100mg), and tosufloxacin (75mg) were administered orally 2 hours before surgery. The tissue concentration of OFLX was 1.61±0.46μg/ml on average and was higher than the serum concentration (0.72±0.21μg/ml), the tissue/serum ratio (2.24) was significant. The tissue concentration of OFLX was higher than that of lomefloxacin and tosufloxacin. In addition, clinical and bacteriological trials on patients with otorhinolaryngological infections was carried out. OFLX was administered orally at a dose 600mg for more than three days. The incidence of stains resistant to OFLX (MIC>3.13μg/ml) was 5.8%. The overall clinical efficacy rate was 86.7% and there were no safety problems. It was concluded that OFLX is a useful drug for treating otorhinolaryngological infections.

A 62-year-old woman visited our hospital complaining of abnormal sensation in the pharynx. Physical examination revealed a pulsating mass on the right side of the posterior wall of the mesopharynx. CT and angiography confirmed that the internal carotid artery had an abnormal course and was compressing the pharyngeal wall.The clinical importance and etiology of tortuosity of the internal carotid artery are discussed.

A 57-year old man had a left anterior neck tumor, and another small tumor was found in the laryngeal ventricle by indirect laryngoscopy. A CT scan showed a well-circumscribed tumor growing from the thyroid lamina into the paraglottic space. Under general anesthesia the tumor was dissected with fenestration of the thyroid ala without any complications, such as hoarseness or deformity. In Japan 35 cases of cartilagenous tumors arising in the laryngeal cartilage have been reported, including our case. In six of these 35 cases the tumor was in the thyroid cartilage. Both chondrosarcoma and chondroma are often seen in the thyroid cartilage, whereas chondroma is seen more frequently than chondrosarcoma in the cricoid carilage.

In adult humans, hypothyroidism has been associated with a reduced sense of smell. There are few reports on the effect of hypothyroidism on the sense of smell in adult animals. We examined whether hypothyroidism abolishes the sense of smell in adult mice and examined the changes of the olfactory epithelium. Hypothyroidism was produced in adult mice by addition of thiamazole to their drinking water or intra-peritoneal injection. The olfaction of mice was estimated by successful recording of behavioral task, using cycloheximide, which has been commonly used as a repellent in rodents. The sense of smell was tested before, during, and after thiamazole treatment. Thyroid function was assessed by radioimmunoassay of blood serum for free thyroxine. The mice were killed after treatment and the olfactory epithelium was studied at the light microscopic level to determine the effects of thiamazole treatment.Mice given 0.01% thiamazole in the drinking water for 100 days were not hyposmic. The control mice given tap water to drink for 100 days maintained their sense of smelll. Mice given daily intra-peritoneal injection of 0.5 mg thiamazole for 100 days were not hyposmic. Daily i. p. injection of 1.5mg thiamazole to the mice for 20 days attenuated their sense of smell. By contrast, the control mice, given daily i. p. injection of 0.1ml normal saline were normosmic. In the olfactory epithelium of the hypothyroid and hyposmic mouse, the structures composed of basal cells, olfactory cells, and supporting cells were preserved. However, a marked decrease was observed in the number of olfactory cells. These findings indicate that hypothyroidism produces olfactory disturbance in mice and injures the olfactory receptor neurons.