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Biomedical subjects

T Yagi

Publications and source records attributed to T Yagi.

At least 253 records · Page 14Linked to original sources
PubMed1998

Improved cardiac function after catheter ablation in a patient with type B Wolff-Parkinson-White syndrome with an old myocardial infarction.

A 67-year-old man was admitted to hospital for the treatment of exertional dyspnea. He suffered from congestive heart failure due to an old inferior myocardial infarction with type B Wolff-Parkinson-White syndrome. Asynchronous wall motion caused by pre-excitation through a right-side bypass tract caused his cardiac function to deteriorate. Catheter ablation of the bypass tract increased the ejection fraction, and improved his symptoms, prior to surgical revascularization.

Aged↗
PubMed1998

Optimization for beta-mannanase production of a psychrophilic bacterium, Flavobacterium sp.

We found that a psychrophilic bacterium, Flavobacterium sp., characterized in this study, has a beta-mannanase (EC 3.2.1.78) activity in the culture medium. The mannanase activity was the highest in the culture medium, containing 1.0% (w/v) guar gum (as a carbon source), 0.3% (NH4)2SO4 (as a nitrogen source), and 0.06% (w/v) yeast extract, of five-days cultivation at 4 degrees C. No mannanase activity was found in the medium containing a monosaccharide or a disaccharide as a carbon source, although the psychrophile could use them. The enzyme activity was found only when the bacterium was cultured in the medium containing a polysaccharide. The enzyme preparation showed a single activity band on a washed gel of SDS-PAGE. The optimal temperature for the enzyme activity was 35 degrees C. When the reaction was done at 10 degrees C, the enzyme showed 25% of the optimal activity. The beta-mannanase preparation efficiently hydrolyzed guar gum, locust bean gum, and glucomannan as well as beta-mannan.

Bacterial Proteins↗
PubMed1998

Role of dorsal neck proprioceptive inputs to vestibular compensation in humans.

To investigate the role of cervical proprioceptive inputs in the process of vestibular compensation, we performed static posturography in patients with acute and compensated unilateral vestibular dysfunction, by applying vibratory stimulation to the dorsal neck muscles. Neck vibration induced disequilibrium in both groups of patients, but was more pronounced in the compensated patients. These results indicate that manipulation of the neck afferents causes discompensation in subjects whose vestibular dysfunction has already been compensated by multisensory inputs including neck afferents.

Acute Disease↗
PubMed1998

["Direct" indirect training approach to rehabilitation of dysphagia patients--a new method for rehabilitation with a feeding-tube].

The rehabilitation approaches for training patients with dysphagia consist of both direct approaches (eating training) and indirect approaches (basic training for dysphagia patients without food). On the other side, some recent reports revealed that some patients who had had severe dysphagia were improved while the feeding approach was with a naso-gastic tube and an oral-esophago feeding tube. So we thought that stimulation of these feeding tubes for the pharynx and the larynx would produce some useful reactions for dysphagia patients. We developed a new method for the rehabilitation of such patients. The technique is the repeated insertion of the naso-gastric tube at the time of the swallowing motion, which we called the "direct" indirect training approach. Sometimes, other basic training procedures for dysphagia patients are admissible. We treated 26 patients by this method. The patients included those with disorders of the corticobulbar tract (n = 11), a disorder of the medulla (n = 5), a disorder of the peripheral nerve (n = 7), and a long-lasting disused state (n = 3). Twenty-four patients were improved and could eat orally without major problems. Laryngeal elevation curves of this approach in the pre- and post-therapeutic states revealed that the threshold of the swallowing reflux was lower, and the swallowing actions were changed dynamically, and became more useful.

Adult↗
PubMed1998

[A case of thymic carcinoma producing granulocyte colony-stimulating factor].

A 73-year-old man was admitted complaining of chest pain and weight loss. A chest X-ray film and chest CT scan showed a tumorous mass in the anterior mediastinum with moderate pleural effusion. Percutaneous needle biopsy specimens from the mass resulted in a diagnosis of poorly differentiated squamous cell carcinoma of the thymus. Laboratory findings on admission showed marked leukocytosis with no evidence of infection or bone marrow metastasis. The level of serum granulocyte colony-stimulating factor (G-CSF) was abnormally high (79.2 pg/ml, normal < 30). Carcinoma cells in the specimen showed positive staining with anti G-CSF monoclonal antibody, thus indicating that they produced G-CSF. Because multiple metastatic lesions on the chest wall and liver were detected, we performed combination chemotherapy with cisplatin, vindesine and mitomycin C. After 2 courses of chemotherapy, a decrease in tumor size was verified by CT scan. As the tumor size decreased, the patients white blood cell count and serum G-CSF concentration fell to normal levels.

Aged↗
PubMed1998

[Automated cardiac output measurement by color Doppler echocardiography].

Recently, automated cardiac flow measurement (ACM) has been developed for measuring the volume flow rate of blood flow through the left ventricular outflow tract. Measurements of left ventricular cardiac output by the ACM method were compared with those by the thermal dilution method with a Swan-Ganz catheter in 27 patients (16 men and 11 women; aged 44 +/- 3 years) in whom clear two-dimensional and color Doppler images of the left ventricular outflow tract were obtained. The total time required for left ventricular stroke volume calculation by both ACM and pulsed Doppler methods was measured in 10 patients (six men and four women; aged 41 +/- 2 years). There was an excellent correlation in the measurements of cardiac output between the ACM and thermal dilution methods (y = 0.77x + 0.77, r = 0.84, SEE = 0.4 l/min). The total time required for left ventricular stroke volume calculation by the ACM method was significantly shorter than that by the pulsed Doppler method (92 +/- 10 vs 177 +/- 30 sec, p < 0.01). The ACM method is simple, quick, and accurate for the automated assessment of cardiac output.

Adult↗
PubMed1998

[A preventable case who died of miliary tuberculosis after receiving contact examination].

A 30-year-old-man was admitted to our hospital because of headache and fever. His consciousness on admission was clouding. Sputum examination was positive for acid fast bacilli which later identified as Mycobacterium tuberculosis. Chest-X-ray and computed tomogram on admission showed multiple cavitary lesions on bilateral upper lung fields and bilateral diffuse nodular shadow. He was diagnosed as miliary tuberculosis with tuberculous meningitis. His mother admitted because of pulmonary tuberculosis four months ago, and her sputum examination was smear positive for acid fast bacilli, Gaffky 4, and she complained of cough for 6 months before admission. Because of this situation, he rapidly underwent the contact examination with chest X-ray, but not examined by tuberculin skin test because he was 30-year-old. As then chest X-ray was normal, he was not indicated of chemoprophylaxis, and he died of miliary tuberculosis and tuberculous meningitis 4 months after the contact examination.

Adult↗
PubMed1998

[Measurement of coronary flow reserve using adenosine 5'-triphosphate in dogs].

Adenosine 5'-triphospate (ATP) was compared with adenosine and papaverine for the measurement of coronary flow reserve in 12 anesthetized dogs. Intracoronary bolus injection of ATP (1 ml, 1-500 microM) produced a dose dependent increase in the blood flow of the left anterior descending artery, which attained the plateau at the dose of 100 microM. The ratio of peak to resting coronary flow volume (coronary flow reserve) with 100 microM of ATP (3.5 +/- 0.5) was similar to that with 200 microM of adenosine (4.0 +/- 0.7) and 50 mM of papaverine (3.7 +/- 0.8). Hemodynamic variables did not change after administration of each drug, except left ventricular regional wall motion abnormality during papaverine injection. The coronary flow reserve as measured after intracoronary ATP administration (100 microM) decreased as the grade of stenosis of the left anterior descending artery progressed. In addition, the flow reserve was similar to that of adenosine or papaverine administration at each stenosis grade. Intravenous administration of ATP (1,000 micrograms/min) caused a similar increase in coronary blood flow as intracoronary ATP injection (100 microM). However, premedication with 8-phenyltheophylline, an adenosine receptor blocker, significantly suppressed the coronary dilatory effect of intravenous ATP and intracoronary adenosine but not the effect of intracoronary ATP. These results indicate that intracoronary ATP is useful for measuring coronary flow reserve and that its coronary dilatory effect is not mediated by metabolysis to adenosine.

Adenosine↗
PubMed1998

[A case of miliary tuberculosis with multiple cerebral tuberculoma and spinal tuberculosis owing to total delay].

We reported a case of miliary tuberculosis with multiple cerebral tuberculoma and spinal tuberculosis. The case was a 37 year old man. In the last sixteen months to the first visit to a hospital, he has been suffering from low grade fever, cough, and back pain, but he bared his symptoms without any therapy. At a hospital he first visited, he was told that he might have a malignant disease, which prevented him to visit the hospital because of a fear for his disease. Six months later, he was admitted to other hospital because of severe back pain. At last, he was diagnosed as tuberculosis and referred to our hospital. By the examinations on admission he was diagnosed as multiple cerebral tuberculoma and spinal tuberculosis, and anti-tuberculous therapy was started. It is thought that his severe disease status on admission is caused by the total delay, namely the delay in visiting a doctor and the doctor's delay in making diagnosis.

Adult↗
PubMed1998

[A case of cutaneous tuberculosis associated with steroid therapy for mixed connective tissue disease].

Patients receiving immunosuppressive therapy, such as adrenocorticosteroids, are high risk groups of tuberculosis. We report a case of cutaneous tuberculosis associated with steroid therapy for mixed connective tissue disease. A 63-year-old female was hospitalized after 6 months' treatment with prednisolone for connective tissue disease and bilateral abnormal shadows were revealed on her chest X-ray films. As her sputum smear was positive for acid-fast bacilli, the patient was transferred to our hospital for isolation and treatment. After three months' treatment with INH, RFP and EB, she complained the swelling of her left palm, left arm, and right leg, and skin puncture was performed. As smears of fluid aspirated from the swelling showed acid-fast bacilli, and fluid PCR tests showed positive for M. tuberculosis, she was diagnosed as cutaneous tuberculosis (scrofuloderma). In spite of administration of antituberculous agents, the swelling showed little improvement. Therefore, the dose of prednisolone was reduced and cutaneous lesions were resected by surgery. High risk of tuberculosis should be considered when a patient administered immunosuppressive drugs, such as adrenocorticosteroids.

Anti-Inflammatory Agents↗
PubMed1998

[Assessment of coronary flow reserve in patients with hypertrophic cardiomyopathy using transthoracic color Doppler echocardiography].

Abnormal coronary flow pattern and coronary vasodilator reserve have been identified in patients with hypertrophic cardiomyopathy (HCM) using invasive techniques. The characteristics of coronary flow velocity and coronary flow reserve were evaluated by noninvasive-recording of coronary flow velocity in the distal portion of the left anterior descending coronary artery in 7 patients with HCM and 7 normal subjects using transthoracic color Doppler echocardiography. Coronary flow velocity was measured at rest and during intravenous infusion of adenosine triphosphate (0.15 mg/kg/min). Diastolic peak velocity, diastolic mean velocity, the time from the beginning of diastole to peak velocity (TVP) and velocity half time from peak velocity was measured in each group. Coronary flow reserve was obtained as the ratio of hyperemic mean velocity to resting mean velocity. TVP was significantly prolonged in the patients with HCM compared with the normal subjects (159 +/- 38 vs 103 +/- 54 msec, p < 0.05). Velocity half time was significantly shorter in the patients with HCM compared with the normal subjects (304 +/- 138 vs 451 +/- 109 msec, p < 0.05). Although diastolic mean velocity during hyperemia was not different between the 2 groups (62 +/- 8 vs 70 +/- 19 cm/sec), diastolic mean velocity at rest was significantly higher in the patients with HCM than in the normal subjects (39 +/- 6 vs 26 +/- 7 cm/sec, p < 0.01). Therefore, coronary flow reserve was significantly lower in the patients with HCM than in the normal subjects (1.6 +/- 0.4 vs 2.7 +/- 0.4, p < 0.001). There was a good correlation between diastolic mean velocity and the ratio of interventricular septal to posterior left ventricular wall thickness (y = 0.024x + 0.46, r = 0.75). Transthoracic assessment of coronary flow velocity using color Doppler echocardiography reveals that coronary flow reserve is reduced in patients with HCM because of increased baseline resting diastolic mean velocity.

Cardiomyopathy, Hypertrophic↗
PubMed1998

[The relationship between subjective sleepiness and polysomnographic findings in sleep apnea syndrome].

We investigated factors of daytime sleepiness in 22 middle-aged male patients with sleep apnea syndrome (SAS) using the Epworth sleepiness scale (ESS) and polysomnography. The subjects were classified into two groups according to ESS score as follows; low ESS group: ESS score < 10, and high ESS group; ESS score > or = 10. ESS score was significantly correlated with duration in which nocturnal oxygen saturation decreased below 90% (Time of SpO2 < 90%) (r = 0.54, p < 0.05). Time of SpO2 < 90% and percent of movement arousals at the termination of apnea/hypopnea (number of movement arousal/total number of apnea/hypopneas x 100) were significantly higher in high ESS group than in low ESS group. Our findings suggest that the severity of oxygen desaturation and sleep fragmentation caused by arousal response at the termination of apnea/hypopnea may be important factors of daytime sleepiness in patients with SAS.

Aged↗
PubMed1998

Mechanisms of IL-6, IL-8, and GM-CSF release in nasal secretions of allergic patients after nasal challenge.

Cytokines are potentially active biological peptides that are known to play an important role in several immune responses. Several studies have reported the existence of a variety of cytokines in the nasal mucosa of patients with allergic rhinitis. However, there are few reports on cytokines released into the nasal secretion. In the present study, we investigated the sources, and levels of three key proinflammatory cytokines namely, IL-6, IL-8, and GM-CSF in the nasal secretion, as well the mechanisms of their release, by ELISA and immunohistochemistry. Firstly, we examined the levels of IL-6, IL-8, and GM-CSF in the nasal secretion after in vivo nasal challenge with methacholine (MC), histamine (HI) and allergen (Ag) in patients with nasal allergy to house dust mite (HDMAR). Next, we examined the levels of IL-6, IL-8, and GM-CSF released, in vitro, after Ag challenge of nasal scrapings from patients with HDMAR. Finally, we examined the sources of these cytokines in the nasal mucosa, by immunohistochemistry. After MC challenge in patients with HDMAR, the concentration of IL-6, but not IL-8, and GM-CSF, was significantly greater on the challenged side than on the contralateral side. Ag and HI provocation induced significantly greater levels of IL-6 and IL-8 secretion in patients with HDMAR, on the challenged side than on the contralateral side. GM-CSF was only detected in the nasal secretion after Ag challenge. Immunoreactivity for IL-6 and IL-8 was very similar in that it was predominantly localised to the apical portion of epithelial cells, the superficial lamina propria, gland cells, and migrating cells. The immunoreactivity for GM-CSF varied slightly from that of IL-6 and IL-8: strong immunoreactivity was detected in the basal part of epithelial cells, basement membrane, glandular ducts, and migrating cells. These results suggest that the levels, sources, and mechanisms of release of IL-6, IL-8, and GM-CSF in the nasal secretion of patients with HDMAR do vary, but are important in the manifestation of the allergic reaction.

Animals↗
PubMed1997

Efficient virus transmission from dendritic cells to CD4+ T cells in response to antigen depends on close contact through adhesion molecules.

Monocyte-derived cultured dendritic cells (DCs) are potent antigen-presenting cells (APCs) and are susceptible to HIV-1Lai infection. Compared to the low level of virus production by HIV-1-infected DCs alone, a level of virus two to three orders of magnitude higher was produced by cocultivation of HIV-1-infected DCs with autologous resting CD4+ T cells in the presence of a nominal antigen. In this coculture system, direct contact of HIV-1-infected DCs with T cells was crucial for efficient virus transmission and subsequent virus production. Blocking of the LFA-1/ICAM-1 or LFA-3/CD2 interaction between these cells substantially reduced virus production, without influence or IL-2 production by activated T cells. In contrast, cell-cell transmission of HIV between non-APCs and activated T cells was not blocked by an antibody against LFA-3. Since a low level of virus production by HIV-infected DCs was upregulated by cross-linking of CD40, it was suggested that not only focal adhesion, but also mutual activation of HIV-infected DCs and T cells through adhesion molecules, may potentiate virus transmission and production and that such activation signals to HIV may be distinct from signals responsible for IL-2 production in activated T cells.

Antigen Presentation↗
PubMed1997

Unusual ligand structure in Ni-Fe active center and an additional Mg site in hydrogenase revealed by high resolution X-ray structure analysis.

BACKGROUND: The hydrogenase of Desulfovibrio sp. catalyzes the reversible oxidoreduction of molecular hydrogen, in conjunction with a specific electron acceptor, cytochrome c3. The Ni-Fe active center of Desulfovibrio hydrogenase has an unusual ligand structure with non-protein ligands. An atomic model at high resolution is required to make concrete assignment of the ligands which coordinate the Ni-Fe center. These in turn will provide insight into the mechanism of electron transfer, during the reaction catalysed by hydrogenase. RESULTS: The X-ray structure of the hydrogenase from Desulfovibrio vulgaris Miyazaki has been solved at 1.8 A resolution and refined to a crystallographic R factor of 0.229. The overall folding pattern and the spatial arrangement of the metal centers are very similar to those found in Desulfovibrio gigas hydrogenase. This high resolution crystal structure enabled us to assign the non-protein ligands to the Fe atom in the Ni-Fe site and revealed the presence of a Mg center, located approximately 13 A from the Ni-Fe active center. CONCLUSIONS: From the nature of the electron-density map, stereochemical geometry and atomic parameters of the refined structure, the most probable candidates for the four ligands, coordinating the Ni-Fe center, have been proposed to be diatomic S=O, C triple bond O and C triple bond N molecules and one sulfur atom. The assignment was supported by pyrolysis mass spectrometry measurements. These ligands may have a role as an electron sink during the electron transfer reaction between the hydrogenase and its biological counterparts, and they could stabilize the redox state of Fe(II), which may not change during the catalytic cycle and is independent of the redox transition of the Ni. The hydrogen-bonding system between the Ni-Fe and the Mg centers suggests the possible.

Binding Sites↗
PubMed1997

Automated assessment of mitral regurgitant volume and regurgitant fraction by a newly developed digital color Doppler velocity profile integration method.

Recent development of the automated cardiac flow measurement (ACFM) method has provided automated measurement of stroke volume and cardiac output by spatial and temporal integration of digital Doppler velocity profile data. The purpose of this study was to evaluate the clinical usefulness of the ACFM method using digital color Doppler velocity profile integration in the assessment of mitral regurgitant volume and regurgitant fraction from measurements of both aortic outflow and mitral inflow volumes. We calculated both aortic outflow and mitral inflow volumes from the apical approach with the ACFM and pulsed Doppler (PD) methods in 20 patients with isolated mitral regurgitation. Mitral regurgitant volume and regurgitant fraction were calculated by the following equation: mitral regurgitant volume = (mitral inflow volume) - (aortic outflow volume), % regurgitant fraction = (mitral regurgitant volume)/(mitral inflow volume) x 100. Mitral regurgitant volume and regurgitant fraction were compared with that determined by the PD method. Mitral regurgitant volume measurement by the ACFM method showed a good correlation with that measured by the PD method (r = 0.90, y = 0.77x + 11.6, SEE = 9.0 ml); the mean differences between PD and ACFM measurements was -1.7 +/- 12.5 ml. Regurgitant fraction estimated by the ACFM method correlated well with that of the PD method (r = 0.92, y = 0.98x + 2.1, SEE = 8.8%). The mean difference for the measurement of regurgitant fraction between the PD and ACFM methods was 0.8 +/- 6.6%. Total time required for mitral regurgitant volume calculation in 1 cardiac cycle by the ACFM method was significantly shorter than that of the PD method (126 +/- 15 seconds vs 228 +/- 36 seconds, p <0.01). In conclusion, the newly developed ACFM method is simple, quick, and accurate in the automated assessment of mitral regurgitant volume and regurgitant fraction.

Adult↗
PubMed1997

Humoral injury in porcine livers perfused with human whole blood.

BACKGROUND: We investigated the influence of humoral injury during xenoperfusion of porcine livers by human blood. METHODS: The porcine livers were perfused under physiological conditions for 9 hr. The perfusates consisted of porcine whole blood in group 1, human whole blood in group 2, and human whole blood with soluble complement receptor type 1 (300 microg/ml) in group 3. RESULTS: Liver enzyme release and serum hemoglobin in group 2 increased significantly after 3 hr of xenoperfusion, compared with those in group 1 and group 3 (P<0.05). Severe histological damage with minimal cellular infiltration was observed in group 2 after 6 hr of xenoperfusion, but was present only at trace levels in group 1 and group 3. In group 2, von Willebrand factor, a possible target of natural antibodies, was induced on sinusoidal endothelial cells after 3 hr of xenoperfusion, correlating with diffuse deposition of human IgM and membrane attack complex. In group 3, von Willebrand factor, human IgM, and membrane attack complex staining in the intralobular region were present at trace levels. In group 3, the indocyanine green removal capacity, representing hepatocyte function, was significantly higher than in group 2 (P<0.05). CONCLUSIONS: Based on these results, we suggest that humoral injury is a major cause of liver damage during liver xenoperfusion. The pattern of humoral injury in xenoperfused livers may be attributed to anatomical features of the liver and unique responses of sinusoidal endothelial cells to xenoperfusion.

Animals↗