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Biomedical subjects

R Osanai

Publications and source records attributed to R Osanai.

11 recordsLinked to original sources
PubMed2001

Stapedial reflex in myotonic dystrophy type 1 and CTG repeat expansion.

The severity of clinical symptoms of myotonic dystrophy type 1 (DM1) has been shown to be closely related to the size of a CTG triplet repeat in the gene encoding myotonin protein kinase. Neuro-otological examinations that include eye movement and stapedial reflex (SR) tests can contribute to the quantitative evaluation of muscular involvement in DM1. We previously found that saccadic eye movement velocity in DM1 patients was significantly lower than that in control subjects and that the saccadic velocity and size of the CTG triplet repeat in DM1 patients had a strong inverse correlation. We now report a case-control study that compared the SR wave form (latency: L, contraction time: C50, and relaxation time: D50) measured by the acoustic impedance method in 13 patients with DM1 and in 14 control subjects matched for age and sex. The correlation between the SR wave form and CTG repeat length in DM1 patients obtained by Southern blot analysis with EcoRI was also examined. We found (1) no significant difference between the pure tone audiometric threshold at 500 Hz in the DM1 patients and that in the control subjects; (2) or between the SR thresholds in the patients and controls (500 Hz stimuli); (3) C50 and D50 in DM1 patients to be significantly prolonged, whereas L was not; (4) C50 and D50 in DM1 patients to be significantly correlated with CTG repeat length, whereas L was not. Measurement of SR by the acoustic impedance method is completely non-invasive, causes no discomfort to the subject, and does not depend on the person's effort or cooperation. Our findings show that SR measurement can be used for a quantitative evaluation of muscle involvement in DM1. We believe that the prolongation of D50 in DM1 is caused by myotonia, which has to be confirmed by further clinical and pathological studies.

Adult↗
PubMed2000

CTG triplet repeat expansion in a laryngeal carcinoma from a patient with myotonic dystrophy.

A 66-year-old Japanese man with myotonic dystrophy (DM) underwent total laryngectomy for laryngeal carcinoma. The size of the expanded DNA fragment (EF) from the leukocytes and normal laryngeal tissues of this patient was only slightly longer than that in normal subjects. EF, however, was markedly longer in the laryngeal carcinoma. These findings support the hypothesis that elongation of the CTG repeat in the DM kinase gene occurs during acquired cell proliferation.

Aged↗
PubMed1999

Differences in mossy and climbing afferent sources between flocculus and ventral and dorsal paraflocculus in the rat.

Sources of mossy and climbing fiber inputs to the flocculus (FL), ventral paraflocculus (VP) and/or dorsal paraflocculus (DP) were identified in the vestibular ganglion, medulla oblongata and pons of 19 Wistar rats after 26 local injections of horseradish peroxidase, wheat-germ agglutinin-conjugated horseradish peroxidase, fast blue or diamidino yellow into the FL, VP and/or DP. There were large differences in the sources of mossy fibers to the FL and VP/DP. Labeled neurons after injections into the FL were observed mainly in the ipsilateral vestibular ganglion, bilaterally in the vestibular and prepositus hypoglossal nuclei, and in the caudal part of the nucleus reticularis tegmenti pontis. Labeled neurons were rarely observed in the pontine nuclei after localized injections into the FL. By contrast, after injections into the VP and/or DP, numerous labeled neurons were observed in the pontine nuclei with a contralateral predominance and in the rostral part of the nucleus reticularis tegmenti pontis bilaterally, but not in the vestibular nuclei in either side. Sources of climbing fibers to the FL and paraflocculus were completely contralateral to the injection side. After injection into the FL, labeled neurons were observed in the caudal dorsal cap and ventrolateral outgrowth of the inferior olivary nucleus. After injections into the VP, labeled neurons were observed mainly in the rostral dorsal cap, ventral medial accessory olivary nucleus (MAO) and caudal half of the ventral leaf of the principal olivary nucleus. After injections into the DP, labeled neurons were observed in the ventral MAO and caudal half of the ventral leaf of the principal olivary nucleus. These differences in the sources of mossy and climbing fiber inputs may suggest functional differences between the FL and VP/DP. The present results are consistent with our previous observations in monkey that the FL and VP/DP exhibit quite different mossy fiber input organizations.

Amidines↗
PubMed1998

Saccadic slowing in myotonic dystrophy and CTG repeat expansion.

Recent studies have shown that the severity of the several clinical symptoms of myotonic dystrophy (DM) is closely related to the size of a CTG triplet repeat in the gene encoding myotonin protein kinase. Although neurotological findings, including saccadic slowing in patients with DM, have been reported, the relationship between these neurotological findings and elongation of the CTG triplet repeat has not been discussed to our knowledge. We made a case-control study that compared the saccadic velocity in 13 patients with DM and in 13 controls matched for age and sex. We also examined the correlation between the saccadic velocity in DM patients and the size of the expanded DNA fragment (EF) obtained by Southern blot analysis with EcoRI or BglI. We found: (1) The primary eye position was normal in 9 of 12 patients. Divergent strabismus was present in 3 patients. (2) The range of ocular movement was normal in 2 patients, nearly normal in 5 and minimally limited in the other 5. (3) Only 1 patient had lateral gaze nystagmus, which was fine and transient. (4) The horizontal saccades were essentially normometric in 11 of the 13 patients, slightly hypometric in 1 and obviously hypometric in 1. These last 2 patients had the second longest and longest EF sizes. The vertical saccades were essentially normometric in 8 of 12 patients, hypermetric in 3, and hypometric in the 1 with the longest EF size. (5) The saccadic velocity in the DM patients was significantly lower than that in the controls in the horizontal or vertical direction, the difference being more prominent in the horizontal direction. (6) The correlation coefficients between horizontal saccadic velocity and EF size, 0.801 (EcoRI) and 0.756 (BglI), had a strong negative correlation (P < 0.01 for both EcoRI and BglI). No statistically significant correlation was found between vertical saccadic velocity (upward and downward) and EF sizes. Although it was difficult to determine whether saccadic slowing was caused by central oculomotor system involvement or extraocular muscle atrophy, the absence of gaze-evoked nystagmus in almost all of the patients favours the latter. Our study shows that neurotological examinations that include a saccadic velocity test are very useful for detecting subtle eye movement abnormalities in DM and for quantitatively evaluating the clinical severity of DM.

Adult↗
PubMed1997

Acute effects of tetrahydrobiopterin on the dynamic characteristics and adaptability of of vestibulo-ocular reflex in normal and flocculus lesioned rabbits.

The acute effects of (6R)-5,6,7,8-tetrahydro-L-biopterin (R-THBP) on the dynamic characteristics of horizontal vestibulo-ocular reflex (HVOR) were examined in chronically prepared alert pigmented rabbits. The HVOR gain was measured by 10 degrees-0.1 Hz sinusoidal oscillation of the turntable in darkness. In control rabbits, intramuscular injection of R-THBP (10 mg/kg) induced an increase of HVOR gain by 0.1-0.2, which lasted for 1-3 h. Sustained 10 degrees-0.1 Hz sinusoidal oscillation of the turntable and screen in the reversed direction induced an adaptive increase of HVOR gain by 0.2 in 3 h, which was not affected by applications of R-THBP. In flocculus lesioned rabbits, the HVOR gain reduced by 23%, and applications of R-THBP no longer induced a HVOR gain increase. These experimental observations suggested that the R-THBP affected on the HVOR dynamics within the cerebellar flocculus or its related neural areas.

Animals↗
PubMed1995

Neuro-otological and neuropathological findings in two cases with Machado-Joseph disease.

We report chronological changes of neuro-otological findings and associated neuropathological findings in 2 patients. Concerning gaze limitation, upward gaze was primarily disturbed, followed by downward gaze and abduction. Adduction tended to be preserved although convergence was disturbed at the early stage. And, upward gaze limitation was followed by loss of oculocephalic responses (OCRs). Bell's phenomenon was preserved until the late stage of the disease. Caloric nystagmus was absent at the early stage. One patient showed dissociation between nystagmus and vestibulo-collic reflex in the caloric test at the early stage of the disease. Neuropathological examination revealed gliosis in the interstitial nucleus of Cajal and the MLF as well as neuronal loss and gliosis in the oculomotor nuclei. The vestibular nuclei also showed gliosis and atrophy of nerve cells.

Brain Stem↗
PubMed1994

Laryngeal electromyography with separated surface electrodes in patients with multiple system atrophy presenting with vocal cord paralysis.

When recording the activity of the posterior cricoarytenoid muscle (PCA) with surface electrodes, there is contamination from the surrounding muscles such as the cricopharyngeal muscle. We therefore devised a new oesophageal catheter electrode of the separate type, having three individual surface electrodes for the PCA, cricopharyngeal muscle and diaphragm. The records obtained with this catheter demonstrated satisfactory separation between PCA and cricopharyngeal muscle activities. We used this catheter in patients with multiple system atrophy presenting with vocal cord paralysis, who were awake or asleep. There were two interesting electromyographical findings, which were inspiratory activity of the adductor muscle (the thyroarytenoid muscle) and fade-out of the abductor muscle, that is, PCA activity during sleep. Although vocal cord paralysis is one of the most serious life-threatening complications, the precise mechanism has not been clarified. We believe that our catheter may be useful in investigating the mechanism of vocal cord paralysis which could cause sudden death in neurodegenerative disorders, including multiple system atrophy.

Aged↗
PubMed1992

Stapedial reflex in Parkinson's disease.

In 27 patients with Parkinson's disease (PD), stapedial reflexes were measured using impedance audiometry and compared with those of 11 age-matched control subjects. The reflex threshold of PD patients was lower than that of control subjects. A prolongation of contraction time (C50) and relaxation time (D50) was revealed. Between patients with and without L-dopa, there was no significant difference for any reflex parameter. But, the D50 of patients without anticholinergic drugs was longer than that of patients with anticholinergic drugs. The authors could not find any relationship between the severity of PD and the reflex parameters. The authors assume that the prolongation of reflex parameters might be attributed to the hyperactivity of the indirect pathways of the stapedial reflex.

Acoustic Impedance Tests↗
PubMed1991

Olfactory dysfunction in Parkinson's disease.

An olfactory function test in 18 patients with Parkinson's disease (PD) and 10 age-matched control subjects was performed. Both detection and recognition thresholds were measured with five kinds of synthesized odorants (T & T olfactometry). Before each test, rhinoscopic inspections were performed to exclude subjects who could have respiratory hyposmia. Both detection and recognition thresholds in patients with PD were significantly elevated in comparison with those of control subjects. Auditory acuity of PD patients, however, was well preserved and there was no significant correlation between auditory and olfactory threshold. On the basis of the present study, the authors conclude that olfactory dysfunction is one of the characteristic symptoms of PD and it may be attributed to lesions in the olfactory neural pathway including olfactory neuroepithelium.

Adult↗
PubMed1991

[Clinical studies of 23 patients with multiple system atrophy presenting with vocal cord paralysis].

In order to elucidate the clinical features and the prognosis for life in the patients with multiple system atrophy (MSA) presenting with vocal cord paralysis (VCP), we studied the correlation between VCP and other neurological findings including cerebellar, pyramidal, extrapyramidal and autonomic nervous signs. Subjects were 48 MSA patients: 23 with VCP and age- and illness duration-matched 25 without VCP. MSA in this paper comprised clinically Shy-Drager syndrome, olivopontocerebellar atrophy, and striatonigral degeneration. MSA patients with VCP had in general more severe neurological findings, compared with those without VCP. Urinary incontinence developed in the relatively early stage of illness and preceded VCP in all patients. VCP developed not only in far-advanced stage but at any time in the course of illness. As to swallowing function when a diagnosis of VCP was established, about half of the patients with VCP needed nasogastric tube feeding and the remaining half tolerated oral feeding. VCP correlated strongly with urinary incontinence but not always with the severity of orthostatic hypotension or extrapyramidal tract sign such as parkinsonism. Five of the eight patients without tracheostomy came to sudden death. The mean duration from making a diagnosis of VCP to death was 1.1 years. In contrast, nine of the 11 patients with tracheostomy were alive and the survival periods after tracheostomy reached a maximum, five years. These facts suggest that the prognosis for life in the patients with VCP depends in part upon whether tracheostomy was carried out or not.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗