Search PubMed⌕ Search

Biomedical subjects

Y Terada

Publications and source records attributed to Y Terada.

At least 343 records · Page 19Linked to original sources
PubMed1989

[Human mandibular movements during swallowing saliva. 1. Tooth contacts and rest position].

We investigated the swallowing of saliva on 11 adults with a normal tooth alignment and a normal occlusion. The envelope of sagittal incisal point movements of the mandible was analyzed by means of the infrared sensor system. Frankfurt horizontal plane was used as a reference plane. The following conclusions were obtained based on the experimental results. 1. The mean linear distance between retruded tooth contact position (RCP) and intercuspal position (ICP) was 1.35 mm. 2. The mean linear distance between most retruded tooth contact position during swallowing saliva (SRCP) and ICP was 0.13 mm. The ratio of SRCP to RCP was about 10 percent. 3. The rest position of the mandible induced by swallowing saliva (RP) was 1.05 mm apart from ICP. 4. The maximum interocclusal distance during a cycle of swallowing saliva (MOP) was 1.70 mm in the average of 11 subjects. RP and MOP were significantly different from each other in the average of 11 subjects. However, individuals whose RP and MOP were significantly different were 6 subjects of 11.

Adult↗
PubMed1989

[Chromatic studies of porcelain veneered crown. Application of ceramco opaque porcelain].

Chromatic characteristics were compared between the porcelain fused metal substructures using a gold alloy and a nickel-chromium alloy with or without superficially sprayed with gold alloy. From the stand point of the hiding efficiency for the metallic color of the substructure by opaque porcelain fusing, the gold alloy and the sprayed nickel-chromium alloy were superior to the nickel-chromium one as a metal for the porcelain-fused-to-metal crown. The likeness in color of the gold alloy and the sprayed one was also shown. As the conclusion, the application of wire explosion spraying technique which combines the advantages of the gold alloy and the nickel-chromium one appears to be quite useful for providing an excellent substructure for porcelain-fused crowns.

Chromium Alloys↗
PubMed1989

[Interaction of hydroxyapatite with amino acids].

The interaction of Hydroxyapatite (HAP) with organic molecules is biologically important. Some proteins display a high adsorption affinity for HAP and they have been implicated in the mineralization of bone. In order to understand the interaction of HAP with proteins, it is important to know which amino acid side-groups are involved in the protein-HAP interaction and what type of interaction takes place. We investigated the interaction of HAP with amino acids and their derivatives by crystal growth experiment. The rate of crystal growth was measured by adding seed crystals of HAP (synthetic apatite) to a solution of CaCl2 and KH2PO4, pH 7.4 at 37 degrees C. Basic amino acids, acidic amino acids and amino acids with polor side-groups inhibit the rate of crystal growth. These findings suggest that amino acid side-groups, such as carboxyl group, amino group, hydroxyl group and imidazole, are related to the affinity for HAP.

Amino Acids↗
PubMed1989

[Non-destructive stress analysis of porcelain-fused-to-metal crown. 2. X-ray diffraction and radiograph stress measurement of various gold alloys for porcelain fusing].

Porcelain-fused-to-metal crowns though having a better aesthetic appearance, are admittedly inferior in strength, as compared with full cast crowns. We have used the X-ray stress measurement method that is the means of a non-destructive measurement, and this method is used to assess the residual stresses of various metals. X-ray diffraction examinations were made to evaluate the possibility of X-ray stress measurement of precious metals. Precious metal strips were then prepared to determine the change in the stress value during the porcelain firing process. The high compression stress produced by polishing was reduced by degassing. X-ray stress measurement of precious metals were successfully obtained.

Crowns↗
PubMed1989

[Chromatic studies of porcelain veneered crown. Influence of the dentin porcelain on the color of opaque porcelain fused on the metal substructure].

The metals for porcelain fusing used in this study were gold alloys and nickel-chromium alloys. Chromatic characteristics were compared between samples of 0.1, 0.2 and 0.3 mm thickness. The dentin porcelain was fused on the opaque surface. Chromatic analyses were then carried out at each stage of 0.1 mm-incremental reductions of the dentin thickness starting from 0.5 mm. In conclusion, the metallic color was not sufficiently hidden by opaque porcelain 0.1 mm thick for both the gold alloy and nickel-chromium alloy samples. The metallic color was sufficiently hidden by opaque porcelain of 0.2 mm thick for the gold alloy sample but was not sufficiently for the nickel-chromium alloy sample.

Chromium Alloys↗
PubMed1989

[Adsorption of amino acids onto hydroxyapatite].

The interaction of Hydroxyapatite (HAP) with organic molecules is of biological importance, since the former is considered as the prototype mineral found in calcified tissues, such as bone and teeth. Some proteins display a high affinity for HAP and they are involved in the mineralization of bone. Another important aspect in biological systems is the role that various molecules play as inhibitors of crystal growth. We investigated the interaction of HAP with amino acids and their derivatives by comparing HAP adsorption experiment with crystal growth experiment. It was reported aspartic acid or phosphoserine adsorbed onto HAP and that they inhibited the seeded crystal growth. In this work, histidine and imidazole derivatives also displayed the crystal growth inhibitory activity and its adsorption isotherm was described by a Langmuir-type model.

Adsorption↗
PubMed1989

[Radiograph stress measurement of metallic denture base formed by wire explosion energy. 1. Stress changes during various stages of manufacturing metallic denture base].

The radiograph stress measurement method is the only known means of a non-destructive measurement, and this method is used to assess the residual stresses of various metals. This study was made to evaluate the possibility of radiograph stress measurement of the metallic denture base formed by the wire explosion energy. Radiograph stress measurements of stress changes during various stages of manufacturing metallic denture base were successfully obtained.

Dental Stress Analysis↗
PubMed1989

[Nasal allergy and leukotriene. 2. Kinetics of peptide leukotrienes and inflammatory cells in nasal lavage fluid after antigen challenge].

The purpose of this study is to clarify the role of peptide leukotrienes (LTs) on the onset of characteristic hyperreactive nasal symptoms of nasal allergy by observing the time course of the correlation among degrees of nasal symptoms, and by observing the amount of chemical mediators and the number of inflammatory cells in the nasal lavage fluid after nasal antigen challenge in subjects with Japanese cedar pollinosis during off season. Sneezing was terminated within 10 minutes and nasal discharge within 2 hours. However, time course change of the percent increase of nasal airway resistance showed dual response consisting of immediate and late phase responses. The peak of the former was seen at 30 minutes and the latter was at 7 hours after provocation. The significant increase of eosinophils in the nasal lavage fluid was observed during both the immediate and the late phase responses, but during the late phase response, the increase was more prominent. Basophilic cells definitely increased during the late phase response. The amount of LTs in the nasal lavage fluid increased significantly during both the immediate and the late phase responses. In contrast, the level of histamine increased significantly only during the immediate phase response. Considering that LTs, especially LTD4, has potent and persistent effect on causing swelling of nasal mucosa, LTs may play important role in causing nasal obstruction during both the immediate and the late phase responses after antigen challenge. On the other hand, the role of histamine may be confined to cause the hyperreactive nasal symptoms during the immediate phase response.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens↗
PubMed1989

[Long-term results of mechanical valves in aortic position and biological valves in mitral and tricuspid positions].

The long-term results of patients undergoing aortic valve replacement (AVR) with a mechanical valve (AM), mitral valve replacement with a biological valve (MB), and tricuspid valve replacement (TVR) with a biological valve (TB) operated upon from 1977 to 1988 were retrospectively analysed. A total of 899 patients received 1117 valves (381 AM, 633 TB, 103 TB) with a follow-up 3778 patient-years and 4582 valve-years. A significant incidence of thromboembolism, hemorrhage, and endocarditis was not found among AVR, MVR, TVR, or multiple valve replacement. We found a significantly decreased incidence of survival rate in multiple valve replacement compared with AVR or MVR, and a significantly increased incidence of reoperation in MB compared with AM and TB. We use AM and TB in any adult patients as a first choice. However, we prefer a mechanical valve in the mitral position except in patients over 65 years old, who have a short life expectancy, in whom anticoagulation is thought to be difficult, and who desire a biological valve.

Adolescent↗
PubMed1989

[A case of traumatic tricuspid regurgitation].

Tricuspid regurgitation due to nonpenetrating trauma occurred in a 60-year-old male patient who had received chest trauma in a motorcycle accident. He was admitted because of shortness of breath and palpitation on exertion. On admission physical examinations revealed pulsated and dilated jugular veins, hepatomegaly, and systolic murmur. The chest X-ray film showed an enlarged heart and electrocardiograms revealed complete right bundle branch block. Echocardiography demonstrated systolic prolapse of the tricuspid anterior leaflet into the right atrium. Right atrial v wave pressure was 20 mmHg. Tricuspid valve replacement with a Carpentier-Edwards 33 mm using super interpose method was performed successfully 13 years after the trauma. At operation, it was found that the chordae tendineae of the anterior leaflet was ruptured.

Chordae Tendineae↗
PubMed1989

[A thoracic aortic aneurysm with respiratory failure caused by the mechanisms of stenosis of the left bronchus and ipsilateral pulmonary artery--report of a case and review of the literature].

Clinical symptoms of thoracic aortic aneurysm vary widely from symptoms resulting from its rupture to those due to compression of surrounding organs. Furthermore, the onset of symptoms is frequently followed by a fatal outcome unless emergency measures are taken. We have recently experienced a patient who developed respiratory insufficiency caused by an aneurysm of the descending thoracic aorta compressing the left primary bronchus and the right pulmonary artery, the former causing ventilatory failure in the left lung and the latter interfering with blood flow in the right lung. The patient underwent emergency prosthetic graft replacement and showed temporary symptom improvement. However, a postoperative complication of esophageal perforation due to ischemic necrosis occurred and eventually caused acute empyema followed by death. The patient was a 48-year-old male who presented with symptoms similar to bronchial asthma. Angiographic examination (iv-DSA) revealed compression of right pulmonary artery by an aneurysm of the descending thoracic aorta. Bronchoscopic findings included extramural stenosis of the left bronchus accompanied by arterial pulsation. As an emergency measure, artificial blood vessel replacement of the descending thoracic aorta was performed. However, the patient developed postoperative acute empyema and died on the 19th postoperative day. Autopsy revealed ischemic necrosis on the esophageal wall where the aneurysmal lesion had touched before operation. This seems to have formed a perforation into the left thoracic cavity and ultimately to have caused acute empyema. Since we believe that the pathogenesis and clinical course observed in this patient is rather rare, the case is reported in accompanied by relevant data from the literature.

Aorta, Thoracic↗
PubMed1989

[A study on six cases of renal cell carcinoma detected by renal ultrasound during health screening].

From April 1986 to March 1988, 7,800 subjects (3,887 men and 3,913 women, age from 24 to 80 years, with a mean age of 48.7 years) underwent renal ultrasound during a screening by our Health Service. Of these subjects 29 were suspected to have solid masses in the kidneys. Further examination with computerized tomography (CT) was employed. Four angiomyolipomas and 16 malformations of the kidneys were diagnosed clinically at that time. Among 9 subjects who underwent complete urological evaluation including excretory urography (IVP), CT and renal angiography 6 malignant renal tumors were disclosed. Six patients were treated by radical nephrectomy. In this report we studied the 6 patients whose tumors were pathologically diagnosed as renal cell carcinoma (RCC). The six patients were 48 to 60 years old with a mean age of 55.8 years. There were 4 men and 2 women. There are no signs or symptoms referable to RCC. In 1 patients microscopic hematuria was detected via a laboratory study. Erythrocyte sedimentation rate (ESR) was slightly evaluated in 4 patients. In the 6 patients, the renal tumors were diagnosable by CT and all tumors had positive findings for malignant neoplasms angiographically. An IVP, without nephrotomography, did not reveal a small tumor growing in the upper pole of the right kidney of 1 patient. Surgical specimens were 180-475 g in weight. Tumors, were found in the right kidneys (2) and in the left kidneys (4), were well circumscribed. The size of the tumors measured from 3 to 7 cm in the longest axis. Pathological diagnosis was made as renal cell carcinoma 3 with G1, pT2a, 2 with G2, pT2a and 1 with G2, pT2b.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma, Renal Cell↗
PubMed1989

[Long-term results of the 19 mm low-profile bileaflet valve prosthesis in the small aortic anulus].

Between April, 1979, and November, 1986, 20 patients underwent aortic valve replacement (AVR) in the small aortic anulus with either 19 mm St. Jude Medical valve prosthesis or 19 mm Duro-Medics valve prosthesis, which are relatively new, low-profile bileaflet valve prostheses. There were two male and 18 female patients ranging from 35 to 69 years old (mean, 54.7 years). Average body surface area was 1.37 +/- 0.11 m2 (range 1.20 to 1.55 m2). One patient died of arrhythmia at 22 postoperative day. The 19 survivors have been followed up for as long as 61 months (mean, 31.2 months). There were two late complications, cerebral infarctions, and event free ratio was 0.85 at five years. All long-term survivors were in New York Heart Association Functional Class I (15 patients) and Class II (three patients). Preoperative and postoperative echocardiograms demonstrated significant decreases in mean left ventricular end-diastolic diameter (LVDd) (48.9 +/- 8.3 mm vs 42.2 +/- 5.7 mm; p less than 0.01) and in left ventricular end-systolic diameter (LVDs) (32.2 +/- 8.2 mm vs 25.7 +/- 4.9 mm; p less than 0.01). Mean left ventricular wall thickness was decreased to 24.5 +/- 3.7 mm from 25.8 +/- 6.4 mm. The average peak systolic gradient at rest with Doppler ultrasound was 26.0 +/- 9.3 mmHg (range nine to 36 mmHg). Though transprosthetic gradient did occur in patients who received 19 mm low-profile bileaflet valves in narrow aortic roots, progressive prosthetic stenosis was not observed and small aortic prostheses provide acceptable palliation for long-term results clinically.

Adult↗
PubMed1989

[Report of 108 patients with valvular heart disease who underwent re-operations through repeated median sternotomy incision].

108 patients who underwent redo median sternotomy between January 1975 and April 1988 were studied to determine factors affecting risk of cardiac reoperations. (1) Seventeen of 108 patients died, yielding an overall mortality of 15.7%. (2) Preoperative diagnosis had a significant correlation with mortality, which was higher with prosthetic valve endocarditis (50.0%) than with all other indications for reoperation. (3) Operative mortality was related to pre-reoperation functional class: 8.7% for New York Heart Association (NYHA) class II, 9.8% for class III and 27.8% for class IV. (4) Based on the degree of urgency, elective reoperation had a mortality of 5.4%, while emergency procedures carried a mortality of 61.5%. (5) Cardiac catheterization information was available in 53 patients. The pulmonary artery pressure was higher in the died group. There were no significant differences in pulmonary capillary wedge pressure and cardiac index between the survived and died. (6) Operation time, aortic cross clamp time and pump run were significantly longer in the died than in the survived group. The died had more blood loss during operative procedure. To decrease operative mortality, technical improvement and increased experience were necessary for surgeons. We prefer to free entirely pericardial adhesion to facilitate mobilization and evacuate air, and to make intra-cardiac procedure more easier and safety. Furthermore early reoperation before irreversible deterioration occurs was necessary since myocardial function was found to be a major determinant of surgical results.

Adult↗
PubMed1989

[Pulmonary nodule confirmed by rib consolidation on thoracic computed tomography].

Coin lesions in the thoracic cavity, skin, muscle and connective tissue are clearly observed by computed tomography (CT). However, it is very difficult to detect abnormal shadows in the ribs by thoracic CT at the mediastinal level. We describe 3 cases of pulmonary nodules that were not detected by CT at the mediastinal or lung field level, however, but could be detected at the bone level. When pulmonary nodules cannot be detected by thoracic CT at the mediastinal or lung field level, it is recommended to change the window to the bone level.

Adult↗
PubMed1989

[Biological versus mechanical valves in the mitral position].

The long-term late results of isolated mitral valve replacement before April 1981 were retrospectively evaluated in 54 patients receiving a Hancock valve (HX) with a total follow-up of 424 patient-years (py) and 37 patients receiving a Björk-Shiley valve (BS) with a total follow-up of 366 py. There was no significant difference in regard to preoperative age, cardiothoracic ratio, electrocardiogram, or New York Heart Association functional class between the two groups. All of the BS group and 43 of the HX patients received long-term anticoagulant therapy. No significant difference was notable between the two groups in hospital mortality. Actuarial survival rate excluding hospital deaths was 75.5 +/- 6.7% for the HX group, and 80.8 +/- 7.1% for the BS group at ten years (not significant). There was no significant difference between the two groups in overall incidence of thromboembolism (HX 1.4% py, BS 1.9% py), anticoagulant related bleeding (HX 0.5% py, BS 0.8% py), or endocarditis (HX 0.5% py, BS 0.3% py). Actuarial freedom from reoperation at ten years was 69.6 +/- 8.1% for the HX group, and 93.5 +/- 4.4% for the BS group (p less than 0.01). Event free survival excluding hospital deaths at ten years was 49.2 +/- 8.1% for the HX group, 70.6 +/- 8.3% for the BS group (p less than 0.05). We prefer a mechanical prosthesis except in patients over 65 years old, who have a short life expectancy, in whom anticoagulation is thought to be difficult, and who hope a biological valve.

Adult↗