Search PubMed⌕ Search

Biomedical subjects

S Miyoshi

Publications and source records attributed to S Miyoshi.

At least 145 records · Page 8Linked to original sources
PubMed1997

Mature CD4 single positive thymocytes in human Thymoma: T cells may differentiate in the thymic epithelial cell tumor.

Human thymoma, which is occasionally associated with autoimmune disease, is a thymic epithelial cell tumor and often contains a large number of lymphocytes. In a previous study, we have shown that a proportion of CD4 single positive T cells in human thymomas lack CD3, suggesting immaturity. In this study, we focused on the rest of the CD4 single positive T cells in thymomas that expressed CD3/TcR alpha beta and investigated the maturity of single positive T cells by analyzing lymphocyte surface antigens and the cells' proliferative response to a mitogen. CD4 single positive cells that expressed CD3 or TcR alpha beta also expressed CD69 and had probably undergone positive selection in the tumor. Further, isolated CD4 or CD8 single positive cells from the thymomas responsed to a mitogen although at lower levels than the corresponding single positive cells in the peripheral blood. These results indicate that thymomas contain single positive T cells which have mature phenotype and proliferative ability, and suggest that T cells may differentiate in thymoma.

Adult↗
PubMed1997

Preliminary study of improved perception of words with the same sound but different intonation in tinnitus patients following electrical stimulation of the ear.

The present study aimed to explain how tinnitus relief following electrical promontory stimulation affects detection of changes in pitch frequency. To determine the effects of tinnitus relief on the auditory system. Japanese words with the same sound but different intonation were used to verify the effects of tinnitus relief on pitch detection in tinnitus patients Eight out of 11 patients experienced relief of tinnitus following treatment. The averaged number of the ratio in 8 patients with relief of tinnitus, 0.58, was significantly higher (p < 0.02) than that in 3 patients without relief, 0.15. In comparison with averaged hearing level, there was no significant difference in averaged hearing level between 8 patients with relief of tinnitus (52.4 dBSL; SD: 11.4) and 3 without relief of tinnitus (58.0 dBSL; SD: 14.7) (p > 0.68). No significant difference in age between patients with and without relief of tinnitus was observed.

Aged↗
PubMed1997

Improved word perception in tinnitus patients following electrical stimulation of the ear: a preliminary report.

The present study showed that there were close relationships between tinnitus relief and improved word perception by means of a grammatically correct but non-sense Japanese word perception test. Fourteen out of 20 patients reported tinnitus relief and improvement in hearing. Nine out of the 14 patients were thought to be significantly improved in word perception. Improved word perception was observed in 7 out of 10 patients whose ears tested were opposite to ears treated while in 2 out of 10 patients whose ears tested were the same as ears treated. Improved word perception was observed in 5 patients at one segment, 2 patients at two segments and 2 patients at three segments. Improved word perception was observed in one patient at the first segment, 5 patients at the second segment, 5 patients at the third segment and 5 patients at the fourth segment. There were no significant differences in hearing level nor age in patients with and without relief of tinnitus.

Electric Stimulation↗
PubMed1997

Improved word perception following electrical stimulation of the ear in hearing-impaired patients without tinnitus.

Improved word perception in hearing-impaired patients following electrical stimulation of ears was shown by means of a grammatically correct but non-sense Japanese 4-segment sentence perception test. Improved word perception was reported in 15 out of 20 patients without tinnitus following electrical stimulation of ears. In 11 out of 15 patients, the number of incorrect words significantly decreased, showing that electrical stimulation of ears improved word perception. Improved word perception was observed in 5 out of 8 patients whose tested ears were contralateral to treated ears while in 8 out of 12 patients whose tested ears were the same as treated ears. The present study suggests that electrical stimulation of ears improves word perception in hearing-impaired patients without tinnitus.

Aged↗
PubMed1997

Evaluation of the tripolar electrode stimulation method by numerical analysis and animal experiments for cochlear implants.

We have proposed the Tripolar Electrode Stimulation Method (TESM) which may enable us to narrow the stimulation region and to move continuously the stimulation site for the cochlear implants. We evaluated whether or not TESM works according to a theory based on numerical analysis using the auditory nerve fiber model. In this simulation, the sum of the excited model fibers were compared with the compound actions potentials obtained from animal experiments. As a result, this experiment showed that TESM could narrow a stimulation region by controlling the sum of the currents emitted from the electrodes on both sides, and continuously move a stimulation site by changing the ratio of the currents emitted from the electrodes on both sides.

Animals↗
PubMed1997

Evaluation of Implanted Tinnitus Suppressor Based on Tinnitus Stress Test.

An electrical tinnitus suppressor developed at the Hokkaido University was implanted in two women and five men, aged 44-77 years old. To evaluate the efficacy of the suppressor, a self-administered tinnitus stress test (TST), annoyance index (AI), and tinnitus intensity index (TII) were conducted 1 1/2-3 years after implantation of the device. Residual inhibition results found at outpatient clinics and at the homes of patients with implanted suppressors were closely correlated except in one patient in whom the device's electrode was free from the promontorium tympani. The AI registered at a severe level in five patients and a moderate level in two patients before implantation of the suppressor. However, the AI improved after the operation, being moderate in three patients and mild in two, and achieving no level in two patients. After the operation, the TST improved except in one patient whose device had electrode trouble. The TII registered as extreme in all patients before implantation of the suppressor, although the intensity of tinnitus varied from patient to patient according to the loudness balance test. After device implantation, the TII did not register any level in two patients, was mild in another two patients, was moderate in yet two more patients, and was severe in a patient whose device had electrode trouble. After the operation, at TST, AI, and TII results were positively correlated (p =.01), though there was no correlation among these parameters before the operation.

Journal Article↗
PubMed1997

[Induction chemotherapy based on histoculture drug response assay for a patient with advanced thymic cancer--a case report].

Histoculture drug response assay (HDRA) was applied to a biopsy specimen of advanced thymic cancer from a 68 years-old male patient. HDRA revealed that the tumor was not sensitive to CDDP but highly sensitive to 5-FU, ADM and MMC, which were administered as induction chemotherapy. The tumor regressed to 14% of the pretreatment size and was able to be completely resected with right and left brachiocephalic veins, superior vena cava, pericardium, right phrenic nerve and a part of right lung. Histologically, only a few small cancer nests remained in the fibrous tissue. The patient is alive and disease free 32 months after surgery. This result suggests that HDRA is useful to select anticancer agents which are sensitive to a rare kind of carcinoma such as thymic cancer.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

[A case of renal cell carcinoma found after skin metastasis].

A case of renal cell carcinoma, found after skin metastasis is presented. A 76-year-old woman came to our hospital complaining of two painless subcutaneous tumors in her left chest. Histopathological diagnosis was clear cell carcinoma. She underwent left nephrectomy and histopathological findings revealed renal cell carcinoma, alveolar type, clear cell subtype, grade 1. Lung metastasis was proved soon after the operation. We removed skin metastasis several times after the nephrectomy.

Aged↗
PubMed1996

Phospholipase A2 from Naja naja sputatrix venom is a muscarinic acetylcholine receptor inhibitor.

A variety of snake venoms was tested for the ability to inhibit the binding of antagonists to specific muscarinic acetylcholine receptors (mAChRs); the highest activity was found in the venom of Naja naja sputatrix. The active principle in this venom was isolated by column chromatography on Sephadex G-50, Sephadex G-150, and CM-Sephadex C-25. The final preparation was homogeneous as determined by polyacrylamide gel electrophoresis and HPLC; about sevenfold purification was achieved with a yield of 12%. The isolated active component, which was designated "muscarinic inhibitor," was found to displace various antagonists from rat synaptosomal membranes, which contain all subtypes of mAChRs. The m1 and m2 recombinant human receptors were also competitive with N. naja sputatrix muscarinic inhibitor. This antagonist-displacing action was dose dependent, but was independent of the reaction temperature. The isolated muscarinic inhibitor was determined to be a 13.6 kDa, monomeric, neutral protein and to have an N-terminal amino acid sequence which is highly homologous with phospholipase A2 from the venoms of genus Naja. N. naja sputatrix muscarinic inhibitor could hydrolyze phosphatidylcholine in a dose- and temperature-dependent manner. This phospholipase A2 enzymatic activity was augmented by the addition of the calcium ion, while it was almost completely abolished by a competitive inhibitor of phospholipase A2 enzymes. However, the antagonist-displacing activity was only slightly affected by these agents. The treatment of the muscarinic inhibitor with p-bromophenacyl bromide, which selectively modifies the histidine residue in the catalytic site of a phospholipase A2 enzyme, caused completed elimination of both activities. These findings indicate that N. naja sputatrix muscarinic inhibitor is a protein with two distinct activities, phospholipase and antagonist displacement, the active centers of which may be in close physical proximity for both actions. This is the first finding that a phospholipase A2 is an inhibitor of the muscarinic receptor.

Amino Acid Sequence↗
PubMed1996

Immunohistochemical localization of kallikrein in salivary glands of the Japanese monkey, Macaca fuscata.

The immunofluorescence staining using anti-human urinary kallikrein polyclonal antiserum was intense in the luminal rim of the striated duct cells, but decreased in the excretory duct cells and was weak in the intercalated duct cells. Western blot analysis demonstrated the monospecificity of the antiserum to glandular kallikrein in Macaca submandibular gland homogenate. The staining was observed to a similar degree as that in salivary glands with long and numerous striated ducts in the following order: the submandibular, the parotid and the sublingual gland. These findings suggest that kallikrein is secreted by exocytosis from the duct cells, mainly from the striated duct cells.

Animals↗
PubMed1996

Autonomic and antiarrhythmic drug modulation of ST segment elevation in patients with Brugada syndrome.

OBJECTIVES: We examined the modulatory effects of autonomic nervous system and antiarrhythmic drugs on the ST segment in patients with Brugada syndrome to gain an insight into the mechanism of ST segment elevation. BACKGROUND: Right bundle branch block, ST segment elevation and ventricular tachyarrhythmias define a distinct clinical and electrocardiographic (ECG) syndrome (Brugada syndrome). However, the mechanism of ST segment elevation and the causes of this syndrome are unknown. METHODS: The study included four patients in whom structural heart or coronary artery disease was excluded by noninvasive and invasive tests. High take-off ST segment elevation of either the coved or saddle-back type in precordial leads V1, V2 and V3 was seen in all patients. Three patients experienced recurrent episodes of syncope or aborted sudden cardiac death, and the remaining patient had palpitation. Autonomic receptor stimulation and blockade and intravenous administration of antiarrhythmic drugs were performed during sinus rhythm while the 12-lead ECG was recorded. Metaiodobenzylguanidine (MIBG) scanning and Holter monitoring were also performed. RESULTS: Beta-adrenoceptor stimulation by intravenous isoproterenol consistently reduced (> or = 0.1 mV) ST segment elevation at or 80 ms after the J point in all four patients. Selective alpha-adrenoceptor stimulation by intravenous norepinephrine in the presence of propranolol or by intravenous methoxamine consistently augmented, whereas alpha-adrenoceptor blockade reduced, ST segment elevation in three patients. Intracoronary acetylcholine or intravenous edrophonium or neostigmine augmented ST segment elevation without inducing coronary spasm in three of four patients. Class IA antiarrhythmic drugs also consistently augmented (three patients), whereas class IB drugs had no effect on (two patients) ST segment elevation. No abnormality was found on MIBG imaging or heart rate variability in three patients, suggesting that autonomic dysfunction is not a primary disease process. Class IA drugs had no effect on ST segment in three control patients, suggesting that the ST segment elevation seen in patients with Brugada syndrome in response to the drugs is not a nonspecific response. CONCLUSIONS: ST segment elevation in patients with Brugada syndrome was augmented by selective stimulation of alpha-adrenoceptors or muscarinic receptors or by class IA drugs but was mitigated by beta-adrenoceptor stimulation or alpha-adrenoceptor blockade. These responses might be explained by postulating the presence of an area of early repolarization or a local "depolarized" area in the ventricle causing ST segment elevation in this syndrome. Because only a small number of patients were studied, these possibilities need further evaluation.

Adult↗
PubMed1996

Tuft cells in the main excretory duct epithelia of the three major rat salivary glands.

We report the tuft cells in the main excretory duct epithelia of rat salivary glands. These cells exhibit similar fundamental characteristics in the salivary glands and in other organs. However, numerous membrane-bound electron-dense granules are present among the microvilli of the tuft cells in the submandibular gland, but not in other organs. The apical cytoplasm contains numerous vesicles with a filamentous substance that reacts positively for glycoconjugates. The vesicles frequently are close to the apical plasma membrane and seem to open into the lumen. Nerve endings with synaptic vesicles are seen close to the basal portion of the tuft cells. The ratio of the tuft cells to principal cells is highest in the submandibular gland and lowest in the sublingual gland. The functions of the tuft cells in the salivary glands are suggested to be secretion, absorption, and reception.

Animals↗
PubMed1996

Regional cerebral oxygen saturation during electroconvulsive therapy: monitoring by near-infrared spectrophotometry.

Electroconvulsive therapy (ECT) increases neuronal energy consumption and alters systemic hemodynamics. We examined the effects of ECT on regional cerebral oxygen saturation (rSo2) using a near-infrared spectro-photometer. Heart rate (HR), mean arterial blood pressure (MAP), and rSo2 were continuously monitored throughout ECT under general anesthesia in 43 patients. In all subjects, rSo2 changed in a consistent pattern during ECT, initially decreasing (-9.4% +/- 0.9%) just after application of the electrical current and subsequent increasing (8.7% +/- 0.9%) beyond the pre-ECT value. A close correlation was demonstrated between the increase in rSo2 and the mean blood pressure after the electrical shock (r2 = 0.832, P < 0.0001). We conclude that ECT initially may increase cerebral metabolic rate of oxygen more than cerebral blood flow and that rapidly increasing blood pressure transiently may overwhelm cerebral pressure autoregulation.

Anesthesia, General↗
PubMed1996

Involvement of vulnibactin and exocellular protease in utilization of transferrin- and lactoferrin-bound iron by Vibrio vulnificus.

In vitro growth experiments were conducted to evaluate the ability of vulnibactin, a siderophore produced by Vibrio vulnificus, to sequester transferrin- or lactoferrin bound iron for growth. Comparative studies with the strain producing vulnibactin and its exocellular protease-deficient mutant revealed the involvement of the protease in addition to vulnibactin in effective utilization of iron ion (Fe3+) bound to transferrin and lactoferrin. It appears that the protease causes cleavage of these proteins, thereby making bound iron more accessible to vulnibactin.

Amides↗
PubMed1996

Proposal of a new auditory nerve stimulation method for cochlear prosthesis.

The stimulation electrodes of cochlear implants are covered by a lymph liquid with high electrical conductivity, which causes the transmitted information to be reduced by channel interaction. Even if this problem were solved, the stimulation regions may be discrete; therefore, there may be regions in which the electrode array cannot stimulate selectively. To solve these problems, we proposed a new auditory nerve stimulation method which we call the tripolar electrode stimulation method for cochlear implants. Our method stimulates using 3 adjacent electrodes selected from among the electrodes of the electrode array. The center electrode receives the currents emitted from the electrodes on both sides. We conducted animal experiments using this method. On the basis of the results we obtained, we concluded that our method may succeed in narrowing the stimulation region and continuously moving the stimulation site.

Animals↗
PubMed1996

An experience of the usage of electrical tinnitus suppressor.

An electrical tinnitus suppressor based on the use of an extracochlear stimulator has been developed at Hokkaido University, Sapporo, Japan, and was implanted in 2 male and 2 female patients. Tinnitus improved in all patients because the auditory nerve was able to be stimulated at home whenever patients wanted treatment. Additional benefits reported after electrical stimulation of the cochlea included sound sleep, relaxation in all cases, and improved hearing acuity in Cases 1, 2, and 4. Minimal temporary complications, including habituation and ear drum perforation, were observed.

Adult↗
PubMed1996

Expression of virulence-related properties by, and intestinal adhesiveness of, Vibrio mimicus strains isolated from aquatic environments.

A study of the major pathogenic characteristics of Vibrio mimicus was carried out with 77 strains isolated from aquatic environments in Okayama, Japan. Of the strains tested, 96% demonstrated in vitro adherence to the rabbit intestinal mucosa, of which 36, 20, and 43% belonged to the strongly, moderately, and weakly adhesive groups, respectively. Of the 27 strains which appeared to be enterotoxigenic in the experiments using rabbit ileal loops, 74% belonged to the strongly adhesive group. All strains of V. mimicus at early log phase showed cell-mediated hemagglutination, and 70% of strongly hemagglutinative strains belonged to the strongly adhesive group, implying a possible correlation between cell-mediated hemagglutination and bacterial adherence. However, no significant correlation could be detected in the production of putative exocellular pathogenic factors and bacterial adherence or enterotoxigenicity.

Animals↗