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Biomedical subjects

Jin Kanzaki

Publications and source records attributed to Jin Kanzaki.

10 recordsLinked to original sources
PubMed2003

Compensatory changes in static and dynamic subjective visual vertical in patients following vestibular schwanoma surgery.

OBJECTIVE: Among patients with vestibular schwanoma (VS), vestibular function is nonhomogeneous, both before and after surgical removal of the VS. This paper reports investigations of neural changes, especially changes in the contribution of visual input to vestibular system integration, after VS surgery. METHODS: We examined 33 patients who underwent VS surgery via a middle fossa approach. Static and dynamic subjective visual vertical (SVV) was measured once after surgery and compared to those measured in control subjects. SVVs were assessed using a paradigm requiring the subject to manually adjust an image of a bar to the perceived vertical alignment. SVVs were measured when the background was stationary or rotating. RESULTS: In almost all patients, static SVV deviated toward the operated side. In VS subjects, the mean static SVV was 1.8+/-2.2 degrees; the amount of deviation in the dynamic SVV toward the operated side (11.7+/-8.3 degrees ) was significantly larger than that to the intact side (8.8+/-5.5 degrees ). In VS subjects, static SVV was correlated with dynamic SVV only in cases of bar adjustments toward the operated side (R=0.67, P<0.001), but not in cases of adjustments toward the intact, unoperated side. The axis of rotation was defined as the mean value of dynamic SVV for adjustments toward either side. There was only a weak correlation between the static SVV and the axis of rotation (R=0.31; P<0.05) in the control subjects. On the other hand, a more robust correlation between static SVV and axis of rotation was found (R=0.67, P<0.001) in VS subjects. There was no correlation between the static SVV and the deviation of dynamic SVV from static SVV for CCW and CW in control subjects. In contrast, there were significant correlations between static SVV and deviation of dynamic SVV from static SVV for adjustments made toward both operated (r=0.48, P<0.001) and intact sides (r=038, P<0.05). CONCLUSION: It is assumed that the amount of deviation in static SVV reflects the individual level of compensation. In addition, increased visual dependency evoked a symmetrical bias of the dynamic SVV from the measures at initial SVV assessment (i.e. static SVV or the center of tilt). As a result, we conclude that the contribution of visual inputs had changed after surgery, while at the same time, each patient used their static SVV as their reference point for orientation.

Adaptation, Physiological↗
PubMed2003

Effect of single-drug treatment on idiopathic sudden sensorineural hearing loss.

OBJECTIVES: In order to evaluate the effect of a medical administration for the sudden deafness patients, single-drug treatment for idiopathic sudden sensorineural hearing loss (ISSHL) was assessed at multi-centers participating in the Acute Severe Hearing Loss Study Group sponsored by the Ministry of Health, Labor and Welfare of Japan. METHODS: The subjects consisted of ISSHL patients who were (1) 20 years of age or older, (2) diagnosed within 2 weeks after the onset of hearing loss, (3) showing a mean hearing level of 40-90 dB at five frequencies from 250 to 4000 Hz, (4) previously untreated, and (5) with normal for age in hearing of the opposite ear. The drugs used in this study were ATP, alprostadil, hydrocortisone and amidotrizoate, which were administered intravenously, and beraprost sodium and betamethasone, which were given orally. Two drugs were assigned to each center, one of which was selected according to the code hidden in envelopes and administered for 1 week. The treatment after the single-drug administration was conducted at the discretion of each center. The hearing gain and recovery rate at 1 week after the initiation of single-drug treatment and at 1 month or over when the hearing level was fixed, were evaluated based on the criteria for hearing recovery prepared by the Acute Severe Hearing Loss Study Group. RESULTS: There was no statistically significant difference in the recovery rate among drugs either at 1 week after the initiation of single-drug treatment or at the time of fixed hearing level. At the time when the hearing level was fixed, a statistically significant difference in the complete recovery rate was detected only between amidotrizoate and beraprost sodium. CONCLUSION: From these results, we could not find any specific drugs recommended for ISSNHL. In evaluating the effect of the drugs, however, several problems in the clinical trial for ISSHL should be considered.

Adenosine Triphosphate↗
PubMed2002

Expression of c-Fos after noise-induced temporary threshold shift in the guinea pig cochlea.

c-Fos is known to be a component of a transcription factor, activator protein-1, which is induced by oxidative stress. Guinea pigs were exposed to 4 kHz band noise of 110 dB SPL for 1 or 5 h and the expression of c-Fos in the organ of Corti was determined using Western blotting analysis and immunocytochemistry. c-Fos was expressed only after the noise exposure. The c-Fos expression was mainly found in the Hensen's cells, Claudius' cells and Deiter's cells of the basal and second turns of the cochlea. Since the threshold shift was temporary, the expression of c-Fos is therefore considered to contribute to the survival or protective function of the organ of Corti.

Acoustic Stimulation↗
PubMed2002

Haemorrhagic venous infarction following the posterior petrosal approach for acoustic neurinoma surgery: a report of two cases.

The authors report two surgical cases with acoustic neurinoma in which haemorrhagic infarction occurred via a compromise in cerebral deep venous outflow. In both cases, surgery was performed via the posterior petrosal approach, and the neurinomas were completely removed. In the first case, the haemorrhagic infarction was considered to have resulted from transection of the tentorial sinus, the presence of which had not been predictable by preoperative angiography. In the second case, the haemorrhagic infarction was caused by a coagulation of the petrosal vein, which was firmly adherent to a tumour. With the posterior petrosal approach, meticulous care is necessary to preserve the deep anastomotic veins into and around the cerebellar tentorium. Thereby, catastrophic morbidity related to compromised deep cerebral venous outflow can be avoided.

Aged↗
PubMed2002

Three-dimensional analysis of nystagmus in benign paroxysmal positional vertigo. New insights into its pathophysiology.

Nystagmus is a rhythmical rotation of the eyeball. Its characteristics can be defined mathematically by the axis of rotation and the angular velocity around this axis. We analysed the axis of rotation for the nystagmus in benign paroxysmal positional vertigo (BPPV) to elucidate its pathophysiology. Thirteen patients with typical unilateral BPPV participated in the present study. The axis of rotation for the nystagmus was calculated from images recorded on digital videotape with an infrared CCD camera, using an algorithm that we developed. The patients' responsiveness to Semont's liberatory maneuver was also assessed.The results showed that patients could be assigned to one of two groups based on the rotation axis of the nystagmus. In one group of patients (n = 7; Group A), the axis of rotation was almost vertical to the plane containing the posterior semicircular canal (PSC) on the presumed affected side. In the other group of patients (n = 6; Group B), it was clustered around the naso-occipital axis. These results suggest that in the patients in Group A the responsible lesion is confined to the PSC, whereas the pathogenesis underlying the conditions in those in Group B is considered to be more complicated. This speculation was reinforced by the difference in responsiveness to Semont's liveratory maneuver. All of the patients in Group A showed remission of vertigo within 10 days (mean, 2.4 days) after onset of treatment using Semont's liberatory maneuver, whereas the patients in Group B required much longer periods of time for remission to occur (mean, 25.7 days). Our findings lead to the conclusion that by considering the spatial orientation of individual semicircular canals, in the patients in Group B the pathophysiology is not confined to the PSC, but most probably all three semicircular canals are involved.

Adult↗
PubMed2002

Dynamic and static subjective visual vertical with aging.

OBJECTIVE: Our vestibular function is gradually deteriorating during aging, although, its behavioral consequences are not easily recognized due to a substitution process by other sensory modalities as visual or proprioceptive inputs. METHODS: To reveal such a hidden substitution process by visual signals, the measurement of the static as well as the dynamic subjective visual vertical (SVV) was performed among 63 healthy subjects of different age. RESULTS: The static SVV was found to be stable among all subjects, whereas the shift of the dynamic SVV during rotation of a background scene gradually increased with age. CONCLUSION: This result indicates that the substitution process identified as a function of age in a perceptual test may have its counterpart in postural stabilizing reflex.

Adult↗
PubMed2002

Effect of prostaglandin E1 on idiopathic sudden sensorineural hearing loss: a double-blinded clinical study.

OBJECTIVE AND STUDY DESIGN: The authors conducted a prospective, randomized, double-blinded clinical trial for the purpose of elucidating the effects of prostaglandin E1 (PGE1) on idiopathic sudden sensorineural hearing loss. SETTING AND PATIENTS: With the approval of the institute ethics committee, a total of 57 consecutive patients with diagnoses of idiopathic sudden sensorineural hearing loss were included in the study. The patients in the PGE1 group received continuous infusion containing 60 microg PGE1 and 100 mg hydrocortisone for 7 days, and the patients in the placebo group were treated with continuous infusion containing an inactive placebo and 100 mg hydrocortisone. RESULTS: No significant differences were observed in the improvements of pure-tone average and subjective symptoms between the PGE1 and the placebo groups. However, the hearing improvement at high frequencies (4 kHz and 8 kHz) was significantly higher in the PGE1 group than in the placebo group, especially in the patients with severe tinnitus. CONCLUSIONS: These results failed to prove a beneficial effect of PGE1 in the treatment of idiopathic sudden sensorineural hearing loss. Further studies will be needed to clarify the pharmacologic actions of PGE1 in the cochlea.

Adult↗
PubMed2002

[Statistical analysis of maxillary sinus squamous cell carcinoma].

Cases of squamous cell carcinoma of the maxillary sinus initially treated at Keio University Hospital between January 1981 and December 1998 studied retrospectively involved 60 untreated cases--46 men and 14 women aged 36 to 86 years (mean: 59.8 years). Of these, 7 had T2, 41 T3 and 12 T4 tumors based on 1997 AJCC TNM classification. Seven (11.7%) had nodal involvement but none had distant metastasis at diagnosis. Of the 60, 53 (88.3%) were stage III or IV. Prognostic factors and survival were statistically analyzed for 59 cases, excluding the 60th who died of another cause. Follow-up was 4 to 227 months, with a median of 59 months and a mean of 38 months. Of the 59, 48 (81.4%) underwent neoadjuvant chemotherapy (NAC). Survival was estimated using the Kaplan-Meier method as univariate analysis. Cause-specific 5-year survival was 56.8% for all stages, 68.2% for T2, 60.0% for T3, and 41.7% for T4. T stage classification was thus a significant independent prognostic factor in multivariate analysis using Cox's proportional hazards model (p = 0.0240). It also identified T stage classification (p = 0.0486) and NAC (p = 0.0419) as significant independent factors affecting survival with organ preservation. We also statistically analyzed 48 cases treated with NAC, which showed complete response (CR) for 11, partial response (PR) for 25, no change (NC) for 11, and progressive disease (PD) for 1. Responders (CR + PR) showed significantly better survival and organ preservation than nonresponders (NC + PD). The NAC response enables us to predict prognosis. T4 cases without NAC response should be treated intensively.

Adult↗
PubMedDate not supplied

Classic hypoglossal-facial nerve anastomosis after acoustic neuroma resection. A review of 46 cases.

To clarify the factors contributing to patient satisfaction with facial movement after the classic hypoglossal-facial nerve anastomosis, we examined 46 such patients who consented to an interview and video-recording. No correlation was seen between the physician's evaluation of returned function (according to Yanagihara's 40-point scale and the grading system of House-Brackmann) and the scores (full marks: 100 points) the patients assigned to their own facial movements. Instead the scores that the patients assigned were closely related to subjective oral dysfunction, such as difficulty in masticating, articulating, and swallowing. Those scores did not correlate with eye-related functional deficits. These findings indicate that modified techniques to minimize the hypoglossal nerve deficit may enhance patient satisfaction without sacrificing recovery of facial movements.

Adult↗