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Biomedical subjects

Y Tamura

Publications and source records attributed to Y Tamura.

At least 199 records · Page 11Linked to original sources
PubMed1998

Immusorba TR and Immusorba PH: basics of design and features of functions.

Immusorba was reported by Yamazaki et al. to be the world's first practical immunoadsorbent in 1982. Since then, this immunoadsorbent has accumulated an abundance of clinical achievements. Immusorba has such unique functions that it is used in treating various diseases and holds possibilities for application to more diseases. Immusorba was designed as an artificial receptor for rheumatoid factor (RF) based on structural analysis of heat-denaturated globulin. Subsequently, new substances that it can adsorb have been found as seen in reports on the adsorption performance of Immusorba to anti-acetylcholine receptor antibodies (anti-AChR Abs) and antiganglioside antibodies. Along with this, Immusorba has been used in treating a wide range of diseases. The greatest characteristic of Immusorba is that its adsorption capability is selective rather than specific, making it effective against a great number of diseases.

Acetylcholine↗
PubMed1998

Recurrent dislocation of the extensor carpi ulnaris tendon.

Five patients with recurrent dislocation of the extensor carpi ulnaris (ECU) tendon resulting from an athletic injury were treated by reconstruction of the ECU tendon sheath, and each had a satisfactory result. Two types of disruption of the fibro-osseous sheath were found. In two cases in which the fibro-osseous sheath ruptured radially, the torn sheath lay on its ulnar groove beneath the ECU tendon. These patients were treated by direct suture of the sheath over the ECU tendon. In three cases in which the fibro-osseous sheath ruptured ulnarly, the torn sheath lay superficial to the ECU tendon. These patients were treated by reconstruction of the sheath using a piece of the extensor retinaculum. We believe that surgical reconstruction of the fibro-oseous sheath of the ECU tendon should be considered for symptomatic dislocation of the ECU tendon, even in an acute case.

Adult↗
PubMed1998

Relationship between left atrial function and plasma level of atrial natriuretic peptide in patients with heart disease.

To investigate the relationship between left atrial function and secretion of atrial natriuretic peptide (ANP), we analyzed left ventricular inflow and pulmonary venous flow, left atrial dynamics, intracardiac pressures, and plasma ANP level in 92 patients with various cardiac diseases. From the apical four-chamber view, maximal left atrial volume and percent fractional change of the left atrial area during atrial systole (LA-%AC) were calculated. The ratio of peak early filling velocity to peak atrial systolic velocity (E/A) in the left ventricular inflow and the ratio of peak systolic velocity to peak diastolic velocity (S/D) in the pulmonary venous flow were measured with the pulsed Doppler method. A significant linear correlation was found between plasma ANP levels and pulmonary capillary wedge pressure. Significant linear correlations were also found between left ventricular end-diastolic pressure and both maximal left atrial volume and LA-%AC. Plasma ANP level was significantly correlated with maximal left atrial volume, LA-%AC, E/A, and S/D. A multivariate analysis revealed that only LA-%AC was significantly correlated with the plasma ANP level. These results suggest that left atrial systolic dysfunction associated with a left atrial afterload mismatch is closely related to the ANP secretion.

Aged↗
PubMed1998

Echocardiographic assessment of right atrial function in patients with myocardial infarction with reference to obstructive lesions of the coronary arteries.

We assessed the relationship between right atrial (RA) function and obstructive lesions of the coronary arteries in 29 patients with recent or old myocardial infarction (MI). Patients were divided into 3 groups according to the location of obstructions as follows: obstruction at the proximal right coronary artery (segments 1 and 2) (RCA proximal group, n=9); obstruction at the distal RCA (segments 3 and 4) (RCA distal group, n=6); and obstruction at the left anterior descending coronary artery (LCA group, n=14). The RA volume and the fractional change in the RA area during atrial contraction (RA %AC) were evaluated by apical 2-dimensional echocardiography. The right ventricular (RV) end-diastolic pressure (RVEDP) was measured in 4 patients in the RCA proximal group and 4 patients in the LCA group. The ejection fraction of the right ventricle (RVEF) was measured by radionuclide angiography or 2-dimensional echocardiography in 7 patients in the RCA proximal group, 5 patients in the RCA distal group, and 7 patients in the LCA group. The RVEF tended to be lower in the RCA proximal group than in the RCA distal and LCA groups. The RA volume was significantly greater in the RCA proximal group than in the LCA group. The RA %AC was significantly smaller in the RCA proximal group than in the RCA distal and LCA groups. There were no significant differences in the early diastolic RV inflow velocity among groups, but the late diastolic RV inflow velocity was significantly lower in the RCA proximal group than in the RCA distal and LCA groups. There was no significant difference in the RVEDP between the RCA proximal and LCA groups. Thus, RA dysfunction in the RCA proximal group appeared to be due to myocardial damage rather than to afterload mismatch. These findings suggest that RA dysfunction may occur in patients with an inferior MI who have an obstructive lesion of the proximal RCA.

Aged↗
PubMed1998

Protective effect of MKC-231, a novel high affinity choline uptake enhancer, on glutamate cytotoxicity in cultured cortical neurons.

This study was performed to examine the neuroprotective action of 2-(2-oxopyrrolidin-1-yl)-N-(2,3-dimethyl-5,6,7,8-tetrahydrofuro [2,3-b]quinolin-4-yl)acetoamide (MKC-231), which enhances choline uptake and acetylcholine release in the central nervous system. Glutamate neurotoxicity was assessed with cortical cultures obtained from fetal rats. Exposure of cultures to MKC-231 for 12-24 hr ameliorated glutamate cytotoxicity. MKC-231 reduced cytotoxicity induced by ionomycin, a calcium ionophore, but did not affect the cytotoxicity induced by S-nitrosocysteine, a nitric oxide (NO) donor. These findings suggest that MKC-231 protects against glutamate neurotoxicity by suppressing the NO formation triggered by Ca2+-influx.

Animals↗
PubMed1998

Seroprevalence against Toxoplasma gondii in domiciled cats in Japan.

A serological survey with latex agglutination test to detect anti-Toxoplasma gondii antibodies was conducted on 800 serum samples collected from domiciled cats at animal hospitals in various areas of Japan. The overall prevalence was 6.0% (48/800). Among 48 positive individuals, there was no specific distribution of strength of antibody titers; the titers were 1:64 in 8 cats, 1:128 in 12, 1:256 in 8, 1:512 in 10, 1:1,024 in 8 and 1:2,048 in 2. The maximum prevalence was 15.4% in 13 cats at 17-23 yrs old group, whereas all were negative in 58 cats aged 12-16 yrs. The age groups in the order of higher prevalence were 8, 4, 10, 5, 3, and 7 yrs, showing no aging effect to the prevalence. In terms of rearing conditions of those cats, they were classified into 4 groups, i.e., indoor, free, outdoor, and others. The prevalence in the outdoor group (11.1%) was significantly higher (p < 0.05) than that in the free group (4.8%). Epidemiological aspects observed in the domiciled cats were different from those reported in the stray cats.

Animals↗
PubMed1998

Production of recombinant porcine tumor necrosis factor alpha in a baculovirus expression system.

Porcine tumor necrosis factor alpha (TNF-alpha) was produced using a baculovirus system in Spodoptera frugiperda (SF21AE) cells. Cytotoxic activity was detected in supernatant of sonicated SF21AE cells infected with recombinant viruses. The recombinant protein was also demonstrated to be functionally active by its ability to cause apoptosis in Wehi 164 cells. Three distinct bands of 26, 17 and 14 kDa were revealed by Western blot analysis using anti-human TNF-alpha antibody. Moreover, the anti-human TNF-alpha antiserum significantly neutralized the cytotoxic activity of the supernatant of sonicated SF21AE cells infected with recombinant viruses.

Animals↗
PubMed1998

Right heart flow dynamics after tricuspid valve annuloplasty. Characteristics and time course.

To evaluate the effect of tricuspid annuloplasty (TAP) on right heart flow dynamics, we analyzed tricuspid inflow velocity pattern, jugular venous pulse and color Doppler flow signal of tricuspid regurgitation (TR) before and after surgery in 16 patients who underwent TAP (TAP group). Cardiac rhythm was atrial fibrillation in all patients. Twelve patients with lone atrial fibrillation served as controls (AF group). Patients in the TAP group were studied before and serially after surgery with a mean follow-up period of 2.7 years. TAP was performed according to the modified De Vega technique in all patients. In a comparison of the most recent data in the TAP group and the data in the AF group, the maximum tricuspid inflow velocity was significantly increased, and both the deceleration time of the tricuspid inflow velocity wave and the y-h interval of the jugular venous pulse were significantly prolonged in the TAP group compared to the AF group. Immediately after surgery, in the TAP group, the area of the TR jet was markedly decreased, and the deceleration time of the tricuspid inflow velocity wave was significantly prolonged compared to those before surgery. The area of the TR jet was dramatically decreased and remained small during the follow-up period. Thus, TAP may produce mild tricuspid stenosis but may also confer sustained preventive effects against TR.

Adult↗
PubMed1998

Relationship between flow dynamics in the left atrium and hemostatic abnormalities in patients with nonvalvular atrial fibrillation.

To investigate the relationship between left atrial (LA) flow dynamics and hemostatic markers in nonvalvular atrial fibrillation (AF), 45 patients with nonvalvular AF who had not received anticoagulants were evaluated by transesophageal echocardiography. We determined the LA appendage flow and the presence of LA spontaneous echo contrast (SEC) or thrombus. We measured plasma levels of thrombin-antithrombin III complex (TAT), fibrinopeptide A, D-dimer, beta-thromboglobulin, and platelet factor 4 in peripheral blood as hemostatic markers. The patients were divided into a low-velocity group (n = 19; sum of peak emptying and filling LA appendage flow velocities < 40 cm/s) and a high-velocity group (n = 26; > or = 40 cm/s). The maximum LA diameter was significantly greater and the LA expansion fraction was significantly smaller in the low-velocity group than in the high-velocity group. LA SEC or thrombus was observed in 11 patients (58%) in the low-velocity group, but not in any patients in the high-velocity group (p < 0.001). The plasma levels of TAT, fibrinopeptide A, D-dimer, beta-thromboglobulin, and platelet factor 4 were significantly higher in the low-velocity group than in the high-velocity group. The plasma levels of TAT, fibrinopeptide A, beta-thromboglobulin, and platelet factor 4 were significantly higher in 8 patients without LA SEC or thrombus in the low-velocity group than in 26 patients in the high-velocity group. Patients with nonvalvular AF accompanied by an enlarged and dysfunctioning LA and a decreased LA appendage flow velocity had increased intravascular coagulation-fibrinolysis activity and platelet activation. These abnormalities may be closely related to the thrombogenetic state in patients with nonvalvular AF.

Adult↗
PubMed1998

Long-term effects of the angiotensin-converting enzyme inhibitor enalapril on chronic heart failure. Examination by 123I-MIBG imaging.

To examine the long-term effects of the angiotensin-converting enzyme (ACE) inhibitor enalapril on chronic heart failure, 10 patients (7 men and 3 women, mean age: 62 +/- 11 years) with chronic stable heart failure, classified as New York Heart Association (NYHA) functional class 2-3 for more than 3 months, and a left ventricular ejection fraction less than 45% were treated with 2.5-5.0 mg of enalapril once a day for 3-15 months (mean 7 months). The causes of heart failure were old myocardial infarction (n = 7), hypertension (n = 2), and atrial fibrillation (n = 1). Radioiodinated metaiodobenzyl guanidine (123I-MIBG) imaging, radionuclide angiography, and treadmill exercise test were performed before and after the treatment. With enalapril treatment, (1) left ventricular ejection fraction (LVEF) increased significantly from 38.3 +/- 6.9% to 47.5 +/- 14.7%; (2) sub-maximal exercise time increased significantly from 205 +/- 112 to 272 +/- 120 seconds; (3) the heart to mediastinum (H/M) ratio of 123I-MIBG increased significantly (early image: 1.99 +/- 0.38 versus 2.20 +/- 0.50; delayed image: 1.86 +/- 0.44 versus 2.09 +/- 0.51); and (4) the washout rate of 123I-MIBG decreased slightly from 29.1 +/- 9.1% to 25.4 +/- 7.0%. The improvement rate of LVEF was significantly correlated with the improvement rates of the H/M ratio and washout rate after treatment with enalapril. Thus, the long-term effects of enalapril can be observed in the cardiac sympathetic nervous system, and 123I-MIBG imaging appears to be useful for evaluating the therapeutic effects of enalapril on the cardiac sympathetic nervous system in patients with chronic heart failure.

3-Iodobenzylguanidine↗
PubMed1998

A selective transthyretin-adsorption column for the treatment of patients with familial amyloid polyneuropathy.

A transthyretin (TTR)-adsorption column has been developed for the removal of variant TTR from the plasma of patients with familial amyloid polyneuropathy (FAP). The adsorbent is an ion-exchange resin made of porous beads of polyvinyl alcohol gel covalently bound with dimethylaminoethanol. This column was used for three patients with type I FAP. It reduced the concentrations of both normal and variant TTR in the plasma to about half of their pre-adsorption levels. Except for thyroxine, retinol-binding protein and IgM, other proteins in serum were not significantly decreased and there were no adverse effects in long term clinical usage of this TTR-adsorption column. In this trial, we did not obtain concrete evidence that TTR-adsorption therapy can stop or delay the progression of the disease in a FAP patient. However, if we are able to apply this technique more frequently and effectively, TTR-adsorption therapy using our column might be useful for the treatment of FAP patients.

Adsorption↗
PubMed1998

[Evaluation of cardiac function by various cardiac imaging techniques in mitochondrial cardiomyopathy: a case report].

A 39-year-old man with cardiomyopathy due to point mutation of mitochondrial DNA(3243) was admitted to our hospital because of exertional dyspnea accompanied by hearing disturbance and diabetes mellitus. Echocardiography revealed asymmetric hypertrophy of the anterolateral and posterior walls and systolic dysfunction of the left ventricle (fractional shortening = 18%). Pulsed Doppler mitral inflow velocity wave showed a pseudonormalized pattern. Iodine-123 betamethyl-p-iodophenyl-pentadecanoic acid (123I-BMIPP) myocardial scintigraphy showed decreased accumulation in the anterolateral, posterior, and apical walls. Left ventriculography showed moderately decreased ejection fraction (43%), and left ventricular end-diastolic pressure was mildly elevated (18 mmHg). Angiography showed normal coronary arteries, but coronary flow reserve measured by administering intravenous adenosine triphosphate was impaired in the left anterior descending and left circumflex arteries compared to the right coronary artery. Intracellular accumulations of abnormal mitochondria were detected by histologic examination of the cardiac and skeletal muscles. Evaluation of cardiac function showed that the area of myocardial hypertrophy was nearly consistent with the region of decrease in 123I-BMIPP accumulation and coronary flow reserve.

Adult↗
PubMed1998

Progression to moderate or severe mitral regurgitation after percutaneous transvenous mitral commissurotomy using stepwise inflation technique.

Progression to moderate or severe mitral regurgitation (MR) was studied after Inoue balloon percutaneous transvenous mitral commissurotomy (PTMC) using the stepwise inflation technique, performed at increments of 1 mm of balloon diameter, in 49 consecutive patients with rheumatic mitral stenosis (aged from 32-73 years; 8 males, 41 females). The patients were classified on the basis of the degree of MR after PTMC, compared with that before PTMC, into either Group A, development of moderate or more severe (> or = grade 2) MR (n = 8) or Group B, no increase in MR or development of mild (grade 1) MR (n = 41). Progression to moderate or severe MR was significantly associated only with advanced age (60 +/- 8 vs 52 +/- 10 years, p < 0.05) and narrower mitral valve area (0.87 +/- 0.35 vs 1.11 +/- 0.29 cm2, p < 0.05), but other characteristics before PTMC were similar in both groups. There was no difference between the two groups in the total number and degree of balloon inflation. Immediately before the final inflation, the left atrial mean pressure and v wave pressure were decreased in smaller degrees in Group A compared with Group B (-2 +/- 2 vs -5 +/- 4 mmHg, p < 0.05; -2 +/- 2 vs -6 +/- 6 mmHg, p < 0.05, respectively). Thus, the stepwise inflations require careful monitoring of changes in the left atrial pressure and waveform to recognize the aggravation of MR, especially in older patients with severe stenosis. Patients who do not have a significant drop in left atrial mean pressure and v wave pressure during stepwise inflations of the balloon might be at risk of development of moderate or severe MR after further dilations.

Adult↗
PubMed1998

Development of perioral muscle activity during suckling in infants: a cross-sectional and follow-up study.

The activity of the perioral muscles during breastfeeding in infants was investigated using EMGs. Fifty-six infants aged from 1 to 5 months were classified into five groups according to month of age in the cross-sectional study. Follow-up was carried out on 18 infants whose mean age was 2.5 months at the initial examination, and 4.8 months at the second. During suckling, EMGs were recorded unilaterally from the temporalis (TM), the masseter (MM), the orbicularis oris (OM), and the suprahyoid (SM) muscle groups. The activity of the SM increased significantly with age, while there was no appreciable increase in the activity of the TM, MM, and OM in either the cross-sectional study or the follow-up. However, total muscle activity was shown to increase significantly in both parts of the study. These findings suggest that the active tongue- and jaw-lowering movement may play a primary role in increasing sucking strength during the suckle-feeding period in infants.

Cross-Sectional Studies↗
PubMed1998

[Cardiac amyloidosis with atrioventricular valve thickening and left atrial dysfunction: a case report].

A 70-year-old man with cardiac amyloidosis was referred to our hospital because of exertional chest pain accompanied by ischemic changes on electrocardiography on April 2, 1997. Transthoracic echocardiography revealed a normal size and normally contracted left ventricle without hypertrophy and "granular sparkling" quality of the myocardium, thickening of the mitral and tricuspid valves, and enlargement of the left atrium with reduced booster pump function. Pulsed Doppler mitral inflow velocity wave showed a pseudonormalized pattern, and pulmonary venous flow velocity wave showed a non-compliant pattern. Transesophageal echocardiography revealed thickening and reduced movement of the interatrial septum and reduced flow velocity in the left atrial appendage, suggesting left atrial dysfunction. Adenosine triphosphate (ATP) stress thallium-201 myocardial scintigraphy showed reversible patchy defect mainly in the posterolateral wall. Left ventricular end-diastolic and pulmonary capillary wedge pressures were mildly elevated. Angiography showed normal coronary arteries, but coronary flow reserve measured by administering intravenous ATP in the left anterior descending artery was severely impaired. A rectal biopsy specimen was positive by Congo red staining. Thus, angina pectoris in this patient may be due to amyloid infiltration of the small intramural coronary arteries. Atrioventricular valve thickening and left atrial dysfunction are important clues to diagnose cardiac amyloidosis.

Adenosine Triphosphate↗
PubMed1998

Canal-down tympanoplasty; one-stage tympanoplasty with mastoid obliteration, for non-cholesteatomatous chronic otitis media associated with osteitis.

We operated on 54 ears using the canal-down procedure consisting of one-stage tympanoplasty with mastoid obliteration for non-cholesteatoma otitis media with lesions in the ossicular chain and compared the results with those of patients treated with the canal-up procedure. Complications, such as mastoid problems, which have been observed in surgery with the simple canal-down procedure, were not observed in operations combining mastoid obliteration. The success rate for our procedure as evaluated by postoperative hearing levels, according to the standards established by the Japan Society of Clinical Otology, Committee on Nomenclature 1987, was 77.4% with tympanoplasty (ceramic P type) with reconstruction of the ossicular chain; 70.6% with reconstructive surgery using T type ceramic; and 50.0% with reconstructive surgery using the patient's own bone. Overall, the success rate was 72.2%. Our procedure seems to be superior to the canal-up procedure with respect to improvement of hearing levels in the treatment of patients with chronic otitis media associated with lesions in the ossicular chain.

Cholesteatoma, Middle Ear↗