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Biomedical subjects

M Aoyagi

Publications and source records attributed to M Aoyagi.

At least 145 records · Page 8Linked to original sources
PubMed1994

Facial nerve enhancement in Gd-MRI in patients with Bell's palsy.

The diagnostic value of a contrast enhanced MRI in patients with Bell's palsy was investigated. It was a characteristic finding that the internal acoustic meatal segment of the facial nerve was enhanced only on the affected side. The signal intensity ratio of the geniculate ganglion and the tympanic segment was significantly higher on the affected side than on the normal side. The severity of the facial palsy and the results of physiological examinations showed no relation to the results of MRI scans. Gd enhanced MRI thus appears to provide some useful findings for estimating the affected region of Bell's palsy, whereas it is not considered to be valuable in the diagnosis of severity.

Contrast Media↗
PubMed1994

Gd-DTPA enhanced MRI in Ramsay Hunt syndrome.

Ten patients with Ramsay Hunt syndrome underwent magnetic resonance (MR) scans. In many examinations, abnormal enhancement of the 7th nerve in the internal acoustic meatal segment through the mastoid segment was observed. Out of seven patients with cochlear and/or vestibular symptoms, only one showed abnormal enhancement of the 8th nerve, in addition to the 7th. The other 6 patients showed the same findings as in Bell's palsy, showing no enhancement of the 8th nerve. This suggests that clinical symptoms have no relation to the results of MRI. Enhanced MRI is the most sensitive means of making differential diagnoses between Hunt's syndrome and tumors, but it is impossible to detect all lesion sites corresponding to the symptoms in Hunt's syndrome.

Adult↗
PubMed1994

Effects of supernatant from tonsillar cell culture on neutrophil functions.

The palatine tonsil is the most important element of Waldeyer's ring as a defense mechanism against various microorganisms. The neutrophils are the initial active participants in bacterial infection and inflammation, but their interaction with other cellular participants is poorly understood. To clarify this point, the effects of culture supernatant from human tonsillar cells on the peripheral neutrophil function were investigated. Supernatants from tonsillar cells were incubated in the presence or absence of streptococcal preparation (OK-432) enhanced chemiluminescence, adherence, phagocytosis, chemotaxis, and superoxide production of human peripheral neutrophils. The results suggest that tonsils play an important role in the regulation of neutrophil function.

Bacterial Infections↗
PubMed1994

Neutrophil activating activity of tonsillar cells from patients with tonsillitis.

The previous paper demonstrated that tonsillar cells cultured in vitro in the presence or absence of a streptococcal preparation, OK-432, produce factors that activate various neutrophil functions. In the present study, examination was made of the factor productivity of tonsillar cells from patients with chronic tonsillitis of varying severity, and palmoplantar pustulosis (PPP). Tonsillar cells from patients with severe tonsillitis and PPP incubated with culture medium alone produced a much greater amount of active factors compared with those from patients with mild tonsillitis. When tonsillar cells were incubated in the presence of OK-432, augmentation in factor production by the addition of OK-432 was less in former than latter cases, suggesting that factor production from tonsils correlates with the course of inflammation in this organ.

Adolescent↗
PubMed1994

[Effects of acoustic overstimulation of 2F1-F2 distortion product in cochlear microphonics].

The cochlear microphonics (CM) response to two-tone stimuli was measured before and after exposure to 4 kHz pure tone at 100 dB SPL or 125 dB SPL. The 2f1-f2 distortion products in the CM (CM-DPs) were markedly suppressed by the sound exposure at either intensity, although the loss of CM output at the primary frequencies was limited to 4 dB or less. The suppression of CM-DPs was greater as the intensity of primary tones decreased, especially at primary intensities below 55 dB. These results show that the active transduction process in the cochlea was affected by acoustic overstimulation. This impairment of active transduction was postulated to be an initial process in developing noise induced temporary and/or permanent threshold shift.

Acoustic Stimulation↗
PubMed1994

[The clinical manifestations of Sjögren's syndrome in children].

Sjögren's syndrome (SS) is thought to be uncommon in children. We studied the clinical manifestations and laboratory findings of 12 pediatric patients with SS, all of children did not have sicca symptoms but have lymphocytic infiltration of salivary glands, abnormal sialograms or abnormal results of scintigraphy compatible with typical SS. Seven cases had primary SS and five were secondary SS and had other autoimmune disorders (three cases with systemic lupus erythematosus, one case with dermatomyositis, and the other with mixed connective tissue disease). All patients were female. The mean age at onset of symptoms, including other autoimmune manifestations, was 12.2 years (range 9-15 years). The initial symptoms were some systemic manifestations (fever, exanthema, arthralgia, etc.) and various autoimmune phenomena (butterfly rash, Raynaud's phenomenon, proteinuria, weakness of muscles, etc.). On the other hand, no patients complained sicca symptoms. Laboratory studies in our patients revealed elevated levels of IgG (92%), antinuclear antibody (92%), rheumatoid factor (58%), anti-SS-A antibody (75%). These findings were similar to those found in adult patients with sicca symptoms previously reported in literature. From these studies, we suggest that lip biopsy, sialography and/or salivary gland's scintigraphy should be carried out in patients who had abnormal laboratory findings as mentioned above, irrespective of absence of sicca symptoms, in order to diagnose SS at early period.

Adolescent↗
PubMed1994

[Study of peripheral neutrophil functions of patients with Wegener's granulomatosis].

Recently, the detection of anti-neutrophil cytoplasmic antibodies (ANCA) has gained worldwide acceptance as an important additional diagnostic tool of Wegener's granulomatosis (WG). A possible pathogenic role of ANCA has been suggested by the finding that the addition of purified IgG-ANCA to healthy neutrophils in vitro causes activation of these cells. But, investigation on neutrophil functions of patients with WG has been rare. To clarify this point, peripheral neutrophil functions (adherence, chemiluminescence and chemotaxis) of patients with active WG were examined. Adherence, chemiluminescence and chemotaxis of patients with WG were significantly suppressed when compared with control subjects. The effects of ANCA positive serum on neutrophil chemiluminescence were also examined. ANCA positive serum did not affect neutrophil chemiluminescence. These results indicate that the mechanism of WG is not simply due to neutrophil activation by ANCA.

Chemotaxis, Leukocyte↗
PubMed1994

[Anesthesia for bronchoscopy: application of laryngeal mask airway and "minidose midazolam anesthesia"].

Bronchoscopy distresses most of the patients. Therefore, we combines a small dose of midazolam (ca. 2 mg) with laryngeal mask airway. This method of anesthesia has the following features: (1) mild discomfort, (2) day care, (3) putting bronchoscope in or out easily, (4) mild effect on respiration and circulation, and (5) easy respiratory care. But improper cases for this method include non-fasting patients, those at high risk for regurgitation, and those with low pulmonary compliance. This is a very usefull anesthetic method for bronchoscopy.

Adult↗
PubMed1994

Diagnostic specificity of anti-neutrophil cytoplasmic antibodies (ANCA) in otorhinolaryngological diseases.

The incidence and titer of ANCA were examined with 871 sera from patients with otorhinolaryngological diseases at our hospital. The cytoplasmic pattern of ANCA (c-ANCA) whose titer was more than 16 was detected only in the sera of patients with Wegener's granulomatosis (WG). The incidence of c-ANCA in active WG was more than 90%. The perinuclear staining pattern of ANCA (p-ANCA) was detected in almost 40% of patients with Sjögren's syndrome, 2.0% of inflammatory diseases and 1.0% of tumorous diseases. A high diagnostic value of c-ANCA in WG was found in patients with otorhinolaryngological diseases.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1994

An experimental study on the generator of amplitude-modulation following response.

To clarify the contribution of the auditory cortex and the inferior colliculus to amplitude-modulation following response (AMFR), lesion experiments were conducted on 8 cats. Bilateral auditory cortices of 2 cats were aspirated, and the right inferior colliculus of 3 cats, and the left inferior colliculus of another 3 cats were electrocoagulated to make lesions. Auditory brainstem response (ABR) evoked by clicks and AMFR elicited with 1000 Hz sinusoidally amplitude-modulated tones, at modulation frequencies (MF) of 20-200 Hz in 20-Hz steps, were examined before and after making lesions. Stimulus intensity was fixed at 90 dB SPL in both responses. AMFR was detected by phase spectral analysis using fast Fourier transformation. No change was observed in the phase spectral analysis of AMFR after bilateral cortical lesions. Remarkable changes were observed in AMFRs at MFs lower than 80 Hz and 200 Hz after lesions in the ipsilateral inferior colliculus and at all MFs after contralateral lesions of the inferior colliculus, while no such change was observed in ABR. The results suggest that the auditory cortex is not the source of AMFR, but that the inferior colliculus has great impact on the generation of AMFR at modulation frequencies of 20 to 200 Hz.

Acoustic Stimulation↗
PubMed1993

Extracellular matrix modulates the proliferation of rat astrocytes in serum-free culture.

The mechanism of glial proliferation in the developing nervous system, as well as in response to injury, inflammation, and tumor invasion, is unknown. Several growth factors and extracellular matrices have been shown to stimulate the proliferation of cultured cells of various origin, including astrocytes. We investigated the effect of extracellular matrix components, including fibronectin (FN), laminin (LN), and collagen types I and IV, on the growth of astrocytes during stimulation by various growth factors. When astrocytes were grown on FN- and LN-coated wells in a serum-free, chemically defined medium, their increase in number significantly exceeded that of cells grown on plastic wells. The addition of platelet-derived or basic fibroblast growth factor to cells cultured on FN- or LN-coated wells significantly potentiated astrocyte proliferation. The collagen preparations had no such effect. These observations indicate that FN and LN have a fundamental part in converting the quiescent astrocyte into the proliferating phenotype, which may be required for remodelling damaged brain tissues in vivo.

Animals↗
PubMed1993

Kinetics of 125I-PDGF binding and down-regulation of PDGF receptor in arterial smooth muscle cells derived from patients with moyamoya disease.

Progressive stenosis or occlusion of bilateral internal carotid arteries by fibrocellular intimal thickening results in cerebral ischemia in moyamoya disease. We recently found that cultured smooth muscle cells (SMC) derived from arteries of patients with moyamoya disease responded poorly to serum mitogens, especially to platelet-derived growth factor (PDGF). In the present study, we investigated further the binding and processing of 125I-PDGF, as well as down-regulation of the PDGF receptor in arterial SMC derived from patients with moyamoya disease. The specific binding sites of 125I-PDGF were reduced significantly at both 4 degrees C and 22 degrees C on SMC from moyamoya disease compared with those from control (4.78 vs. 11.92 x 10(4)/cell at 4 degrees C), though the apparent dissociation constant (Kd) were the same. Kinetics of 125I-PDGF binding at 37 degrees C in cells from moyamoya disease showed fewer binding sites (less than 1/3 of controls) and lower degradation per cell than in those from controls, though no difference was observed in either internalization or degradation of each receptor. When SMC were exposed to lower concentrations of nonlabeled PDGF at 37 degrees C, the percentage of remaining binding sites on cells from moyamoya disease was significantly less than that from controls. This excess down-regulation of PDGF receptor in SMC from moyamoya disease may be interpreted as insufficient recycling or a decreased intracellular pool of the PDGF receptor. These results are closely correlated with the diminished proliferation responses to PDGF in SMC from moyamoya disease and provide evidence that functional alterations in vascular cells are involved in the mechanism of development of intimal thickening in moyamoya disease.

Cell Division↗
PubMed1993

Invasion of experimental rat brain tumor: early morphological changes following microinjection of C6 glioma cells.

We present morphological data of the early stage of tumor invasion in the central nervous system. C6 rat glioma cells were injected into the caudate-putamen of rat brain using glass micropipettes to minimize traumatic reactions. Four days after the inoculation, we examined the tumor-brain interface using light and electron microscopy. Ultrastructurally the tumor processes were attached to the perivascular basement membrane instead of the astroglial end-feet. At the tumor periphery, the vessel walls were in contact with both tumor processes and astroglial end-feet. Astrocytes withdrew their processes from the vascular walls and changed into a reactive phenotype, while the neuronal cells remained virtually intact, even when surrounded by tumor cells. Immunohistochemical study using C6 cells labeled with bromodeoxyuridine showed migration of the cells toward the perivascular space that was distant from the site of injection. These observations represent the earliest morphologically detectable changes of the tumor-brain interface, and suggest that the C6 cells possess the characteristics of high affinity to the endothelial basement membrane and invade along the preexisting blood vessels with brain parenchymal infiltration.

Animals↗
PubMed1993

Capillary permeability in experimental rat glioma and effects of intracarotid CDDP administration on tumor drug delivery.

We have examined the capillary permeability within and adjacent to experimental rat gliomas, and the effect of intracarotid administration of cisplatin in this model. Permeability to 14C-sucrose was 25-fold and six-fold higher within the brain tumor and in the tumor periphery and adjacent tissue respectively than in the normal cortex. Intracarotid administration of cisplatin resulted in ten-fold increase in experimental gliomas and also a significant increase in the tumor periphery and adjacent tissue, when compared to the intravenous route. Intracarotid administration of cisplatin to rat did not cause acute vascular damage in either the brain or brain tumor at the dosage used.

Animals↗
PubMed1993

Optimal modulation frequency for amplitude-modulation following response in young children during sleep.

In young children, there appears to be no advantage to recording steady-state response (SSR) at a stimulus rate of 40 Hz. To determine the optimal modulation frequency in auditory SSR evoked by sinusoidally amplitude-modulated (SAM) tones (amplitude-modulation following response: AMFR) in children during sleep and compare response patterns of AMFR at different modulation frequencies while awake with those during sleep, AMFR was examined in 10 adults with normal hearing while awake and during sleep and in 10 young children with normal hearing during sleep. The stimulus was a 1000 Hz, 50 dBnHL SAM tone with a modulation depth of 95%. Modulation frequency was varied from 20 to 200 Hz in 20 Hz steps. Response was determined by phase spectral analysis and the S/N ratio calculated by spectral amplitude at the modulation frequency and noise level around the modulation frequency using fast Fourier transform. Although AMFR was clearly evoked only by a modulation frequency of 40 Hz in adults while awake, AMFRs at modulation frequencies of 80 and 100 Hz were detected during sleep, in addition to 40 Hz AMFR. In children, 40 Hz AMFR was difficult to detect, but response could be clearly detected at higher modulation rates, especially at modulation frequencies of 80 and 100 Hz, compared with response in adults during sleep. Modulation frequencies from 80 to 100 Hz would thus appear optimal for detecting AMFR during sleep in children.

Adult↗
PubMed1993

Conjunctival malignant melanoma with xeroderma pigmentosum.

A 10-year-old male patient with xeroderma pigmentosum had a recurrent, pigmented, conjunctival tumor. Conjunctival malignant melanoma was diagnosed from the histopathological examination of the resected biopsy specimens. To our knowledge, this case of conjunctival malignant melanoma in a patient with xeroderma pigmentosum may be the second such report in the literature. We believe that malignant melanoma must be considered with squamous cell carcinoma in the differential diagnosis of conjunctival tumors in patients with xeroderma pigmentosum. Fontana-Masson and S-100 staining techniques helped diagnose this conjunctival malignant melanoma.

Child↗
PubMed1993

An application of phase spectral analysis to amplitude-modulation following response.

A phase spectral analysis developed by Fridman (1982) was applied to the detection of amplitude-modulated frequency following response (AMFR) and its clinical usefulness was evaluated. A 1000 Hz sinusoidally amplitude-modulated tone with a modulation frequency of 40 Hz and a modulation depth of 90% was delivered to the right ear of 10 normal-hearing subjects. According to Fridman's technique, an ensemble of sweeps was divided into 10 groups and group averages were obtained. Then phase variances were calculated using fast Fourier transform for the group averages. In order to determine the optimal conditions of analysis for constructing an automatic detection program using phase spectral analysis, frequency spacing, number of sampling points and number of sweeps averaged per group were investigated. The sensitivity of phase spectral analysis for automatic detection of AMFR was also evaluated. The results suggested that the optimal number of sampling points and frequency spacing are 512 points and 4.9 Hz (observation window 204.8 ms), respectively. Concerning the average number of sweeps, the synchrony measure of the frequency component corresponding to the modulation frequency increased as the number of sweeps increased. Furthermore, it was demonstrated that threshold determination by phase spectral analysis is more sensitive than detection of the threshold by visual analysis of waveform configuration.

Adult↗