Biomedical subjects

K Shimoyama

Publications and source records attributed to K Shimoyama.

At least 37 records · Page 2Linked to original sources

PubMed1996

[Anterior denture teeth selected for complete dentures].

The purpose of this study was to investigate the influence of sex and age on the selection of color, size, and form of anterior teeth for complete dentures. A sample representing one hundred eighty-five edentulous patients whose complete dentures were made with. Real Crown teeth (Shofu Inc.) was obtained. The results were as follows: 1) Lighter teeth were selected for females than males, but age had no relation to the selected color of the teeth. 2) Larger teeth were selected for males than females, but age had no relation to the selected size of the teeth. 3) The combination and tapering forms were selected frequently, the combination form was used more frequently for females than males and the tapering form was used more frequently for males than females.

Adult↗

PubMed1996

CT of the pulmonary hilum: evaluation with thin-section ultrafast CT.

The recent progress of CT technology, such as spiral and ultrafast CT, has made it possible to obtain contiguous thin-section CT images of the pulmonary hilum during rapid injection of contrast material. These CT images consistently provide clear images of the pulmonary hilum, including normal peribronchovascular interstitium, bronchi, and pulmonary vessels, enabling a more precise and detailed evaluation of various pathological conditions than CT previously allowed. This article illustrates high-quality CT images in normal and abnormal conditions occurring in the pulmonary hilum and discusses the present CT diagnosis of various pulmonary hilar diseases.

Contrast Media↗

PubMed1996

[Ultra-low-dose spiral (helical) CT of the thorax: a filtering technique].

To reduce the radiation dose from spiral (helical) CT, a custom-made aluminium filter was installed in the X-ray tube and a reduction of effective tube current was attempted. A pronounced reduction of effective tube current, namely, 6 and 3 mA, was achieved with 26 and 37 mm thick aluminium filters, respectively. Visualization of normal lung structure was accomplished with both 6 and 3 mA settings. However, images of 3 mA failed to delineate mediastinal structures because of marked beam hardening resulting from the bone structure of the thoracic inlet. Six mA was considered the lowest dose setting of spiral (helical) CT of the thorax that could be used for lung cancer screening.

Adult↗

PubMed1995

[A morphological study of interactions of Candida albicans and Streptococcus mutans].

Denture stomatitis is caused mainly by infection of Candida albicans and Streptococcus mutans, the most predominant members of the bacterial flora on denture surfaces. The purpose of this study was to investigate the adhesion in vitro of C. albicans and of S. mutans to acrylic surfaces and their interactions. Concentrations of C. albicans and of S. mutans (mutational phase I and III in which activities of glucosyltransferases are higher and lower respectively) were of high levels (> or = 5.0 x 107 colony-forming-units per ml; CFU/ml). The colonies in brain-heart-infusion (BHI) broth added 5% sucrose incubated at 37 degrees C for 18 and 72 hours. Then the samples were dried and evaporated, and examined by S-700 and S-4100 SEM (HITACHI). It was found that S. mutans (mutational phase I) synthesized water-insoluble glucans concomitantly with the adhesion of both S. mutans and C. albicans to the acrylic surfaces. Also, adhesion of C. albicans, mediated by cell-to-cell interactions with S. mutans (especially mutational phase III), to the surfaces was observed.

Acrylic Resins↗

PubMed1994

Chest wall and mediastinal invasion by lung cancer: evaluation with multisection expiratory dynamic CT.

PURPOSE: To assess the utility of multisection expiratory dynamic (ED) computed tomography (CT) in evaluation of tumor invasion in the chest wall or mediastinum. MATERIALS AND METHODS: Fifteen patients with lung cancer underwent multisection ED CT. At each section level, 10 images were obtained at an interval of 1 second during a single expiratory maneuver. These images were evaluated in cine mode to assess tumoral movement along the chest wall or mediastinum. RESULTS: ED CT showed that the tumors in five patients were fixed to the chest wall (n = 2) or mediastinum (n = 3); free movement of tumor along the peripheral (n = 7) or mediastinal (n = 3) pleura was proved in the 10 other patients. At pathologic examination, the ED CT findings were proved correct in all patients. In six patients, ED CT provided additional information about tumor invasion that could not be obtained with conventional criteria. CONCLUSION: Multisection ED CT may improve the accuracy of CT in prediction of chest wall or mediastinal invasion of lung cancer.

Aged↗

PubMed1994

Side branches of the pulmonary artery in the hilar region.

The pulmonary air space between the large bronchi at the hilum is supplied by small daughter bronchi that stem from axial main branches. In this study, we evaluated the morphological appearance of the pulmonary artery which corresponds to the daughter bronchus using an inflated-fixed lung specimen. In contrast to the relationship in the subpleural area, the pulmonary artery did not follow the corresponding airway in the area supplied by the daughter bronchus. Only at the tip of the terminal bronchiole was a close association found. Each terminal bronchiole showed a tendency to receive its blood supply from the nearest parent branch of the pulmonary artery.

Aged↗

PubMed1994

Accurate contiguous sections without breath-holding on chest CT: value of respiratory gating and ultrafast CT.

OBJECTIVE: To image truly contiguous CT sections without breath-holding, we developed a respiratory-gating device combined with ultrafast CT. The purpose of this study was to evaluate the utility of this system, especially focusing on the contiguity of the images. SUBJECTS AND METHODS: In 37 patients, we obtained respiratory-gated scans and breath-hold scans with 6-mm collimation and 6-mm incrementation (19 patients) and with 3-mm collimation and 3-mm incrementation (18 patients). We compared these two sets of images with respect to quality and contiguity. In nine patients who could not hold their breath because of dyspnea or infancy, we obtained only respiratory-gated scans with 3-mm collimation and 3-mm incrementation. Our respiratory-gating device was composed of a commercial ECG and respiratory monitor, a triggering device, an original amplifier, and an original switching unit. It was designed to control the scan timing of an ultrafast CT scanner at a user-selected level of the respiratory curve obtained with transthoracic impedance plethysmography. RESULTS: The respiratory-gated images were equal in quality to the breath-hold images in 31 of the 37 patients who had both sets of images. In 15 of 19 patients who had 6-mm-thick sections and in 11 of 18 patients who had 3-mm-thick sections, satisfactory contiguous images of bronchi and pulmonary vessels were obtained. Additionally, in seven of the nine patients who could not hold their breath, satisfactory contiguous sections were obtained. CONCLUSION: The respiratory gating system combined with ultrafast CT can provide contiguous CT scans without breath-holding or patients' cooperation. The procedure could improve the diagnostic accuracy of CT, especially in severely ill patients, infants, and senile patients.

Female↗

PubMed1994

Unexpected atrial fibrillation during tooth extraction in a sedated elderly patient.

A case is reported of unexpected atrial fibrillation in response to tooth extraction under intravenous sedation in a 70-yr-old patient with thoracic aneurysm of the aorta. Atrial fibrillation developed after the additional injection of a 2% solution of lidocaine containing 1:200,000 epinephrine. After 20 min, the arrhythmia disappeared spontaneously. The arrhythmia was associated with insufficient analgesia for tooth extraction, epinephrine in the local anesthetic, decreased blood pressure, and the presence of cardiovascular disease. Even when a low concentration of epinephrine is employed, caution should be paid to development of unexpected cardiovascular reactions in elderly patients with severe cardiovascular disease. We conclude that an electrocardiogram, blood pressure device, and pulse oximeter should be used in high-risk patients in order to prevent and detect potentially dangerous cardiovascular emergencies, even if dental treatment is scheduled under local anesthesia.

Aged↗

PubMed1993

Long-term observation of the relation between pain intensity and serum carbamazepine concentration in elderly patients with trigeminal neuralgia.

The relation between changes in pain intensity and serum carbamazepine (CBZ) concentration was studied in five elderly patients with trigeminal neuralgia. Measurement of pain intensity and serum CBZ concentration, and blood studies, were performed approximately every 2 or 3 months after initiation of CBZ therapy. Fluctuations in pain intensity were observed in four patients. In these patients, even when the serum CBZ concentration was maintained within a relatively high range, there were periods in which pain intensity increased. On the other hand, there were periods in which pain was relatively well controlled even though the CBZ concentration was relatively low. There were considerable interindividual differences in response to CBZ. The fluctuations in pain showed that the CBZ response curve varies from period to period even within an individual. It was concluded that it is essential to observe spontaneous variations in pain intensity and monitor serum CBZ during long-term administration.

Aged↗

PubMed1993

Mechanical properties of artificial teeth.

In selecting the teeth for fabrication of complete or partial dentures, each patient's anatomic and physiologic requirements and the properties of the artificial teeth themselves should be taken into consideration. The purpose of this study was to evaluate the mechanical properties of the artificial teeth by the static compression test and the impact test. Specimens were the lower first molar porcelain and resin teeth (Livdent FB-20 teeth by G. C. Co., Tokyo, Japan). All were of the same shape. In the static compression test, the fracture load and deformation of the artificial teeth were measured with an Instron-type universal testing machine at a cross-head speed of 1.0 mm/min. Elastic modulus, ultimate strength and absorbed energy were calculated. In the impact test, the acceleration of a falling impactor was measured with a drop impact apparatus. The load applied to the specimen was equivalent to 300N. Absorbed energy and deformation were calculated. The resin teeth showed a lower elastic modulus, higher fracture toughness and shock-absorbing ability than the porcelain teeth. Resin teeth should be selected when the first requisite is high shock-absorbing ability, and porcelain teeth should be selected when the first requisite is high masticating efficiency.

Dental Porcelain↗

PubMed1992

An autopsy case of renal cell carcinoma associated with extensive peliosis hepatis.

An autopsy case of renal cell carcinoma with extensive peliosis hepatis is reported. The patient was a 34-year-old female, who had had a left nephrectomy for renal cell carcinoma but died of multiple metastases one year and 4 months after surgery, despite chemotherapy and interferon treatment. At autopsy, the liver was enlarged markedly with multiple metastatic nodules and the non-neoplastic hepatic parenchyma had a spongy appearance, due to diffusely scattered, blood-filled cystic lesions. Histological examination showed the oval to irregular shaped blood-filled spaces were lined by hepatic cell cords and located mainly in the periportal area. In addition, almost all of the sinusoids were dilated and communicated with the cystic blood-filled spaces, which also communicated directly with branches of the portal veins at various levels. Several interlobular portal branches were obstructed. The causative mechanism of peliosis hepatis has yet to be elucidated, although some causative conditions have been proposed. In this case, renal cell carcinoma may have caused the sinusoidal dilatation and the vascular changes in the portal areas, such as obstruction of terminal portal branches, may have contributed to its formation.

Adult↗

PubMed1992

[A case of granulomatous interstitial nephritis presented reversible renal failure treated with the steroid therapy: repeated renal biopsy case].

This report describes clinical and histopathological findings of a case of a 43-year-old male with granulomatous interstitial nephritis. The patient developed renal failure following renal insufficiency of 4 months duration. The patient presented with lethargy and nocturia. The first renal biopsy revealed granulomatous interstitial nephritis. There was no apparent evidence of a systemic granulomatous disease or drug hypersensitivity. Therapy with reducing regime of prednisolone produced a marked improvement in symptoms and renal function. Relapse occurred 3 months later in association with early discontinuation of the corticosteroid therapy. Ga-scintigraphy demonstrated an abnormal accumulation of gallium in both kidneys. The second renal biopsy did not show the obvious improvement. With the re-administration of the corticosteroid therapy, renal function rapidly improved again. Twelve months after the re-administration of the steroid therapy, Ga-scintigraphy showed no renal uptake. Corticosteroid therapy yielded a favorable outcome for renal function. The third renal biopsy showed disappearance of the granulomas lesion. Re-administration of the corticosteroid therapy continued for 22 months and the patient has not yet relapsed 9 months after the withdrawal of the steroid therapy.

Acute Kidney Injury↗

PubMed1991

Evaluation with Fourier analysis on radionuclide angiography of viable but stunned myocardium in patients with right ventricular myocardial infarction.

Stunned myocardium of right ventricle was studied by radionuclide angiography (RNA) and Thallium myocardial scintigraphy (TL) in 39 patients with inferior myocardial infarction with and without right ventricular myocardial infarction (RVMI). RNA was performed within 1 week of the onset (acute phase) and after 1 month, when exercise cardiac scintigraphy (EX-TL) was also performed. The ejection fraction (EF) of each ventricle calculated from RNA and the phase and amplitude evaluated visually and quantitatively by Fourier analysis were compared between the acute phase and 1 month after the onset of myocardial infarction. The degree of visualization of right ventricle was examined in EX-TL 1 month after the onset. (1) In RNA obtained in the acute myocardial infarction, abnormalities in the right ventricle (delayed phase or low amplitude image) were observed in 18 (46%) but not in 21 (54%) of the 39 patients (N group). Of those 18 patients, the abnormalities in the right ventricle alleviated in 11 (RVMI-A group) but persisted in 7 (RVMI-B group) in RNA obtained 1 month after the onset. (2) In the acute phase, the right ventricular ejection fraction (RVEF) was 39.4 +/- 10.4% in N group, 30.8 +/- 5.3% in RVMI-A group, and 29.6 +/- 8.9% in RVMI-B group, with significant differences between N group and the other two groups (P less than 0.05) but no significant difference between RVMI-A and RVMI-B groups. (3) After 1 month, RVEF was 40.1 +/- 10.1% in N group, 42.2 +/- 8.4% in RVMI-A group, and 32.2 +/- 9.8% in RVMI-B group, being improved in RVMI-A group and showing a significant difference as compared with RVMI-B group (p less than 0.05). (4) In EX-TL of RVMI-A group, the right ventricle was visible although the uptake of TL was reduced in the entire right ventricle. In RVMI-B group, only part of the right ventricular free wall was visible with defects in the other areas of right ventricle. The sign of RVMI showed improvements in many of the patients after the acute phase, and their condition was considered to have been so-called stunned myocardium, which is a complex of symptoms of reversible myocardial ischemia, rather than RVMI.

Aged↗

PubMed1991

[Assessment of denervated but viable myocardium in patients with myocardial infarction--by myocardial imaging with 201Tl and 123I-MIBG].

The present study assessed sympathetic function in viable infarcted areas of the myocardium following the onset of myocardial infarction. The subjects were 19 patients with myocardial infarction. After exercise on a bicycle ergometer, simultaneous SPECT with Tl-201 and I-123 MIBG was performed. The behavior of MIBG following exercise remains to be clarified, but in the present study MIBG provided images different from those obtained with Tl. While the redistribution of Tl in the infarcted area was observed in 8 of 19 patients, MIBG was absent in the infarcted area in both the initial and delayed scans. In the patient undergoing CABG, the infarcted area showed no MIBG despite the normal perfusion of Tl. The previous proposal that the redistribution of Tl indicates myocardial viability to some extent suggests that the sympathetic function of the area of the myocardium showing the redistribution of Tl decreases even though the area is viable. These findings indicate that after the onset of myocardial infarction, there is a denervated but viable area in the myocardium, despite the viability demonstrated by Tl imaging. They also indicate that concurrent myocardial imaging with MIBG is useful for the detection of such a myocardium.

3-Iodobenzylguanidine↗

PubMed1990

[Effect of 3-mercaptopropyltrimethoxysilane coupling agent on stainless steel and silica surface].

Mixed silanes, 3-mercaptopropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane, were used as a primer for adhesion of poly(methyl methacrylate) to stainless steel and glass plate. The tensile bond strength of the resin to those substrates was measured after immersion in water at 37 degrees C for 3 days. The mean bond strengths of the resin to the stainless steel and to the glass plate were 23 and 17 MPa, respectively. In addition, cohesional fracture of the resin occurred in both cases. The mixture of the silanes was highly adhesive for the stainless steel and the glass plate surface treatment.

Adhesiveness↗

PubMed1990

[Usefulness of rest-redistribution on thallium myocardial scintigraphy in patients with acute myocardial infarction by SPECT: analysis by bull's eye and unfolded map images].

The purpose of this study was to clarify the clinical significance of rest-redistribution in myocardial scintigraphy (SPECT) in acute myocardial infarction (AMI). Thirty patients with AMI within one week after the onset of attack were studied. SPECT images were obtained 10 min and three hours after injection of 201Tl. Bull's eye images and unfolded map images were prepared. A 201Tl uptake was studied at the infarct and non-infarct sites. Exercise SPECT and radionuclide angiography (RNA) were performed in all patients one month after the onset of AMI, and the findings were compared with clinical and coronary angiographic (CAG) findings. 1. Redistribution of thallium at rest was observed at the infarct sites in nine of the 30 patients. 2. Redistribution at rest was observed at the non-infarct sites in eight patients. 3. Redistribution at rest was observed during exercise SPECT one month after the onset of AMI in patients with redistribution at rest in the acute phase. 4. In patients with redistribution at rest at the infarct site, left ventricular ejection fraction (EF) improved one month after the onset of AMI (delta EF greater than 5%), but it decreased slightly during exercise. 5. Wall motion at the infarct site was not much impaired in patients who showed redistribution at rest at the infarct site. 6. Angina pectoris and recurrence of myocardial infarction were observed more frequently in those with redistribution at rest on SPECT. 7. No characteristic findings were obtained on CAG in those with redistribution at rest.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1989

[Studies on the flow properties of autopolymerizing hard-setting resins used as direct relining materials for denture bases].

Autopolymerizing hard-setting direct relining resin is currently being used in dentistry to attain denture bases that conform to the supporting tissues with a high degree of accuracy. The purpose of this study is to investigate the flow of six commercial hard-setting direct relining resins (Denture Liner, Kooliner, New Truliner, Rebaron, Swift, Tokuso Rebase) and several types of impression materials (zinc oxide-eugenol, polysulfide rubber, silicone rubber) using the parallel plate viscometer. The viscometer is used to measure the spread radius of samples (a volume of 0.5 cm3) between two parallel flat plates when a load of 750-gram weight is applied at 1, 10, 60, 100 seconds after loading has begun. In this experiment, the load was applied at 120, 150, 180, 210, 240, 300 seconds after mixing had begun. All the samples were mixed according to the manufacturer's recommendations. The findings were as follows; 1. The flow of the six commercial hard-setting direct relining resins could be compared with one another by the spread radius at 1 second after loading (r1) with no relation to time lapse after initiation of the mix. 2. Denture Liner, Kooliner, Rebaron and Swift had the same flow characteristic when r1 was the same. 3. Polysulfide rubber impression materials had similar flow characteristic to hard-setting direct relining resins.

Acrylic Resins↗

PubMed1989

[Successful CYVADIC combination chemotherapy of metastatic pulmonary lesions involving a mediastinal leiomyosarcoma--a case report].

Discussed is a 34-year-old man who hospitalized for manifesting the superior vena cava syndrome. Chest radiograph and chest CT scan revealed a gross tumor shadow in the superior mediastinum and a tiny shadow in the right lung. Superior vena cavography showed intimal stenosis, irregularities, and stiffness of the superior vena cava. Thus, radiotherapy applied to primary lesion of the mediastinum was provided to relieve his complaints. One year later, predominant metastatic pulmonary lesions and skin lesions developed. Light and electron microscopic findings of a biopsied specimen of the skin lesion were consistent with leiomyosarcoma. CYVADIC combination chemotherapy reduced the pulmonary metastatic lesions dramatically. The literature of mediastinal leiomyosarcoma is reviewed and the origin of this tumor is discussed.

Adult↗