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Biomedical subjects

M Aoyagi

Publications and source records attributed to M Aoyagi.

At least 163 records · Page 9Linked to original sources
PubMed1993

[Clinical application of transiently evoked otoacoustic emissions in screening for auditory dysfunction].

Transiently evoked otoacoustic emissions (TEOAE) should be used clinically as an objective and noninvasive screening test for auditory dysfunction in children. The features of TEOAE measured by "ILO88" with non linear click stimuli are discussed. The following results were obtained: 1) The normal range of a power spectrum was determined using 42 adults with normal hearing and compared with data for sensorineural hearing disturbance. The power spectrum of TEOAE in adults with normal hearing sloped downward at high frequency and was the same for right and left ears in both males and females. For comparison with sensorineural hearing disturbance, a significant correlation between the audiogram and power spectrum of TEOAE was sought. 2) Patients with otitis media with effusion (109 ears in 67 children) were examined by audiometry, tympanometry and TEOAE. The hearing disturbance threshold of 45 cases with TEOAE was lower than that in cases with no TEOAE. In tympanometry, low intratympanic pressure was noted in the absence of TEOAE. 3) TEOAE and spontaneous otoacoustic emission were examined in 42 adults with normal hearing and 27 neonates using the same probe and level of stimuli to clarify differences in TEOAE according to age. The amplitude of TEOAE and the highest peak of the frequency component at 4kHz in neonates exceeded those of adults. The peak stimuli recorded with the intracanal probe in neonates was also larger than that of adults. Three out of 15 neonates had spontaneous otoacoustic emission and essentially the same proportion was noted in young adults.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Impedance Tests↗
PubMed1992

Peritumoral cerebral edema in meningiomas: the role of the tumor-brain interface.

We investigated the role of the tumor-brain interface in the production of peritumoral cerebral edema in meningiomas by analysing the size, shape, histological type and location of the tumor, and radiological and operative findings. Our results suggest that changes of the boundary zone between the tumor and the brain such as the disappearance of the subarachnoid space, cortical thinning or loss, and possibly partial loss of the arachnoid membrane are the most important factors in edema production, and that multiple other factors determine the morphological changes which occur at the tumor-brain interface.

Adult↗
PubMed1992

Heterotopic brain tissue of the soft palate.

Heterotopic brain tissue is an unusual substance which is very difficult to diagnose correctly preoperatively. We report on a 7-month-old male infant with heterotopic brain tissue of the soft palate, and describe the results of preoperative examinations including brain scintigraphy, angiography, brain computed tomography and magnetic resonance imaging (MRI). MRI was found useful to show that the tumor had no junction with the intracranial space. The patient was treated successfully without complication or recurrence after 1.5 years follow-up.

Brain↗
PubMed1992

Diagnosis of the ossicular chain in the middle ear by high-resolution CT.

This study was conducted to assess the usefulness and limitations of high-resolution CT for diagnosing the ossicular chain in the middle ear. The CT images in this study were obtained in as much detail as possible and 2 direction images. Preoperative CT findings of the ossicular chain were compared with operative findings in 26 patients with ossicular defects. Preoperative detection of the complete defect of the malleus head and the body and long process of the incus by high-resolution CT was possible in all cases, while detection of the defect of the manubrium of the malleus and superstructure of the stapes could be made in 33.3 and 60%, respectively. The defect of the incudostapedial joint (1 case) and partial defect of the stapes crus (2 cases) could not be diagnosed correctly by preoperative estimation.

Cholesteatoma↗
PubMed1992

[Conservative treatment of idiopathic facial palsy--effects of the administration of high-dose steroids in Bell's palsy].

The etiology of Bell's palsy is still obscure and its treatment remains controversial. As a conservative treatment for Bell's palsy, Stennert developed a new treatment method for the purpose of improving microcirculation, and reported an extremely high cure rate of 96%, drawing a great deal of attention. However, since the electrophysiological findings and side effects in these patients were not described satisfactorily in his report, this method has not yet come into wide clinical use. In the present study the efficacy of Stennert's method was assessed by electrophysiological examination in patients, and was compared with patients treated by conventional methods. The subjects of this study were 157 patients with Bell's palsy who were treated with a modification of Stennert's method between September 1987 and August 1990. The treatment protocol for the modified Stennert's method was as follows: hydroxyethyl starch 40 with 20% mannitol is given instead of Dextran 40 and prednisolone is stopped depending on the findings of electrical examinations. Fifty-three patients with Bell's palsy treated by the conventional method used in our clinic between November 1983 and August 1987 were used for the control group. The most remarkable difference between these two methods was the initial dose of prednisolone. In the group treated by the modified Stennert's method, 111 patients (70.7%) showed complete recovery within 1 month, and 154 patients presented (98.1%) showed complete recovery within 6 months, 3 cases presented slight sequelae. In the conventional treatment group, on the other hand, only 2 patients (3.8%) recovered within 1 month, and 43 patients (81.0%) recovered within 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Diagnosis of ossicular chain in the middle ear by high-resolution CT].

This study was conducted to assess the usefulness and limitation of high-resolution CT for evaluating the condition of ossicular chain in the middle ear. Preoperative CT findings of the ossicular chain were compared with the operative findings of ossicles in 26 patients with chronic otitis media or congenital ossicular anomaly who underwent tympanoplasty. Total defect of head of the malleus, body of the incus and long process of the incus were completely detected by high-resolution CT. But the reliability in detecting the defect of handle of the malleus and superstructure of the stapes were 33.3% and 60%, respectively. Defect of the I-S joint (1 case) and partial defect of stapes crus (2 cases) could not be diagnosed correctly in the preoperative estimation. Although these findings demonstrate the limitations of high-resolution CT in the diagnosis of ossicular chain, it will be diminished by the advanced space resolution of CT in the future.

Ear Diseases↗
PubMed1991

Altered cellular responses to serum mitogens, including platelet-derived growth factor, in cultured smooth muscle cells derived from arteries of patients with moyamoya disease.

Progressive stenosis or occlusion of bilateral internal carotid arteries by fibrocellular intimal thickening results in cerebral ischemia in moyamoya disease. The etiology is unknown. We examined cultured arterial smooth muscle cells (SMC) from scalp arteries of five patients with moyamoya disease. In this study we investigated the responsiveness of the cells in culture to serum mitogens including platelet-derived growth factor (PDGF), a major mitogen of SMC, and compared the response to that of cells derived from age-matched control patients. SMC from patients with moyamoya disease proliferated less rapidly in a medium with 15% serum than did control SMC and responded poorly to the addition of PDGF to 5% serum. PDGF alone did not stimulate SMC in a quiescent state to initiate DNA synthesis in moyamoya disease, without serum factors other than bovine serum albumin, though it significantly stimulated the controls. Simultaneous additions of epidermal growth factor, insulin-like growth factor-I, and PDGF stimulated initiation of DNA synthesis in cells from moyamoya disease, but not as much as PDGF alone did in the controls. Although direct correlations with the pathogenesis of the disease remain to be clarified, the results indicate altered interrelations between serum factors and the cellular responses in vessels of moyamoya disease.

Adolescent↗
PubMed1991

Perioperative complications of encephalo-duro-arterio-synangiosis: prevention and treatment.

We performed encephalo-duro-arterio-synangiosis on 169 sides of 81 Moyamoya and 8 non-Moyamoya patients in the past 10 years. The advantage of this operation is its minimal operative invasion, giving rise to few operative complications. During 10 years of practice, however, we encountered some perioperative problems. Perioperative cerebral infarction of varying severity was seen in six Moyamoya patients. Severe hyperventilation with crying was the main trigger of infarction. Two patients developed wound infection with Gram-negative rods. Removal of an infected bone flap was necessary. One Moyamoya patient developed malignant hyperthermia during the operation. One acute epidural hematoma necessitated an emergency hematoma removal. Five patients showed a temporary aggravation of involuntary movements. Prolonged mild fever and temporary and limited hair loss around the wound were often observed. Cases and their treatment are presented with discussion of preventive measures.

Adolescent↗
PubMed1991

Effects of encephalo-duro-arterio-synangiosis on childhood moyamoya patients--swift disappearance of ischemic attacks and maintenance of mental capacity.

The effect of encephalo-duro-arterio-synangiosis (EDAS) upon chronic cerebrovascular ischemia in 65 pediatric moyamoya patients was evaluated by the postoperative interval before complete disappearance of ischemic attacks and changes in pre- and postoperative intelligence (IQ) or development quotients (DQ). The ischemic attacks disappeared after a mean period of 239 days, in three-fourths of patients within a year and in about one-fourth within the second year. This was very fast compared with the natural course of the disease. There was no significant difference in DQ/IQ before and after the operation. The mentally normal (IQ/DQ greater than or equal to 86) population in the postoperative patients was greater than in the natural course of the disease, although fewer in the preoperative group. This shows that EDAS delayed or prevented the deterioration in mental capacity usually present but often overlooked in the natural course of pediatric moyamoya disease.

Adolescent↗
PubMed1991

Quantitative analysis of ocular movements in Parkinson's disease.

In the present study, oculomotor abnormalities were investigated in 24 patients with idiopathic Parkinson's disease. Pursuit gain, slow and fast phase velocity of optokinetic nystagmus (OKN), saccade latency, amplitude and velocity, as well as vestibulo-ocular reflex (VOR) gain were quantitatively analyzed. Twenty-one out of 24 patients showed some abnormalities in their ocular movement. A reduction in pursuit gain, impaired OKN and a significantly increased saccade latency were observed in 11 patients. In 12 patients, hypometric saccade was seen, while a decrease in saccade velocity was observed in 10 patients. All patients registered normal values for VOR gain. Only one patient who had impaired smooth pursuit and decreased saccade velocity before treatment with a dopaminergic drug showed a remarkable improvement in these ocular abnormalities after treatment. These results suggest the possibility of dopaminergic control on these ocular movements.

Aged↗
PubMed1991

Cross-correlation function in the analysis of auditory brainstem response in spinocerebellar degeneration.

Cross-correlation functions were derived from the analysis of auditory-evoked brainstem response (ABR) and compared with measurements of wave latency and computed tomography findings in the assessment of ABR findings in spinocerebellar degeneration (SCD). Gender-specific normative ABR templates were produced from 30 normal males and 30 normal females separately. The cross-correlation indices used were the correlation coefficient at time 0, the maximal correlation coefficient and the latency delay in milli-seconds. The technique was applied to 33 patients with SCD. The incidence of abnormal cross-correlation functions (81.8%) was greater than the incidence of abnormal ABR peak latencies assessed according to gender (75.8%) which, in turn, was more common than the abnormal peak latencies assessed conventionally (69.7%). Moreover, the incidence of abnormal cross-correlations and latencies in Menière's disease was much lower (less than 8%). These results suggest that the evaluation of ABR waveform characteristics with cross-correlation functions using normative ABR templates of the same gender contributes to the precise detection of abnormality in the brainstem auditory pathway.

Adult↗
PubMed1991

[Antigenic determinants on ovalbumin and ovomucoid: comparison of the specificity of IgG and IgE antibodies].

To delineate the antigenic determinants on ovalbumin (OA) and ovomucoid (OVM) recognized by specific IgG and IgE antibodies in sera from patients with allergy to hen's egg, we studied the binding activities of IgG and IgE antibodies to native OA or OVM and seven different OA or OVM preparations, i.e. heated OA or OVM (100 degrees C for 3 min and 80 degrees C for 30 min) or 0.3 M NaOH, dithiothreitol (DTT), sodium dodecyl sulfate (SDS), 6 M urea or HCl treated OA or OVM. Eight patients with IgE anti-OA antibodies and 12 patients with IgE anti-OVM antibodies were used in these studies. The binding activities of IgG and IgE antibodies to physically or chemically denatured OA were partially decreased compared with those to native OA, whereas IgG and IgE antibodies in sera from patients bound well to denatured OVM with similar binding activities to native OVM. These results strongly suggest that antibodies to OA recognize partially conformational antigenic determinants on OA, whereas antibodies to OVM mainly recognize sequential antigenic determinants on OVM, and that antigenic determinants of OVM recognized by antibodies in sera from patients are more stable than those of OA under these denaturation conditions. In addition, the binding activities of IgE antibodies to denatured OA or OVM were significantly different from those of IgG antibodies to these OA or OVM, suggesting that the specificities of IgE antibodies to OA or OVM may be different from those of IgG antibodies to OA or OVM.

Adolescent↗
PubMed1991

Synthesis of imidazo[4,5-e][1,4]diazepine and 3-substituted 3-deazapurine nucleosides from 1-substituted inosines.

New synthetic methods of imidazo[4,5-e][1,4]diazepine nucleosides 8-11 and 3-substituted 3-deazainosines 14 from inosine have been reported. Treatment of N1-substituted inosines 1-3 with aqueous NaOH gave 5-amino-4-(N-substituted carbamoyl)imidazole ribosides 5-7, followed by appropriate manipulations to afford ring-expanded guanosine, inosine, and xanthosine analogues. Additionally, the 5-amino group of 4-N-allylcarbamoyl derivative 12 was converted into corresponding 5-iodo nucleoside 13. We found that 13 was cyclized to form 3-deaza-3-methylinosine (14) in the presence of Pd catalysts.

Imidazoles↗
PubMed1991

[Minidose midazolam anesthesia].

Midazolam is a widely used drug which has anxiolytic, sedative-hypnotic, muscle relaxing, anticonvulsant action and strong anterograde amnesic effect. But misuse of large doses were reported. We determined the minimum effective dose of midazolam using nitrous oxide (75%) and pentazocine. Induction of anesthesia needed only 0.03-0.04 mg.kg-1 of midazolam. There were no patients who were awake during operation. Anterograde amnesic effect of midazolam was significantly correlated with age. Older patients should be given midazolam slowly and carefully. Dose of midazolam should be reevaluated for wider application of midazolam.

Adolescent↗
PubMed1990

Mental outcome following encephaloduroarteriosynangiosis in children with moyamoya disease with the onset earlier than 5 years of age.

The mental prognosis of children with moyamoya disease, in whom the onset was when they were younger than 5 years of age, has been reported to be very poor. We studied the mental outcome of these patients after encephaloduroarteriosynangiosis (EDAS) in relation to the age at the onset of the disease and the age at operation. For patients in whom the onset of moyamoya disease occurs when they are younger than 2 years of age, the prognosis is very poor with regard to mental abilities even if they have an operation within a year after the onset. Slight hope remains if the operation is within 3 months of the onset. For patients in whom the disease begins when they are 2-5 years of age, EDAS performed before the age of 9 years may result in a good outcome with regard to mental ability, as well as resolution of the paroxysmal symptoms and cerebral revascularization.

Adolescent↗
PubMed1990

Symptoms and their pattern of progression in childhood moyamoya disease.

In the series of 81 childhood moyamoya patients, the common pattern of clinical progression seen in 77 patients was revealed to be no more than four. The characteristics of each type of clinical progression were presented for a better understanding of the disease and for an initiation of early treatment of this rather rare and insidiously progressive disease. Type I (21 cases) and type II (15 cases) are cases without infarction, even in those types there are cases with poor IQ. Type III (17 cases) and type IV (24 cases) are cases with infarction and an early operation is mandatory. Types I and II are also good candidates for early operation, for IQ deterioration insidiously progress in these types and there is no way of knowing them from type III before infarctions occur. We now have effective surgical measures to improve the ischemic conditions of this disease.

Age Factors↗
PubMed1990

Head size as a basis of gender difference in the latency of the brainstem auditory-evoked response.

In order to discuss the source of gender difference in the latencies of the brainstem auditory-evoked response (ABR), correlation analysis between head size (nasion to inion, ear to ear and circumference) and ABR latencies were investigated in 107 adults (57 males and 50 females) with normal hearing. Wave III and wave V latencies and I-III and I-V interpeak latency intervals (IPL) were significantly shorter in females than in males. Moreover, head size of the male subjects was significantly larger than the female subjects' head size with respect to all three parameters. Significant positive correlations were obtained between head size and the above-mentioned ABR wave latencies and IPLs, even when each gender was analyzed separately. These results suggest that head size, which may reflect brain size, is one of the important factors for the basis of gender difference in ABR latencies.

Adolescent↗