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Biomedical subjects

Toshiaki Yagi

Publications and source records attributed to Toshiaki Yagi.

At least 19 recordsLinked to original sources
PubMed2006

Pathological localization of so-called posterior canal BPPV.

OBJECTIVE: Based on the hypothesis that the origin of nystagmus is from the posterior canal (PC), the nystagmus in the head hanging and sitting position should be mirror images. To clarify the anatomical origin of positioning nystagmus in BPPV patients, we analyzed the positioning nystagmus of benign paroxysmal positioning vertigo (BPPV) patients three-dimensionally. METHODS: Twenty-six patients with BPPV participated in this study. The positioning nystagmus was recorded in complete darkness from the patient's left eye by means of an infrared CCD camera. We performed three-dimensional analysis of nystagmus using video image analysis system (VIAS). Subsequently, the rotation axis of the 3D eye movements of the positioning nystagmus was calculated. RESULTS: Among the 26 patients tested, 20 patients demonstrated the axes of nystagmus in good or relatively good alignment to the PC axis. However, in 11 of these 20 patients there was poor alignment of the axis of nystagmus in the sitting position to the PC axis. In addition, six patients showed axes of nystagmus with poor alignment to the PC in the head hanging position. Among them, two patients exhibited axes of nystagmus in good alignment with the anterior canal, in spite of diagnosis of these patients as PC BPPV by experienced examiner based on the positioning nystagmus test. CONCLUSION: These results demonstrated that only one-third of patients who were diagnosed as BPPV, could be diagnosed as true BPPV which originates from a PC pathology. Besides the possibility that the pathology may originate from the AC, it is still unclear which part of the inner ear may be the candidate site of origin of the pathology of BPPV in the other 15 patients.

Adult↗
PubMed2005

Three-dimensional analysis of eye movements using four times high-speed video camera.

In order to record and analyze the rapid eye movement non-invasively in human subjects, a four times high-speed video camera (4TC) with a new computer software was developed and utilized. Nine healthy volunteers and four patients with vestibular dysfunction participated in this study. Caloric stimulation was applied to the healthy subjects and the eye movements were recorded using a standard camera (SC) and a 4TC. In four patients, the positional and/or positioning nystagmus was recorded using SC and 4TC. Analysis of the eye speed of the quick phase of nystagmus was performed manually from the print out of the chart. The quick phase of the caloric nystagmus was adequately analyzed from the data using 4TC. However, using SC the sampling rate was not sufficiently enough for this purpose, as prospected. The adaptability of the 4TC in clinical examination is exactly similar to that of SC, because of the size and weight of the camera. Although the time taken to analyze eye movements using 4TC is about four times longer than that using SC, this system is quite useful and adequate for analyzing the quick eye movements in vestibular nystagmus, in an out-patient clinic set up.

Adult↗
PubMed2005

Expression of full-length Cochlin p63s is inner ear specific.

OBJECTIVE: The COCH gene mutated in DFNA9, murine an autosomal dominant hereditary hearing impairment, encodes Cochlin. Cochlin is also suggested to be the self-antigen of autoimmune sensorineural hearing loss. We previously reported that Cochlin constitutes 70% of the inner ear proteins and is classified into three types of isoform, p63s, p44s, and p40s. To study the specificity of expression of Cochlin isoforms in various organs, here we have investigated expression of the COCH gene at both the transcriptional and translational level. METHODS: COCH gene expression was studied by RT-PCR and Southern blot analysis. Cochlin isoforms were studied by Western blot analysis using an isoform specific antibody. RESULTS: At the transcriptional level, COCH mRNA was detected only in the inner ear by RT-PCR. Southern blot analysis of RT-PCR products detected a high level of COCH mRNA in the inner ear, lower level in spleen, and very low levels in the cerebrum, cerebellum/brain stem, eye, liver and kidney. At the translational level, Western blot analysis showed that a set of isoform, p63s, p44s, and p40s was detected at high levels only in the inner ear. In contrast, multiple proteins were detected at much lower levels in other organs tested. Notably, full-length Cochlin p63s was detected only in the inner ear. CONCLUSION: Our findings demonstrate that the COCH gene is expressed preferentially in the inner ear and that expression of full-length Cochlin p63s is specific to the inner ear. These results will be central to understanding the function of Cochlin and its role in the pathophysiology of DFNA9.

Animals↗
PubMed2005

Expression of cochlin in the vestibular organ of rats.

The COCH gene mutated in autosomal dominant sensorineural deafness (DFNA9) encodes cochlin, a major constituent of the inner ear extracellular matrix. Cochlin constitutes 70% of the inner ear protein and cochlin isoforms can be classified into three subgroups, p63s, p44s and p40s. Symptoms of some DFNA9 patients are consistent with those of Ménière's disease. Here, we report the expression of cochlin in the vestibular organ of rats using isoform-specific antibodies that recognize all three isoforms. Cochlin is highly expressed in the stromata of the maculae of otolithic organs and cristae of semicircular canals, and in the channels in the bony labyrinth that transmit the dendritic innervation to the cristae and maculae. Cochlin cannot be detected in the sensory cells, dark cells, nor in the acellular structures, otolithic membrane or in the cupula. These findings support the theory that deposition of acidophilic substance in the inner ear caused by mutation of cochlin can induce a secondary retrograde dendritic degeneration of the vestibular nerves.

Animals↗
PubMed2005

[Spontaneous dislocation of the arytenoid cartilage].

Dislocation of the arytenoid cartilage occurs following medical instrumentation involving the laryngeal cavity or laryngeal injury from outside the larynx. We reported a case of spontaneously posterior dislocation of the arytenoid cartilage. A 53 year-old man suffering from suddenly recurring aphonia and its improvement many over 3 months without laryngeal injury or inducement eventually ceased to improve. Laryngoscopic findings showed that the left vocal fold was tensely prolonged and the vocal process of the arytenoid cartilage on the left side was dislocated posterolaterally. X-ray videofluorography of the larynx on repetitive phonation of /he/ showed abnormally high and diagonal displacement of the vocal fold and the upper structure of the arytenoid cartilage on the left side. Palpating the cricoarytenoid joint on the left side showed abnormal swelling with tenderness. Electomyography of the intrinsic laryngeal muscle on the left side showed normal action potential. From these findings, we diagnosed his voice disorder as spontaneously posterior dislocation of the arytenoid cartilage. We manually reduced it by pulling up a balloon inserted from the piriform sinus of the affected side to the esophagus.

Arytenoid Cartilage↗
PubMed2004

Identification of a novel Cochlin isoform in the perilymph: insights to Cochlin function and the pathogenesis of DFNA9.

The COCH gene mutated in DFNA9, an autosomal dominant hereditary sensorineural hearing loss and vestibular disorder, encodes Cochlin. Previously, we reported three bovine Cochlin isoforms, p63s, p44s, and p40s, which exhibit significant molecular heterogeneity in vivo. Here we have characterized Cochlin isoforms by generating four isoform-specific anti-Cochlin antibodies. The same three Cochlin isoforms, p63s, p44s, and p40s, were detected in human and cow inner ear tissue; however, p44s and p40s were not detected in perilymph. We identified a novel short 16kDa isoform in human perilymph and a 18-23kDa isoform in cow perilymph, named Cochlin-tomoprotein (CTP), corresponding to the N-terminus of full-length Cochlin (p63s) and the LCCL domain. Notably, CTP contains all of the known mutation sites associated with DFNA9. The pathogenesis of DFNA9 is not fully clarified as yet, and this novel perilymph-associated CTP isoform might provide mechanistic clues to how mutations in the COCH gene damage the inner ear function.

Amino Acid Sequence↗
PubMed2004

Use of free flaps for reconstruction in head and neck surgery: a retrospective study of 182 cases.

OBJECTIVE: In order to clarify the factors affecting the survival of flaps, we performed a retrospective study on free flaps (187) used for reconstruction in head and neck surgery in 182 patients. METHODS: Free jejunum flaps were used on 68 occasions, rectus abdominus myocutaneous flaps on 67, radial forearm flaps on 49, scapular osteocutaneous flaps on 2 and latissimus dorsi myocutaneous flap on ones occasion, during the period from May 1996 to April 2003. Post-operative circulatory complications at the recipient site were analyzed mainly in relation to a history of previous surgery, radiotherapy and chemotherapy. RESULTS: Circulatory crisis was observed in seven cases and circulation was restored in two of them after emergency exploration, whereas the other five flaps failed to survive. The overall failure rate of free flaps was 2.7%. Wound infection at the recipient site was frequent in patients with a history of previous local cervical surgery. Flap failure was significantly more frequent in patients with a history of previous surgery and infection, except for 2 patients in whose case the microsurgical technique was inadequate. Flap failure was not observed in those patients whose irradiation field could be analyzed, or in the patients who received chemotherapy. Although the incidence of circulatory crisis as a consequence of inadequate microsurgical technique was observed in the early period of this retrospective study, their frequency has diminished in the last 2 years. CONCLUSION: The survival of flaps was affected by a history of previous surgery following wound infection, although a history of irradiation and chemotherapy would have no effects on flap failure. The appropriate choice of vessels and surgical skill are crucial for the success of free flaps from our experience. Emergency exploration was also crucial for the survival of the flap in the case of circulatory crisis.

Adult↗
PubMed2004

Subjective evaluation of post-tympanoplasty hearing in relation to the pure tone threshold.

OBJECTIVE: In the year 2000, the Otological Society of Japan proposed a new criteria to assess the levels of hearing known as Criteria 2000. However, these criteria are intended to assess pure tone threshold after tympanoplasty and the results do not necessarily reflect the hearing condition from the patient's perspective. Thus, it is essential to study the relationship between the subjective evaluation of post-operative hearing based on the patient's own assessment and the objective assessment by audiometry. METHODS: The present study is a questionnaire-based survey on the levels of post-operative hearing in 460 patients whose degree of satisfaction with their levels of hearing was assessed by visual analogue scale (VAS). The hearing level was assessed based on the Criteria 2000 established by the Otological Society of Japan. RESULTS: The post-operative results indicated a success rate of 78.7%. According to the questionnaire-based survey, 64.4% patients considered their hearing as "improved". The average VAS score was the highest in the "improved" group and gradually decreased when in the "deteriorated" group. The highest success rate was obtained in patients who assessed their hearing as "improved" and the lowest rate was seen in those who assessed their hearing as "deteriorated". On the other hand, the success rate in the three groups, "slightly improved", "unchanged", and "slightly deteriorated", was almost similar and did not relate to the objective audiometry findings. Therefore, except for the "improved" and deteriorated" groups, there is no relation between the subjective self-assessment and the objective post-operative hearing. CONCLUSION: A bi-directional approach, one from an audiological (objective) and one from the patient's perspective (subjective), especially using VAS, is quite useful for the post-operative assessment of hearing.

Adolescent↗
PubMed2004

Brain abscess secondary to the middle ear cholesteatoma: a report of two cases.

We experienced two cases of brain abscess secondary to middle ear cholesteatoma. One, a 61-year-old woman, presented with left otalgia, appetite loss and nausea. The computed tomography obtained on admission revealed a middle ear cholesteatoma. The magnetic resonance image showed the presence of a brain abscess in the cerebellum. The brain abscess was drained and the cholesteatoma was removed using the canal down procedure under general anesthesia. Part of the cholesteatoma invaded the posterior cranial fossa was could not be removed from the otological surgical field. The patient has been under observation as an outpatient for 6 months already and no abnormal signs have been detected. The other patient, a 55-year-old man, was admitted to our hospital for a detailed examination because he had right otalgia and progressive headache. The examination of spinal fluid obtained by lumbar puncture showed marked elevation of the white blood cells count. Computed tomography revealed a middle ear cholesteatoma. The magnetic resonance image obtained on admission showed an area of low-intensity encapsulated by an area of high-intensity in the right temporal lobe. The abscess was drained and the cholesteatoma was removed using the canal down procedure under general anesthesia. The patient has been under observation for 1 year already and has presented no signs of recurrence.

Anti-Bacterial Agents↗
PubMed2004

Interferon-gamma expression in the inner ear of rats following secondary immune reaction in the endolymphatic sac.

Recently, we demonstrated increased intercellular adhesion molecule-1 (ICAM-1) expression in the inner ear of systemically pre-sensitized rats after antigen [keyhole limpet hemocyanin (KLH)] challenge into the endolymphatic sac (ES), in good correlation with the cellular infiltration. Interferon-gamma (IFN-gamma) is an important cytokine that upregulates the expression of ICAM-1. Here, we report upregulation of IFN-gamma expression in the inner ear of systemically pre-sensitized rats after antigen (KLH) challenge into the ES. Immunoreactivity for IFN-gamma was detected in the spiral ligament, suprastrial region, spiral modiolar veins, spiral collecting venules, surface membrane of the perilymphatic compartment and perilymphatic space of immunized, but not control, rats. IFN-gamma expression was detected at 1.5 h post-challenge, peaked at 6 h and gradually returned to baseline levels after 7 days. Interestingly, the time kinetics of IFN-gamma expression were in good correlation with those of ICAM-1. These observations demonstrate that antigen challenge into the ES induces IFN-gamma expression, which can then upregulate ICAM-1 expression and induce cell infiltration, suggesting that IFN-gamma may play a crucial role in immune-mediated inner ear diseases.

Animals↗
PubMed2004

Acoustic stimulation promotes the expression of inducible nitric oxide synthase in the vestibule of guinea pigs.

Loud acoustic stimulation is known to cause inner ear disturbance. We examined immunohistochemically the vestibule of 12 guinea pigs after acoustic stimulation. The animals were divided into two equal groups: a control group and an acoustic stimulation group. The temporal bones were fixed by means of a cardiac infusion of fixative and immunohistochemically stained for inducible nitric oxide synthase (iNOS). The temporal bones in the control group did not show any iNOS. In the acoustic stimulation group, immunoreactivity for iNOS was detected in the supporting cells and sensory cells of the sensory epithelium, in the dark cell areas and in the vestibular ganglion cells. These findings suggest that free radicals are involved in the pathogenesis of noise-induced inner ear damage. Furthermore, free radicals may cause vestibular damage, as is seen in noise-induced inner ear damage.

Acoustic Stimulation↗
PubMed2004

Congenital malformations of the middle ear with an intact external ear: a review of 38 cases.

In patients with middle ear malformations, one can expect an improvement in hearing following ear surgery. Thus, it is crucial for the ear surgeon to have an increased awareness of this disease. For a better understanding of this condition, 38 patients who underwent ear surgery were studied. All patients had congenital ossicular malformations but with an intact external ear. On the basis of our intra-operative observations, 15 cases were assigned to group A (single malformation) and 23 cases to group B (multiple malformations). The pre-operative air-conduction threshold in group B patients was higher than that in group A. Pre-operatively in group A 2 out of 20 ears had mild, 17 had moderate and 1 had severe hearing loss (HL). In group B, out of 25 ears, 3 had mild, 13 had moderate and 9 had severe HL. Post-operatively in group A, 2 had normal hearing, 16 had mild, 2 had moderate and none had severe HL. In group B, postoperatively 1 had normal hearing, 18 had mild, 4 moderate and 2 severe HL. Therefore, in patients with multiple middle ear malformations, the surgeon should know that the prospect of an improvement in the hearing threshold is rather low even after surgical reconstruction.

Adolescent↗
PubMed2004

Subcutaneous emphysema after tonsillectomy: a case report.

We experienced a case of a subcutaneous emphysema after tonsillectomy. The patient, a 24-year-old man, complained of a recurrent sore throat and was diagnosed as having chronic tonsillitis. Pre-operative general examinations revealed no abnormalities. The operation was carried out under general anesthesia. The adhesions between the tonsils and the surrounding tissues were moderate. The bi-lateral tonsils were easily removed. The recovery period was uneventful. On the next morning, marked swelling of the left cheek and submandibular area was noted. On palpation, there was a characteristic crepitation and softness in these areas. The X-ray examination revealed subcutaneous emphysema. There was no finding of airway obstruction. We diagnosed him as having a subcutaneous emphysema and administered antibiotics for 5 days. From clinical findings, the subcutaneous emphysema was thought to be caused by surgical rather than anesthetic factors. The subcutaneous emphysema gradually disappeared. One year after the tonsillectomy, the patient is under observation as an outpatient and is free from any abnormal symptoms. To avoid this kind of complication, we should pay attention to carefully separate the tonsil from its fossa and to make appropriate selection of surgical equipments.

Adult↗
PubMed2004

Subjective evaluation and overall satisfaction after tympanoplasty for chronic simple suppurative otitis media.

A questionnaire survey was conducted in 324 patients with chronic, simple, suppurative otitis media who had undergone tympanoplasty 6 months or more previously to investigate post-operative hearing, tinnitus, vertigo, occlusive feeling of the ear and otorrhea. In addition, the overall satisfaction with tympanoplasty was assessed by VAS value. Subjective hearing improvement was observed in 73.1% of the patients whose hearing was poor and in 50% of those whose hearing was good before the operation. The degree of satisfaction assessed by VAS value corresponded with the subjective hearing assessment. As to tinnitus, 66.2% of the patients became aware of the disappearance or alleviation of symptoms. In the case of patients who had tinnitus before the operation, the degree of awareness of tinnitus and the degree of satisfaction assessed by VAS value coincided. However, no changes in the VAS value were observed in those who did not have tinnitus before the operation. As for vertigo, 30.5% of the patients who had vertigo preoperatively became aware of the disappearance of the symptoms after the operation. The degree of satisfaction assessed by VAS value corresponded with the presence or absence, severity and frequency of vertigo. As to the fullness of the ear, alleviation of the symptoms was subjectively noted by 85.9% of the patients who had symptoms before the operation. The degree of satisfaction assessed by VAS value corresponded with the severity of the symptoms in those who had symptoms before the operation. As for otorrhea, the disappearance of the symptoms was subjectively noted by 85.5% of the patients who had otorrhea before the operation. The degree of satisfaction assessed by VAS value corresponded with the post-operative changes in otorrhea. Based on the above results, it was assumed that the patients placed greatest expectation on hearing improvement when they underwent tympanoplasty. VAS is considered a useful method to evaluate the degree of satisfaction of patients after surgery.

Adolescent↗
PubMed2004

A comparative study on the observation of spontaneous nystagmus with Frenzel glasses and an infrared CCD camera.

OBJECTIVES: To compare the usefulness of a CCD camera with infrared illumination (IR-CCD camera) over Frenzel glasses (F Glasses) for the observation of spontaneous nystagmus, the incidence and direction of nystagmus, and the frequency, amplitude and slow phase of spontaneous nystagmus. METHODS: One hundred vertiginous patients, fifty-three females and forty-seven males participated in this study. Before undergoing routine neurotological examination, their eye movements were recorded by electronystagmogram (ENG) in conjunction with observations of eye movements under F glasses and through an IR-CCD camera. The data was collected from patients who exhibited spontaneous nystagmus either under F glasses or the IR-CCD camera. RESULTS: Thirty-three patients showed spontaneous nystagmus under F glasses. On the other hand, under the IR-CCD camera, all patients examined exhibited spontaneous nystagmus. The frequency of nystagmus was not significantly different between these two systems. However, the amplitude and slow phase velocity exhibited significantly larger values under the IR-CCD camera in patients with spontaneous nystagmus both under the IR-CCD camera and F glasses. CONCLUSION: From these observations and evidence, the IR-CCD camera can be recommended as a more useful system and powerful tool for neurotological examination than F glasses.

Adolescent↗
PubMed2004

Significance of preserving the posterior branch of the great auricular nerve in parotidectomy.

OBJECTIVE: Sensory disturbance due to excision of the great auricular nerve in patients who have undergone parotidectomy sometimes causes discomfort to the patients. In order to reduce the postoperative discomfort of the pinna, we tried to preserve the posterior branch of the great auricular nerve. METHODS: Forty patients with parotid tumor were included in this study. Twenty-one of these patients had pleomorphic adenoma, 16 had adenolymphoma and 3 had a low grade malignant tumor. Sensations of the pinna and the quality of life (QOL) after parotidectomy were evaluated using a 0-100 Visual Analogue Scale (VAS) assessed at 2 weeks, 1 month, 2 months, 3 months and 6 months after parotidectomy. RESULTS: The posterior branch of the great auricular nerve was preserved in 26 out of 40 patients (65%). No difference was observed in the incidence of complications except sensory disturbance of the pinna with this surgical procedure as compared to the surgical technique where the great auricular nerve was excised. The VAS score for the sensation was significantly higher in the group of patients whose great auricular nerve was preserved at 2 months (35.0+/-20.8 vs. 18.5+/-9.2), 3 months (64.4+/-18.3 vs. 26.4+/-13.8) and 6 months (66.9+/-16.2 vs. 26.6+/-11.4) after parotidectomy. The VAS score for the QOL was also significantly higher in the group of patients whose great auricular nerve was preserved at 2 months (50.3+/-21.8 vs. 35.1+/-14.5), 3 months (69.5+/-27.5 vs. 45.9+/-22.6) as well as 6 months (71.9+/-24.1 vs. 45.7+/-19.1) after parotidectomy. CONCLUSION: Preservation of the posterior branch of the great auricular nerve during parotidectomy is valuable in order to reduce the postoperative sensory disturbance of the pinna that follows conventional surgery. It further helps to improve the QOL of these patients after parotidectomy.

Adenolymphoma↗
PubMed2003

The effect of gravity on the stability of human eye orientation.

OBJECTIVE: The stabilization of both the horizontal (H) and vertical (V) eye movements during voluntary fixation is believed to depend upon the visual feedback system in the upright position. However, ocular stability in the tilted position has been less well investigated. Therefore, in the present study, we examined the gaze stability of healthy human subjects in the three dimensions in the tilted position using a video image analysis system (VIAS). METHODS: In 10 healthy human subjects, the eye movements were recorded after fixating the eye on a target in an upright position and also in the tilted position. The standard deviations of the eye movements in the three dimensions were calculated to evaluate the stability of the movements. RESULTS: In the tilted position, there were no significant changes in the horizontal and vertical eye movements as compared those in the upright position. However, the standard deviation of the torsional (T) segment was significantly larger in the tilted position, compared to that in the upright position. CONCLUSION: From these results, we speculate that, a combination of otolith and somatosensory inputs play a major role in maintaining the stability of eye movements.

Adult↗