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T Hamada

Publications and source records attributed to T Hamada.

At least 343 records · Page 19Linked to original sources
PubMed1995

[A transient sinus arrest after right stellate ganglion block--assessment of autonomic function by heart rate spectral analysis].

We experienced a case of sinus arrest probably induced by right stellate ganglion block (SGB). A healthy medical student volunteered in our study of the cardiac autonomic nervous system and received the SGB. After the Holter ECG had been attached, the SGB was performed with mepivacaine 8 ml. Horner's sign was observed after about 3 minutes. A transient (15 s) sinus arrest occurred suddenly after about 6 minutes of the tilt test probably due to a vasovagal reflex, and the subject lost consciousness. From spectral analysis of the Holter ECG recording, the right SGB may be closely involved in the induction of the sinus arrest. Our present case suggests that sinus arrest may occur if a patient stands up after right SGB.

Adult↗
PubMed1995

[Infection route of MRSA to pregnant women and to newborns].

It has been reported that newborn babies are compromised hosts, and to be MRSA carriers means that the danger of occurrence of MRSA infection is high. Our department has focused on improving the hospital environment to guard against hospital infections. Infection from the hospital environment was prevented by looking for staphylococcus bacteria in the nasal cavity during pregnancy, and isolating pregnant MRSA carriers from others. Such effects as MRSA infection of the body members and organs, the newborn babies, nasal cavities of their family members, and discharging MRSA into hospital environments were investigated. 1. The rate of MRSA carriers among pregnant women was 0.8% (3.7% of pregnant women engaged in medical services, and 0.5% of pregnant women engaged in non-medical services). In the former case it was suspected that their children became MRSA carriers for some reason and they became infected through their children. In the latter case, there are two possibilities; one was that MRSA was picked up at the place of work was not removed by sterilization, so that they became carriers and the other is infection through children similarly to non-medical workers. 2. A healthy carrier was observed to be spreading MRSA in to the environment. 3. In the environment where hospital infections were fully dealt with, MRSA infection of newborn babies was always from puerperal women who were carriers. 4. The rates for both MRSA carrying in the nasal cavities of newborn babies at the time of dehospitalization and 1-month-old babies were distinctly low, when the nasal MRSA of puerperal was removed by sterilization, compared to without sterilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Carrier State↗
PubMed1995

Mapping of the gene for Machado-Joseph disease within a 3.6-cM interval flanked by D14S291/D14S280 and D14S81, on the basis of studies of linkage and linkage disequilibrium in 24 Japanese families.

The gene locus of Machado-Joseph disease (MJD) has recently been mapped within a 29-cM subregion of 14q chromosome. We did a linkage study of 24 multigenerational MJD Japanese pedigrees, in an attempt to narrow the candidate region of this gene. Pairwise and multipoint linkage analysis, together with haplotype segregation analysis, led to the conclusion that the MJD gene is located at the 6.8-cM interval between D14S256 and D14S81 (Zmax = 24.78, multipoint linkage analysis). D14S291 and D14S280, located at the center of this interval, showed no obligate recombination with the MJD gene (Zmax = 5.93 for D14S291 and 9.99 for D14S280). A weak, but significant, linkage disequilibrium of MJD gene was noted with D14S81 (P < .05) but not with D14S291 or D14S280. These results suggest that a 3.6-cM interval flanked by D14S291/D14S280 and D14S81 is the most likely location of the MJD gene and that it is closest to D14S81.

Adult↗
PubMed1995

[Evaluation of neck lymph node dissection and extended lymphadenectomy through a collar incision and median sternotomy for lung cancer].

Since 1983, 421 patients have been treated for lung cancer at this institute. Since 1988, neck lymph node dissection (11 cases) and new extended lymphadenectomy through a collar incision and median sternotomy (22 cases) have been conducted. Indications for this new radical operation are scalene, supraclavicular or highest mediastinal node involvement, or superior pulmonary sulcus carcinoma, in patients aged 70 or less without distant metastasis and NSCLC. No major complications and operative mortality were encountered in this study. Patients with scalene or supraclavicular node involvement showed poor prognosis. Postsurgical local recurrence was frequent. Whether resection in N3 disease should be conducted or not, remains a point of controversy. The authors consider that lymphadenectomy should be conducted more extensively. A significant better survival of N2 disease and satisfactory prognosis of patients without metastasis of cervical lymph nodes demonstrates the effectiveness of neck lymph node dissection in the present superradical operation for lung cancer.

Adult↗
PubMed1995

Establishment and characterization of immortalized human coronary endothelial cells.

We established an immortalized cell line from endothelial cells derived from a human coronary artery, isolated at autopsy from 76-year-old male, by transfecting the cells with origin-minus simian virus 40 DNA. These cells showed SV40 T antigen in the nuclei and Ulex europaeus I agglutinin and factor VIII-related antigen, as endothelial cell markers, in their cytoplasm. This cell line synthesized prostacyclin, tissue-type plasminogen activator (tPA), and plasminogen activator inhibitor-1 (PAI-1) as well as produced the proform of matrix metalloproteinase 1, which was activated by cultivating the cells with plasminogen. These findings reveal that this immortalized endothelial cell line retains characteristics of human coronary endothelial cells, indicating that this cell line is useful for studying atherogenesis of the coronary artery.

Aged↗
PubMed1995

[Diagnostic assistance system based on possibility for evaluation of long bone tumorous lesions].

We constructed a diagnostic assistance system for long bone lesions using a relational data base management system, in which we categorized radiographic findings of all parameters in various lesions and stored them as degrees of possibility. Possible diagnoses of unknown lesions were listed by max-min calculation between the data base and findings of the lesions. Integration of parameters narrowed the scope of possible diagnoses. Fifty-six cases with long bone lesions were tested. Experts diagnosed correctly up to 64 percent, while the system showed a correct diagnosis rate of 43 percent as the first rank of possibility. However, the system gave 75 percent correct diagnosis when listed up to the third rank, and this increased up to 100 percent at the ninth rank. The rate of true diagnosis by experts did not exceed 73 percent. The diagnostic assistance system based on possibility analysis proved to be useful for suggesting differential diagnoses in diagnosing long bone tumorous lesions from plain radiographs.

Bone Neoplasms↗
PubMed1994

Cloning of a cDNA encoding tobacco omega-3 fatty acid desaturase.

A cDNA was isolated from a tobacco (Nicotiana tabacum cv. SR1) leaf cDNA library using, as a hybridization probe, a cDNA fragment from the gene (fad7) encoding Arabidopsis thaliana chloroplast omega-3 fatty acid (FA) desaturase. The deduced 379-amino-acid (aa) sequence has 67-71% identity to those deduced from the previously described genes encoding the omega-3 FA desaturases of A. thaliana. The absence of an N-terminal extension transit peptide in the deduced aa sequence of the cDNA clone and the accumulation pattern of the mRNA corresponding to this cDNA in leaf and root tissues indicate that the isolated cDNA encodes a tobacco microsomal omega-3 FA desaturase.

Amino Acid Sequence↗
PubMed1994

Receptor-mediated endocytosis of thrombin-antithrombin III complex by the human monocytoid cell line U937.

Receptor-mediated endocytosis of thrombin-antithrombin III (TAT) complex was characterized with the monocytoid cell line U937. At 4 degrees C, U937 cells bound TAT but not antithrombin III in a rapid, specific, saturable, and reversible manner. [125I]TAT binding to U937 cells was not inhibited by antithrombin III and hardly by thrombin, but 75% inhibited by a 50 molar excess of the unlabeled TAT. There were about 79,000 binding sites/cell (Kd = 68 nM). The TAT receptor on U937 cells may be distinct from the serpin-enzyme complex (SEC) receptor, since a synthetic peptide corresponding to the recognition sequence of SEC receptor did not compete with TAT binding to the cells. Receptor-bound TAT was internalized into the cells after switching the temperature from 4 to 37 degrees C and thereafter degraded in lysosomes.

Amino Acid Sequence↗
PubMed1994

Effects of nitric oxide synthase inhibitors on N-methyl-D-aspartate-induced phase delay of circadian rhythm of neuronal activity in the rat suprachiasmatic nucleus in vitro.

Excitatory amino acid (EAA) receptors such as N-methyl-D-aspartate (NMDA) and non-NMDA receptors have been suggested to play an important role in the regulation of photic information from the retina to the suprachiasmatic nucleus (SCN). Therefore, we investigated the role of glutamate as a retinohypothalamic transmitter by analyzing the phase-resetting effects of NMDA and a non-NMDA agonist, (R,S)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), on the circadian rhythm of SCN firing activity. Nitric oxide (NO) production is believed to be an essential intermediate in NMDA-induced cGMP production in the CNS. Thus, we examined the effects of blockers of NO production on NMDA- or AMPA-induced phase delay of SCN activity rhythm. N-nitro-L-arginine methylester (L-NAME) blocked NMDA- but not AMPA-induced phase shift, indicating the involvement of NO synthesis in NMDA-induced phase changes. L-arginine but not D-arginine caused a phase delay, and L-NAME blocked L-arginine-induced phase delay. In addition, cotreatment with NMDA and L-arginine did not have an additive effect. These results suggest that NO production itself is involved in the phase change of SCN neuron activity, and NMDA-induced phase changes are also mediated via activation of NO synthesis in this nucleus.

Amino Acid Oxidoreductases↗
PubMed1994

Protein-synthesis inhibitor blocks (R,S)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-or substance P-induced phase shift of the circadian rhythm of neuronal activity in the rat suprachiasmatic nucleus in vitro.

The mammalian suprachiasmatic nucleus (SCN) has been identified as a circadian pacemaker. N-methyl-D-aspartate (NMDA), non-NMDA and substance P receptors have been suggested to be involved in handling of photic information in the SCN. In the Aplysia eyes, in which the circadian clocks are involved, serotonin- or cAMP-induced phase changes of the circadian rhythm were reported to be blocked by protein-synthesis inhibitors. Therefore, we investigated whether protein-synthesis inhibitor can block the non- NMDA receptor agonist (R,S)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid hydrobromide (AMPA)- or substance P (SP)-induced phase changes of SCN activity rhythm. Although application of 10 microM cycloheximide alone during the early part of the subjective night did not cause phase change, it blocked both 10 microM AMPA- and 1 microM SP-induced phase delay. The present result suggests that protein synthesis may be required in the manifestation of AMPA- and SP-induced phase change of circadian clock.

Animals↗
PubMed1994

GABAA receptor agonist muscimol can reset the phase of neural activity rhythm in the rat suprachiasmatic nucleus in vitro.

We investigated the phase-resetting effect of muscimol, gamma-amino butyric acid (GABA)A receptor agonist, on the circadian neural activity rhythm of the rat suprachiasmatic nucleus (SCN), which contains a circadian pacemaker. Acute application of muscimol inhibited the neural activity of the SCN in a dose-dependent manner. Under the tissue culture condition, the treatment with 10 microM muscimol during the early- to mid-subjective day on the first day (day 1) in vitro produced the largest phase advance in neural activity rhythm of the SCN on day 2. By contrast, the administration of muscimol during the subjective night produced no change. These phase changes were similar to those reported for dark pulses in constant light. These findings indicate that muscimol can directly affect SCN neurons and reset the circadian pacemaker in the SCN. The GABA neural function through the activation of GABAA receptors may play a role in modulating the phase of the SCN clock, especially during the subjective day.

Animals↗
PubMed1994

Vanadium induced hemolysis of vitamin E deficient erythrocytes in Hepes buffer.

Several vanadium compounds were tested for their ability to induce in vitro hemolysis of vitamin E-deficient hamster erythrocytes. Free vanadyl caused hemolysis in Hepes buffer but not in Tris or phosphate buffer, while hemolysis was inhibited by catalase, chelators such as deferoxamine mesylate and EDTA, and hydroxyl radical scavengers such as ethanol and D-mannitol. Although metavanadate itself could not induce hemolysis, metavanadate with NAD(P)H caused hemolysis in Hepes buffer only, and superoxide dismutase prevented it. Hydrogen peroxide, hydroxyl radical and Hepes radical were involved in vanadyl-induced hemolysis, superoxide anion was further involved in metavanadate plus NAD(P)H-induced hemolysis. Vitamin E prevented hemolysis under both conditions.

Analysis of Variance↗
PubMed1994

Synaptotagmin can cause an immune-mediated model of Lambert-Eaton myasthenic syndrome in rats.

The possible antigenicity of synaptotagmin, a synaptic vesicle protein acting as a cooperative calcium (Ca2+) receptor in exocytosis, was tested to determine whether it is involved in the induction of Lambert-Eaton myasthenic syndrome in which antibodies against voltage-dependent Ca2+ channels or related molecules play a pathogenic role. Repeated injections to Lewis rats with peptides of synaptotagmin residues 20 through 53 or 1 through 30 that are presumably exposed at the nerve terminal surface during exocytosis induced corresponding antipeptide antibodies; on immunoblots, antibodies recognized synaptotagmin that was expressed in the clonal cells. Electrophysiologically, the peptide (residues 20-53)-immunized rats showed (1) reduced acetylcholine quantal content of end-plate potential, (2) an increase in quantal content at high extracellular Ca2+ concentration, and (3) early facilitation followed by less marked depression of end-plate potential amplitude at a tetanic rate of repetitive nerve stimulation. Findings are similar to those in human Lambert-Eaton myasthenic syndrome and passively transferred Lambert-Eaton myasthenic syndrome in mice, and thus suggest that antibody to a synaptotagmin-voltage-dependent Ca2+ channel complex may be involved in the pathogenesis of Lambert-Eaton myasthenic syndrome. The peptide (residues 1-30)-immunized rats showed no electrophysiological abnormality.

Amino Acid Sequence↗
PubMed1994

Ambient pressure stimulates immortalized human aortic endothelial cells to increase DNA synthesis and matrix metalloproteinase 1 (tissue collagenase) production.

In the present study, we investigated the effect of ambient pressure on [3H]-thymidine incorporation and on the production of matrix metalloproteinase 1 (tissue collagenase/proMMP-1) using human aortic endothelial cells immortalized with simian virus 40 (SE-1). Incubation of cells at ambient pressures of 50 and 100 mmHg for 24 h slightly increased [3H]-thymidine incorporation when directly compared with normal culture conditions. The amount of [3H]-thymidine incorporated in SE-1 reached a maximum at 150 mmHg, while a further increase in pressure to 200 mmHg decreased incorporation. The same ambient pressure slightly stimulated human aortic intimal smooth muscle cells (SMC) to increase [3H]-thymidine incorporation but not medial SMC. Immunoblot analysis also showed that ambient pressure, ranging from 50 to 200 mmHg, like 12-O-tetradecanoyl-phorbol-13-acetate stimulated SE-1 to produce proMMP-1, an effect not seen with either intimal or medial SMC. The amount of proMMP-1 produced also reached a maximum level at 150 mmHg. We postulate that human endothelial cells are ambient pressure sensitive and that relatively lower ambient pressures play an important role in the growth of endothelial cells, while higher pressures injure endothelial cells, resulting in the initiation of atherosclerosis. This cell line may prove useful in the investigation of both the physiological and pathological roles of blood pressure on endothelial cell function.

Aorta↗
PubMed1994

Phase advances of circadian rhythms in somatostatin depleted rats: effects of cysteamine on rhythms of locomotor activity and electrical discharge of the suprachiasmatic nucleus.

Somatostatin is synthesized in the suprachiasmatic nucleus (SCN), a circadian pacemaker in mammals. To explore the functional significance of somatostatin in the circadian system, we examined rhythms of rat locomotor activity and electrical firing rate of SCN neurons in the brain slice after temporal depletion of somatostatin levels in the SCN. Intraperitoneal administration of cysteamine (200 mg/kg), a somatostatin depletor, significantly reduced somatostatin level in the in vivo SCN 5 min after injection and kept low level as long as 3 to 4 days. This administration, on the other hand, induced significant phase advances of about 51 min in the subsequent free-running rhythm of locomotor activity of the rat. A marked phase advance in the circadian rhythm of firing rate in the SCN was also observed after administration of cysteamine in coronal hypothalamic slices. These persistent phase shifts after administration of a somatostatin depletor may suggest that the change of somatostatin level in the SCN have a feedback influence on the circadian pacemaker.

Animals↗
PubMed1994

Genetic heterogeneity of dominantly inherited olivopontocerebellar atrophy (OPCA) in the Japanese: linkage study of two pedigrees and evidence for the disease locus on chromosome 12q (SCA2).

We did a linkage study of 2 multigenerational pedigrees with dominant olivopontocerebellar atrophy (OPCA) other than SCA1, with chromosome 12q microsatellites. Multipoint linkage analysis led to the conclusion that the disease locus locates within the 6.2 cM interval between IGF1 and D12S84/D12S105. This result coincides with that of Cuban ataxia pedigrees designated as SCA2. Our study provides genetic evidence that dominant OPCA in the Japanese consists of at least two genetically different disorders; SCA1 and SCA2.

Adolescent↗
PubMed1994

The effect of antifungal agents on the in vitro susceptibility of Candida albicans to apo-lactoferrin.

The effect of subminimal inhibitory concentrations (MICs) of nystatin, amphotericin B, clotrimazole, miconazole and 5-fluorocytosine on the in vitro susceptibility of Candida albicans to physiological concentrations of apo-lactoferrin was investigated. Pre-exposure of C. albicans in 1:4 and 1:16 MICs of the antifungals resulted in an increased resistance to apo-lactoferrin-mediated cell death. Preincubation of Candida in tunicamycin (an agent that inhibits the synthesis of yeast cell-wall mannoproteins) and subsequent exposure to apo-lactoferrin enhanced the antifungal activity, whilst addition of ergosterol (a yeast cell-wall component) to the assay suspension had no significant effect. These results taken together indicate that apo-lactoferrin, an important component of saliva, interacts with cell-membrane constituents of C. albicans such as mannoproteins, and may modulate the effect of topical antifungal agents commonly prescribed for oral candidoses.

Amphotericin B↗