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Biomedical subjects

T Ohtsuka

Publications and source records attributed to T Ohtsuka.

At least 127 records · Page 7Linked to original sources
PubMed1999

[The efficacy and practice of exercise training in patients with chronic obstructive pulmonary disease (COPD)].

Exertional dyspnea is a most popular symptom in COPD patients often lead to exercise intolerance. Indeed the reduced activity in patient's daily life due to dyspnea may lead to deconditioning and peripheral muscle weakness. Bronchodilators and anti-inflammatory drugs are an important treatment to reduce symptoms and improve airflow limitation but not improve deconditioning. Impairment of exercise tolerance is a common problem in patients with COPD and therefore exercise training is an important component of all pulmonary rehabilitation programs. It is now clearly established that exercise training reduce dyspnea, improve exercise tolerance and improve activities of daily living (ADL) and health related quality of life (QOL). Oxygen therapy during exercise are often considered in the COPD patients with exercise induced hypoxemia.

Activities of Daily Living↗
PubMed1999

Hypertrophic cardiomyopathy with mid-ventricular obstruction and splenic infarction associated with paroxysmal atrial fibrillation: a case report.

A 54-year-old woman had been treated for hypertrophic cardiomyopathy and paroxysmal atrial fibrillation since 1992. She was admitted with paroxysmal atrial fibrillation which was resolved by medical treatment. However, on the next day, left lateral chest pain appeared. Computed tomography disclosed a low density area in the spleen. She received anticoagulant therapy under a diagnosis of splenic infarction, and the pain disappeared. Echocardiography showed hypertrophic cardiomyopathy with mid-ventricular obstruction. She was treated with cibenzoline to prevent paroxysmal atrial fibrillation attack and attenuate the hemodynamic load. After treatment, the pressure gradient decreased from 41 to 7 mmHg. This patient with hypertrophic cardiomyopathy suffered a rare isolated splenic infarction associated with paroxysmal atrial fibrillation.

Anti-Arrhythmia Agents↗
PubMed1998

Nexilin: a novel actin filament-binding protein localized at cell-matrix adherens junction.

We isolated two novel actin filament (F-actin)-binding proteins from rat brain and rat 3Y1 fibroblast. They were splicing variants, and we named brain big one b-nexilin and fibroblast small one s-nexilin. b-Nexilin purified from rat brain was a protein of 656 amino acids (aa) with a calculated molecular weight of 78,392, whereas s-nexilin, encoded by the cDNA isolated from rat 3Y1 cells by the reverse transcriptase-PCR method, was a protein of 606 aa with a calculated molecular weight of 71,942. b-Nexilin had two F-actin- binding domains (ABDs) at the NH2-terminal and middle regions, whereas s-nexilin had one ABD at the middle region because 64 aa residues were deleted and 14 aa residues were inserted in the first NH2-terminal ABD of b-nexilin, and thereby the first ABD lost its activity. b- and s-nexilins bound along the sides of F-actin, but only b-nexilin showed F-actin cross-linking activity. b-Nexilin was mainly expressed in brain and testis, whereas s-nexilin was mainly expressed in testis, spleen, and fibroblasts, such as rat 3Y1 and mouse Swiss 3T3 cells, but neither b- nor s-nexilin was detected in liver, kidney, or cultured epithelial cells. An immunofluorescence microscopic study revealed that s-nexilin was colocalized with vinculin, talin, and paxillin at cell- matrix adherens junction (AJ) and focal contacts, but not at cell-cell AJ, in 3Y1 cells. Overexpressed b- and s-nexilins were localized at focal contacts but not at cell-cell AJ. These results indicate that nexilin is a novel F-actin-binding protein localized at cell-matrix AJ.

Actins↗
PubMed1998

Regulation of Zn-alpha2-glycoprotein-mediated cell adhesion by kininogens and their derivatives.

MC3T3-E1 (mouse osteoblast-like) cells adhered to a tissue culture plate coated with human Zn-alpha2-glycoprotein (Znalpha2gp). The adhesion of MC3T3-E1 cells to Znalpha2gp was inhibited by synthetic peptides such as RGDS and ELRGDV, and by antibody against vitronectin receptor. These findings suggested that the RGD region of Znalpha2gp interacts with the vitronectin receptor (alphavbeta3) on the MC3T3-E1 cell surface. Furthermore, we found that the common heavy chain of both HMW- and LMW-kininogens accelerated the Znalpha2gp-mediated MC3T3-E1 cell adhesion. Among the three domains of the common heavy chain of both kininogens, domain 3 promoted the cell adhesion by up to 200%. Among the nine synthetic peptides covering domain 3, the peptide, N334AEVYVVPWEKKIYPTVN351 accelerated in a dose-dependent manner the Znalpha2gp- and vitronectin (VN)-mediated MC3T3-E1 cell adhesion. These findings suggested that a defined region of domain 3 is responsible for the acceleration of cell adhesion.

3T3 Cells↗
PubMed1998

Relationship between nerve and muscle fiber conduction velocities of the same motor unit in man.

To test the hypothesis that the nerve fiber conduction velocity of a motor unit is correlated with the muscle fiber conduction velocity of the unit, the collision technique was used to discriminate the motor unit action potentials elicited by stimulation of a group of nerve fibers with known conduction velocity. Muscle fiber conduction velocity was determined from the propagating action potentials of the unit recorded by a surface electrode array. A weak but significantly positive correlation was found between nerve and muscle fiber conduction velocities in the thenar muscle of human subjects. The results indicate that the size principle that governs the relation between nerve and muscle fiber size is a fairly weak principle with occasional exceptions.

Action Potentials↗
PubMed1998

[Video-assisted MICABG for the patient with right mammary carcinoma--a case report].

A 69-year-old female with advanced right mammary carcinoma presented to us with diffuse stenosis of the proxymal left anterior descending artery (LAD). Right mastectomy had been suspended. The LAD was treated with minimally invasive CABG (MICABG) assisted with a thoracoscopic procedure. The left internal thoracic artery (LITA) was taken down through thoracoscopy from the upper margin of the 1st rib to the lower margin of the 5th rib using only the Harmonic Scalpel (Ethicon Endo-Surgery). Coronary anastomosis to the LAD was completed without cardiopulmonary bypass through a small thoracotomy on the anterior 4th intercostal space. The operation time was 4 h 30 min and the blood loss was 120 ml. Post operative course was uneventful. Doppler study and angiography demonstrated patent LITA to the LAD. Right mastectomy was achieved 29 days after MICABG. MICABG can be a veneficial alternative method for the patient with malignant disease, allowing quick convalescence and early cancer operation. Thoracoscopy allows for sufficient LITA harvest up to the 1st rib or higher with the Harmonic Scalpel.

Aged↗
PubMed1998

Regulated expression of neurogenic basic helix-loop-helix transcription factors during differentiation of the immortalized neuronal progenitor cell line HC2S2 into neurons.

Expression of nine neurogenic basic helix-loop-helix (bHLH) transcription factors was examined in an immortalized neuronal progenitor cell line HC2S2, which differentiates into neurons after suppression of the v-myc expression with tetracycline. Expression of MASH-1, NeuroD, NeuroD-related factor (NDRF) and HES-1 was demonstrated in HC2S2 cells by Northern blot analysis using total RNA. Expression of MASH-1 mRNA was downregulated upon differentiation of HC2S2 cells into mature neurons. In contrast, NeuroD and NDRF mRNA expression was maintained all through the differentiation. The expression of HES-1, a negative regulator of the neuronal differentiation, was upregulated temporarily in accordance with the suppression of the v-myc expression and was downregulated upon the differentiation of HC2S2 cells into neurons. The reduced expression of HES-1 mRNA in undifferentiated HC2S2 cells may be explained by the transcriptional suppression of HES-1 by the myc oncoprotein. The above data imply that both HES-1 and MASH-1 need to be downregulated at the time of accomplishment of the terminal differentiation into mature neurons and that NeuroD and NDRF participate in the regulatory process of the terminal differentiation in combination.

Animals↗
PubMed1998

Thoracoscopic limited pericardial resection with an ultrasonic scalpel.

We employed an ultrasonic scalpel, the Harmonic Scalpel (Ethicon Endo-Surgery, Cincinnati, OH), for thoracoscopic limited pericardial resection in consecutive 10 patients with massive pericardial effusion or pericarditis. The mean operative time was 27 minutes for pericardial effusion. No dangerous arrhythmias were induced even in the patient with dense pericardial adhesions. There were no operation-related complications or deaths. The thoracoscopic ultrasonic scalpel technique can be an efficacious minimally invasive alternative for pericardial window.

Endoscopy↗
PubMed1998

Myocardial tactile stiffness: a variable of regional myocardial function.

OBJECTIVES: We developed a new sensor system for in situ measurement of myocardial tactile stiffness-stiffness in a direction perpendicular to the wall-and validated its use for providing a reasonable estimation of regional myocardial function. BACKGROUND: Numerous attempts have been made to directly assess regional myocardial function. The complexity and highly invasive nature of the measuring devices have hampered their in situ application. METHODS: In open chest mongrel dogs, myocardial tactile stiffness, ventricular pressure and ventricular volume were monitored. Under the preload reduction, these variables were measured to determine the relation between the end-systolic pressure-volume relation (ESPVR) and the end-systolic tactile stiffness-volume relation (ESSVR). The changes in myocardial tactile stiffness were monitored in the regional ischemic myocardial model and infarcted model to evaluate their usefulness as indexes of regional myocardial function. RESULTS: Myocardial tactile stiffness changed cyclically and followed a time course similar to left ventricular pressure. When preload was altered, the ESSVR was as linear as the ESPVR. The slope of the ESSVR and that of the ESPVR showed a strong correlation over a wide range of contractility. These results suggest that myocardial tactile stiffness can be a good index of regional wall stress or fiber stress. End-systolic myocardial tactile stiffness of ischemic and infarcted regions decreased significantly, with a concomitant increase in end-diastolic stiffness compared with that of intact myocardium. CONCLUSIONS: Using our tactile sensor system, regional myocardial tactile stiffness of a beating heart was measured with reasonable temporal resolution. We consider myocardial tactile stiffness to be a useful index of regional myocardial function.

Animals↗
PubMed1998

Left ventricular geometry as an independent predictor for extracardiac target organ damage in essential hypertension.

Left ventricular hypertrophy (LVH) is an independent cardiovascular risk factor. It has not been established, however, whether left ventricular geometry is an independent predictor of extracardiac target organ damage in essential hypertension. Study groups were classified according to relative wall thickness: 27 patients with concentric LVH and 50 patients with eccentric LVH. Age and left ventricular mass indexes of two groups were matched. As indexes of extracardiac target organ damage, retinal funduscopic grade, and serum creatinine level were measured. The severity of hypertensive retinopathy and the renal involvement were more severe in patients with concentric LVH than in patients with eccentric LVH. Extracardiac target organ damage was consistently higher in patients with concentric LVH than in those with eccentric LVH. Systemic hemodynamics paralleled ventricular geometric patterns, with higher peripheral resistance and lower aortic compliance in patients with concentric LVH, whereas end-diastolic volumes and stroke volumes were higher in patients with eccentric LVH than in patients with concentric LVH. In addition, total peripheral resistance was related to retinal fundoscopic grade (r = 0.41, P < .01), and serum creatinine level (r = 0.28, P < .05). Even in the presence of an identical degree of LVH, echocardiographically determined left ventricular geometry may provide a further independent stratification of extracardiac target organ damage in essential hypertension.

Aged↗
PubMed1998

Early results of thoracoscopic internal mammary artery harvest using an ultrasonic scalpel.

OBJECTIVE: We developed a thoracoscopic internal mammary artery harvest technique using an ultrasonic scalpel, the Harmonic Scalpel (Ethicon Endo-Surgery, Cincinnati, OH). This is the first report of 9 month follow-up using this technique. METHODS: The Harmonic Scalpel is activated ultrasonically by vibrating at 55000 Hz. Compared with electrocautery, lower heat (<100 degrees C) and less smoke are generated. Thoracoscopic harvest using the Harmonic Scalpel with a hook blade was performed for 48 internal mammary arteries (42 left, six right) in 46 patients. Four (8.7%) of them were redo cases. The left internal mammary to left anterior descending artery and the right internal mammary to right coronary artery anastomoses were accomplished on the beating heart. Two left internal mammary arteries were sequentially, anastomosed to diagonal branches. Graft flow velocity was evaluated with pulsatile wave color Doppler test on the second or third postoperative day and repeated 3 and 6 months later. RESULTS: The mean harvest time was 65 min (range 35-95 min) for the left internal mammary artery and 37 min (range 25-45 min) for the right internal mammary artery. One left internal mammary artery was lost due to intimal dissection. The Harmonic Scalpel-related morbidity was transient left phrenic palsy in one case and mild heat injury at the skin incision in the majority of cases. One Patient (2.2%) expired due to ischemic bowel on the second postoperative day. At a mean of 9 months follow-up, 45 alive patients have been free of angina. Doppler studies revealed diastolic augmentation of the graft flow velocity in 22 left and two right internal mammary arteries on the second or third postoperative day and 23 left and five right internal mammary arteries 3 and 6 months after operation. CONCLUSIONS: Thoracoscopic internal mammary artery harvest is feasible and facilitated by the use of the Harmonic Scalpel. Early results of this technique are encouraging.

Coronary Disease↗
PubMed1998

Right ventricular rupture in minimally invasive direct coronary artery bypass grafting.

We report a rare case of the rupture of the right ventricle which occurred in a minimally invasive direct coronary artery bypass grafting (MIDCABG) for a redo bypass surgery. A 52-year-old male patient underwent a left internal thoracic artery (LITA) to the left anterior descending artery (LAD) bypass. Rupture of the right ventricle occurred abruptly during dissection to find the LAD. Too much dissection of the interventricular groove under undue traction of the pericardium may cause a rupture of the heart.

Humans↗
PubMed1998

The predictive value of quantitative nailfold capillary microscopy in patients with undifferentiated connective tissue disease.

The present prospective study was undertaken to follow the natural history of patients with Raynaud's phenomenon and to document in these patients the frequency with which secondary disorders develop. Seventeen patients with primary Raynaud's phenomenon (PRP) and 43 patients with undifferentiated connective tissue disease (UCTD) were examined after 6-8 years to see whether they had developed into UCTD or systemic sclerosis (SSc), respectively. Their nailfold capillary parameters were analysed statistically to ascertain whether they would predict for the development of the diseases into UCTD or SSc. Two patients with PRP(12%) developed into UCTD, and 10 patients with UCTD (23%) into SSc. In PRP, all three parameters of the patients who developed into UCTD showed a tendency to be larger than in those who did not develop UCTD. In UCTD, the apical limb width (P < 0.02), capillary width (P < 0.01) and capillary length (P < 0.01) of the subjects who developed SSc were significantly larger than those who did not. Of the clinicolaboratory findings in patients with UCTD, the occurrence rate of abnormal apical limb width (relative risk 20. 7, P < 0.01), abnormal capillary width (relative risk 10.7, P < 0. 01), abnormal capillary length (relative risk 9.2, P < 0.02) and antinuclear antibody (relative risk 9.6, P < 0.05) showed a significant predictive value for the development of UCTD into SSc. These results indicate that quantitative nailfold capillary microscopy, as well as antinuclear antibody, will provide exact predictive information in patients with UCTD in clinical practice.

Adolescent↗
PubMed1998

Elevated expression of epidermal ornithine decarboxylase mRNA in scleroderma.

Using in situ hybridization techniques, we examined the expression of ornithine decarboxylase (ODC) mRNA in the skin of five patients with systemic sclerosis (SSc) and five normal controls. Sections treated with an anti-sense probe showed concentrated grains exclusively in the epidermis of SSc patients, but not in that of normal controls. Because our subcloned anti-sense probe specifically hybridizes with ODC mRNA, these findings indicate that the expression of ODC mRNA is elevated in SSc epidermis. Possibly polyamines have an important part to play in the skin changes of SSc.

Humans↗