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T Imada

Publications and source records attributed to T Imada.

At least 73 records · Page 4Linked to original sources
PubMed1996

Somatic evoked high-frequency magnetic oscillations reflect activity of inhibitory interneurons in the human somatosensory cortex.

High-frequency potential oscillations in the range of 300-900 Hz have recently been shown to concur with the primary response (N20) of the somatosensory cortex in awake humans. However, the physiological mechanisms of the high-frequency oscillations remained undetermined. We addressed the issue by analyzing magnetic fields during wakefulness and sleep over the left hemisphere to right median nerve stimulation with a wide bandpass (0.1-2000 Hz) recording with subsequent high-pass (> 300 Hz) and low-pass (< 300 Hz) filtering. With wide bandpass recordings, high-frequency magnetic oscillations with the main signal energy at 580-780 Hz were superimposed on the N20m during wakefulness. Isofield mapping at each peak of the high-pass filtered and isolated high-frequency oscillations showed a dipolar pattern and the estimated source for these peaks was the primary somatosensory cortex (area 3b) very close to that for the N20m peak. During sleep, the high-frequency oscillations showed dramatic diminution in amplitude while the N20m amplitude exhibited a moderate increment. This reciprocal relation between the high-frequency oscillations and the N20m during a wake-sleep cycle suggests that they represent different generator substrates. We speculate that the high-frequency oscillations represent a localized activity of the GABAergic inhibitory interneurons of layer 4, which have been shown in animal experiments to respond monosynaptically to thalamo-cortical input with a high-frequency (600-900 Hz) burst of short duration spikes. On the other hand, the underlying N20m represents activity of pyramidal neurons which receive monosynaptic excitatory input from the thalamus as well as a feed-forward inhibition from the interneurons.

Adult↗
PubMed1996

AL0671, a new potassium channel opener, inhibits nonenzymatic glycation of protein and LDL oxidation.

1. The effects of AL0671, a novel potassium channel opener, on protein glycation and low-density lipoprotein (LDL) oxidation were tested. 2. AL0671 dose-dependently inhibited both fluorescence development of bovine serum albumin and cross-linking of lysozyme. These inhibitory effects for glycation were no less potent than aminoguanidine. 3. AL0671 dose-dependently inhibited both increase in negative charge and apo B-100 fragmentation during incubation of LDL with Cu2+. In addition, AL0671 significantly decreased the LDL degradation in rat peritoneal macrophages. 4. Neither pinacidil nor levcromakalim inhibited protein glycation and LDL oxidation. 5. Antioxidant properties of AL0671 might be due to its potent electron-donating ability, and this agent is expected to be useful for hypertensive diabetes.

Animals↗
PubMed1996

Noncytopathogenic and cytopathogenic bovine viral diarrhea-mucosal disease viruses do not affect in vitro embryonic development into the blastocyst stage.

Bovine oocytes enclosed within follicular epithelial (FE) cells were exposed to noncytopathogenic or cytopathogenic strains of bovine viral diarrhea-mucosal disease virus (BVD-MDV). After culture at 39 degrees C in humidified air with 5 percent CO2 for 24 h, the oocytes matured and then in vitro fertilization was performed. Some of the fertilized oocytes developed into blastocysts from day 8 to day 10 (day 1: date of insemination), and the rate of development to blastocysts was the same as for the unexposed control oocytes. In the developmental medium, each strain of BVD-MDV was present at 10(3) to 10(6) TCID (50)/0.25 ml from day 3 to day 10, respectively and the virus was isolated from the FE cells at high titers and from the embryos at low titers on day 10. BVD-MDV antigen was detected in the cytoplasm of the FE cells by indirect immunofluorescence. These findings indicate that BVD-MDV replicates well in FE cells. The results of this study suggest that BVD-MDV replication in cells around embryos has no effect on bovine embryo development.

Animals↗
PubMed1996

A putative receptor protein kinase gene in Ipomoea trifida.

We have characterized a cDNA clone, IRK1, for a putative receptor kinase from a stigma cDNA library of Ipomoea trifida. IRK1 protein contains an extracellular receptor-like domain and the consensus sequences diagnostic of serine/threonine protein kinase. Both the pattern of gene expression and the results of RFLP analysis indicate that the IRK1 gene is not primarily involved in the self-incompatibility system of Ipomoea.

Amino Acid Sequence↗
PubMed1996

Chemiluminescence response of cervine neutrophils to various stimuli.

The chemiluminescence response of cervine neutrophils to various stimuli was investigated in comparison with that of bovine and human homologues. The cervine cells showed a strong and consistent response, as observed in other species, to opsonized zymosan, phorbol myristate acetate and concanavalin A. The cells, however, like bovine homologues, failed to respond to n-formyl-methionyl-leucyl-phenylalanine which is a potent stimulant of human neutrophils.

Animals↗
PubMed1996

[A case report of concomitant UFT-E and CDDP against lung epidermoid carcinoma].

A 52-year-old male with the chief complaint of hemo-sputum was diagnosed after detailed examination as epidermoid carcinoma in the right upper lobe bronchus through the bifurcation. Thoracotomy revealed infiltration of carcinoma into the right main pulmonary artery and the superior vena cava, which could not be excised. Subsequent postoperative radiotherapy (69 Gy) showed NC. Then concomitant administration of UFT-E and a low dose of CDDP was started on an outpatient basis. After the third course of treatment (six weeks per course), a significant reduction was noted in the size of the carcinoma. Bronchoscopy revealed CR with the elimination of carcinoma to mere traces. Besides the myelosuppression seen at the end of the second course of treatment, which resulted in a two-week hospitalization for blood transfusion, no adverse effect prevented the patient from continuing the outpatient treatment courses and from returning to work. We consider that the treatment was very successful not only for its effectiveness in reducing the carcinoma but also for the high QOL achieved.

Administration, Oral↗
PubMed1995

Lymphoepithelial cyst of the pancreas: a preoperatively diagnosed case based on an aspiration biopsy.

This paper reports an extremely rare case of lymphoepithelial cyst of the pancreas. The patient, a 58-year-old man with no subjective symptoms, was found to have a pancreatic tumor during a physical examination. He visited our clinic and was admitted for a follow-up examination. Based on the ultrasonographic findings, superselective angiography, and aspiration biopsy, an epidermoid cyst was diagnosed. Enucleation was easily performed. Macroscopically, this cyst resembled an atheroma. Histologically, the cavity of the cyst was lined with a squamous epithelium with a nucleated layer and below that, lymphatic tissue. No malignancy was found. Tumors of the pancreas with a squamous epithelial covering are extremely rare; only a few such cases have been reported in the literature. As of 1991, only 12 cases, including the present case, had been reported. With the advances in diagnostic techniques, the detection of pancreatic tumors is expected to improve. This paper reports a case in which the use of an aspiration biopsy and superselective angiography proved to be useful in making an accurate diagnosis.

Angiography↗
PubMed1995

Neuromagnetic measurements of the human primary auditory response.

The spatio-temporal organization of the human primary auditory response (N19 and P30) was determined by analyzing magnetic fields from the right hemisphere evoked by monaural clicks to the left ear. The magnetic response consisted of peaks corresponding to electrical N19 (N19m) and P30 (P30m) within 40 msec after stimulation. However, the onset of electrical N19 occurred 5-9 msec earlier than that of the magnetic counterpart. Furthermore, the relative amplitude of N19 and P30 (N19/P30) was larger (more than 1) than that (about 0.5) of N19m and P30m (N19m/P30m). The findings suggest an additional contribution from a subcortical source for electrical N19. The estimated equivalent sources for N19m and P30m were localized at the postero-medial part of Heschl's gyrus (the primary auditory cortex). Furthermore, the dipole orientation of N19m was directed postero-ventrally and that of P30m was in the opposite direction, which is compatible with the anatomy of the supratemporal primary auditory cortex. These results resolve a long standing controversy of cortical vs. subcortical structures as the generators of the N19.

Auditory Cortex↗
PubMed1995

A mutant of pseudorabies virus with deletion of glycoprotein gIII gene prepared from a Japanese isolate: it fails to agglutinate mouse erythrocytes.

A mutant with deletion of the glycoprotein gIII gene was produced from a Japanese isolate of pseudorabies virus (PrV) and characterized. Viral titers of the mutant propagated in PK-15 cells were always lower than those of the parental virus. The parental virus agglutinated BALB/c mouse erythrocytes, whereas the deletion mutant showed no hemagglutinating activity. Pigs inoculated with the parental virus produced not only neutralizing but also hemagglutination-inhibiting antibodies. On the other hand, the mutant induced high titers of neutralizing antibody comparable to the parental virus but no hemagglutination-inhibiting antibody in inoculated pigs, suggesting that glycoprotein gIII is an essential component for hemagglutination of PrV. Finally, no evidence that the deletion mutant lost virulence for mice was obtained.

Animals↗
PubMed1995

Multichannel detection of magnetic compound action fields with stimulation of the index and little fingers.

Magnetic compound action fields (CAFs) over the right arm were measured from 63 sensor positions with two 7-channel SQUID gradiometer systems following electrical stimulation of the index and little fingers as well as the ring finger separately. The wave forms of the CAFs were primarily biphasic, corresponding to the depolarization and repolarization currents of the stimulated nerves. Maximum amplitudes of the CAFs were 60-140 fT for the index finger stimulation and 40-90 fT for the little finger stimulation. The field mapping of the CAFs revealed a propagating quadrupolar pattern with different distributions for the index and little fingers. The results agree with the anatomical location of the median and ulnar nerves for the index and little finger stimulation respectively. The isofield maps, due to ring finger stimulation, showed complex patterns as a result of simultaneous activation of the median and ulnar nerves. By comparing the amplitudes of the maxima of the CAFs due to index finger stimulation with those after median nerve stimulation at the wrist, the numerical ratios of the constituent digital nerve fibers for the index finger within the median nerve at the wrist were estimated. The ratios of 0.14-0.41 (mean 0.27), determined with measurement of the CAFs, are fairly consistent with those calculated from the reported histological data.

Adult↗
PubMed1995

[Empyema caused by perforation of metastatic colon cancer: a case report].

The patient was a 51-year-old female, underwent total gastrectomy for gastric cancer 6 years ago. She was admitted to a local hospital with the complaint of fever, the chest X-ray showed niveau in the left pleural cavity. Fecal material flowed out by drainage. Barium enema showed fistula of diaphragma from transverse colon. She was transferred to our hospital. Partial transverse colon resection and removal of the diaphragma fistula were performed. The colon tumor was histologically determined to be metastasis from gastric cancer with thoracic empyema.

Adenocarcinoma↗
PubMed1995

[A case of hepatocellular carcinoma with bone metastasis responding to oral administration of UFT].

A 63-year-old male patient with a mass in the left chest wall was referred to our hospital. An osteoclastic area was found in the mass of the left 4th rib by computed tomography; the mass was hard and little movable. There was an irregular and poorly demarcated low-density area, 5 cm in diameter, in the liver anterior superior segment. Aspiration from the mass of the chest wall indicated adenocarcinoma (class V) and forecast of metastatic lesion. The titer of serum AFP showed an extremely high level of 1,100 ng/ml. According to these findings, the patient was diagnosed as having hepatocellular carcinoma with bone metastasis and treated by the administration of oral UFT (300 mg/day). Six months later, the mass in the left chest wall was completely eliminated, the size of the hepatic lesion changed to 2.5 cm, and the titer of AFP decreased to the normal range (8.4 ng/ml). Treatment of hepatocellular carcinoma with bone metastasis is often ineffective, but this is a rare case showing the clinical effectiveness of oral administration of UFT.

Administration, Oral↗
PubMed1995

[Aortic aneurysm complicated with coarctation of the aorta and Turner syndrome].

A 23-year-old female with Turner syndrome and horse-shoe kidney underwent the operation of the coarctation of the aorta associated with the thoracic aortic aneurysm. The aortic aneurysm was located between the left carotid artery and the coarctation of the aorta, and the subclavian artery which was branched away from the aortic aneurysm was also aneurysmal. Aneurysmectomies and the reconstruction of the descending thoracic aorta and the left subclavian artery were performed with knitted Dacron grafts under assisting of the left atriodescending thoracic aortic bypass with Bio-pump. The disease was rare and such a case was not reported previously.

Adult↗
PubMed1994

Glucocorticoid induction of rat angiotensin II type 1A receptor gene promoter.

Promoter/luciferase reporter analysis indicated that the 5'-flanking region of rat angiotensin II type 1A receptor gene was functional, both in the rat aortic smooth muscle cells (RASMCs) and in Y1 cells derived from mouse adrenal cortex. In response to dexamethasone (Dex), transcriptional activity of promoter increased in transfected RASMCs, suggesting the functional cis-action of a glucocorticoid responsive elements (GRE). Furthermore, the expression of the rat AT1A gene was also up-regulated by Dex at the levels of both mRNA and protein in RASMCs.

Adrenal Cortex Neoplasms↗
PubMed1994

Cyclic hexapeptide endothelin receptor antagonists highly potent for both receptor subtypes ETA and ETB.

A cyclic hexapeptide, cyclo(-D-Asp-Trp-Asp-D-Leu-Leu-D-Trp-), designed from cyclo(-D-Glu-Ala-D-alloisoleucyl-Leu-D-Trp-), an ETA receptor-selective antagonist, possessed not only affinity similar to that of BQ-123 for ETA but also higher affinity for ETB than BQ-123. Further modification led to the discovery of cyclo(-D-Asp-Asp(Php)-Asp-D-Thg-Leu-D-Trp-) (Asp(Php): 1-beta-aspartyl-4-phenylpiperazine; Thg: 2-(2-thienyl)glycine) that inhibited [125I]ET-1 binding to the ETA and ETB receptors with IC50 values of 0.082 nM and 120 nM, respectively. Although this compound possesses 1470-fold less affinity for ETB than for ETA, it behaves as a non-selective antagonist that equipotently inhibits vasoconstriction mediated by both receptor subtypes ETA and ETB.

Amino Acid Sequence↗
PubMed1994

Visualization of a moving quadrupole with magnetic measurements of peripheral nerve action fields.

Magnetic compound action fields (CAFs) over the right arm were measured from 63 sensor positions with two 7-channel SQUID gradiometer systems following electrical stimulation of the median nerve at the wrist. The field mapping of the CAFs revealed a propagating quadrupolar pattern with the leading depolarization and trailing repolarization fronts. The average distribution of the CAFs in the longitudinal direction was 9.0 cm in length for the depolarization field and 7.3 cm for the repolarization field in good agreement with a theoretical prediction based on the duration (3 msec) of the CAFs and the conduction velocity of the nerve (50 m/sec). The distance between the maxima of the depolarization front and the minima of the repolarization front was 6.3 cm. This spatial separation of the leading and trailing dipole locations suggests in part mutual cancellation of the fields with opposite polarity at or near the depolarized segment of nerve fibers.

Adult↗