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Biomedical subjects

T Hamano

Publications and source records attributed to T Hamano.

At least 37 records · Page 2Linked to original sources
PubMed2000

Impression pressures against teeth in a partially edentulous model with a mobile tooth: influence of impression tray design.

The purpose of the present study was to examine the effect of custom tray designs on local pressures against teeth during the impression procedure. In a previous study, a partially edentulous simulation model with a mobile tooth was used, and the effect of custom tray designs on the displacement of the mobile tooth was examined during the impression procedure. Based on that study's results, we have assumed that the differences in impression pressures between the labial and the lingual sides of a mobile tooth could either cause or affect displacement. The present study was undertaken to determine the local impression pressures against each side of three anterior teeth, including one mobile tooth, using the same simulation model and the same custom trays as in the previous study. It was found that the local pressures exerted against teeth during the impression procedure were affected by the custom tray designs and varied according to the coronal shape, axis inclination and location of the teeth.

Analysis of Variance↗
PubMed2000

IgD multiple myeloma preceding the development of extensive extramedullary disease without medullary involvement.

We present a unique case of IgD multiple myeloma (MM) preceding the development of extensive extramedullary disease without medullary involvement. A 63-year-old man was diagnosed with IgD-lambda MM when he developed anemia. After 3 months of chemotherapy, he was in complete remission as evidenced by the disappearance of bone marrow (BM) plasmacytosis, monoclonal IgD protein in his serum, and Bence Jones proteinuria. Six months after diagnosis, his disease took an unusual course with the development of plasmacytomas in the skin, without medullary involvement. He then received chemotherapy, resulting in the complete disappearance of the subcutaneous plasmacytomas. Two years after the initial diagnosis, his disease took an aggressive clinical course with retroperitoneal relapse, leading to the patient's death within 1 month. The two separate episodes of extramedullary disease were associated with elevated serum lactic dehydrogenase levels and the absence of plasma cells in the BM. This case provides evidence of two separate transformations of the original malignant MM clone.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Cortical potentials associated with voluntary mandibular movements.

Movement-related cortical potentials (MRCPs) are negative potentials over the scalp, which gradually increase prior to voluntary movements, and might be applied to elucidate the cortical efferent function of the mandibular movements. We compared the MRCPs accompanying various mandibular movements to study the motor control mechanism underlying these movements. Electroencephalograms (EEGs) were recorded from 11 electrodes placed over the scalp (F3, Fz, F4, T3, C3, Cz, C4, T4, P3, Pz, and P4), according to the International 10-20 System, and electromyograms (EMGs) were obtained from surface electrodes over the masseter muscle and the anterior belly of the digastric muscle. Ten healthy subjects were requested to make brisk and self-paced mandibular movements in 4 different directions (mouth-opening and -closing, and left and right lateral movements). We obtained MRCPs by averaging the EEG, using the visually determined EMG onset as a trigger signal. In all the movements, a slowly increasing, bilaterally widespread negativity starting 1.5 to 2.0 sec before the EMG onset (Bereitschaftspotential, or BP proper) was observed, with the maximum over the vertex region. The negative slope (NS') occurred about 300 to 700 msec before the EMG onset. The cortical maps of BP/NS' (BP and NS' combined), immediately prior to the mouth-opening and closing, showed a symmetrical distribution, whereas that for the lateral movements showed a tendency of predominance over the hemisphere ipsilateral to the direction of the movement. BP/NS' amplitudes at the onset of movement differed significantly or tended to do so between open, close, and lateral movements, suggesting that MRCP recordings may thus provide a means to explore the role of the cerebral cortex in the control of mandibular movements.

Adult↗
PubMed2000

[Dopamine transporter SPECT in patients with Parkinson's disease].

The major neuropathological feature in Parkinson's disease (PD) is severe degeneration of the dopamine (DA) neurons in the substantia nigra. Dopamine transporter (DAT) is an important protein in the regulation of DA neurotransmission. It has been reported that PD patients show a loss of DAT in striatum. We report here the findings of single photon emission computed tomography (SPECT) of the DAT with 2 beta-carboxymethoxy-3 beta-(4[123I]iodophenyl)tropane ([123I] beta-CIT) to investigate striatal DAT in 10 patients with PD, one patient with vascular parkinsonism (VP), and one patient with dystonia syndrome. Patients were evaluated using the Webster rating scale. Specific/nondisplaceable striatal binding ratio (V3") was obtained in each case. In PD patients, the uptake of [123I] beta-CIT was reduced, especially in the tail of putamen compared with caudate nucleus. Even in the early stage of PD, the uptake of beta-CIT was reduced not only in the severely affected side, but also in the mildly disturbed side of the brain. Putamen caudate ratio was generally low in PD patients. In VP patient, the uptake was reduced, but putamen caudate ratio was not decreased. V3" values showed significant correlation with the severity of clinical symptoms such as self-care, facies, posture, gait, speech, and Hoehn-Yahr's stage. On the other hand, V3" values were not significantly correlated with the degree of tremor, seborrhea, and duration of the illness. In conclusion, we found that SPECT of the [123I] beta-CIT is a useful method for the diagnosis in the patients presenting parkinsonism, and for the clinico-physiological estimation of parkinsonian symptoms such as self-care, facies, posture, gait, and speech.

Adult↗
PubMed2000

[Lewis-Sumner syndrome presenting unilateral quadriceps amyotrophy as an initial symptom].

We report a 55-year-old man with a chief complaint of wasting and weakness of the left quadriceps muscle. At age 54, he noticed difficulty in running and weakness in the left thigh, which gradually progressed. On the first admission to our hospital, based on the nerve conduction studies (NCS), the muscle biopsy findings showing neurologenic changes, and no abnormality of spinal MRI, we diagnosed as unilateral quadriceps amyotrophy, which resulted from an atypical form of spinal progressive muscular atrophy. One year later, he showed the bilateral hand weakness, conduction blocks on the right median and ulnar nerves by NCS, and the presence of serum anti-GM 1 antibody. From these findings, Lewis-Sumner syndrome was diagnosed. The therapy of high-dose intravenous immunoglobulin moderately improved his symptoms. The clinical symptoms of quadriceps amyotrophy is produced by various disorders including spinal progressive muscular atrophy, spinal extradural arachnoid cyst, rimmed vacuole myopathy, Becker dystrophy, limb-girdle dystrophy, and focal myositis. However, there have been no reports of a case of Lewis-Sumner syndrome. It is important to consider Lewis-Sumner syndrome in the differential diagnosis of quadriceps amyotrophy.

Demyelinating Diseases↗
PubMed1999

Effect of graft-versus-host disease (GVHD) on host hematopoietic progenitor cells is mediated by Fas-Fas ligand interactions but this does not explain the effect of GVHD on donor cells.

The acute graft-versus-host disease (GVHD) generated in BDF1 mice by the injection of spleen cells from the C57BL/6 parental strain induces a direct cell-mediated attack on host lymphohematopoietic populations, resulting in the reconstitution of the host with donor hematopoietic stem cells. We examined the effect of GVHD on the donor and host hematopoiesis in parental-induced acute GVHD. The bone marrow was hypoplastic and the number of hematopoietic progenitor cells significantly decreased at 4 weeks after GVHD induction. However, extramedullary splenic hematopoiesis was present and the number of hematopoietic progenitor cells in the spleen significantly increased at this time. Fas expression on the host spleen cells and bone marrow cells significantly increased during weeks 2 to 8 of GVHD. Host cell incubation with anti-Fas Ab induced apoptosis, and the number of hematopoietic progenitor cells decreased during these weeks. A significant correlation between the augmented Fas expression on host bone marrow cells and the decreased number of host bone marrow cells by acute GVHD was observed. Furthermore, the injection of Fas ligand (FasL)-deficient B6/gld spleen cells failed to affect host bone marrow cells. Although Fas expression on repopulating donor cells also increased, Fas-induced apoptosis by the repopulating donor cells was not remarkable until 12 weeks, when more than 90% of the cells were donor cells. The number of hematopoietic progenitor cells in the bone marrow and the spleen by the repopulating donor cells, however, decreased over an extended time during acute GVHD. This suggests that Fas-FasL interactions may regulate suppression of host hematopoietic cells but not of donor hematopoietic cells. Hematopoietic dysfunctions caused by the reconstituted donor cells are independent to Fas-FasL interactions and persisted for a long time during parental-induced acute GVHD.

Animals↗
PubMed1999

MRI findings of benign monomelic amyotrophy of lower limb.

We report here magnetic resonance imaging (MRI) findings of two patients with benign monomelic amyotrophy of lower limb. Both subjects showed unilateral amyotrophy of the lower limb with a benign clinical course, and the affected muscles demonstrated neurogenic changes. On T1- and T2-weighted MRI, marked atrophy and increased signal intensity were found mainly in gastrocnemius and soleus muscles. Moreover, MRI examination also revealed that thigh muscles including semitendinosus, semimembranosus, and vastus intermedius and lateralis muscles were involved in one of the patients. We concluded that muscle MRI is very useful for detecting affected muscles, especially deep skeletal muscles in patients with benign monomelic amyotrophy of lower limb.

Adult↗
PubMed1999

Cortical distribution of Bereitschaftspotential and negative slope potential preceding mouth-opening movements in humans.

Cortical potentials associated with the voluntary movement of various body parts are known as movement-related cortical potentials, which allow evaluation of the cortical efferent function and other higher functions controlling voluntary movement. The cortical potentials have three main components: the Bereitschaftspotential (or 'readiness potential'), the negative slope and the motor potential. Here, the cortical potentials preceding mouth-opening movements were recorded to investigate which of these components could be observed. Electroencephalograms (EEGs) were recorded from 11 electrodes placed over the scalp (F3, Fz, F4, T3, C3, Cz, C4, T4, P3, Pz and P4) according to the international 10-20 system. Electromyograms (EMGs) were recorded from the anterior belly of the digastric and the masseter. The 10 healthy participants were requested to make brisk and self-paced mouth-opening movements. All data were digitized with a sampling frequency of 200 Hz and stored for off-line analysis. Movement-related cortical potentials were obtained by averaging the EEG, using the digastric EMG onset as a trigger signal. The Bereitschaftspotential was recorded as a gradually increasing, bilaterally widespread negativity starting 1.7 s (mean) +/-0.23 s (S.D.) before the onset of the opening movement. The amplitude, which was measured at movement onset, was maximum at Cz (3.8 +/- 1.3 microV). The negative slope was observed 500-600 ms before the movement onset, and the motor potential was not clearly identified, because of postmotion artefacts. The cortical maps of the Bereitschaftspotential and negative slope combined together before to the mouth opening showed a symmetrical distribution with a maximum at the vertex region. The study reveals that the Bereitschaftspotential and the negative slope, two components of the movement-related cortical potentials, can be observed preceding mouth-opening movements and are similar to those associated with other voluntary movements. Findings such as distribution, amplitude and onset of the potentials could provide important information for studying the cortical control of mandibular movements.

Adult↗
PubMed1999

Inhibitory effect of regucalcin on Ca(2+)-dependent protein kinase activity in rat brain cytosol: involvement of endogenous regucalcin.

The effect of regucalcin, a Ca(2+)-binding protein, on Ca(2+)-dependent protein kinase activity in the brain cytosol of rats with different ages (5 and 50 weeks old) was investigated. The addition of calmodulin (10 microg/ml) or dioctanoylglycerol (5 microg/ml) in the enzyme reaction mixture caused a significant increase in protein kinase activity in the presence of CaCl2 (1 mM), indicating that Ca2+ calmodulin or protein kinase C is present in the cytosol. Such an increase was completely prevented by the addition of regucalcin (10(-7) M). Moreover, regucalcin (10(-7) M) significantly inhibited cytosolic protein kinase activity without Ca2+/calmodulin or dioctanoylglycerol addition. Meanwhile, the presence of anti-regucalcin monoclonal antibody (10-50 ng/ml) in the enzyme reaction mixture caused a significant elevation of protein kinase activity, suggesting an inhibitory effect of endogenous regucalcin. Brain cytosolic protein kinase activity was significantly elevated by increasing age (50-week-old rats). Also, regucalcin (10(-7) M) significantly decreased protein kinase activity without Ca(2+) addition in the brain cytosol of aged rats. However, the effect of anti-regucalcin monoclonal antibody (50 ng/ml) in elevating protein kinase activity was not seen in the brain cytosol of aged rats. These results suggest that regucalcin has an inhibitory effect on Ca(2+)-dependent protein kinase activity in rat brain cytosol, and that the effect of endogenous regucalcin may be weakened in the brain cytosol of aged rats.

Animals↗
PubMed1999

Abnormal contingent negative variation in writer's cramp.

OBJECTIVE: To investigate the physiological abnormality in writer's cramp, a focal dystonia which specifically affects writing. METHODS: We recorded brain potentials that precede hand and neck movements (contingent negative variation or CNV) in 11 patients and 11 age-matched normal subjects. A 1000 Hz tone burst (S1) was delivered to the right or left ear in random sequence, and 2 s after, a 2000 Hz tone burst (S2) was delivered to both ears simultaneously. For the response task to S2, the subjects were instructed to extend their fingers ipsilateral to the ear to which S1 was given in one experiment or to rotate the head to the side of the S1 presentation in another. All the patients had symptoms in the right hand only, and performed both tasks normally. CNV amplitudes were compared between normals and patients using unpaired t test. RESULTS: They showed normal CNV for neck movement but significantly decreased CNV amplitudes for movements both in the affected and unaffected hands. CONCLUSIONS: Our findings suggest that motor programming is specifically abnormal for the affected body part, including the asymptomatic contralateral limb, and that the clinical symptom may result from a deficient compensatory mechanism for abnormal motor programs or subroutines.

Adult↗
PubMed1999

[Determination of sennoside A and sennoside B in formulation using capillary electrophoresis].

The determination of sennoside A (SA) and sennoside B (SB) by capillary zone electrophoresis was developed. The separation of SA and SB was performed in 100 mM of the 3-[cyclohexylamino]-1-propanesulfonic acid (CAPS) buffer (pH 10.0), and the migration time of SA and SB was found to be both less than 7 min. This method was applied to the analyses of seven commercial formulations containing SA and SB without previous treatment. The statistical comparison of the results obtained from both capillary electrophoresis and HPLC methods revealed an absolute correlation.

Anthraquinones↗
PubMed1999

Successful treatment of a patient with febrile, lobular panniculitis (Weber-Christian disease) with oral cyclosporin A: implications for pathogenesis and therapy.

We report a 15-year-old Japanese girl with severe systemic Weber-Christian disease (WCD) who presented with acute onset of high fever associated with tender subcutaneous nodules. Laboratory tests showed an elevated serum concentration of lactate dehydrogenase (LDH), leukopenia, and coagulation abnormalities. The anti-nuclear and anti-DNA antibodies were negative, and the serum pancreatic enzymes and alpha 1-antitrypsin levels were normal. Pulse steroid therapy was not effective, and eventually cerebellar hemorrhage occurred. After initiation of oral cyclosporin A (CyA) therapy, fever came down and her clinical condition improved markedly. Extremely high serum concentrations of interferon-gamma (IFN-gamma) and soluble interleukin-2 receptor (sIL-2R) in this patient returned to normal with CyA therapy. These findings suggest that T-cell immune responses are involved in the pathogenesis of WCD, and that CyA is effective against the disease via suppression of T-cell reactions.

Administration, Oral↗
PubMed1999

Inhibitory effect of regucalcin on Ca2+/calmodulin-dependent protein phosphatase activity in rat brain cytosol.

The effect of Ca2+-binding protein regucalcin on neutral phosphatase activity in rat brain cytosol was investigated. Phosphatase activity was assayed in a reaction mixture containing the cytosolic protein in the presence of phosphotyrosine, phosphoserine, and phosphothreonine. The presence of calcium chloride (10(-5) and 10(-4) M) in the enzyme reaction mixture caused a significant increase in phosphatase activity toward three phosphoaminoacids. The enzyme activity toward phosphoserine and phosphothreonine was significantly enhanced by the addition of calmodulin (1 or 5 microg/ml) in the presence of calcium (10(-5) M). Such an effect was not seen in the presence of phosphotyrosine. Trifluoperazine (2x10(-5) M), an antagonist of calmodulin, completely inhibited calcium (10(-5) M)-increased phosphatase activity toward phosphoserine and phosphothreonine, whereas it had no effect on the enzyme activity toward phosphotyrosine. Regucalcin (10(-9) M) significantly inhibited phosphatase activity toward three phosphoaminoacids without or with Ca2+ addition. The inhibitory effect of regucalcin (10(-10) and 10(-9) M) was also seen in the presence of Ca2+ (10(-5) M) and calmodulin (5 microg/ml). The presence of anti-regucalcin monoclonal antibody (20 or 50 ng/ml) in the enzyme reaction mixture caused a significant elevation of phosphatase activity toward three phosphoaminoacids; this effect was completely abolished by addition of regucalcin (10(-9) M). The present study suggests that the endogenous regucalcin has an inhibitory effect on Ca2+/calmodulin-dependent protein phosphatase activity in rat brain cytosol.

Animals↗
PubMed1999

A method of predicting color stability of autopolymerizing acrylic resins using electron spin resonance.

Synopsis. Long periods can be required to determine the color stability of acrylic resins. The concentration of propagating radicals with unpigmented experimental resins (UER) and initiator solution (IS) of two initiator systems (binary and ternary) and five products were measured using electron spin resonance (ESR). The radical concentration was estimated from the area under the integrated ESR spectrum. The discoloration was measured using a color computer. Higher content of benzoylperoxide led to higher radical concentrations. The radical concentration for the ternary system increased slightly with time, but were lower than those of the binary system. Significant positive correlations were found between the radical concentration and delta E*ab for UER (r = 0.900, p < 0.01), IS (r = 0.953, p < 0.001) and the products (r = 0.808, p < 0.05). It was suggested that the color stability of these resins was predictable by measuring the radical concentration using ESR.

Acrylic Resins↗