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Biomedical subjects

Y Terada

Publications and source records attributed to Y Terada.

At least 325 records · Page 18Linked to original sources
PubMed1990

[Human mandibular movements during swallowing saliva. 2. Duration of swallowing saliva and that of tooth contact].

The sagittal incisal jaw movement during swallowing saliva was measured on 11 subjects (range: 24-30 years old) with "normal occlusion" by using a two-dimensional system applied infrared sensor. The duration of swallowing saliva and that of tooth contact were calculated with the program developed in our laboratory. The results obtained were as follows: 1. The average of the duration of swallowing saliva (T1) was approx. 3.5 sec on 11 subjects. 2. The average of the duration of tooth contact during swallowing saliva (T2) was approx. 2.1 sec on 11 subjects. Type Ia had the longest T2 (approx. 2.5 sec) among the types of tooth contact. 3. Type Ia had a greater ratio T2/T1 (74.4%) than those of the other types. In conclusion, it was clearly shown that the subject of type Ia had a longer duration of tooth contact during swallowing saliva than those of the other types in the absolute and relative values.

Adult↗
PubMed1990

[Adherence of porcelain and metal after firing in H2. 1. Dental porcelain and nickel-chromium alloy].

The materials for porcelain fusing used in this study were nickel-chromium alloy and ceramco opaque porcelain. The opaque porcelain was fused on the metal surface firing in routine method and in H2. And, the shearing test, X-ray diffraction and quantative analysis of O2 were done. The strengths of the specimens firing in H2 were larger than those of ones firing in routine method. We found that SnO2 of porcelain changed into Sn after firing in H2.

Adhesiveness↗
PubMed1990

[A case of CABG in a patient with chronic idiopathic thrombocytopenic purpura].

This is a report of the management of a patient with chronic idiopathic thrombocytopenic purpura (ITP) and ischemic heart disease. High-dose transvenous gamma-globulin therapy (400 mg/kg/day for five days) was started five days prior to operation, yielding an increase in platelet count from 5.8 X 10(4)/mm3 to 12.8 X 10(4)/mm3. Platelet transfusion was used at the end of cardiopulmonary bypass and on the first postoperative day. There were no problems with hemostasis during the operative procedure and the postoperative course was uneventful. We prefer high-dose transvenous gamma-globulin therapy for ITP prior to open heart surgery as a treatment of choice.

Aged↗
PubMed1990

[Coronary artery bypass grafting with combined arterial grafts].

Coronary artery bypass grafting with combined arterial graft using the left internal mammary artery (IMA), right IMA, and the right gastroepiploic artery (GEA) was performed in 45 patients with saphenous vein graft (SVG) (29 patients) or without SVG (16 patients) from February 1989 to October 1989. The left IMA was used in all patients, the right IMA was used in 9 patients, and the GEA was used in 43 patients. Perioperative myocardial infarction was noted in two patients who had hospital deaths. Reopening the chest for postoperative bleeding was performed in two patients, and the cerebral accident was noted in one patient. Fourteen patients were operated on without the requirement for blood transfusion. Studied within 3 postoperative months, all arterial grafts were patent though the patency was 97.7% (43/44) in SVG. It is concluded that the combined arterial graft utilizing the IMAs and GEA can be used safely and effectively.

Adult↗
PubMed1990

Association between mechanical stress and bone remodeling.

Stress patterns and levels were analyzed by use of the three-dimensional finite element method. Three-dimensional models were constructed for the human upper central incisor (1205 nodes and 920 elements) and the sheep metacarpus (240 nodes and 128 elements). Orthodontic and orthopedic forces were applied to the tooth and the bone, simulating orthodontic tooth movement and experimental loading test for the bone. Three principal stresses were determined in the alveolar bone and the sheep long bone. The following results were obtained. 1. Stress distributions in the lateral alveolar bone were similar to those with bone deformation from cantilever bending mode. On the medial surface of the alveolar bone, a bending stress was observed, however, remaining stresses exhibited changes corresponding to those in the PDL produced by tipping displacement of the tooth. 2. In the sheep long bone, tensile and compressive stresses were induced on the dorsal and volar sides, respectively. The magnitude of stresses was greatest at the mid-diaphyseal region. Compressive and tensile stresses were related with bone resorption and apposition. The magnitude of principal stresses was almost proportional to dimensional changes of the bone at the mid-diaphyseal region. Bone remodeling in the long bone is related with mechanical stress, principal stress in particular, indicating that remodeling of the alveolar bone may be induced by application of orthodontic force in addition to conventional change of the bone adjacent to the PDL. Thus, it is shown that mechanical stress in living structures may be a trigger to induce biological remodeling of bones.

Alveolar Process↗
PubMed1990

[Cerebrospinal fluid transfer of cefbuperazone in the blood-brain barrier lesions of neurosurgical patients].

Cefbuperazone (CBPZ) was given in 15 patients after surgery. There was no infections except for 1 case in which signs of infections were suspected. As side effects, slight elevations in hepatic transaminase levels were observed in 3 patients during the CBPZ chemotherapy. CBPZ concentrations in 7 patients were studied. The subjects were divided into 3 groups according to CT finding during the chemotherapy to correlate CBPZ concentrations to degrees of blood-brain barrier lesions; Group I: no enhancement, Group II: mild or focal enhancement, Group III: diffuse and marked enhancement. It was interesting to note that the more marked enhancement were obtained, the higher levels of CSF concentration of CBPZ.

Adolescent↗
PubMed1990

[Long-term results of coronary artery bypass grafting: comparison of angiographic evaluation of internal thoracic artery and saphenous vein grafts].

The long term (10 to 15 years) results of coronary artery bypass grafting (CABG) were studied in 20 patients. The duration of follow-up was ranged from 130 to 170 months with mean 146.4 months. Ten out of 20 patients underwent coronary angiography (CAG), which disclosed that the late patency of saphenous vein (SV) grafts was 68.8% (11/16), but 54.5% (6/11) of patent SV grafts showed atherosclerotic changes such as irregularity and localized narrowing. On the other hand, internal thoracic artery (ITA) grafts were all patent without any atherosclerotic luminal changes. We recognized that ITA grafts were superior to SV grafts from an angiographic standpoint of view in the long term in Japan.

Adult↗
PubMed1990

[Valve replacement in infective endocarditis with mycotic aneurysm].

We successfully performed craniotomy and mitral valve replacement on a patient with bacterial endocarditis and ruptured intracranial aneurysm. A 15-year-old woman with fever and heart murmur was admitted to another hospital. Infective endocarditis and mitral valve regurgitation was diagnosed and treated with antibiotics. About one month after admission the patient suddenly showed severe headache and hemiparesis. Brain CT demonstrated intracerebral and subarachnoidal hemorrhage. The patient was unconscious when transferred to Mitsui Memorial Hospital where cerebral angiography showed anterior cerebral aneurysm and echocardiography showed mitral valve vegetation. We judged the necessary mitral valve replacement could be delayed until the aneurysm had been stabilized. We therefore began treatment using a different antibiotic but, in spite of this, 10 days later the aneurysm had enlarged dramatically. As conservative treatment was ineffective, a clipping operation was done to prevent re-rupture at the time of mitral valve replacement which could not be delayed much longer. 10 days later, cerebral 4 vessel study was done which showed no abnormality. Mitral valve replacement was then done and the patient was discharged in good health 64 days after the valve replacement.

Adolescent↗
PubMed1990

[A successful repair of post-infarction left ventricular free wall rupture].

Left ventricular free wall rupture secondary to acute myocardial infarction is almost invariably fatal. This report is the case presentation of a successful repair of left ventricular free wall rupture. A 55-year-old man, with a diagnosis of acute infero-lateral myocardial infarction, was transferred from another hospital to our CCU having recurrent chest pain on the fourth day after infarction. Shortly after admission, he lost his consciousness and fell into cardiogenic shock. Echocardiography showed a large pericardial fluid. He was immediately transferred to the operating room with the diagnosis of the heart rupture. After opening the pericardium containing 200 cc of blood, cardiac tamponade was relieved. The posterolateral portion of the left ventricle was found to be bluishly discolored, with a 8 mm-long tear of epicardium. Using cardiopulmonary bypass, the tear was closed with Teflon-reinforced sutures. The post-operative course was uneventful.

Aged↗
PubMed1990

[Valve prostheses of mitral position in children].

Twenty children less than 15 years old of age who had undergone mitral (left-sided atrioventricular) valve replacement before August 1983 have been followed up until October 1988. Fourteen biological valves (B-group) and seventeen mechanical valves (M-group) were used in them. Preoperative conditions had been similar between B- and M-groups. For the B-group, there were one operative death and two late deaths. For the M-group there were no operative death and three late deaths. An actuarial survival rate at ten years was 53.5 +/- 23.3% for the B-group and 85.7 +/- 9.4% for the M-group (not significant). All biological valves were calcified and failed in 27 to 89 months. Three mechanical valves caused thrombosis. There was no other complication for both groups. An event free rate was 0% at eight years for the B-group, however it was 70.6 +/- 11.0% at ten years for the M-group (p less than 0.025). Our data indicates that the mechanical valve is more suitable than the biological valve for children.

Bioprosthesis↗
PubMed1990

[Investigation of primary tissue failure in mitral bioprostheses].

A study was conducted on 118 Hancock (HX) porcine valves, 251 Carpentier-Edwards (CE) porcine valves, and the biological valves in children used in the mitral position. Twenty-three HX valves, twenty-seven CE valves, and all valves except one operative death in children were diagnosed as primary tissue failure (PTF). Freedom from PTF for HX valves was 70.1 +/- 6.0% at ten years and for CE valves was 45.7 +/- 17.0% at ten years, although for children it was calculated 0% at eight years (significantly poor results compared with adults). No relation was found between the degree of calcified cusps and the duration of PTF valves used. The ruptures and calcifications of the cusps were most commonly observed in commissure. The peeled off commissures were characteristic in CE valves. Three adults and two children died without reoperation caused by calcified stenotic valves. Since the risk of reoperation was higher in NYHA functional class four, we recommend earlier elective reoperation.

Adult↗
PubMed1990

[A case of bioprosthetic mitral valvular dysfunction due to pannus-formation].

A case of bioprosthetic mitral valvular dysfunction accompanied by mitral stenosis due to pannus is reported. A 69-year-old woman, whose mitral valve had been replaced with a Hancock bioprosthetic valve in June 1979, underwent the second mitral valve replacement in September 1988 because of valvular dysfunction. The ring and cusps of this Hancock valve was partially covered with hard and milky white pannus which resulted in mitral stenosis. The tear of cusp was observed at the point of contact with pannus, which resulted in mitral regurgitation. Histologically, pannus was consisted of two-layered structure, fibrin and collagen fiber, which demonstrated this over-growth was based on thrombus. Main causes of bioprosthetic valve dysfunction are calcification and tear of cusps. But, valvular dysfunction due to pannus-formation described in this case has been experienced very rarely.

Aged↗
PubMed1989

Defect of calmodulin-binding protein in expression of interleukin-1 beta gene by LPS-nonresponder C3H/HeJ mouse macrophages.

Peritoneal macrophages of Lipopolysaccharide (LPS)-refractory C3H/HeJ mouse failed to express the mRNA coding interleukin 1 (IL-1) beta when stimulated by the Ca2+ ionophore A23187 or LPS, though macrophages of LPS-responsive C3H/He responded to these stimulants. These results suggest that the defect of the response in C3H/HeJ macrophages toward LPS stimulation may be related to the Ca2+-dependent signal pathway. The extracts from the C3H/HeJ macrophages showed normal activities of both protein kinase C (PKC) and calmodulin (CaM) in comparison with those from LPS-responsive C3H/He macrophages. However, one species of CaM-binding proteins could hardly be detected by the cross-linking assay with 125I-CaM in C3H/HeJ macrophages stimulated by LPS. These results suggest that the LPS-refractory site in C3H/HeJ macrophages is related to the lack of this CaM-binding protein, and the Ca2+-dependent CaM system may play an important role in the activation of cells by LPS.

Animals↗
PubMed1989

Leukotriene D4 inhibits atrial natriuretic factor-dependent cGMP production in rat glomerulus.

The effects of leukotriene D4 (LTD4) on guanosine 3',5'-cyclic monophosphate (cGMP) production induced by atrial natriuretic factor (ANF) or sodium nitroprusside (SNP) were investigated in isolated rat glomeruli. First, the isolated glomeruli were preincubated in Krebs-Ringer buffer containing 3-isobutyl-1-methylxanthine for 10 min, then incubated with varying concentrations of ANF, SNP, and LTD4 for 3 min. cGMP content was determined by radioimmunoassay. cGMP production (fmol.glomerulus-1.3 min-1) was not increased by LTD4. cGMP accumulation was increased by ANF (1 microM) and SNP (100 microM) remarkably from 0.19 +/- 0.09 to 3.24 +/- 0.21 (n = 7, mean +/- SE), and from 0.19 +/- 0.09 to 3.67 +/- 0.47 (n = 4), respectively. The increase in cGMP production by ANF was significantly and dose-dependently inhibited by LTD4 (P less than 0.05). Maximum suppression was observed at the concentration of 100 nM (from 3.06 +/- 0.33 to 1.43 +/- 0.09; P less than 0.05). However, LTD4 caused no significant change in the level of cGMP production induced by SNP. Second, particulate or soluble guanylate cyclase from glomeruli were similarly investigated. ANF selectively activated particulate guanylate cyclase and the response was selectively inhibited by LTD4 from 9.07 +/- 1.79 fmol.micrograms-1.3 min-1 (n = 6) to 4.70 +/- 0.70 (n = 6, P less than 0.05). These results suggest the site where LTD4 has effect on cGMP production induced by ANF was the particulate guanylate cyclase system, but not the soluble guanylate cyclase system.

1-Methyl-3-isobutylxanthine↗
PubMed1989

Na+-K+-ATPase activities in renal tubule segments of rat inner medulla.

Recent studies have revealed that both the thin segment of the long loop of Henle and the inner medullary collecting duct (IMCD) are morphologically and functionally nonuniform along their lengths. In the present study, we have carried out measurements of Na+-K+-ATPase activity in thin limb and IMCD segments microdissected from different positions along the axis of the rat inner medulla. Among collecting duct segments, in control rats, Na+-K+-ATPase activity was highest in the initial quarter of the IMCD. The Na+-K+-ATPase activity was lower and relatively uniform along the remaining three quarters of the IMCD. Na+-K+-ATPase activities in cortical and outer medullary collecting duct segments were similar to previously reported values. The Na+-K+-ATPase activity in the initial quarter of the IMCD was increased following in vivo deoxycorticosterone administration (by 140%) and following dietary NaCl restriction (by 100%). These procedures increased Na+-K+-ATPase activity by smaller degrees or not at all in the remaining three-quarters of the IMCD. Thin descending limbs and thin ascending limbs from all regions of the inner medulla had low but readily measurable values. Based on these results, we conclude that all inner medullary renal tubule segments have measurable Na+-K+-ATPase activities that could potentially drive solute active transport.

Animals↗
PubMed1989

Aldose reductase activities in microdissected rat renal tubule segments.

Osmoregulation in inner medullary cells depends in part on cellular accumulation of sorbitol, the production of which from glucose is catalyzed by aldose reductase. To identify nephron segments that contain aldose reductase, we developed a fluorometric ultramicroassay to measure aldose reductase activity in microdissected nephron segments from collagenase-treated kidneys of Sprague-Dawley rats. DL-Glyceraldehyde (10 mM) was used as a substrate. Substantial aldose reductase activities were found in all three inner medullary renal tubule segments: thin descending limbs, thin ascending limbs, and inner medullary collecting ducts. Activity increased with depth into the inner medulla in all three segments. When aldose reductase activities were normalized by cell volume the activities in the three inner medullary segments were similar. Little or no aldose reductase activity was measured in glomeruli or any cortical or outer medullary nephron segment. Both proximal convoluted and proximal straight tubules were found to have a substantial capacity to reduce DL-glyceraldehyde, but the finding of greater reductase activity with D-glucuronate (10 mM) than with D-xylose (10 mM) indicated that the activity was due to aldehyde reductase. Sorbitol dehydrogenase (measured by a similar ultramicroassay method) was present in substantial amounts in proximal tubules, but not in inner medullary collecting ducts. The overall pattern of enzyme activities is consistent with the proposed osmoregulatory role for sorbitol in all three inner medullary renal tubule segments.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldehyde Reductase↗
PubMed1989

Continuous-flow quantitation of Na+ and K+ in nanoliter samples using chromogenic macrocyclic ionophores.

Continuous-flow colorimetric methods for measurement of sodium and potassium contents in 1- to 30-nl aqueous samples are described. The methods employ macrocyclic ionophores (cryptahemispherands) that selectively bind sodium or potassium, altering the absorbance spectra of covalently attached chromophores. The potassium method is linear in the range 0-350 pmol and exhibits a high degree of precision (coefficient of variation of approximately 2% in the 150- to 350-pmol range). It can detect as little as 8 pmol of K+. The sodium method is linear in the range 0-2,700 pmol and also exhibits a high degree of precision (coefficient of variation of approximately 3% in the 1,700- to 2,700-pmol range). It can detect as little as 57 pmol of Na+. The instrumentation and reagents are available from commercial sources. These methods are proposed for measurement of K+ and Na+ fluxes in isolated perfused tubules.

Colorimetry↗