[Show abstract][Hide abstract] ABSTRACT: The statistical properties of the center of pressure (COP) change over time, and time-invariant methods of the COP analysis is not sufficient to monitor the changes. Therefore, dynamic temporal information of the COP signals has been important in assessing the postural stability. The purpose of this study was to evaluate the characteristic pattern of time-frequency dynamics during the upright stance in patients with unilateral vestibular dysfunction (UVD) This study included 20 dizzy patients with UVD and age-matched 20control subjects without any vestibular disorder. The COP signals were collected using a single standard force platform and a spectral analysis including the time-frequency dynamics was carried out on the basis of the maximum entropy method (MEM) by using a segment time series analysis. The power spectral density (PSD) analysis exhibited an exponential decreasing shape (1/f −β) when plotted on a double logarithmic scale. The average value of β in the low frequency range of less than 1 Hz in the UVD group was significantly lower than that in the control group (p < 0.05) in the medial-lateral (ML) direction under eyes closed condition. In the segment time series analysis, the peak frequency of the COP signals in the patients with UVD gradually converged to the frequency range of 0.1 to 0.2 Hz in the ML direction under EC condition. Our results suggest that the segment time series analysis of the COP signals can derive a characteristic pattern related to the UVD. It may indicate an increased reflexivity of the COP fluctuation by the UVD, resulting in inducing the instability.
[Show abstract][Hide abstract] ABSTRACT: The inner ear is constituted by complicated cochlear and vestibular compartments, which are derived from the otic vesicle, an embryonic structure of ectodermal origin. Although the inner ear development has been analyzed using various techniques, the developmental events have not been fully elucidated because of the intricate structure. We previously developed a Sox10-IRES-Venus mouse designed to express green fluorescent protein under the control of the Sox10 promoter. In the present study, we showed that the Sox10-IRES-Venus mouse enabled the non-destructive visualization and understanding of the morphogenesis during the development of the inner ear. The expression of the transcription factor Sox10 was first observed in the invaginating otic placodal epithelium, and continued to be expressed in the mature inner ear epithelium except for the hair cells and mesenchymal cells. We found that Sox10 was expressed in immature hair cells in the developing inner ear, suggesting that hair cells were generated from the Sox10-expressing prosensory cells. Furthermore, we demonstrated that scattered Sox10-expressing cells existed around the developing inner ear, some of which differentiated into pigmented melanocytes in the stria vascularis, suggesting that they were neural crest cells. Further analyzing the Sox10-IRES-Venus mice would provide important information to better understand the development of the inner ear.
[Show abstract][Hide abstract] ABSTRACT: The morbidity of orthostatic hypotension (OH) increases with aging and the elderly often complain of dizziness associated with OH, which is implicated in white matter lesions (WMLs) on MRI. However little is known how WMLs are contributed to the development of dizziness in elderly patients.
We evaluated the involvement of cerebral WMLs in the vertical perception in the elderly with OH.METHODS: This study consisted of 71 dizzy patients who underwent the examinations including the Schellong orthostatic test and subjective visual vertical (SVV) test.
The male patients aged ⩾ 65 years with OH (1.9 ± 0.9°) showed a significantly higher magnitude of variance of SVV, which reflects an impaired vertical perception, in comparison with the male patients aged ⩾ 65 years without OH and the male patients aged < 65 years with OH (1.0 ± 0.4°, 0.9 ± 0.4°, p < 0.05). The variance of SVV significantly correlated with the volume of WMLs in both sides on MRI in the male, but not female patients (p < 0.01).
Our results suggest that severe WMLs in the elderly with OH are involved in impaired perception of verticality, resulting in inducing subjective dizziness.
Journal of Vestibular Research 01/2013; 23(2):85-93. · 1.00 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Surgery is not usually indicated for the involvement of cervical lymph node metastasis to the subclavian vein. Although surgery is indicated for the involvement of cervical lymph node metastasis to the venous angle, the usual visual field associated with cervical lymph node dissection cannot sufficiently visualize the subclavian vein, and the possibility exists of causing great vessel injury when involved lymph nodes are large and their mobility is restricted. In such cases, surgical excision may be avoided based on the expectation that ligating or cutting the internal jugular vein will be difficult. We examined 10 patients who underwent surgery for the adhesion or invasion of the primary tumor or involved lymph nodes to the venous angle or subclavian vein. The clavicle was removed or displaced to secure the visual field. The sternoclavicular joint was conserved and the clavicle, separated from the first rib, was lifted in 4 patients, while the medial two thirds of the clavicle was removed in 6 patients. Involved lymph nodes could be securely dissected without causing great vessel injury. A chylous leak occurred in one patient undergoing the procedure on the left side.
[Show abstract][Hide abstract] ABSTRACT: Aims: A proportional-integral-derivative (PID) control has recently been used as a control algorithm of body balance. The purpose of this study was to elucidate an association of the proportional and derivative gain based on the PID control gain for balance for quiet standing with the risk factor for falls in the elderly. Methods: The movement of a marker on the back of 23 elderly participants (age 75.6 ± 6.6 years) was measured by our developed device with a complementary metal oxide semiconductor video camera and the trunk sway speed in the medial/lateral (M/L) direction (TSSX) was calculated as absolute values of the whole time series. The PID control gain (proportional gain: K(P) , integral gain: K(I) , derivative gain: K(D) ) was identified using the trunk sway data, and normalized by individual height and weight (K(P) n, K(D) n and K(I) n). Individual risk factor for falls was additionally assessed with the Tinetti Performance Oriented Mobility Assessment (POMA) and the fall risk questionnaire. Results: The score in the POMA and the K(D) n significantly decreased with age (P < 0.01). The score in the POMA showed a positive correlation with the K(D) n, and negative correlations with the TSSX and K(P) /K(D) ratios (P < 0.01). The average K(D) n and the score in the POMA of fallers were significantly lower than those of non-fallers (P < 0.05). Conclusion: These results suggest that the decreased damping control by derivative gain for balance in the M/L direction is one of the risk factors for falls in the elderly. Geriatr Gerontol Int 2012; ••: ••-••.
[Show abstract][Hide abstract] ABSTRACT: To assess the clinical outcomes of single or oligo-fractionated stereotactic radiotherapy (SRT) using dynamic conformal arcs (DCA) for head and neck tumors (HNTs).
Thirty-four consecutive patients with 35 lesions treated between 2005 and 2009 were retrospectively evaluated, of whom 85.7 % had recurrent or metastatic disease, and 45.7 and 34.3 % had previous radiotherapy and surgery, respectively. The median SRT dose was 22.3 Gy (11.2-32.8) in 2-4 fractions with a median interval of 7 days and 10.4 Gy (9.2-12.4) in one fraction. SRT was combined with upfront conventionally fractionated RT in 48.6 % of patients.
The median follow-up periods were 18.4 months (2-84.1) for the entire cohort and 49.6 months for the survivors. The 1- and 2-year local control (LC) rates were 84.3 and 70.5 %, with the 1- and 2-year overall survival (OS) rates of 78.6 and 51.6 %. LC was significantly better for tumor volumes <25.6 cm(3) (p = 0.001). OS was significantly longer in patients without any disease outside the SRT site (p < 0.001), whereas LC after the SRT did not affect the OS. Late adverse events occurred in 9 patients, including cranial nerve (CN) injury (grade 3/4) in 2, brain radionecrosis in 5 (grade 1), and fatal bleeding in 2 patients harboring uncontrolled lesions abutting the carotid artery.
DCA-based SRT can confer relatively long-term LC with acceptable toxicity in selected patients with HNTs. The patients with CN involvement or tumor volume ≥25.6 cm(3) were deemed unsuitable for this treatment regimen.
Journal of Cancer Research and Clinical Oncology 04/2012; 138(9):1511-22. · 2.91 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: There is little definitive evidence of the clinical significance of the vestibular-cardiovascular reflex in humans, despite the fact that the vestibular system is known to contribute to cardiovascular control in animals. The present study involved 248 dizzy patients (127 male patients and 121 female patients) aged 65 years and younger. We classified all participants into three groups based on their vestibular evoked myogenic potential (VEMP) responses; absent VEMP, asymmetry VEMP and normal VEMP. To investigate the effect of the otolith disorder, which was estimated by the VEMP, on the orthostatic blood pressure responses, the subjects' systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate were monitored during the orthostatic test after they actively stood up. The male patients in the absent VEMP group had a significant drop in their DBP at 1 min after active standing up (P < 0.05) without any change in their SBP. Conversely, male patients in the asymmetry VEMP and normal VEMP groups showed a significant increase in the SBP at 1 min after active standing up (P < 0.05). Female patients in the absent VEMP group did not show any significant drop in their blood pressure after standing up (P > 0.05). In the entire group of participants, a total of 19.6% of the patients in the absent VEMP group fulfilled the criteria for orthostatic hypotension (OH), which was significantly > the 8.6% of patients in the normal VEMP group and the 7.2% in the asymmetry VEMP group (P < 0.05). Our results suggest that vestibular disorders due to the dysfunction of otolith organs provoke OH.
Experimental Brain Research 12/2011; 217(2):251-9. · 2.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Tinnitus interferes with sleep and concentration which is associated with depression; however, no drug has been effective in treating tinnitus. Our purpose is to evaluate our hypothesis that the treatment with lyophilized powder of enzymolyzed honeybee larvae as a complementary medicine may provide a therapeutic effect on tinnitus-related symptoms.
Sixty tinnitus sufferers participated in a randomized double-blind placebo-controlled trial using the lyophilized powder of enzymolyzed honeybee larvae or a placebo. The Tinnitus Handicap Inventory, a visual analog scale to rate the severity of tinnitus, hearing levels, and hypothalamus-pituitary-adrenal axis-related hormones drawn early in the morning were measured upon entry into the study and after 12 wk of follow-up.
The lyophilized powder of enzymolyzed honeybee larvae was not superior to placebo with regard to the total score on the Tinnitus Handicap Inventory and the visual analog scale. However, subjects in the honeybee larvae group showed significant improvements in some items about depression associated with tinnitus, whereas subjects in the placebo group showed no improvement in any items. The honeybee larvae group showed significant improvements in the hearing levels at 2 and 4 kHz in the audiogram of the better ear. The intervention of the lyophilized powder of enzymolyzed honeybee larvae was associated with lower serum cortisol levels, serum prolactin levels, and cortisol/dehydroepiandrosterone sulfate ratios. The ratios in the placebo group significantly were increased.
Our results suggest that the lyophilized powder of enzymolyzed honeybee larvae represents an effective complementary medicine to alleviate depression associated with tinnitus by regulating the activity of the hypothalamus-pituitary-adrenal axis.
Ear and hearing 10/2011; 33(3):430-6. · 2.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the association of the HPA (hypothalamus-pituitary-adrenocortical) axis-related hormones with the progression of cochlear symptoms in patients with Ménière's disease.
Clinical assessments (Tinnitus Handicap Inventory: THI, visual analog scale to rate the degree of the tinnitus: VAS, hearing levels in pure-tone audiometry) were conducted upon entry into the study (baseline) and at 12 weeks follow-up (week 12). Blood sampling to measure HPA axis-related hormones took place between 9:00 and 10:00 a.m. at baseline and at 12 weeks follow-up. STUDY SAMPLES: This study consisted of 20 unilateral Ménière's disease patients and 21 patients with other diseases with unilateral sensorineural hearing loss and tinnitus.
A significant deterioration of the hearing level at high frequency range, especially at 2 kHz, was found during the 12 weeks follow-up in the Ménière's disease group (p < 0.05). The average hearing levels significantly correlated with the serum cortisol level at baseline and week 12 in the Ménière's disease group, especially regarding the high frequency levels (p < 0.01).
Our results suggest that the cortisol levels influence the endolymphatic homeostasis resulting in a deterioration of hearing at high frequency with upstaging of Ménière's disease.
International journal of audiology 09/2011; 50(12):897-904. · 1.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Superior semicircular canal dehiscence (SCD) syndrome exhibits pressure- and/or sound-induced oscillopsia and vertigo due to an absence of bone overlaying the superior semicircular canal. A 33-year-old man with right-ear SCD reported dizziness in a noisy hall three years earlier followed by dizziness during flatulence, straining or coughing, and right-ear autophony. Audiography showed a right-ear low-frequency air-bone gap, with positive Tullio phenomenon and a Valsalva maneuver against closed glottis causing torsional-vertical nystagmus. Temporal-bone computed tomography (CT) led to a diagnosis of right-ear SCD syndrome. Surgical dehiscence plugging with calcium phosphate cement via the middle fossa resolved vestibular and cochlear symptoms in the more than two years since.
[Show abstract][Hide abstract] ABSTRACT: Recent studies have demonstrated that assuming the postural corrective torque is regulated by a proportional-integralderivative (PID) controller in the anterior/posterior direction, although few studies have discussed the medial/ lateral (M/L) direction through PID control. Instability in the M/L direction has been reported to be closely related with the risk of falling in the elderly. The purpose of this study is to evaluate the mechanism of postural control in the M/L direction in the elderly.
The movement of a marker on the subject's back was measured by a CMOS video camera and trunk sway speeds in the M/L direction (TSSX) were calculated as absolute values in whole time series. Using trunk sway data, we identified the gain of PID parameters (proportional gain: KP, integral gain: KI derivative gain: KD). In addition, we calculated the frequency spectrum of trunk sway using the marker locus from 0.016 to 5 Hz by fast Fourier transform. A total of 40 healthy subjects aged from 20 to 85 years old was evaluated with the PID control algorithm in a model of postural control in the M/L direction and their parameter values were estimated.
KP significantly increased with age, whereas KD tended to decrease. The TSSX and power ratio of medium frequency (0.2-2.0 Hz) significantly increased with age, but the power ratio of low frequency (0.02-0.2 Hz) tended to decrease. KP and KI were significantly correlated with the power ratio of medium frequency. There was a significant negative correlation between KD and TSSX.
Our results indicate that dependence on hip and ankle stiffness, which may be controlled by proportional gain, increases with age for postural control in the M/L direction. A disability in the feedback mechanism based on velocity information for postural control, which may be associated with derivative gain, tends to increase with age but shows considerable individual variation.
Aging - Clinical and Experimental Research 04/2011; 24(2):162-70. · 1.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: It has become clear through epidemiological analysis that the incidence of cancers of the lung, liver, colon, and rectum are increasing in Japan every year. However, there have been few epidemiological analyses of nasopharyngeal carcinoma (NPC) in Japan. The aim of this study was to analyze the epidemiology and current incidence of NPC in the Chubu region of Japan during the period from 1996 to 2005.
Takeshita et al. conducted a similar investigation in the Chubu region 10 years ago, and, as a result, this is a comparative study. The Chubu region is the central region of Japanese main island. We researched NPC patients treated in hospitals in each prefecture over a 10-year period (1996-2005) using a questionnaire.
A total of 525 cases (male:385, female:134, unknown:6) were analyzed epidemiologically, histologically, serologically, and clinically in this study. The incidence per 10(5) population per year was 0.29. For the period of 1986-1995, the age-standardized incidence of NPC was 0.28 per 10(5) persons per year in Takeshita's report. There was no significant difference between the two periods. The ages of the patients ranged from 13 to 90 years. The mean age of was 55.2 years. On the basis of the World Health Organization (WHO) histological criteria, 36% of the patients were classified as WHO I, 27% as WHO II, and 37% as WHO III. Carcinoma was located in the posterosuperior region in 56%, lateral in 41%, and inferior in 3%. Tumor staging showed that 6% to belonged to stage I, 25% to stage II, 31% to stage III, and 38% to stage IV. A neck mass was present in 52% of the patients, ear symptoms in 48%, nasal symptoms in 27%, headaches in 10%, pharyngeal symptoms in 9%, ophthalmologic symptoms in 9%, and cranial neurological symptoms in 9%. The positive rates of serum titers of the antibodies to Epstein-Barr virus (EBV)-related antigens were calculated. The positive rate of anti-EBV-viral capsid antigen (VCA) immunoglobulin (Ig) G titers was 58.6%, that of anti-EBV-VCA IgA titers was 53.6%, and that of EBNA was 81%. The five-year survival rate for all patients was 67.6%, and that for those in stage I, II, III, and IV was 75%, 84%, 69%, and 53%, respectively. The five-year survival rate for stage IV was significantly lower than those for the other stages (P<0.05).
The age-standardized annual incidence of NPC in our survey was 0.29 per 10(5) persons per year, being relatively low and stable.
[Show abstract][Hide abstract] ABSTRACT: An elevation of the plasma arginine vasopressin (AVP) level has frequently been observed in Meniere's disease patients. However, little is known regarding the mechanism behind this elevation. The plasma AVP levels in acute phase were determined in 21 Meniere's disease patients and 16 patients with other types of vertigo. The plasma AVP levels of Meniere's disease patients in the acute phase were significantly higher than in those of other vertigo patients (p < 0.01). In Meniere's disease patients with abnormally high levels of AVP (more than 3.5 pg/ml) in the acute phase, 36% of patients were resistant to conservative treatments for frequent vertigo attacks for the follow-up period of at least 2years. A significant correlation was observed between the plasma AVP in the acute phase and the highest hearing threshold level at a frequency of 1kHz for the follow-up period of at least 1 year (r=0.45, p < 0.05). These results suggest that the elevation in plasma AVP level in the acute phase is associated with the prognosis of Meniere's disease.
International journal of audiology 01/2010; 49(1):1-6. · 1.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We herein report a 59-year-old male patient with a recurrent carcinoid tumor of the middle ear 7 years after a tympanomastoidectomy. The CT and dynamic MRI demonstrated an extensive tumor close to the carotid artery canal and the jugular bulb, and the tumor was removed by a partial petrosectomy with a transmastoid approach. The histopathological findings revealed a solid and trabecular tumor with cells positive for cytokeratin, chromogranin A, synaptophysin, and CD56. The MIB-1 antibody for the Ki-67 antigen was positive in 6.6% of the tumor cells. The relevant literature is reviewed in regard to the present case.
International Journal of Otolaryngology 01/2010; 2010:818673.
[Show abstract][Hide abstract] ABSTRACT: In the present study, we investigated the body sway in patients with unilateral vestibular dysfunction by the largest Lyapunov exponents using a chaotic time series analysis. The largest Lyapunov exponent is regarded as a parameter indexing an orbital instability.
Subjects consisted of 55 normal healthy subjects, 11 patients diagnosed as having vestibular neuritis (VN), 6 patients diagnosed as having sudden deafness (SD) with vertigo, 23 patients diagnosed as having Meniere disease (MD), 11 patients diagnosed as having benign paroxysmal positional vertigo (BPPV) and 14 patients diagnosed as having other vestibular disorders. Using a stabilometer, the sway of the body center of gravity in an upright standing position was recorded with eyes open and closed for 60 seconds under each condition. From the time series data obtained, the largest Lyapunov exponents were calculated using a chaos analysis program.
In normal healthy subjects and patients with unilateral vestibular dysfunction, the largest Lyapunov exponents on right-left sway were larger than those on forward-backward sway with eyes open and closed. The largest Lyapunov exponents in patients with unilateral vestibular dysfunction on forward-backward sway with eyes closed were significantly larger than those in normal healthy subjects. A few patients with the instability of standing posture judged from conventional analysis (area of sway, locus length per time) showed higher values of the LLE. We investigated the variation of the values of the largest Lyapunov exponents in patients with unilateral vestibular dysfunction at each stage during recovery from their vestibular damage. The largest Lyapunov exponents at the early stage with stable standing posture were significantly higher than those at the late stable stage with stable standing posture. Some patients at the very early stage had lower values of the largest Lyapunov exponents.
We speculate that the orbital instability indicated by the values of the largest Lyapunov exponents has a different significance from instability of standing posture indicated by a conventional analysis. We propose that the largest Lyapunov exponents may be an useful subsidiary measure to evaluate postural stability and its change due to vestibular dysfunction.
[Show abstract][Hide abstract] ABSTRACT: 5-Fluorouracil (5-FU) is a widely used chemotherapeutic agent that inhibits the growth and initiates the apoptosis of epithelial tumors, including squamous cell carcinoma of the head and neck region. However, resistance to this drug is often observed in a clinical setting. The primary mode of action of 5-FU is believed to be the inhibition of thymidylate synthase. Overexpression of the enzymes involved in thymidine synthesis has been shown in some cases to be associated with resistance. However, the detailed mechanisms of resistance of squamous cell carcinoma are not fully understood. In the present study, we examined the involvement of survival signaling pathways in the resistance of squamous carcinoma cells to 5-FU. 5-FU induced the activation of the ERK and Akt kinases in UM-SCC-23 human squamous carcinoma cells, indicating that this anticancer drug activates survival signaling pathways as well as apoptotic signals. In 5-FU-resistant UM-SCC-23 cells established by our group, ERK and Akt signals were constitutively activated. U0126 is an inhibitor of MEK, which is an upstream activator for ERK. U0126 failed to sensitize resistant UM-SCC-23 cells to 5-FU-induced apoptotic cell death. This is in sharp contrast to LY294002, which is an inhibitor of phosphatidylinositol 3-kinase, an upstream activator for Akt. LY294002 drastically enhanced 5-FU-induced apoptotic cell death in resistant UM-SCC-23 cells. These results indicate that the Akt survival signal plays an important role in the resistance of squamous carcinoma cells to 5-FU treatment, and suggest that the modification of Akt activity might provide a new strategy for human 5-FU-resistant squamous carcinoma therapy.
Molecular Medicine Reports 01/2009; 2(4):609-13. · 1.17 Impact Factor