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Biomedical subjects

Michihiro Yoshimura

Publications and source records attributed to Michihiro Yoshimura.

At least 37 records · Page 2Linked to original sources
PubMed2005

Urinary 8-hydroxy-2'-deoxyguanosine levels increase after reperfusion in acute myocardial infarction and may predict subsequent cardiac events.

We assessed serial changes in oxidative stress in patients with acute myocardial infarction by measuring urinary 8-hydroxy-2'-deoxyguanosine excretion. The urinary 8-hydroxy-2'-deoxyguanosine creatinine levels peaked at 4 hours after reperfusion therapy and the levels were higher in the cardiac event group than in the noncardiac event group before and after reperfusion.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2005

Levels of the adipocyte-derived plasma protein, adiponectin, have a close relationship with atheroma.

INTRODUCTION: Inflammation is a key process in atherosclerotic formation. Structural changes in the carotid arterial wall including detection of focal plaques are measured as the intima-media thickness (IMT) providing an index of atheroma. Coronary arterial plaques may be considered as vascular structural changes. Distensibility of the arteries can be assessed by functional changes in pulse wave velocity (PWV) providing an index of sclerosis. Adiponectin has potential antiatherosclerotic properties. We hypothesized that adiponectin was associated with atherosclerotic vascular changes involved in inflammation. MATERIALS AND METHODS: We enrolled 142 patients with coronary artery disease (CAD) and 108 control patients, matched for age, sex, and body mass index (BMI) with CAD patients. We investigated the relationship between adiponectin, C-reactive protein (CRP), and atherosclerotic vascular changes. RESULTS: CRP (p=0.0009), high-density lipoprotein cholesterol (HDL-C; p=0.02), and IMTmax (p=0.02) were determinants of adiponectin independent of glucose intolerance (p=0.0001), BMI (p=0.002), and CAD (p=0.03), all of which have been significantly associated with adiponectin (r=0.38). Adiponectin was not correlated with PWV. CRP, glucose intolerance, and HDL-C that correlated with adiponectin were inversely correlated with IMTmax and CAD. CRP was negatively correlated with HDL-C (r=-0.24, p=0.0002) and positively correlated with glucose intolerance (r=0.15, p=0.01). CONCLUSIONS: Adiponectin has a close relationship with CRP, IMTmax, CAD, HDL-C, and other established risk factors. CRP, glucose intolerance, and HDL-C are common mediators between adiponectin and atheromatous vascular changes, which are contrary to each other. The exacerbation of atherogenesis may be involved in a decrease of adiponectin through abnormal glyco- and lipid-metabolism by promoting inflammation.

Adiponectin↗
PubMed2005

Adrenocorticotropic hormone is produced in the ventricle of patients with essential hypertension.

OBJECTIVE: Aldosterone is produced in the ventricle of patients with hypertension. The present study was designed to examine whether adrenocorticotropic hormone (ACTH) and cortisol are also produced from the heart in patients with essential hypertension. METHODS: The study population consisted of 57 patients with essential hypertension and 28 control subjects. Plasma levels of ACTH, aldosterone, and cortisol were measured in the aortic root, the anterior interventricular vein and the coronary sinus during cardiac catheterization. RESULTS: The plasma levels of ACTH were significantly higher at the anterior interventricular vein and coronary sinus than at the aortic root (12.7 +/- 1.0 versus 10.7 +/- 0.9 pmol/l, P < 0.001; and 12.3 +/- 1.0 versus 10.7 +/- 0.9 pmol/l, P < 0.001, respectively) in the hypertension group, whereas there were no significant differences in the levels among these sites in the control group. The plasma levels of aldosterone were significantly higher at the anterior interventricular vein and the coronary sinus than at the aortic root (261.7 +/- 16.4 versus 239.1 +/- 15.1 pmol/l, P < 0.001; and 258.8 +/- 17.0 versus 239.1 +/- 15.1 pmol/l, P < 0.01, respectively) in the hypertension group, whereas there were no significant differences in the levels among these sites in the control group. CONCLUSIONS: ACTH as well as aldosterone is produced, but cortisol is not produced, from the ventricle of patients with essential hypertension.

Adrenocorticotropic Hormone↗
PubMed2005

Increase in the transcriptional activity of the endothelial nitric oxide synthase gene with fluvastatin: a relation with the -786T>C polymorphism.

HMG-CoA reductase inhibitors (statins) increase endothelial nitric oxide (NO) production, although the precise mechanism of this statin induced increase in NO production remains to be elucidated. We examined endothelial nitric oxide synthase (eNOS) mRNA levels, mRNA stability and the transcriptional activities of the eNOS gene in human umbilical vein endothelial cells treated with fluvastatin and simvastatin. We further examined whether the effects of these statins differ dependent upon the -786T>C polymorphism in the eNOS gene, and whether these statins affect gene expression of replication protein A1 (RPA1), which is known to reduce the transcriptional activity of the eNOS gene with the -786C allele. Utilizing the real-time reverse transcription-polymerase chain reaction, fluvastatin significantly increased eNOS mRNA levels and mRNA stability, and decreased RPA1 mRNA levels. Luciferase reporter gene assays revealed that fluvastatin significantly increased the transcriptional activity of the eNOS gene. The effect of fluvastatin was stronger in the -786C/C genotype than in the -786T/T genotype. Simvastatin increased eNOS mRNA levels and mRNA stability, but did not affect the transcriptional activity of the eNOS gene. Fluvastatin increased eNOS mRNA levels by enhancing both the transcriptional activity and mRNA stability. The effect of fluvastatin on the transcriptional activity was augmented in the -786C/C genotype, probably because of a decrease in RPA1 gene expression. Simvastatin increased eNOS mRNA levels only by enhancing mRNA stability. The present study suggests that fluvastatin increases endothelial NO activity and thus may be more beneficial to patients with the -786C allele.

Cell Line↗
PubMed2005

Hypoadiponectinemia is associated with coronary artery spasm in men.

BACKGROUND: The relationship between adiponectin and coronary spastic angina (CSA), both of which are closely involved in coronary endothelial dysfunction, has not been elucidated. METHODS AND RESULTS: Plasma adiponectin concentrations were examined in 55 men with CSA and 55 with chest pain syndrome (CPS). The plasma log-adiponectin levels were significantly lower in patients with CSA than with CPS (0.61+/-0.28 vs 0.80+/-0.21 microg/ml, p < 0.0001). The prevalence of smoking was significantly higher in the CSA patients than in those with CPS (50.9% vs 29.1%, p = 0.0195). In multiple logistic regression analysis, log-adiponectin (p = 0.0008) and smoking (p = 0.0210) were independent determinants of CSA. Conclusions Hypoadiponectinemia is a potential risk factor for CSA in men, independent of smoking.

Adiponectin↗
PubMed2005

TaqMan real-time PCR quantification: conventional and modified methods.

TaqMan real-time polymerase chain reaction (PCR) is a sensitive and reliable method that is widely used around the world. However, its inability to carry out assays using only small amounts of template DNA represents a serious limitation of the method. Recently, measurement of very small quantities of DNA became possible when a slight modification was applied to the conventional TaqMan real-time PCR method. Using the modified real-time PCR method, we were able to measure very small amounts of DNA template, and succeeded in comparing the levels of aldosterone synthase gene expression in samples of cardiac tissue from patients diagnosed with heart failure and control subjects.

Base Sequence↗
PubMed2005

Increased plasma levels of thioredoxin in patients with glucose intolerance.

OBJECTIVE: The aim of the present study was to determine the effects of glucose intolerance on oxidative stress in patients with coronary artery disease (CAD). METHODS: The patients were divided into 3 groups, diabetes mellitus (DM), IGT or normal glucose tolerance (NGT) according to the criteria of the American Diabetes Association. PATIENTS: The present study consisted of 178 consecutive patients who underwent diagnostic coronary arteriography and a 75-g glucose tolerance test. RESULTS: The level of plasma thioredoxin, a marker of oxidative stress was measured in every patient during the fasting state. The levels of plasma thioredoxin were significantly higher in the DM and IGT groups than the NGT group. Furthermore, we found that there was a positive association between thioredoxin levels and glycosylated hemoglobin (sigma=0.225, p=0.018). In multivariate logistic regression analysis, glucose intolerance (DM or IGT) was only independently associated with the high levels of thioredoxin. The levels of plasma thioredoxin were significantly higher in the CAD group compared to the non-CAD group. In multivariate logistic regression analysis, high levels of thioredoxin, male, age and hypertension were independently associated with the presence of CAD. CONCLUSION: Glucose intolerance was associated with the high levels of thioredoxin. High levels of thioredoxin were related to the presence of CAD. The measurement of thioredoxin as the marker of oxidative stress may be useful for monitoring the development of the cardiovascular diseases.

Adult↗
PubMed2005

Sensorineural hearing loss combined with Takayasu's arteritis.

A 49-year-old woman complained of hearing loss and diminution of left radial arterial pulsation. She had been diagnosed with sudden deafness and treated with corticosteroids. Her audibility deteriorated again after the cessation of the therapy. Angiograms showed stenosis in the bilateral carotid arteries, the left vertebral artery, the left subclavian artery, and the pulmonary arteries. She was diagnosed with Takayasu's arteritis. After steroid therapy was restarted, there were improvements in her audibility, radial arterial pulsation, and levels of inflammatory markers (erythrocyte sedimentation rate, C-reactive protein, and gamma-globulin), fibrinogen, interleukin-6, and RANTES (regulated on activation, normal T cell expressed and secreted).

Administration, Oral↗
PubMed2005

Dynamic electrocardiographic changes due to cardiac compression by a giant hiatal hernia.

A 79-year-old woman was admitted due to chest pain with T wave inversion and anasarca. Echocardiography demonstrated a mass compressing the heart and computed tomography revealed a giant hiatal hernia within the intrathoracic stomach located just behind the heart. After drainage of the gastric contents, the T wave inversion disappeared, but subsequent ST elevation in leads V1-V6 was noted. After surgical correction of the hiatal hernia, the ST segment elevation returned to a nearly normal level. The changes in the compressed heart induced by hiatal hernia may cause pericarditis resulting in electrocardiographic changes.

Aged↗
PubMed2005

Platypnea-orthodeoxia syndrome combined with multiple congenital heart anomalies.

A 71-year-old woman was admitted for paralysis on the left side of her body. She developed dyspnea and hypoxemia after admission. Although pulmonary embolism was suspected, hypoxemia and dyspnea occurred repeatedly in spite of anticoagulation therapy. Transesophageal echocardiography revealed a patent foramen ovale (PFO), an atrial septal aneurysm (ASA), and a right-to-left shunt that appeared in an upright position. She was diagnosed with platypnea-orthodeoxia syndrome. Moreover, cardiac catheterization showed congenital anomalies, such as unroofed coronary sinus, partial anomalous pulmonary venous return and persistent left superior vena cava. Simple surgical closure of the ASA and PFO improved all of her symptoms.

Abnormalities, Multiple↗
PubMed2005

Successful coronary stenting of the left anterior descending artery at the branching site of the targeted septal perforator immediately after percutaneous transluminal septal myocardial ablation in hypertrophic obstructive cardiomyopathy.

We report a case of simultaneous percutaneous treatment of hypertrophic obstructive cardiomyopathy (HOCM) and coronary artery disease. Cardiac catheterization revealed a left ventricular outflow tract pressure gradient (LVOTPG) of 130 mmHg and a significant left anterior descending artery (LAD) stenosis at the site of the 1st major septal branch. The LVOTPG was eliminated by injection of ethanol into the branch. Subsequently, a coronary stent was implanted in the LAD. A coil stent was selected due to possibility of repeat septal ablation in the future. Simultaneous treatment of HOCM and LAD stenosis is considered safe and effective using a coil stent.

Aged↗
PubMed2004

Possible association of heart failure status with synthetic balance between aldosterone and dehydroepiandrosterone in human heart.

BACKGROUND: Aldosterone is produced not only in the adrenal gland but also in the extra-adrenal tissues, including failing human heart. This study examined the production of dehydroepiandrosterone (DHEA) in human heart and elucidated the possible physiological significance. Method and Results- Using left ventricular tissues obtained at autopsy, reverse transcription-polymerase chain reaction followed by Southern blot analysis revealed the gene expressions of CYP17. By measuring plasma aldosterone and DHEA levels at the coronary sinuses and aortic roots during cardiac catheterization, we found that DHEA but not aldosterone was secreted from control subjects (P<0.0001 and P=0.74, respectively), whereas aldosterone but not DHEA was secreted from patients with heart failure (P=0.0017 and P=0.67, respectively). To examine the significance of DHEA, we measured myocyte cell sizes and the gene expression of B-type natriuretic peptide (BNP), using a neonatal rat cardiocyte culture system. We found that DHEA (10(-8) mol/L) significantly inhibited the increase in myocyte cell sizes and BNP mRNA levels upregulated by endothelin-1 (P=0.031 and P<0.0001, respectively). CONCLUSIONS: CYP17 gene expression and production of DHEA were demonstrated in human control heart. Also, we found that cardiac production of DHEA was suppressed in failing heart. We postulated that DHEA and/or its metabolites exert a cardioprotective action through antihypertrophic effects.

Adult↗
PubMed2004

Plasma level of B-type natriuretic peptide as a prognostic marker after acute myocardial infarction: a long-term follow-up analysis.

BACKGROUND: Circulating levels of B-type natriuretic peptide (BNP), a cardiac hormone, reflect the severity of cardiac dysfunction. Because the plasma BNP level changes dramatically during the period after the onset of acute myocardial infarction (AMI), identification of a suitable sampling time is problematic. There have been several reports indicating that the plasma BNP level obtained in the acute phase of AMI can be used as a prognostic marker. We examined whether the plasma BNP level measured 3 to 4 weeks after the onset of AMI represents a reliable prognostic marker for patients with AMI. METHODS AND RESULTS: We analyzed 145 consecutive patients with AMI. Plasma BNP levels were measured during the 3 to 4 weeks after onset of AMI. Of those patients, 23 experienced fatal cardiac events during this study. The mean follow-up period was 58.6 months. Log BNP, left ventricular end-diastolic pressure, and pulmonary vascular resistance were all significantly higher in the cardiac death group, and there were more men and more patients with a history of heart failure in the cardiac death group. A Cox proportional hazards model analysis showed that log BNP was an independent predictor of cardiac death. The survival rate was significantly higher in patients with log BNP <2.26 (180 pg/mL) than in those with log BNP > or =2.26. CONCLUSIONS: The plasma BNP level obtained 3 to 4 weeks after the onset of AMI can be used as an independent predictor of cardiac death in patients with AMI.

Adult↗