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Biomedical subjects

Y Hara

Publications and source records attributed to Y Hara.

At least 181 records · Page 10Linked to original sources
PubMed1999

Centrally administered adrenomedullin increases plasma oxytocin level with induction of c-fos messenger ribonucleic acid in the paraventricular and supraoptic nuclei of the rat.

The effects of intracerebroventricular (i.c.v.) administration of adrenomedullin (AM) on plasma oxytocin (OXT), c-Fos protein (Fos), and c-fos messenger RNA (mRNA) in the paraventricular (PVN) and supraoptic nuclei (SON) of the rat were investigated using RIA for OXT, immunohistochemistry for Fos, and in situ hybridization histochemistry for c-Fos mRNA. Central administration of AM caused a significant increase in the plasma OXT level. Intracerebroventricular administration of AM caused a marked induction of Fos-like immunoreactivity (LI) in the PVN and in the dorsal parts of the SON. In the PVN and SON, OXT-LI cells predominantly exhibited nuclear Fos-LI in comparison with arginine vasopressin-LI cells. In situ hybridization histochemistry revealed that the induction of c-fos mRNA in the PVN and SON was increased in a dose-related manner 30 min after i.c.v. administration of AM. This induction was reduced by pretreatment with the AM receptor antagonist, human AM-(22-52)-NH2. These results suggest that central AM is responsible for activating the neurosecretory cells in the PVN and SON via selective AM receptors, and that AM stimulates the secretion of OXT by activating hypothalamic OXT-producing cells.

Adrenomedullin↗
PubMed1999

Left ventricular end-systolic wall stress is a potent prognostic variable in patients with dilated cardiomyopathy.

Dilated cardiomyopathy is an important cause of morbidity and mortality among patients with heart failure. Left ventricular dilation is viewed as a compensatory response to maintain stroke volume, and left ventricular dilation is directly related to the increase of wall stress. However, only a few studies have examined whether wall stress can be a prognostic variable in patients with dilated cardiomyopathy. This study was designed to elucidate whether left ventricular systolic wall stress was related to the prognosis in patients with dilated cardiomyopathy. Twenty-five normal control subjects and 68 patients with dilated cardiomyopathy participated in this study. Hemodynamic parameters and left ventricular systolic wall stress were determined using echocardiography. In addition, the extent score determined by thallium-201 myocardial scintigraphy was measured as an index of cumulative loss of myocardium. During the 53-month follow-up period, 13 patients died of cardiac events. In a stepwise multivariable analysis, end-systolic wall stress and fractional shortening were significant predictors of survival. The extent score was markedly greater in the patients who died than in alive patients. There was a significant correlation between end-systolic wall stress and extent score (r=0.501, p=0.0001). Left ventricular end-systolic wall stress is an important predictor of mortality in patients with dilated cardiomyopathy.

Adult↗
PubMed1999

Diazepam increases calcium sensitivity of the skinned cardiac muscle fiber in guinea pig.

Influences of diazepam, a benzodiazepine derivative, on the contractile response to calcium in skinned trabecular fibers of guinea pig heart were examined. Diazepam (100 microM) enhanced the contractile response of the skinned fiber to calcium and shifted the concentration-response curve to the left. The pCa50 values were 6.07+/-0.03 and 6.28+/-0.03 (P<0.05) in the absence and presence of diazepam, respectively. This result suggests that diazepam increases calcium sensitivity of contractile proteins in heart muscles.

Anesthetics, Intravenous↗
PubMed1999

Radical scavenging activity of tea catechins and their related compounds.

(-)-Epigallocatechin gallate was found to be the most effective scavenger among tea catechins for the superoxide anion, hydroxyl radical, and 1,1-diphenyl-3-picrylhydrazyl radical. Examination of the scavenging effects of tea catechins and their glucosides on superoxide anion showed that the presence of at least an ortho-dihydroxyl group in the B ring and a galloyl moiety at the 3 position was important in maintaining the effectiveness of the radical scavenging ability. Stoichiometric factors of tea catechins were estimated to be 2 for (+)-catechin and (-)-epicatechin, 5 for (-)-epigallocatechin, 7 for (-)-epicatechin gallate, and 10 for (-)-epigallocatechin gallate.

Bepridil↗
PubMed1999

Interaction of tea catechins with lipid bilayers investigated with liposome systems.

Interaction of tea catechins with lipid bilayers was investigated with liposome systems, which enabled us to separate liposomes from the external medium by centrifugation. We found that epicatechin gallate had the highest affinity for lipid bilayers, followed by epigallocatechin gallate, epicatechin, and epigallocatechin. Epicatechin gallate and epigallocatechin gallate in the surface of lipid bilayer perturbed the membrane structure.

Catechin↗
PubMed1999

Methylation of tea catechins by rat liver homogenates.

Methylation of (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), and (-)-epigallocatechin gallate (EGCg) was carried out with a rat liver homogenate and S-adenosyl-L-methionine. A structural analysis of the reaction products by MS and NMR showed that 4'-O-methyl EGC, 4"-O-methyl ECg, and 4"-O-methyl EGCg had been formed from EGC, ECg, and EGCg, respectively. These results suggest that methylation may be one of the metabolic pathways to the catechins.

Animals↗
PubMed1999

Apoptosis-inducing activity of polyphenol compounds derived from tea catechins in human histiolytic lymphoma U937 cells.

Polyphenolic compounds derived from tea catechins were examined for apoptosis-inducing activity in human histiolytic lymphoma U937 cells. (-)-Epigallocatechin gallate, theasinensin D, compound OH-5, theaflavin, and theaflavin digallate induced apoptosis as evidenced by DNA ladder formation, its inhibition by a caspase inhibitor, and chromatin condensation. Theasinensin D was the most potent inducer and the data suggest the importance of the number and three dimensional localization of their phenolic groups in this activity. These apoptosis-inducible compounds may be useful as a cancer chemopreventive and chemotherapeutic agent.

Antineoplastic Agents, Phytogenic↗
PubMed1999

Serum creatinine level underestimates hypertensive renal involvement in elderly patients with essential hypertension.

It is well recognized that serum creatinine level provides a quick general assessment of renal function. However, we frequently encounter elderly hypertensive patients with renal involvement whose serum creatinine levels are within normal limits. The aim of this study was thus to determine whether serum creatinine level is a sensitive indicator of renal function in elderly hypertensive patients. Study groups were classified according to age: 82 elderly patients (aged 65 yr or older) and 98 middle-aged patients (aged 40-65 yr) with essential hypertension. To assess hypertensive renal involvement, serum creatinine and serum uric acid levels were measured. We also measured the left ventricular mass (LVM) index by using echocardiography as a marker of hypertensive target organ damage. There was no age-related difference in the LVM index, but the serum creatinine level in elderly hypertensive patients was significantly lower than that in middle-aged hypertensive patients. There was no significant difference in serum uric acid level between the two groups. In addition, the LVM index was correlated with the serum uric acid level (r = 0.46, p = 0.0001) but not with the serum creatinine level in elderly hypertensive patients. In middle-aged hypertensive patients, the LVM index was related to both serum uric acid level (r = 0.41, p = 0.007) and serum creatinine level (r = 0.43, p = 0.003). In conclusion, serum creatinine level may underestimate hypertensive renal involvement in elderly hypertensive patients. In contrast, serum uric acid level may be a sensitive indicator of hypertensive target organ damage irrespective of age.

Adult↗
PubMed1999

The effects of tea catechins on fecal conditions of elderly residents in a long-term care facility.

This study was carried out to evaluate the effects of tea catechins on fecal contents and metabolites of elderly people who were on a diet of solid food. The subjects were 35 residents in a long-term care facility who were all on the same diet, consisting of rice gruel and minced food. Tea catechins (300 mg), which were divided into 3 doses a day, were a meal supplement every day for 6 weeks. Fecal specimens were collected by the nursing staff, and their moisture content, pH, ammonia, sulfide, and oxidation-reduction potential (ORP) were determined before, during, and after the administration of tea catechins. In a comparison of values before the administration, all these fecal parameters decreased significantly during the tea catechin administration. After termination of the administration, these data tended to return toward the levels before administration. The reduction of such fecal parameters as moisture, pH, ammonia, sulfide, and ORP by tea catechin administration indicated very favorable improvements of the subjects' bowel conditions.

Aged↗
PubMed1999

A new sonographic technique for assessing carotid artery disease: extended-field-of-view imaging.

We describe a new sonographic technique, extended-field-of-view imaging, and its clinical application for carotid artery disease. The technique identifies identical structures on two successive images for position registration to make a panoramic image in real time without position sensors. In 39 of 41 subjects, this technique provided high-quality panoramic images that could not be obtained with conventional real-time sonography, and made findings in the carotid artery more interpretable.

Carotid Arteries↗
PubMed1999

[The significance of duplex ultrasonography examination in the acute cardioembolic stroke patients--with special attention to evaluation of internal carotid arteries].

The aim of this study is to clarify whether it is possible to diagnose occlusions of internal carotid arteries in the acute cardioembolic stroke patients by observing internal carotid arteries with duplex ultrasonography. Twenty-two consecutive patients underwent both duplex ultrasonography examination and cerebral angiography within 24 hours from the onset. Two cases who had no flow velocity and 8 cases who had systolic flow velocity but no anterograde diastolic flow velocity were all diagnosed as having internal carotid occlusions by cerebral angiography. Eleven of 22 cases who had anterograde diastolic flow velocity were diagnosed as having occlusions at distal side of M 1 portion or no occluded lesions. Besides, among 11 cases who were diagnosed as having occlusions of internal carotid arteries by cerebral angiography, five had end diastolic ratios (ED ratio) of common carotid arteries that were less than 4.0s. It is useful to evaluate the existence of anterograde diastolic flow velocity by duplex ultrasonography for the diagnosis of internal carotid occlusions in the acute cardioembolic stroke patients.

Acute Disease↗
PubMed1999

[Cerebral infarction associated with mobile thoracic ascending aortic thrombus in a patient with essential thrombocythemia].

A 77-year-old man with essential thrombocythemia had embolic stroke associated with mobile thoracic ascending aortic thrombus despite of receiving antiplatelet drug. He had history of toe ulcer and ileus within previous 2 years. He was diagnosed as essential thrombocythemia and received antiplatelet drug. He had consciousness disturbance and admitted to our hospital. Cerebral angiography disclosed emboli in the right middle cerebral artery (M2). Transesophageal echocardiography showed evidence of a mobile thrombus attached to the wall of the ascending aorta at the first day. The thrombus was no longer present after treatment with heparin followed by no recurrent embolic event. We prescribed hydroxyurea for essential thrombocythemia for chronic phase treatment. We consider that with essential thrombocythemia the thrombus of the ascending aorta caused the cerebral infarction. And we succeeded of the treatment of the embolic stroke and prevalence of the emboli with essential thrombocythemia.

Aged↗
PubMed1999

[Factors influencing residual renal function of CAPD patients].

It is generally accepted that residual renal function has significant meaning in dialysis adequacy of CAPD patients. However, the factors influencing the residual renal function have not been investigated yet. We evaluated the consequences of following factors on residual urine volume in 50 CAPD patients: deterioration rate of renal function (slope of I/serum creatinine) before dialysis, renal creatinine clearance at the initial point of dialysis and the episodes of rapid reduction of residual urine volume. There was no correlation between the deterioration rate of renal function before dialysis and the residual urine volume. On the contrary, there was significant correlation between renal creatinine clearance at the initial point of dialysis and the residual urine volume in the first 4 years on CAPD. We recognized 67 episodes of rapid reduction of residual urine volume after initiation of CAPD. Inappropriate management or complications attributed to the rapid urine volume reduction in 50 episodes. The residual urine volume did not recover to the previous level in 40 episodes. We concluded that early initiation of CAPD and evasion of decreasing residual urine volume caused by inappropriate management or complications have important meaning and will preserve residual renal function of CAPD patients.

Adult↗
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↗
PubMed1999

[Neovascular glaucoma following cataract surgery--a case report].

A 75-year-old man suffered from right neovascular glaucoma following ipsilateral cataract surgery. Cerebral angiogram showed occlusion of the right internal carotid artery and the steal phenomenon of right ophthalmic artery. Chronic ocular ischemia caused by carotid occlusion and ophthalmic artery steal phenomenon is one of the decisive risk factors for secondary glaucoma after cataract surgery.

Aged↗
PubMed1999

Identification of (-)-epicatechin metabolites and their metabolic fate in the rat.

After oral administration of (-)-epicatechin to rats, three kinds of metabolites (M-1, M-2, and M-3) were detected in the urine. After isolation of the compounds by preparative high-performance liquid chromatography, structural analysis was carried out by mass spectrometry and NMR. As a result, two compounds, M-1 and M-2, were identified as (-)-epicatechin and 3'-O-methyl-(-)-epicatechin, respectively. M-3 was suggested to be a monomethylated (-)-epicatechin, but definitive elucidation was not possible because of its small quantity. Methylation of (-)-epicatechin with rat liver homogenates and subsequent structural analysis showed that M-3 was 4'-O-methyl-(-)-epicatechin. Identification of conjugated forms of the urinary metabolites also was attempted. Two conjugates in the urine were purified and analyzed by mass spectrometry and NMR. These conjugates were shown to be (-)-epicatechin-5-O-beta-glucuronide and 3'-O-methyl-(-)-epicatechin-5-O-beta-glucuronide, respectively. Metabolism and excretion of (-)-epicatechin were examined. (-)-Epicatechin and its methylated derivatives in the free forms were detected in plasma and urine, but not in bile. Significant differences in the excretion ratio of the conjugated forms of (-)-epicatechin and 3'-O-methyl-(-)-epicatechin were observed between urine and bile. Time-course analysis of (-)-epicatechin metabolites showed that the most predominant metabolites in plasma and urine were the conjugates of (-)-epicatechin and 3'-O-methyl-(-)-epicatechin, respectively, and the cumulative amount of the urinary metabolites excreted during the 24-h period was about 8% of the administered (-)-epicatechin.

Administration, Oral↗
PubMed1998

Intestinal absorption of luteolin and luteolin 7-O-beta-glucoside in rats and humans.

In this study, we investigated the intestinal absorption of luteolin and luteolin 7-O-beta-glucoside in rats by HPLC. The absorption analysis using rat everted small intestine demonstrated that luteolin was converted to glucuronides during passing through the intestinal mucosa and that luteolin 7-O-beta-glucoside was absorbed after hydrolysis to luteolin. Free luteolin, its conjugates and methylated conjugates were present in rat plasma after dosing. This suggests that some luteolin can escape the intestinal conjugation and the hepatic sulfation/methylation. LC/MS analysis showed that the main conjugate which circulates in the blood was a monoglucuronide of the unchanged aglycone. Luteolin in propyleneglycol was absorbed more rapidly than that in 0.5% carboxymethyl cellulose. The plasma concentration of luteolin and its conjugates reached the highest level 15 min and 30 min after dosing with luteolin in propyleneglycol, respectively. HPLC analysis also allowed us to demonstrate the presence of free luteolin and its monoglucuronide in human serum after ingestion of luteolin.

Animals↗