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T Hamano

Publications and source records attributed to T Hamano.

At least 73 records · Page 4Linked to original sources
PubMed1997

The cortical generators of the contingent negative variation in humans: a study with subdural electrodes.

Contingent negative variations (CNVs) and Bereitschaftspotentials (BPs) were recorded from subdural electrodes implanted in 14 patients with intractable epilepsy. For recording CNVs, a Go/NoGo S2 choice reaction-time paradigm was employed. Two seconds after presentation of a low tone burst (S1), either a medium (S2m) or a high tone burst (S2h) was delivered at random. Patients were instructed to make middle finger extensions after S2m but not after S2h. For recording BPs, patients repeated self-paced middle finger extensions. BPs were recorded from the primary motor area (MI), the primary sensory area (SI) and the supplementary sensorimotor area (SSMA). CNVs showed a patchy distribution in the prefrontal area and SSMA for the early component and in the prefrontal area, MI, SI, temporal area, occipital area and SSMA for the late component. These results suggest that the CNV recorded from the scalp is the summation of multiple cortical potentials which have different origins and different functions. The cortical distribution of the late CNVs was different from that of BPs. Late CNVs are not equivalent to BPs and are not related to motor preparation alone. After S2, 3 kinds of potentials, probably related to decision making, somatosensory feedback and motor execution under specific conditions, respectively, were observed.

Adolescent↗
PubMed1997

A case of mu-heavy chain disease: combined features of mu-chain disease and macroglobulinemia.

A case of mu-heavy chain disease (HCD) is described. The patient, a 40-year-old man, presented with an intracranial tumor. The bone marrow of this patient showed infiltration with both plasma cells and lymphocytes. The majority of plasma cells were vacuolated and the result of immunoelectrophoresis of serum protein revealed an arc with anti-IgM antiserum and an additional rapid migrating arc of different mobility with anti-kappa antiserum. The urine contained a kappa-type Bence Jones protein. An enzyme-linked antibody study showed that the majority of plasma cells in bone marrow contained both mu and kappa antigenic determinants in their cytoplasm. On Sephadex G-200 gel filtration, the monoclonal IgM-kappa protein and the mu-chain fragment were detected in the serum, suggesting the combined features of mu-HCD and macroglobulinemia. The molecular weight of the mu-chain fragment was approximately 45,000 daltons. The intracranial tumor completely disappeared after irradiation therapy. However, he died 1 year later after development of a huge abdominal tumor.

Adult↗
PubMed1997

Enzymic method for the spectrophotometric determination of benzoic acid in soy sauce and pickles.

A simple spectrophotometric method for the determination of benzoic acid is described. Benzoic acid is measured enzymically through its reaction with benzoate 4-hydroxylase coupled with NADPH and O2. The entire enzymic procedure required 20 min to complete. The method greatly simplifies the procedure for benzoic acid determination and permits the routine inspection of a number of samples with very little laboratory equipment. The method was compared with HPLC and satisfactory agreement was achieved.

Benzoates↗
PubMed1997

Down-regulatory role of surface CD4 molecules on autoreactive helper T cells during B cell activation.

MS202 is an IL-2-dependent Th2 clone reactive to auto-MHC class II antigens as previously reported. It expresses CD4, TCR-alphabeta, Thy 1.2 and H-2k on the cell membrane, as well as CD40 ligand. In order to investigate a functional role of surface CD4 molecules on Th2 cells during B cell activation, we attempted to establish a CD4- variant subclone derived from the CD4+ MS202, and its effect on B cell activation was examined. Briefly, MS202 was incubated with ethyl methanesulfonate to induce mutation followed by extensive treatment with anti-CD4 MoAb and complement. MS1.1.2, a representative subclone of resulting cell lines, was shown to lack CD4 molecules on the cell membrane, although it possessed almost the same amount of surface molecules other than CD4 compared with the original MS202 by analysis with flow cytometry. Interestingly, MS1.1.2 induced the maturation of B cells into IgM-producing cells more potently than MS202. This differentiative effect was markedly greater on activated B cells than resting B cells; each population was prepared from splenic B cells by a gradient separation method, but after treatment with anti-IgM antibodies, resting B cells responded to MS1.1.2, resulting in the secretion of a comparative amount of IgM. Furthermore, the effect of MS 1.1.2 on DNA synthesis of activated B cells was much greater than that of MS202. The present results suggest that surface CD4 molecules on Th2 cells may not be substantially required for B cell activation, and rather mediate a down-regulation signal to B cells.

Animals↗
PubMed1997

Trial of duplication procedure for complete dentures by CAD/CAM.

The purpose of this study was to duplicate the shapes of complete dentures by using a computer-aided design/manufacturing (CAD/CAM) system. The shapes of the complete dentures of an edentulous patient were measured using a non-contact type shape measurement system and morphological data at the interval of 0.25 mm were obtained in the X-axis and Y-axis directions. Measurement was performed from the occlusal surface and mucosal surface sides. Based on the three-dimensional morphological data, cutter paths for cutting were generated. For cutting, the three-step method consisting of rough cutting, finish cutting, and partial finish cutting was used and for duplicating the dentures the modelling wax was cut using a computerized numerical control (CNC) processor and ball-end mills with diameters of 6 mm and 1 mm. The method for the controlling of three axes (X, Y, and Z) of CNC machine was used, and cutting was performed only from two directions. Although further improvements are needed in the measurement and cutting in acute slope areas, the duplication of complete dentures appears to be possible using the CAD/CAM system.

Analog-Digital Conversion↗
PubMed1997

Application of a three-dimensional reconstruction method to analysis of the residual ridge.

The purpose of this study was to develop a new method of analysing the shape of the residual ridge. The line of the residual ridge crest was regarded as the reference for artificial tooth arrangement and a method of determining it was evaluated. The shape of a plaster model was measured with a contact-type shape measurement system. The measurement data in each frontal section were interpolated by cubic splines. The points corresponding to the residual ridge crest were calculated and superimposed onto the image of the plaster model on a monitor screen of an image processor. Using these points and the image of the plaster model, the line of the residual ridge crest was marked on the plaster model. It was concluded that this method could be used to determine the line of the residual ridge crest on a plaster model.

Algorithms↗
PubMed1997

Amyloid beta-protein (A beta) accumulation in the leptomeninges during aging and in Alzheimer disease.

The results of well-characterized two-site enzyme immunoassays showed that the crude leptomeninges (consisting of the pia matter, arachnoid matter, and leptomeningeal vessels [LV]) from aged control brains and brains affected by Alzheimer disease (AD) contain very high levels of amyloid beta-protein (A beta). To learn about the source of A beta, we carefully dissected out both leptomeninges (LM) and LV under a dissecting microscope and determined the levels of soluble A beta in each. The purity of these dissected tissues was confirmed by the absence or presence of alpha-smooth muscle actin representing LV by Western blotting. Surprisingly, the amounts of A beta in each dissected sample were nearly equivalent on a weight basis. In each compartment from aged controls the level of A beta 1-42 was comparable to that of A beta 1-40, while in AD brain A beta 1-40 was a predominant species in both LM and LV. In some cases careful immunocytochemical examination revealed the presence of A beta deposits that were immunolabeled by several A beta monoclonal antibodies in leptomeningeal layers (most often in the arachnoid matter). The extent of A beta deposition in LM appeared to be much less than that explained by the soluble A beta levels, suggesting that immunocytochemically undetectable A beta can accumulate in LM. These observations indicate that leptomeninges are a large reservoir of A beta in normal aged individuals and in AD patients.

Adult↗
PubMed1997

Increased serum CA125 levels in plasma cell dyscrasias.

We report 2 cases of plasma cell dyscrasia presenting with significantly elevated serum CA125 levels. The serum levels of CA125 from these patients correlated well with their serum M-protein levels. One patient had an IgG-kappa type extramedullary plasmacytoma with the culture supernatant from lymph node plasma cells showing a considerably high level of CA125 activity. The serum IgG fraction purified using a protein A column was devoid of any detectable CA125 activity, negating that the serum IgG M-protein from this patient might respond with a false-positive result in the CA125 immunoradiometric assay. The other patient had an IgG-lambda type plasma cell leukemia with the culture supernatant from peripheral mononuclear cells also showing a high level of CA125 activity. These observations may suggest that in plasma cell dyscrasias the CA125 antigen is spontaneously produced by tumor cells.

Aged↗
PubMed1997

Inhibitory effects of shouseiryu-to on two-stage carcinogenesis. II. Anti-tumor-promoting activities of lignans from Asiasarum heterotropoides var. mandshuricum.

Two lignans, asarinin (6) and xanthoxylol (7), were isolated from the radix of Asiasarum heterotropoides var. mandshuricum, which consist of a kampo prescription, Shouseiryu-to, as inhibitors of Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). These lignans also exhibited remarkable inhibitory effects on a two-stage carcinogenesis test of mouse skin and pulmonary tumors. Furthermore, it was confirmed that these hydrophobic lignans dissolved in the water decoction of Shouseiryu-to, and these lignans might be among the active constituents of this kampo prescription in terms of its anti-tumor-promoting activity.

Animals↗
PubMed1996

Abnormal sensorimotor integration in writer's cramp: study of contingent negative variation.

To investigate the pathophysiology of idiopathic focal dystonia, we recorded contingent negative variation (CNV) as a physiological index of sensorimotor integration in 14 right-handed patients with writer's cramp and compared it with normative data. CNV was recorded in the S2 choice reaction time paradigm: Two kinds of auditory S2 (Go or No-Go) were given 2 s after the auditory S1, and the subject reacted only to the Go signal by extending the wrist. In normal subjects, the late CNV amplitude had no difference at Cz between left- and right-hand tasks and was symmetric without significant amplitude laterality irrespective of the side of hand movement. In patients with writer's cramp, the late CNV amplitude at Cz was relatively larger for the left-hand task than the right-hand task (p < 0.03), and a significant amplitude laterality of the late CNV (larger on the right) was present especially at the central area for the right-hand task (p < 0.03). Since the late CNV is known to be generated, at least in part, from primary and supplementary motor cortices, the significant laterality of the late CNV seen with the right-hand task in patients with writer's cramp might represent functional abnormality of motor cortices possibly as the result of basal ganglia function.

Adult↗
PubMed1996

Abnormal excitability of the corticospinal pathway in patients with amyotrophic lateral sclerosis: a single motor unit study using transcranial magnetic stimulation.

The pathophysiology of corticospinal tract degeneration in amyotrophic lateral sclerosis (ALS) was investigated by studying the effect of transcranial magnetic stimulation on discharge characteristics of single motor units during voluntary activation. The motor units were recorded from the first dorsal interosseus muscles of 12 patients with ALS, 14 healthy subjects, 12 patients with upper motor neuron lesions and 9 with pure lower motor neuron diseases. More than 100 magnetic stimuli were delivered over the scalp during minimal muscle contraction. The occurrence of motor unit discharges was plotted in a peristimulus time histogram. An increase in discharge probability at latencies of 20-30 msec, that represents monosynaptic activation (primary peak) was found in normal units. Motor units from ALS patients with short disease durations had significantly increased discharge probabilities in the primary peak (P < 0.001). Motor units from 4 ALS patients with upper motor neuron signs showed double primary peaks: an initial synchronized peak followed by a dispersed peak. The latter was ascribed to a slow corticospinal pathway, which remains undetected or is functionally insignificant in healthy subjects. We conclude that the excitabilities of the surviving corticospinal tract pathways are abnormally increased in ALS, especially in the early stage.

Adolescent↗
PubMed1996

Subdural potentials at orbitofrontal and mesial prefrontal areas accompanying anticipation and decision making in humans: a comparison with Bereitschaftspotential.

Field potentials associated with the execution of a warned choice Go/No-Go reaction task were recorded from prefrontal supplementary (SMA) and primary motor cortex (MI) by using subdural electrodes in 5 epileptic patients during presurgical evaluation. The choice was between a Go and a No-Go imperative stimulus (S2) in the S1-S2 paradigm. Orbitofrontal and mesial prefrontal areas generated a slow preceding potential before S2 (most likely late CNV), and bilateral mesial prefrontal areas generated a transient potential, most likely related to decision making, upon S2 in both Go and No-Go conditions. In self-paced, repetitive movement, the Bereitschaftspotential was seen only at SMA and MI, but not in the prefrontal area. The present result, therefore, suggests that in humans orbitofrontal and mesial frontal areas play an important role in preparation for cognition and in decision making, whereas SMA and MI do so in motor preparation.

Adult↗
PubMed1996

Subdural recording of ictal DC shifts in neocortical seizures in humans.

PURPOSE: Invasive ictal EEG recording is often necessary to delineate epileptogenic areas in patients with intractable partial epilepsy, but even intracranial ictal recordings often reveal ill-defined onset zones in neocortical epilepsy. We studied the physiologic significance of ictal direct current (DC) potentials recorded intracranially in human epilepsy. METHODS: We made intracranial ictal EEG recordings in three patients with intractable partial seizures arising from frontal, lateral temporal, and parietal neocortical areas by using closely spaced subdural electrodes (platinum in two patients and stainless steel in one patient) with both standard (1.5 Hz) and open (0.016 Hz) low-frequency filter (LFF) settings. RESULTS: The initial ictal pattern was localized to two to nine subdural electrodes and characterized by very low voltage and high-frequency rhythmic activity ("electrodecremental pattern"). A slow-rising negative potential (DC potential) was seen in a slightly more restricted area (two to six electrodes) and occurred 1-10 s before the initial ictal EEG discharges in two patients. CONCLUSIONS: These results agree with those of previous studies of ictal DC shifts in animals and suggest that ictal DC shifts may be helpful in delineating the epileptogenic area more precisely in human epilepsy.

Adolescent↗
PubMed1996

Calcium signals in helper T cells after interaction with antigen-specific and antigen-nonspecific B cells.

By confocal fluorescence microscopy we have studied the rises of the intracellular free calcium ion concentration ([Ca2+]i) in helper T cells (KLH-specific, I-Ak-restricted Th1 cells, 28-4) after interaction with antigen-specific and antigen-nonspecific B cells (antigen-presenting cells). Antigen-specific and antigen-nonspecific B cells were prepared by the preincubation of TNP (trinitrophenol)-specific B cell hybridomas (TP67.21 I-Ak) with TNP-conjugated KLH and KLH alone, respectively. Calcium signals in Th1 cells (28-4) were induced by antigen-specific B cells one hundred times more efficiently as those by antigen-nonspecific B cells. Herbimycin A, a tyrosine kinase inhibitor, suppressed the former signals but not the latter. These results indicated that tyrosine phosphorylation was involved in the antigen processing of antigen-specific B cells but not in the processing of antigen-nonspecific B cells.

Animals↗
PubMed1996

Sodium hyaluronate eyedrops enhance tear film stability.

Sodium hyaluronate eyedrops can relieve various dry eye symptoms by prolonging the stability of the precorneal tear film. To determine the most effective concentration of sodium hyaluronate, we studied the concentration-dependent effects of sodium hyaluronate eyedrops on the precorneal tear film breakup time (BUT) in 12 volunteers. These subjects had a BUT of 10 seconds or less and a low tear volume determined with the phenol red thread test. They received four different concentrations of sodium hyaluronate eyedrops (0, 0.05, 0.1 and 0.3%). BUT was measured noninvasively using a non-contact specular microscope before the sodium hyaluronate eyedrop instillation and again after 5, 15, 30, 60, 120 and 180 minutes. The tear film stability period was prolonged significantly with 0.1% and 0.3% eyedrops at all measurement times (P < 0.05), while the eyes treated with 0% and 0.05% eyedrops showed no significant prolongation of tear film stability at any measurement times. The findings of this study confirm that sodium hyaluronate at a concentration of at least 0.1% is required to delay the breakup of the precorneal tear film.

Adult↗
PubMed1996

[Functional analysis of an autoantigen reactive B cell clone derived from MRL/MP-lpr/lpr mice].

MRL/MP-lpr/lpr (MRL/lpr) mice are known to provide a good model for the study on the pathogenesis of systemic lupus erythematosus with massive involvement of abnormal T lymphocytes in the spleen and lymphonodes. However, a direct role of B cells of MRL/lpr mice in autoimmune responses is not clear until this time. In the present study, to investigate the characteristic of B cells of the mice, we tried to establish a B cell clone after hybridization between splenic B cells of these mice and 2.52 M, a HAT selective medium sensitive mutant B cell line in the presence of polyethylene glycol and dimethyl sulfoxide and examined its response to autoantigens. MRL27.4, a subclone of a resulting hybridoma, expressed IgM, B220, IKk, ICAM-1, and LEA-1 on the cell membrane as well as CD5 molecules by analysis with flow microfluorometory (FMF). Also, MRL27.4 was shown to exhibit rosette formation against blood cells treated with bromelain (Br-RBC) at a frequency of more than 95%, and to express DNA-receptor (DNA-R) on its surface by FMF analysis with biotin-labeled ssDNA. In contrast, the parental 2.52 M did not form rosettes with Br-RBC and the expression of DNA-R on the cell membrane of 2.52 M was significantly less compared with that of MRL27.4. Interestingly, MRL27.4 produced a high titer of IgM-anti-ssDNA antibodies and IL-6 after treatment with the purified RBC membrane or immobilized DNA. On the other hand, the parental 2.52 M neither produce IgM-anti-ssDNA antibodies nor IL-6 under the same conditions. The results suggest that MRL27.4 is an autoantigen reactive B cell clone derived from MRL/lpr mice and its surface DNA-R, by itself, function to autoantigens. In this process, there might be an autocrine network mediated by IL-6. In conclusion, MRL27.4 provides a good model for the study on the direct function of B cells of MRL/lpr mice during abnormal immune responses to autoantigens.

Animals↗