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M Okada

Publications and source records attributed to M Okada.

At least 1,189 records · Page 66Linked to original sources
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↗
PubMed1990

The Na(+)-dependent release of endogenous dopamine and noradrenaline from rat brain synaptosomes.

The involvement of intrasynaptosomal-free Ca++ concentration [( Ca++]i) in Na(+)-dependent release of endogenous dopamine and noradrenaline from rat brain synaptosomes was studied. The release of endogenous dopamine and noradrenaline from rat whole brain synaptosomes were measured using high-performance liquid chromatography with electrochemical detector. The change of [Ca++]i was measured fluorometrically using a Ca++ indicator, Quin-2. Whether extracellular Ca++ was present or not, 30 microM veratridine, a Na(+)-ionophore, increased the release of endogenous dopamine and noradrenaline. In the presence of 1.25 mM Ca++, 30 microM veratridine increased [Ca++]i. In contrast, in the absence of extracellular Ca++, veratridine did not affect [Ca++]i. Ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) increased the release of dopamine and noradrenaline in Ca-Mg-free medium. This stimulatory effect of EGTA seemed to be the result of an increase in the influx of Na+ through Ca++ channels in the absence of divalent cation. In Ca-Mg-free medium, EGTA caused a slight decrease in [Ca++]i. The EGTA-stimulated release of dopamine and noradrenaline was blocked by La which also significantly blocked the decrease in [Ca++]i observed after the addition of EGTA. These results suggest that the Na(+)-dependent release of dopamine and noradrenaline may not depend on a change in [Ca++]i. Veratridine (30 microM)-induced release of dopamine and noradrenaline were detected simultaneously. However, the time needed to induce the maximal stimulatory effect of veratridine on the release of dopamine was apparently shorter than that of noradrenaline. This delay might suggest that the Na(+)-dependent release process of dopamine is not similar to that of noradrenaline.

Amiloride↗
PubMed1990

Problems of denture wearers regarding denture cleaning.

With the increase of elderly population, the number of patients who need removable prostheses increase rapidly. Denture wearers have different problems from non-denture wearers in terms of maintaining oral health. In this study, we attempted to find out specific difficulties of denture wearers with questionnaires regarding social life problems as well as oral hygiene problems. Our results indicated that most of the denture wearers considered the cleaning of denture was essential to maintain their oral health, though methods they employed showed a great deal of difference. Also denture wearers felt difficulties in cleaning their dentures when they went out.

Denture Cleansers↗
PubMed1990

Mouth guard and occlusal force distribution.

Mouth guards are effective to prevent traumatic injury in maxillofacial region during sports activities. This study was designed to find out the influence of wearing mouth guards on occlusal force distribution using an occlusal force transducer system (T-Scan system). Occlusal forces were more evenly distributed when mouth guards were in place comparing with natural dentition and with wearing conventional full arch bite planes.

Adult↗
PubMed1990

[Clinical application of T-Scan System. 2. Evaluation of soft mouth guards].

Soft mouth guards are effective to prevent traumatic injury in the maxillofacial region. In this study, we tried to find out the effect of soft mouth guards on the distribution and the magnitude of occlusal force using the T-Scan system. Ten adult subjects volunteered to exert maximum biting force wearing three different types of soft mouth guards. With the limitation of the T-scan system reported in our previous article, following results were obtained. 1) Occlusal forces were more evenly distributed with soft mouth guards than without them. 2) Softer mouth guards were more effective for occlusal force distribution. 3) Since occlusal relationship between mouth guards and mandibular arch could alter the distribution pattern a great deal, occlusion of mouth guards should be examined more carefully.

Adult↗
PubMed1990

[Mouth guard and occlusal force distribution].

Mouth guards are effective to prevent traumatic injury in maxillofacial region during sports activities. This study was conducted to investigate the influence of wearing mouth guards on occlusal force distribution with the T-scan system. With comparison to the value of average occlusal force level per occlusal point (OFL) on natural dentition and wearing conventional full arch bite plane, following results were obtained. 1) Difference of OFL within the same dental arch became smaller when mouth guards were on. 2) Statistically significant difference in OFL was not found between two mouth guards with different hardness. 3) During three seconds clenching, OFL in posterior region changed great deal at the initiation but stayed at about the same level after that.

Bite Force↗
PubMed1990

Incremental pulmonary vascular resistance increases with elevation of pulmonary venous pressure.

The aim of this study was to determine whether elevation of pulmonary venous pressure affects incremental pulmonary vascular resistance. We vascularly isolated the left lower lobe of the lung and perfused with blood using a pulsatile pump. Blood flow to the isolated lobe was decreased in 6 to 7 steps from about 8 to 1 ml/kg/min. Incremental pulmonary vascular resistance was estimated from the slope of the pressure-flow relationship between pulmonary arteriovenous pressure difference and pulmonary blood flow at different pulmonary venous pressures. Incremental pulmonary vascular resistance increased as pulmonary venous pressure was elevated. This result suggests that an increase in cardiac output, i.e., an increase in pulmonary blood flow, results in a larger increase of pulmonary arterial pressure in high pulmonary venous pressure than in low pulmonary venous pressure.

Animals↗
PubMed1990

Controlled trial comparing an elemental diet with prednisolone in the treatment of active Crohn's disease.

To determine whether an elemental diet or prednisolone would be more effective for treating acute Crohn's disease, a controlled trial was conducted on 20 patients with acute Crohn's disease who had never received specific treatment. The first ten patients were put on an elemental diet and the remaining ten were prescribed prednisolone for six weeks at an initial dose of 0.7 mg/kg/day. Patients were assessed using the simple activity index, body weight, erythrocyte sedimentation rate, C-reactive protein and alpha 2 globulin, serum albumin, and radiographic findings of bowel lesions. At six weeks, the patients on the elemental diet showed a significantly greater improvement in the activity index, inflammatory signs such as C-reactive protein and alpha 2 globulin, and radiographic findings of bowel lesions than did those on the steroid. Patients who were given steroids for six weeks and then treated with the elemental diet for four weeks showed improvement in the radiographic findings of bowel lesions and inflammation. The present study strongly suggests that elemental diet is superior to steroids for treating active Crohn's disease.

Adult↗
PubMed1990

[Acute myelomonocytic leukemia with Inv(16) (p13 q22) relapsed in transverse myelopathy].

We report a case of AML (M 4) with eosinophilia who developed meningeal relapse and transverse myelopathy. A 37-year-old woman was admitted to our hospital because of lymphadenopathy and ecchymosis. One week prior to admission, she noticed swelling of the cervical lymph nodes and bleeding tendency. On admission, low-grade fever, gingival swelling, generalized lymphadenopathy, and ecchymosis on the lower legs were found. A white blood cell count was 93,900/microliters with 82% blast cells, and a platelet count was 24,000/microliters. A bone marrow was composed of 45.3% myeloblasts, 27% monocytes and 7.1% eosinophils. Chromosome analysis revealed inv(16). The diagnosis of M4Eo was made. About one year after she gained complete remission, she was readmitted because of disturbance of urination. There was a sign of transverse myelopathy at the seventh vertebral level, and blast cells were detected in the cerebrospinal fluid. Despite of radiation and chemotherapy, paresis of lower extremities and sensory disturbance were persistent, and the patient died on 52th hospital day.

Adult↗
PubMed1990

[Evaluation of experimental proliferative vitreoretinopathy in rabbits].

We established an effective animal experimental model for proliferative vitreoretinopathy (PVR) by intravitreally injecting cultured cells in order to investigate therapies for PVR, including intravitreal drugs, radiation and hyperthermia. After making posterior vitreal separation by injecting SF6 gas into the rabbit's vitreous body, cultured cells were intravitreally injected. Fundus changes were followed up for 4 weeks and PVR stage was recorded according to the classification described by Hida et al. The cultured cells injected were rabbit dermal fibroblasts (5 x 10(4) and 10 x 10(4) and human retinal pigment epithelial (RPE) cells (5 x 10(4]. A total of 37% of animals reached STAGE 5-7 (traction retinal detachment) in 4 weeks in 41 eyes injected with 5 x 10(4) rabbit fibroblasts and were 86% in 14 eyes injected with 10 x 10(4) rabbit fibroblasts. The 10 eyes injected with human RPE cells showed STAGE 2 or less in 4 weeks. Consequently, we selected the experimental PVR model using injecting of 10 x 10(4) rabbit fibroblasts as the most effective method.

Animals↗
PubMed1990

[Characteristic difference of functional tricuspid regurgitation between acquired valvular heart disease and atrial septal defect].

The characteristic difference in functional tricuspid regurgitation (TR) was studied between acquired valvular heart disease (VHD) and adult atrial septal defect (ASD). Fifty patients of VHD and 20 patients of ASD were subjected to this study. In all patients, the TR volume per beat (VTR) was calculated with our original method using 2-dimensional color Doppler (2-DD) and continuous-wave Doppler (CW) echocardiographies. VTR is obtained by the product of the cross-sectional areas (S) of the base of regurgitant jet in 2-DD and the regurgitant volume of one unit area (Vu) in CW (VTR = 1/3.S.Vu). The preoperative evaluation of TR according to VTR showed a good relationship with the operative findings, and the patients with preoperative VTR greater than or equal to 10 cc were candidates for tricuspid valve repair. In all patients with preoperative VTR less than 10 cc (18 patients of VHD and 10 patients of ASD), VTR decreased postoperatively without any tricuspid valve repair. In patients with VTR = 10-20 cc (19 patients of VHD and 5 of ASD), VTR showed a decrease to below 10 cc after tricuspid annuloplasty (TAP) by Kay's method in 18 patients of VHD and 5 of ASD, and with no tricuspid valve repair in one patient of VHD. In patients with VTR greater than or equal to 20 cc (13 patients of VHD and 5 of ASD), the postoperative VTR diminished to below 10 cc after Kay's TAP in 8 patients of VHD and 5 of ASD, and VTR disappeared after valve replacement (TVR) in 2 patients of VHD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Surgical treatment of valvular heart disease associated with Behçet's disease].

We experienced two patients of valvular heart disease associated with Behçet's disease. First patient presented aortic regurgitation (AR) due to perforation of left coronary cusp of the aortic valve and underwent valve replacement (AVR). Second patient showed AR due to shortening of the aortic valve along with mitral regurgitation caused by dilatation of the annulus, and received AVR as well as mitral annuloplasty by Kay's method. Each patient has been doing well for 5 and 2 years after operation, respectively. Patients with Behçet's disease often have perivalvular leakage after valve replacement. We treated our patients as follows to prevent this serious postoperative complication. 1. The operation was performed when the inflammatory signs and findings subsided with enough adrenal steroids. 2. At operation, the prosthetic valve of one size smaller than the size considered suitable was selected for valve replacement. 3. The adrenal steroids have been continuously administrated and adjusted according to the values of CRP and ESR as well as the cutaneous and mucous manifestations of this disease.

Adult↗
PubMed1990

[Extensive surgical treatment of advanced or recurrent carcinoma of the thyroid gland: report of three cases].

Three advanced or recurrent thyroid carcinomas invading the adjacent surrounding organs such as trachea, great vessels or anterior mediastinum were reviewed. In one patient, resection of subtotal thyroid combined with trachea including a part of cricoid cartilage was performed, and followed with end to end anastomosis. In the other two patients with SVC syndrome, a trans-sternal surgical approach was applied in order to resect a large tumor extending into the anterior mediastinum. Replacement of SVC with ringed PTFE graft and chest wall resection was performed in one patient. With these extended surgical intervention, more operative radicality, prolonged surviving time and better quality of life were expected.

Adenocarcinoma↗
PubMed1990

[A case of primary mediastinal liposarcoma which presents a singular appearance].

An operated case of primary mediastinal liposarcoma is reported. A 71-year-old male who was asymptomatic was unexpectedly pointed out a huge abnormal mass shadow in the mediastinum on the chest roentgenogram, when he caught a common cold. The CT scan showed the singular horseshoe-shaped tumor in the posterior mediastinum which was adjacent to the antero-lateral phase of the vertebrae. MRI was useful to our recognition of its whole shape and localization. Extirpation of the tumor via right postero-lateral thoracotomy was performed successfully. The pathological diagnosis was liposarcoma; well differentiated, lipoma-like type. Primary mediastinal liposarcoma is a very rare mediastinal tumor (0.2%). Thirty-six cases of primary mediastinal liposarcoma including our case have been reported at present in Japan, so far as we surveyed. It is generally known that liposarcoma has the low sensitivity to the radiotherapy and chemotherapy and has high incidence of recurrence. We think that this case needs the strict postoperative follow-up.

Aged↗
PubMed1990

Influences of stress on gastric alkaline secretion in rats.

Influences of restraint plus water-immersion stress on gastric alkaline response and mucosal blood flow were investigated in the rat. Under normal conditions, the stomach secreted alkali at the rate of approximately 1 microEq/15 min in the presence of omeprazole (60 mg/kg i.p.) and responded to mucosal acidification (1000 mM HCI for 10 min) by a significant rise of output (approximately 2.5 microEq/15 min), and the latter process was significantly blocked by indomethacin (5 mg/kg s.c.), quinacrine (100 mg/kg s.c.) and vasopressin (10 unit/kg/hr i.v.). Restraint alone decreased basal rates of HCO3- secretion but had no effect on acid-induced HCO3- output. Additional water-immersion stress further reduced alkaline secretion, totally abolished the increased HCO3- response to acid and significantly suppressed the increase of HCO3- output caused by 16,16-dimethyl prostaglandin E2 (3-30 micrograms/kg s.c.). During restraint stress mucosal blood flow was reduced only by 30% but after exposure to additional water-immersion, it further decreased to about 25% of normal values. Both indomethacin and quinacrine had no effect on mucosal blood flow, whereas vasopressin markedly reduced mucosal blood flow by about 80%. These results suggest that stress not only reduced basal rates of alkaline secretion in the stomach but also impaired the mucosal ability to increase HCO3- output in response to acid. These secretory disorders caused by stress may be attributed to both a decrease of mucosal blood flow and prostaglandin deficiency in the mucosa.

Animals↗