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Biomedical subjects

T Eto

Publications and source records attributed to T Eto.

At least 55 records · Page 3Linked to original sources
PubMed2001

[A new protocol of dual energy acquisition on stress 201Tl and rest 99mTc-tetrofosmin myocardial scintigraphy].

We carried out stress 201Tl (Tl) and rest 99mTc-tetrofosmin (TF) myocardial scintigraphy with dual energy acquisition in 24 patients with suspected ischemic heart disease performed coronary arteriography and elucidated the sensitivity of this method. One hour after light meal eating, TF (555 MBq) was injected intravenously at rest and after 3 minutes from injection of TF exercise or pharmacologic stress was performed. During stress Tl (111 MBq) was injected intravenously before end-point or at adequate point of pharmacologic stress. Dual energy acquisition using triple energy windows (TEW) was started after 5 minutes (early) and 4 hours (delayed) from stress. The sensitivity (Sn), specificity (Sp) and accuracy (Ac) in diagnosis of non-infarcted branches by using Tl (early)-TF (rest) and Tl (early)-Tl (delayed) were 79% vs. 53% (Sn), 78% vs. 96% (Sp) and 79% vs. 71% (Ac) respectively. Accordance of uptake score of infarcted region between TF (rest) and Tl (delayed) was 70%. In conclusion, this protocol is seemed to be useful as usual protocol for detection of myocardial ischemia and viability during about only 1 hour.

Aged↗
PubMed2001

[Recent trends in studies of the etiology of hypertension: New endocrine regulators of blood pressure].

The literature review reflects new aspects of humoral regulation in hypertension and target-organ damages with special regard to natriuretic peptide system(NPS) and adrenomedullin(AM). NPS and AM are recently discovered regulators which serve as antihypertensive and target-organ protective factors. These peptides have both diuretic and natriuretic properties and a relaxing effect on the vasculature. Moreover, they antagonize the proliferative and hypertrophic stimuli in the vasculature and heart. Recently, progressive technics of molecular biology clearly revealed crucial roles of these peptides for cardiovascular regulation in both normal and pathological states including hypertension and related organ damages. Natriuretic peptides, potentially AM, are new therapeutic tools for heart failure and main targets for further development of new antihypertensive drugs such as vasopeptidase inhibitor.

Adrenomedullin↗
PubMed2001

Clinical manifestations of influenza a myocarditis during the influenza epidemic of winter 1998-1999.

OBJECTIVES: The clinical features of myocarditis that developed during the influenza epidemic of winter 1998-1999 were investigated to emphasize the need for medical attention to this disease. METHODS: Nine patients were treated under diagnoses of acute myocarditis during the winter of 1998-1999. Five (two males and three females, mean age 52 +/- 18 years) were examined with myocarditis associated with influenza A. The diagnosis of influenza A myocarditis was based on electrocardiographic and echocardiographic abnormalities, increased creatine kinase levels and at least a four-fold increase in influenza A virus titers using paired sera. RESULTS: All patients had preceding flu-like symptoms and fever. Cardiac involvement developed between 4 and 7 days after the onset of influenza symptoms. Dyspnea progressively worsened in three patients, one went into shock and one had persistent fever, cough and mild dyspnea without apparent cardiac symptoms. Three patients had ST elevation associated with Q waves and one had complete left bundle branch block. The creatine kinase levels were abnormally increased and global wall motion of the left ventricle on echocardiography was decreased in all patients. Two patients had diagnoses of fulminant myocarditis. One patient died of pneumonia following cerebral infarction, but the left ventricular dysfunction normalized in the remaining four patients. CONCLUSIONS: Cardiac involvement occurred between 4 and 7 days after the onset of influenza symptoms, and worsening dyspnea was the most common symptom. Electrocardiography, echocardiography and creatine kinase levels should be checked to determine the potential for cardiac involvement when patients present with suspected influenza associated with worsening dyspnea or prolonged weakness. Increasing the awareness of influenza myocarditis may help in the earlier identification and treatment of this disease during influenza epidemics.

Adult↗
PubMed2001

Angiographic features at ischemia- or infarct-related sites in patients with acute coronary syndrome: morphology changing in a relatively short time.

OBJECTIVES: Coronary cineangiography was reviewed in patients with acute coronary syndrome to investigate whether angiographic features at identifiable ischemia- or infarct-related lesions can change in terms of luminal diameter and morphology in a short period after development, and whether the amount of thrombus with/without underlying ruptured plaque is the major determinant. METHODS: The present study included 72 patients with unstable angina, 118 with acute myocardial infarction (< 1 month after onset) and 137 with old myocardial infarction (> or = 1 month after onset). The coronary angiographic findings were compared with those from patients with stable effort angina. The groups of patients were subdivided into two groups based on whether antiplatelet and/or anticoagulant therapy, or fibrinolytic therapy with subsequent anticoagulant agents (antiplatelet and/or anticoagulant, or fibrinolytic therapy) were administered. The morphologies of the ischemia- or infarct-related lesions were classified as totally occlusive, simple (Type I lesion) or complex. Complex lesions were further subdivided into Type IIa lesions indicative of the presence of thrombus accumulation with/without an underlying ruptured atheromatous plaque, e.g., narrowing with irregular, poorly defined or hazy borders, sharp leading or trailing edges that overhang or are perpendicular to vessel walls, and globular endoluminal negative images, Type IIb lesions with two or more serial, closely spaced narrowings together with multiple irregularities, and Type IIc lesions indicative of the presence of some parts of ruptured plaque with a smaller amount of thrombus, e.g., luminal narrowing with extraluminal contrast pooling, single or paired short thin linear radiolucencies with/without a variable degree of outpouching, and narrowing with definite outpouching with/without radiolucency, and Type IId lesions showing narrowing with morphology not included in Type IIa-IIc lesions. The coronary angiographic findings were related to the elapsed time before the coronary angiographic study, and whether each patient underwent antiplatelet and/or anticoagulant, or fibrinolytic therapy. RESULTS: Ischemia- or infarct-related lesions were totally occlusive in 9.7% of patients with unstable angina, 40.7% of those with acute myocardial infarction and 21.9% of those with old myocardial infarction. Total occlusion was significantly more prevalent in patients with acute myocardial infarction than in those with stable effort angina (23.9%, p < 0.05), and total occlusion was more frequent in patients without antiplatelet and/or anticoagulant, or fibrinolytic drugs (50.6% vs 17.1%, p < 0.01). The presence of total occlusion decreased with time after development, and the decrease was more significant with the use of antiplatelet and/or anticoagulant, or fibrinolytic drugs. Type IIa morphology was significantly prevalent immediately after the initial episode, and Type IIa and IIc morphologies increased in the late period, and were more frequent with the use of antiplatelet and/or anticoagulant, or fibrinolytic drugs. CONCLUSIONS: The severity of the luminal diameter at ischemia- or infarct-related lesions sites can progress or even regress in a relatively short period in patients with acute coronary syndrome, and the amount of accumulated thrombus with/without underlying ruptured plaque is a major determinant of luminal diameter narrowing and angiographic morphology.

Adult↗
PubMed2001

[A case of right pneumonectomy and omentopexy for lung cancer after preoperative irradiation].

A 72-year-old man complaining of cough rejected the operation for squamous cell carcinoma obstructing the right intermediate trunk, therefore he was received 82 Gy (40 Gy and 42 Gy) of radiotherapy. However, the tumor did not decrease, in addition, cough and purulent sputum became severe gradually. We performed right pneumonectomy and omentopexy to prevent bronchial fistula, he had no pulmonary complication. Radiotherapy is a risk factor for postoperative bronchial fistula, omentopexy is useful to prevent it.

Aged↗
PubMed2000

Adrenomedullin receptors in rat cerebral microvessels.

To characterize the sites of action of adrenomedullin (AM) in the cerebral microvasculature, we studied the effect of AM on cyclic AMP (cAMP) level as well as expression of AM and its receptor in the rat cerebral microvessels. The microvessels were prepared from rat cerebral cortex by albumin flotation and glass bead filtration technique. AM and calcitonin gene-related peptide (CGRP) increased cAMP level in the microvessels in a concentration-dependent manner. The effect of AM was more than 100 times more potent than that of CGRP. The accumulation of cAMP by AM was inhibited by AM[22-52], an AM receptor antagonist, but not by CGRP[8-37], a CGRP receptor antagonist, suggesting that AM increased cAMP accumulation by acting on receptors specific to AM. [125I]AM binding to the microvessels was displaced by AM and less potently by AM[22-52]. The displacing potencies of CGRP and CGRP[8-37] were very weak. mRNAs for AM as well as calcitonin-receptor-like receptor and receptor-activity-modifying protein 2 which form a receptor specific to AM, were highly expressed in the microvessels. These results provide biochemical and pharmacological evidence that AM is produced in and acts on the cerebral microvessels in an autocrine/paracrine manner and is involved in regulation of cerebral microcirculation.

Adrenomedullin↗
PubMed2000

Visualization of the calcitonin receptor-like receptor and its receptor activity-modifying proteins during internalization and recycling.

Expression of the calcitonin receptor-like receptor (CRLR) and its receptor activity modifying proteins (RAMPs) can produce calcitonin gene-related peptide (CGRP) receptors (CRLR/RAMP1) and adrenomedullin (AM) receptors (CRLR/RAMP2 or -3). A chimera of the CRLR and green fluorescent protein (CRLR-GFP) was used to study receptor localization and trafficking in stably transduced HEK 293 cells, with or without co-transfection of RAMPs. CRLR-GFP failed to generate responses to CGRP or AM without RAMPs. Furthermore, CRLR-GFP was not found in the plasma membrane and its localization was unchanged after agonist exposure. When stably coexpressed with RAMPs, CRLR-GFP appeared on the cell surface and was fully active in intracellular cAMP production and calcium mobilization. Agonist-mediated internalization of CRLR-GFP was observed in RAMP1/CGRP or AM, RAMP2/AM, and RAMP3/AM, which occurred with similar kinetics, indicating the existence of ligand-specific regulation of CRLR internalization by RAMPs. This internalization was strongly inhibited by hypertonic medium (0.45 m sucrose) and paralleled localization of rhodamine-labeled transferrin, suggesting that CRLR endocytosis occurred predominantly through a clathrin-dependent pathway. A significant proportion of CRLR was targeted to lysosomes upon binding of the ligands, and recycling of the internalized CRLR was not efficient. In HEK 293 cells stably expressing CRLR-GFP and Myc-RAMPs, these rhodamine-labeled RAMPs were co-localized with CRLR-GFP in the presence and absence of the ligands. Thus, the CRLR is endocytosed together with RAMPs via clathrin-coated vesicles, and both the internalized molecules are targeted to the degradative pathway.

Calcitonin Receptor-Like Protein↗
PubMed2000

Aclarubicin induces differentiation of leukemic progenitors in myelodysplastic syndrome cooperating with granulocyte colony-stimulating factor.

We have reported that low-dose aclarubicin (ACR) therapy is effective in some patients with myelodysplastic syndrome (MDS). Here, we demonstrate that a low concentration of ACR induces the in vitro differentiation of leukemic progenitor cells from patients with MDS. ACR (0.1 ng/ml) significantly increased the number of granulocyte colony-stimulating factor (G-CSF)-dependent colonies from circulating blast cells in vitro in six out of seven MDS patients with refractory anemia with excess of blast in transformation or chronic myelomonocytic leukemia, but not in all four patients with primary acute myelogenous leukemia. In these MDS patients, the effect of ACR gradually disappeared along with the progression of MDS. Interestingly, the majority of G-CSF/ACR-dependent colonies consisted of rather differentiated myeloid cells such as myelocytes and metamyelocytes, whereas colonies formed by G-CSF alone were composed mainly of immature blastic cells. The number of G-CSF-responding progenitors significantly increased during a 24-48 h incubation with ACR alone. The circulating blasts in MDS patients expressed G-CSF receptors at unchanged levels before and after the incubation with ACR. It is suggested that ACR might increase clonogenic progenitor responsiveness to G-CSF in MDS, probably through modulating downstream signaling cascades associated with G-CSF receptors, and induce these progenitors to differentiate in response to G-CSF.

Aclarubicin↗
PubMed2000

Differential responses of circulating and tissue adrenomedullin and gene expression to volume overload.

BACKGROUND: Adrenomedullin (AM), which is produced by various tissues and organs, also circulates in the blood. Circulating AM levels increase during disease states such as essential hypertension, heart failure, and renal failure. However, little is known about how circulating AM or AM production responds to volume overload (VOL). METHODS AND RESULTS: Progressive VOL was induced in rats by an aortocaval shunt (AC) or by an aortocaval shunt with banding of the abdominal aorta distal to the shunt (AC + B), which created a larger shunt volume. Plasma and tissue AM concentrations, as well as AM gene expression levels, were measured at 1, 5, and 14 days after operation. Plasma concentrations of atrial natriuretic peptide (ANP), aldosterone, and renin activity (PRA) were also examined. Pulmonary congestion, pleural effusion, and ascites rapidly progressed in the AC + B group, suggesting that VOL caused more rapid heart failure under these conditions. Plasma AM concentrations in the AC + B and AC groups at day 1 compared with those in sham-operated rats were increased by 300% and 140%, respectively, and then gradually declined. The time course of plasma AM over 14 days was similar to that of plasma aldosterone and PRA, but not of plasma ANP or intracardiac filling pressure. The increase in plasma AM was accompanied by upregulated AM gene expression in the lung and aorta and by decreased AM concentrations in the atrium, ventricle, and adrenal gland. Cardiac AM gene expression levels were increased in the hypertrophied ventricles of AC and AC + B rats. CONCLUSIONS: The major findings of the present study were 1) a rapid increase in plasma AM after the imposition of VOL in association with increased plasma aldosterone and PRA, 2) the contribution of several organs to this increase, and 3) a late increase in the AM messenger RNA (mRNA) level in the ventricles as VOL-induced ventricular hypertrophy developed.

Adrenomedullin↗
PubMed2000

Diastolic wall stress and ANG II in cardiac hypertrophy and gene expression induced by volume overload.

We investigated the effects of diastolic wall stress (WS) and angiotensin II (ANG II) on the left ventricular (LV) hypertrophy (LVH) induced by volume overload and on the gene expression of LV adrenomedullin (AM) and atrial natriuretic peptide (ANP) in volume overload. Diastolic WS was pharmacologically manipulated with (candesartan) or without (calcium channel blocker manidipine) inhibition of ANG II type 1 receptors in aortocaval-shunted rats over 6 wk. Diastolic WS reached a plateau at 2 wk and subsequently declined regardless of further LVH. Although diastolic WS was decreased to a similar extent by both compounds, candesartan blunted LVH over 6 wk, whereas manidipine blunted LVH at 2 wk but not after 4 wk. Levels of AM and ANP gene expression increased as LVH developed but were completely suppressed by candesartan over 6 wk. ANP expression level was also attenuated by manidipine over 6 wk, whereas AM expression level was suppressed at 2 wk but not after 4 wk by manidipine. We concluded that diastolic WS and ANG II might be potent stimuli for the LVH and LV AM and ANP gene expression in volume overload and that diastolic WS could be relatively involved in the early LVH and in the gene expression of ANP rather than of AM.

Adrenomedullin↗
PubMed2000

Plasma concentration of uroguanylin in patients on maintenance dialysis therapy.

BACKGROUND: Uroguanylin, originally isolated from urine, is a new natriuretic peptide. Its plasma level is increased in association with renal impairment and fluid retention in patients with renal diseases. METHODS: Uroguanylin concentrations were measured in patients on hemodialysis (HD, n = 76) and those on continuous ambulatory peritoneal dialysis (CAPD, n = 10) using a sensitive ra- dioimmunoassay for human uroguanylin. RESULTS: Plasma concentrations of immunoreactive (ir)-uroguanylin in the patients on HD and CAPD (212.0 +/- 17.4 and 245.3 +/- 39.5 fmol/ml) were significantly higher than the value for the normal controls (5.0 +/- 0.3 fmol/ml). Plasma ir-uroguanylin levels before the start of regular HD were correlated with predialysis excess weight based on their dry weights (r = 0.33, p < 0.01) and with dialysis duration (r = 0.26, p < 0.05). The plasma levels in patients with HD, for whom high-flux membranes were used, were decreased at the end of regular HD as compared with the prior levels (p < 0.05), but not in those who underwent HD with conventional membranes. CONCLUSION: These findings suggest that the plasma ir-uroguanylin level is related to the patient's volume status as well as renal impairment. Whether the accumulation of uroguanylin has a pathological effect has yet to be determined.

Adult↗
PubMed2000

Increased plasma levels of mature adrenomedullin in chronic glomerulonephritis.

Adrenomedullin (AM) is a potent vasodilative and natriuretic peptide that is processed from its precursor as the intermediate form, AM-glycine-COOH (iAM). Subsequently, iAM is converted to the biologically active mature form, AM(1-52)-CONH(2) (mAM), by enzymatic amidation. Using immunoradiometric assays that recognize total AM (tAM) and only mAM, we determined the plasma and urinary levels of mAM and iAM in patients with chronic glomerulonephritis (CGN). The plasma mAM concentration was significantly higher in the patients than in the controls (1.8 +/- 0.1 vs. 1.3 +/- 0.1 fmol/ml, p < 0.01), whereas the plasma iAM concentration of the CGN patients did not significantly differ from that of the controls (9.4 +/- 0.5 vs. 8.9 +/- 0.5 fmol/ml). Levels of urinary mAM excretion in the patients did not statistically differ from those of the controls (1. 6 +/- 0.4 vs. 2.0 +/- 0.3 fmol/mg creatinine), whereas urinary iAM excretion was significantly lower in the CGN patients (3.7 +/- 0.7 vs. 5.6 +/- 0.8 fmol/mg creatinine, p < 0.05). Urinary excretion levels of mAM significantly correlated with those of sodium (r = 0. 47, p < 0.05), whereas those of iAM did not. In conclusion, the plasma ratio of mAM to iAM is augmented in CGN patients, and mAM appears to be involved in the regulation of sodium. Therefore, determination of the mAM in addition to the tAM concentration is essential in CGN patients.

Adolescent↗
PubMed2000

Enhanced adrenomedullin production by mechanical stretching in cultured rat cardiomyocytes.

Adrenomedullin (AM) is secreted from cultured cardiac myocytes. In this study, we examined whether mechanical stretching stimulates AM production in cardiac myocytes, and if so, whether angiotensin II (Ang II) is involved in that mechanism. Neonatal rat cardiac myocytes cultured in serum-free medium were stretched 10% or 20% on flexible silicone rubber culture dishes, and AM mRNA expression was examined by quantitative polymerase chain reaction. The AM mRNA levels in the myocytes stretched 10% and 20% for 24 hours significantly increased by 56% (P<0.05) and 88% (P<0.01), respectively, when compared with the levels in nonstretched cells. AM secretion into the medium after the myocytes were stretched 10% and 20% increased by 22% (P<0.05) and 45% (P<0.01), respectively. In nonstretched myocytes incubated with 10(-6) mol/L Ang II for 24 hours, AM mRNA and secretion increased by 86% (P<0.05) and 36% (P<0. 01), respectively. These effects of Ang II were abolished by 10(-6) mol/L CV-11974, an Ang II type I (AT(1)) receptor antagonist, but not by 10(-6) mol/L PD-123319, an Ang II type II antagonist. Stretch-induced increases of AM gene expression and secretion were significantly inhibited (P<0.05) in the presence of 10(-6) mol/L CV-11974 by 46% and 52%, respectively; however, they were not affected by 10(-6) mol/L PD-123319. These findings indicate that AM production from cardiac myocytes is augmented by mechanical stretching, partially through the AT(1) receptors, which suggests a local interaction between AM and the renin-angiotensin system in stretched cardiac myocytes.

Adrenomedullin↗