Biomedical subjects

T Yamaga

Publications and source records attributed to T Yamaga.

At least 19 recordsLinked to original sources

PubMed2003

Breath malodor in an asthmatic patient caused by side-effects of medication: a case report and review of the literature.

OBJECTIVE: The purpose of this report is to document the presence of dimethyl sulfide in mouth air as the predominant volatile sulfur compound (VSC) in an asthmatic patient who was regularly taking suplatast tosilate. STUDY DESIGN: The patient was a 33-year-old woman who complained of bad breath. She had been diagnosed as having asthma and was receiving periodical medical examinations once a month. VSC in her mouth air were measured with a gas chromatograph. Oral physiotherapy was also carried out to remove any oral malodor of which the source was intraoral. RESULTS: With the improvement in oral hygiene and periodontal conditions, the level of VSC was reduced but dimethyl sulfide still remained as the predominant VSC. CONCLUSIONS: Dimethyl sulfide metabolized from suplatast tosilate may be a potential cause of halitosis.

Adult↗

PubMed2002

Classification and examination of halitosis.

In this paper, the classification of halitosis and the examination procedures used in diagnosing halitosis are outlined. Halitosis is classified into categories of genuine halitosis, pseudo-halitosis and halitophobia. Genuine halitosis is subclassified into physiologic halitosis and pathologic halitosis. Pathologic halitosis itself is subdivided into oral and extraoral halitosis. Patients diagnosed with pseudo-halitosis and halitophobia usually complain about having oral malodour that does not really exist. Pseudohalitosis can be treated by dental practitioners, but halitophobic patients must be referred to psychological specialists. Oral malodour can be measured using an organoleptic measurement or a gas chromatography analysis. The organoleptic measurement is the most practical procedure with which one can evaluate oral malodour. Gas chromatography (GC) analysis using a flame photometric detector has been shown to be the gold standard for measuring oral malodour, owing its reputation to its objectivity and reproducibility. Moreover, GC is specific for volatile sulphur compounds (VSC), which are the main causes of oral malodour. It has been demonstrated that there is a high correlation between the intensity of oral malodour and the VSC concentration as measured by GC.

Chromatography, Gas↗

PubMed2002

Acoustic characteristics of sounds from temporomandibular joints with and without effusion: an MRI study.

Joint effusion has been associated with temporomandibular joint (TMJ) pain but can only be diagnosed by magnetic resonance imaging (MRI). For screening of patients with suspected effusion a simple and less expensive method would be desirable. We recorded joint sounds during jaw opening and closing movement from 34 TMJs with internal derangement (ID). Seventeen joints had joint effusion seen on MRI. Spectrograms of the sounds were displayed as waterfall plots showing profiles of the consecutive Hamming windows. If the profiles were similar, as judged by initial evaluation, the displayed pattern was classified as stable. If some profiles were distinctly deviating in their pattern, this was classified as unstable. Joints with effusion showed unstable sound pattern more often than joints without effusion (P < 0.001). It was concluded that TMJ sound analyses have a potential to identify joints with effusion based on their unstable sound pattern.

Adult↗

PubMed2002

[Long time use of percutaneous cardiopulmonary support after cardiovascular operation; clinical problems from our experience].

Result and problems were studied in 12 patients who received percutaneous cardiopulmonary support (PCPS) after cardiac or aortic surgery. Causative diseases included acute myocardial infarction in 7 cases, rupture of the left ventricular septum after infarction, acute mitral valve regurgitation after infarction, rupture of the left ventricular free wall, a stuck valve, and an aortic aneurysm in the thoracicoabdominal region in each 1 case. The time of postoperative PCPS ranged from 2 to 361 hours, and the mean supply flow volume was 1.78 +/- 0.45 l/min/m2. Seven patients could be taken off the treatment or discharged from the hospital (58.3%). The comparison between surviving and non-surviving cases showed a significantly longer assisted circulation time in the latter. An increase of bleeding after surgery was found in all 8 patients who received PCPS for a long period postoperatively. This was assumed to be due to the thrombocytic activation by heparin.

Aged↗

PubMed2001

Iridium-catalyzed transfer hydrogenation of alpha,beta-unsaturated and saturated carbonyl compounds with 2-propanol.

The selective transfer hydrogenation of alpha,beta-unsaturated carbonyl compounds to saturated ones was achieved by the use of 2-propanol as a hydrogen donor under the influence of catalytic amounts of [Ir(cod)Cl](2), 1,3-bis(diphenylphosphino)propane (dppp), and Cs(2)CO(3). Thus, a variety of conjugated enones were allowed to react with 2-propanol in the presence of the [Ir(cod)Cl](2)/dppp/Cs(2)CO(3) system to give the corresponding saturated carbonyl compounds in good to excellent yields without formation of allylic alcohols. Both dppp and Cs(2)CO(3) were essential components to achieve the reduction satisfactorily. Additionally, the reduction of carbonyl compounds to alcohols was also promoted by the same catalytic system. When the reaction of a 1:1 mixture of a conjugated ketone and a saturated ketone with 2-propanol was carried out in the presence of [Ir(cod)Cl](2) combined with dppp and Cs(2)CO(3), the reduction of the alpha,beta-unsaturated ketone was found to take place in preference to that of the saturated ketone.

2-Propanol↗

PubMed2001

Quadricuspid aortic valve associated with aortic stenosis and regurgitation.

A 75-year-old man with moderate aortic stenosis and regurgitation admitted due to heart failure underwent uneventful aortic valve replacement with a Carpentier-Edwards pericardial bioprosthesis valve. A quadricuspid aortic valve discovered incidentally during surgery consisted of 4 of different sizes and a supernumerary cusp between the right and noncoronary cusps. No coronary abnormality was involved. Resected cusps showed fibrotic thickening with calcification and no sign of previous inflammatory disease. Although quadricuspid aortic valve is a very rare anomaly, its potential for severe valve failure in adulthood should not be neglected.

Aged↗

PubMed2001

Simultaneous minimally invasive direct coronary artery bypass and repair of a penetrating atherosclerotic ulcer of the descending thoracic aorta: report of a case.

A 70-year-old man with a descending aortic aneurysm was admitted to the hospital because of an abnormal chest X-ray. The chest computed tomography and magnetic resonance angiography findings showed a saccular aneurysm at the descending thoracic aorta. A preoperative coronary arteriogram showed 75% stenosis of the left anterior descending coronary artery and 99% stenosis of the right coronary artery. A simultaneous minimally invasive direct coronary artery bypass (MI

Aged↗

PubMed1999

Pulmonary artery aneurysm.

Main pulmonary artery aneurysm is an exceedingly rare entity. We present a case of main pulmonary artery aneurysm with patent ductus arteriosus in a sixty-year-old woman. The aneurysm was successfully treated with aneurysmectomy and primary anastomosis of the defect of the main pulmonary artery, and the patent ductus arteriosus was divided. The etiology, operative indication and surgical intervention of main pulmonary artery aneurysm are discussed along with a review of the literature.

Anastomosis, Surgical↗

PubMed1998

Visualization of F-actin filaments by a fluorescently labeled nucleotide analogue.

The tightly-bound nucleotide of F-actin was replaced with 1,N6-etheno-adenosine ATP (ADP). An epi-fluorescence optical microscope was modified to visualize efficiently the fluorescent analogue with an excitation-maximum wavelength of 310 nm. This microscope permitted us to visualize single F-actin filaments in solution using the fluorescence of the strongly bound 1,N6-ethenoadenosine nucleotide. Exchange of the tightly-bound nucleotide of F-actin with a free nucleotide in solution at a high temperature was quantitatively estimated by this method, and the results showed good agreement with results from phosphate release measurements.

Actins↗

PubMed1998

Fine profile of actomyosin motility fluctuation revealed by using 40-nm probe beads.

The displacement of colloidal gold beads only 40 nm in diameter can be detected with spatial and temporal resolutions of 2.8 nm and 0.5 msec by using an optical setup in which two laser beams are reflected on the same field of a prism surface, forming interference fringes in an evanescent field adjacent to the prism surface, and the changes in scattering intensity that occur when the beads move across the fringes are measured in optical microscopic images. Results obtained when using this setup and actin-bound gold beads to measure the movement of actin filaments on myosin motor molecules revealed the fine profile of movement fluctuation and that the duty time of a single stroke of myosin motors is less than 10-20 milliseconds.

Actomyosin↗

PubMed1998

Direct observation of a central bare zone in a native thick filament isolated from the anterior byssus retractor muscle of Mytilus edulis using fluorescent ATP analogue.

To investigate the existence of a central bare zone in native thick filaments isolated from the anterior byssus retractor muscle (ABRM) of blue mussels (Mytilus edulis), the filaments were observed by fluorescence and dark-field microscopy after being incubated in the presence of Ca2+ with the fluorescent ATP analogue, Cy3-EDA-ATP. Filaments appeared under dark-field illumination as thin rods with tapered ends of length 5-30 microm. Fluorescence microscopy revealed that Cy3-EDA-ATP was bound to these filaments, except near their center. Although the boundary between this central non-fluorescent zone and fluorescent regions was not clearly defined, there was a trend for the width of the central non-fluorescent zone to increase with thick filament length (correlation coefficient = 0.45; n = 142). When Cy3-EDA-nucleotides bound to thick filaments were displaced by excess ATP, fluorescent images disappeared with a rate constant of 0. 024 s-1, close to the turnover rate of Cy3-EDA-ATP by myosin on the native thick filaments. These results indicate that each native thick filament isolated from the ABRM has a central bare zone, but its boundary was not sharply resolved.

Adenosine Triphosphate↗

PubMed1998

Unidirectional movement of fluorescent microtubules on rows of dynein arms of disintegrated axonemes.

Tetramethylrhodamine-labelled microtubules were observed to move on rows of dynein arms of sea urchin sperm axonemes exposed by elastase-induced sliding disintegration. The microtubules moved towards the flagellar tip at a velocity of 3.1+/-2.1 microm second-1 (mean +/- s.d., n=53) in the presence of 0.1 mM ATP at 22 degrees C, but none moved towards the sperm head. We also examined the polarity of microtubule binding to axonemal doublet microtubules in the absence of ATP by using microtubules brightly labelled at their minus-ends. In 140 of 210 microtubules studied, they bound to axonemal microtubules with a parallel polarity. These results suggest that tightly packed dynein arms on the outer doublet microtubules of sperm axoneme preferentially bind microtubules to themselves with the same polarity as that of the axoneme and that they generate a force to move only these microtubules in the direction away from the sperm head.

Animals↗

PubMed1997

Clinical observations of noncoping overdenture abutments protected by tannin-fluoride preparation.

STATEMENT OF PROBLEM: The exposed dentin of overdenture abutments can lead to caries. Therefore chemical protection is needed to prevent caries. Considering that dentin contains both organic and inorganic components, reinforcement of both components should give reasonable results. Tannin-fluoride preparation strengthens both the organic and inorganic components of teeth. PURPOSE: This study examined whether the tannin-fluoride preparation protects noncoping abutments. MATERIAL AND METHODS: Thirty-one subjects aged 36 to 86 years participated in the clinical trial. A trial autopolymerizing resin containing the preparation or a conventional autopolymerizing resin was applied to the inner surface of the denture base, which was in contact with the abutments. When there were autopolymerizing resin group abutments, there was also at least one preparation group abutment under the overdenture. RESULTS: The incidence of caries in the preparation and autopolymerizing resin groups were 0% and 0%, respectively, for the first 2 years, 4.5% and 0%, respectively, during the 3- to 4-year period, 13.8% and 75%, respectively, during the 5- to 8-year period, and 10% and 15%, respectively, in total. Gingival crevicular fluid demonstrated a tendency to decrease in both groups over time. CONCLUSION: The trial autopolymerizing resin containing the preparation has a long-term caries prevention effect, and helps to maintain gingival health. Without adding clinical steps, abutments can be protected by the tannin-fluoride preparation.

Adult↗

PubMed1995

Hardness and fracture toughness of four commercial visible light-cured composite resin veneering materials.

Four commercial visible light (VL)-cured composite resin veneering materials with a dentine shade were examined for their Knoop hardness and fracture toughness. Composite specimens were classified into three groups. The first group was cured by VL only, the second group was cured by VL and post-cured by VL and the third group was cured by VL and post-cured by heat. It became evident that one composite containing four-functional urethane monomer had both hardness and fracture toughness greater than those of the other three composites containing two-functional urethane monomer. The filler content (vol%) in the composite tended to be linearly proportional to both hardness and fracture toughness. Post-curing by VL and heat were proven to effectively increase both hardness and fracture toughness of once light-cured composites. These results suggest that the clinical performance (e.g. wear resistance and colour stability) of VL-cured composite resin veneering materials might be improved with the aid of post-curing.

Composite Resins↗

PubMed1994

[A case of pulmonary malignant lymphoma associated with localized amyloid plaque].

A 51-year-old woman admitted to our hospital. Chest X-ray film showed infiltrations in left S4 region, which had been pointed out since two years before. On exploratory thoracotomy, lingual segmentectomy was performed because no metastatic lesions were found in the mediastinal and hilar lymph nodes. Pathological and immunohistological examinations revealed findings corresponding to pulmonary malignant lymphoma (diffuse, small cell type, B cell) with amyloid plaque. The patient is doing well 20 months after operation without any signs of recurrence. The clinical and histological findings of this case may suggest a close relationship between malignant lymphoma and production of amyloid.

Amyloidosis↗

PubMed1994

Clasping system with rotational path of insertion Part 3. Clinical application.

This study investigated the retentive forces of rotational path clasping systems. Twelve rotational path removable partial dentures were applied in the clinical field and the retentive forces of the dentures were measured. The following results were obtained; 1. Retentive forces of the 12 dentures were varied from 187g to 1,380g. 2. As distances between abutment teeth increased from 10.9 mm to 27.7 mm, the retentive forces decreased accordingly (r = -0.56; p < 0.05). 3. As the inclination of the proximal surfaces was increased from 0 degrees to 50 degrees, the retentive forces showed a tendency to increase (r = +0.47). 4. Longer distances between abutment teeth as well as smaller inclination of proximal surface were present in three patients who answered that their dentures showed movement while eating. From these results, it became clear that the distance between abutment teeth and the inclination of the proximal surfaces greatly influenced the retention of the rotational path clasping system in the clinical field.

Dental Abutments↗

PubMed1994

Root surface caries of denture wearers in middle-aged and elderly people.

With an increasing number of elderly people retaining natural dentition, the number of exposed root surfaces and root surface caries is increasing. A total of 100 people, aged from 38 to 86, were examined for exposed root surfaces and root surface caries. Denture wearers and non-denture wearers were examined. The following results were obtained; 1. The percentages of exposed root surfaces were significantly higher (P < 0.05) in the 60's and 70's age groups. Root surface caries showed a tendency to increase until people were in their 60's. 2. Denture wearers had more exposed root surfaces (P < 0.05) and were more likely to have root surface caries than non-denture wearers. Denture wearers showed a tendency to have more severe grades of root surface caries than non-denture wearers. 3. Concerning denture wearers, there were not significant differences in the percentages of exposed root surfaces of buccal and proximal surfaces facing edentulous space. However, proximal surfaces facing edentulous space were more prone to root surface caries than buccal surfaces (P < 0.05).

Adult↗

PubMed1994

[A case of intrathoracic goiter composed of two tumors].

A 70-year-old female was referred to our hospital because of swelling at her frontal neck and an abnormal shadow on a chest X-ray film. CT scan and MRI showed a 11.0 x 7.5 cm well-demarcated tumor in the upper mediastinum. Thyroidal scintigraphy revealed an slight accumulation, leading to a diagnosis of intrathoracic goiter. During operation the mass was found to be composed of two tumors. The upper tumor was attached with fibrous adhesion to the right lobe of cervical thyroid but no connection. Histological examination showed follicular but not malignant adenoma of the thyroid.

Adenoma↗