PubMed Health⌕ Search

Biomedical subjects

H Onitsuka

Publications and source records attributed to H Onitsuka.

At least 19 recordsLinked to original sources
PubMed2005

Angiotensin II stimulates cardiac adrenomedullin production and causes accumulation of mature adrenomedullin independently of hemodynamic stress in vivo.

Adrenomedullin is a potent hypotensive peptide that may act on myocytes to inhibit hypertrophy and on fibroblasts to inhibit growth in vitro induced by mechanical stretching and angiotensin II. Adrenomedullin is processed from the inactive intermediate adrenomedullin precursor with a glycine extension, which is subsequently converted to biologically active mature adrenomedullin by enzymatic amidation. Total adrenomedullin is the sum of intermediate and mature adrenomedullin. We examined the effect of a subpressor dose of angiotensin II on the production of left ventricular adrenomedullin and on protein levels of mature adrenomedullin in the left ventricle in vivo. We also investigated whether the effect is mediated by the angiotensin II type 1 receptor. Concentrations of total and mature adrenomedullin in the left ventricle and mature adrenomedullin-to-intermediate adrenomedullin ratio were significantly increased by angiotensin II infusion, regardless of pressure overload. Total and mature adrenomedullin concentrations significantly correlated with the weight of the left ventricle. Furthermore, increased adrenomedullin gene expression and protein levels were completely suppressed by a subdepressor dose of angiotensin II type 1 receptor blocker. In conclusion, angiotensin II stimulates the production of cardiac adrenomedullin and accumulates mature adrenomedullin in the left ventricle independently of hemodynamic stress. These processes are partially regulated through the angiotensin II type 1 receptor in vivo.

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↗
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↗
PubMed1999

[Reexamination of hepatic falciform artery: angiographic study].

Supraumbilical skin complication during hepatic artery infusion chemotherapy or transcatheter arterial chemoembolization (TACE) for liver tumor has been reported by some authors. This complication is thought to be caused by the flow of chemotherapeutic, agent and embolus into the hepatic falciform artery (HFA). It is important for angiographers to be aware of the presence of HFA to prevent possible supraumbilical skin complication. The rate of visualization of the HFA on angiography has been considered to be only about 2%. In a retrospective study of celiac angiograms performed in 200 patients, we found an incidence of 32/200 (16%). The proximal side of this artery may be tortuous. In all cases, the flow of the HFA is slower than that of the hepatic artery. The paraumbilical vein was visualized with the HFA in 18 cases. Chemotherapy or transcatheter arterial chemoembolization was performed in 10 patients, and there was no postprocedure supraumbilical skin complication.

Aged↗
PubMed1999

[One-hour protocol stress myocardial scintigraphy: prospective study of diagnostic accuracy for the detection of coronary artery stenosis].

A one-hour protocol for stress myocardial scintigraphy using technetium-99m-tetrofosmin (Tc-tetrofosmin) was compared with coronary arteriography for the detection of coronary artery stenosis in 90 consecutive patients without prior myocardial infarction, revascularization procedure or vasospastic angina. Tc-tetrofosmin stress myocardial scintigraphy acquired a rest image 20 min after intravenous administration of Tc-tetrofosmin (185 MBq, 1/5 vial) using a three-head gamma camera collecting 20-sec views over 360 degrees. The stress test using bicycle ergometer was performed and administration of Tc-tetrofosmin (740 MBq, 4/5 vial) was repeated at the peak stress point. The stress image was acquired 15 min after the second injection with 5-sec views over 360 degrees. Coronary arteriography revealed the presence of significant coronary artery stenosis (> 75%) in 56 vessels of 45 patients, including 35 patients with single-vessel disease, 5 with two-vessel disease, 2 with three-vessel disease, and 3 with left main trunk disease. The overall sensitivity and specificity for the detection of coronary artery disease by visual analysis were 91.1% and 77.8%, respectively, and by quantitative analyses (using bull's-eye method) were 95.6% and 91.1%, respectively. The individual stenotic vessel sensitivities in the right coronary artery, left anterior descending artery, and left circumflex artery were 84.6%, 90.9%, and 78.6%, respectively. The specificities were 97.3%, 95.9%, and 100.0%, respectively. These results suggest that stress myocardial scintigraphy using the present new protocol is a promising approach for the detection of coronary artery stenosis.

Angina Pectoris↗
PubMed1995

MR imaging of hepatocellular carcinoma. Correlation of metal content and signal intensity.

In order to clarify the factors contributing to the signal intensities (SIs) of HCC on T1-weighted images, the amount of water, lipid, copper (Cu), iron (Fe), and manganese (Mn) was determined in HCC and surrounding hepatic parenchyma of 13 patients. The relationships among these findings, the histopathologic findings, and the SIs of T1-weighted images were evaluated. Among the 13 HCC, 3 had a high SI, 5 were isointense, and 5 had a low SI on T1-weighted images compared to the surrounding hepatic parenchyma. The paramagnetic ions which contributed to the SI patterns were assumed to be Cu in HCC (38.0 +/- 62.4 micrograms/g ww), and Fe in the liver (61.1 +/- 42.4 micrograms/g ww) and HCC (40.0 +/- 34.3 micrograms/g ww). In 8 HCC with high- or isointensity, 2 were grades I, 5 were grade II, and one was grade III according to the Edmondson-Steiner's histopathologic classification. It is concluded that the SI patterns alone can not be a sign of low grade malignancy because of the existence of Fe in livers and HCC.

Aged↗
PubMed1994

Imaging study on the mode of development and changes in avascular necrosis of the femoral head in systemic lupus erythematosus: long-term observations.

To find out when and how avascular necrosis of the femoral head (ANFH) develops in patients with SLE who are receiving corticosteroids, we carried out a 3-yr prospective study using imaging methods. Twenty-three patients with SLE who were free of hip pain and radiographically negative were enrolled in the study. Initially, abnormal findings characteristic of ANFH were detected in eight (35%) and six (26%) patients on MRI and radionuclide uptake bone scanning, respectively. During a 3-yr observation period abnormalities on MRI, bone scanning and radiography were found in four, five and four patients, respectively and three patients developed hip pain. Analyses of imaging changes demonstrated that only a small proportion of patients (2/8, 25%) who initially showed abnormal MRI progressed to be radiographically positive for ANFH over the 3 years. High doses of corticosteroids over the 3-yr period were to be responsible for the emergence of change in MRI abnormalities. It is also suggested that abnormal MRI findings tend to develop either within a relatively short interval after the start of corticosteroid treatment or are associated with the exacerbation of SLE.

Adolescent↗
PubMed1994

Colonic submucosal tumors: comparison of endoscopic US and target air-enema CT with barium enema study and colonoscopy.

PURPOSE: To compare the imaging characteristics of colonic submucosal tumors at endoscopic ultrasound (US) and target air-enema computed tomography (TACT) with those at conventional double-contrast barium enema study and colonoscopy. MATERIALS AND METHODS: Twenty consecutive patients with suspected colonic submucosal tumors at barium enema study and colonoscopy underwent endoscopic US, TACT, or both. Morphologic features and posture-related change in shape of tumor were evaluated with barium enema study, color and consistency of tumor with colonoscopy, internal echogenicity of tumor and layer of origin in normal colonic wall with endoscopic US, and CT attenuation number with TACT. RESULTS: Eight lipomas, seven carcinoids, three leiomyomas, four lymphangiomas, and one hemangioma were found at histologic examination. Lipomas and lymphangiomas had characteristic findings at endoscopic US and TACT. The differential diagnosis of the other submucosal tumors was facilitated by using endoscopic US. CONCLUSION: Endoscopic US and TACT may play a valuable role in the evaluation of colonic submucosal tumors.

Adult↗
PubMed1994

CT of intraabdominal desmoid tumors: is the tumor different in patients with Gardner's disease?

OBJECTIVE: A retrospective study of abdominal CT scans of patients with proved intraabdominal desmoid tumors was done to determine if any objective characteristics exist to differentiate desmoids related to Gardner's syndrome from isolated desmoids. Because the desmoid tumors of Gardner's syndrome can predate the diagnosis of Gardner's syndrome, it would be helpful to know which patients with desmoids need careful follow-up studies as well as initial workup for Gardner's syndrome and all its ramifications. Also, it would be important to differentiate benign from malignant desmoids associated with Gardner's syndrome. It was hoped that the location, enhancement characteristics, and/or the presence or absence of infiltration might be of value. We were interested in noting if, over time, the growth characteristics of desmoids found in Gardner's syndrome were different from those of isolated desmoids. MATERIALS AND METHODS: We reviewed 101 abdominal CT scans obtained in 23 patients during a 13-year period. Forty desmoid tumors were intraabdominal, including 30 lesions associated with Gardner's syndrome in 13 patients and 10 desmoids of the idiopathic form in 10 patients. These tumors were studied to define location; whether they were single or multiple; and whether they had any specific CT characteristics regarding margins, attenuation numbers, or contrast enhancement. RESULTS: Desmoid tumors associated with Gardner's syndrome were more likely to be multiple (38%, five of 13 patients) and to involve the mesentery (60%, 18 of 30 tumors) and the abdominal wall (40%, 12 of 30 tumors), whereas isolated desmoid tumors were singular (all 10 patients) and were located in the retroperitoneum (six cases), pelvis (three), and anterior wall (one). Desmoids related to Gardner's syndrome also tended to be smaller (mean diameter, 4.8 cm) than idiopathic desmoids (mean diameter, 13.8 cm). No differentiating CT characteristics regarding margins, attenuation numbers, or response to contrast material were ascertained. Ten new lesions (seven intraabdominal, three mesenteric) developed in three patients with Gardner's syndrome, whereas no new intraabdominal lesions developed in patients with idiopathic desmoids. Follow-up data on 16 surgically resected desmoids in nine patients (seven with Gardner's syndrome and two with isolated desmoids) revealed seven local recurrences (two in the two patients with isolated desmoids and five in two patients with Gardner's syndrome). CONCLUSION: No CT characteristics, such as attenuation values, margins, and response to the contrast material, were found that would enable differentiation between isolated intraabdominal desmoids and those associated with Gardner's disease. Desmoid tumors associated with Gardner's syndrome tend to occur in the mesentery and abdominal wall, whereas isolated desmoids involve the retroperitoneum and pelvis. When studying CT scans obtained over time, new lesions were noted to develop in a few of the patients with Gardner's syndrome (three of 13), whereas no new lesions were found in patients with isolated desmoids.

Adult↗
PubMed1993

Hepatocellular carcinoma: prospective assessments of the T-factor with CT, US, and MR imaging.

The capabilities of computed tomography (CT), ultrasonography (US), and magnetic resonance (MR) imaging were studied in order to determine the role of each of these noninvasive examinations for estimating the T-factor of hepatocellular carcinomas (HCCs). Fifty-one patients with surgically proven HCCs received CT (50 patients), US (46 patients), and MR (44 patients). The images of CT, US, and MR were prospectively evaluated for main tumor size, intrahepatic metastases, and vascular invasion, which compose the T-factor of HCC, and compared to pathological results. The sizes of the main tumor were estimated correctly by all examinations. For estimating intrahepatic metastases, US (74%) and MR (73%) were superior to CT (65%). For estimating portal invasion, CT (79%) was superior to US (70%) and MR (66%), because CT could demonstrate the segmental staining caused by portal invasion. The estimates of hepatic venous invasion were difficult during any of the examinations. We conclude that presurgical evaluations of the T-factor require the use of US and CT or MR and CT.

Aged↗
PubMed1993

Large intra-abdominal desmoid tumors in a patient with familial adenomatosis coli: their rapid growth detected by computerized tomography.

A case of familial adenomatosis coli with large intra-abdominal desmoid tumors is described. The patient initially complained of an abdominal mass, which was diagnosed as a desmoid tumor after surgical resection. Further examinations revealed numerous polyps of the colon which were histologically diagnosed as adenomas. Despite intensive medical therapy, the desmoid tumors rapidly increased in size and number, and resulted in abscess and cavity formation that involved the ileum. Although desmoid tumors are classically benign in nature, we consider these tumors to be a therapeutic problem in patients with familial adenomatosis coli.

Abdominal Neoplasms↗
PubMed1992

Characteristic findings of hepatocellular carcinoma: an evaluation with comparative study of US, CT, and MRI.

The sensitivity, specificity, and accuracy of ultrasonography (US), dynamic incremented computed tomography (CT) with delayed phase imaging, and magnetic resonance imaging (MRI) with or without Gd-DTPA were studied for detecting the characteristic appearances of hepatocellular carcinomas (HCC): fibrous capsules, fibrous septa, and mosaic appearances. Results were prospectively evaluated in 30 patients who subsequently underwent hepatic lobectomies or segmentectomies. Pathologic evaluations of the resected liver specimens demonstrated fibrous capsules in 20 tumors (66.7%), fibrous septa in 13 tumors (43.3%), and mosaic appearances in 19 tumors (63.3%). The accuracies for fibrous capsules were 71.4% (20 of 28) for US, 81.5% (22 of 27) for CT, and 92.3% (24 of 26) for MRI. The accuracies for fibrous septa were 57.1% (16 of 28) for US, 59.3% (16 of 27) for CT, and 73.1% (19 of 26) for MRI. The accuracies for mosaic appearances were 71.4% (20 of 28) for US, 51.9% (14 of 27) for CT, and 69.2% (18 of 26) for MRI. Gd-DTPA administered MRI showed higher accuracies than did conventional MRI for all manifestations. In conclusion, the fibrous capsules of HCCs were readily detected by CT and MRI. Gd-DTPA administration demonstrated an advantage in clarifying fibrous capsules, as well as fibrous septa and mosaic appearances.

Aged↗
PubMed1992

Differential diagnosis of hepatic tumors (hepatoma, hemangioma, and metastasis) with CT: value of two-phase incremental imaging.

Two-phase dynamic incremental CT is a technique in which CT scans are obtained 45 sec and 6 min after commencing the rapid bolus injection of contrast medium. We analyzed the contrast enhancement patterns of three types of hepatic tumors (72 hepatomas, 39 hemangiomas, and 28 metastases) in 139 patients to determine if any differences in the patterns are useful in the differential diagnosis of these lesions. Dynamic incremental CT scanning was performed after 100 ml of iodinated contrast material was administered i.v. with a power injector at a rate of 2 ml/sec. A 1-sec scanning time was used with a 1.6-sec inter-scan delay, which allowed table motion between scans. CT scans (eight to 16 sections) were obtained 45-110 sec (early phase) and 6-7 min (delayed phase) after commencing the injection of contrast medium. The enhancement patterns of hepatomas were as follows: 32% were totally hyperdense in the early phase and totally hypodense in the delayed phase, while 24% were totally hypodense in both phases. Most of the hepatomas (88%) appeared as totally hypodense lesions in the delayed phase. In the case of hemangiomas, 56% were peripherally hyperdense in the early phase; in the delayed phase, 36% were isodense and 31% were totally hyperdense. Most hemangiomas (85%) were not totally hypodense in the early phase, and no hemangioma was totally hypodense in both phases. In the early phase, 61% of metastases were hypodense. In the delayed phase, 57% were hypodense. Metastases most commonly were totally hypodense in both phases (43%). We conclude that contrast enhancement patterns of hepatomas, hemangiomas, and metastases seen on two-phase dynamic incremental CT scans are useful in the differential diagnosis of these tumors.

Carcinoma, Hepatocellular↗
PubMed1991

[Role of MRI in diagnosis of adrenal tumors].

The authors evaluated the ability of magnetic resonance imaging (MRI) at 1.5 T to characterize 33 adrenal masses, using visual analysis and the following quantitative variables: signal intensity ratios of tumor/liver, tumor/muscle, and (tumor--muscle)/(fat--muscle) on T2- and T1-weighted images, and the calculated T2 relaxation time of the adrenal masses. All 15 tumors of less than 3 cm in diameter were visually homogeneous on all pulse sequences, whereas the other 18 tumors of over 3 cm appeared to be inhomogeneous. The signal intensity ratios of tumor/liver and tumor/muscle and the calculated T2 relaxation time were not helpful in distinguishing tumors from one another. The ratios of tumor/fat and (tumor--muscle)/(fat--muscle) were useful in distinguishing pheochromocytoma and myelolipoma from other tumors on T2- and T1-weighted images, respectively. However, differentiation among other adrenal tumors appeared to be difficult. The authors concluded that, although MRI might have considerable potential in characterizing adrenal masses, the use of conventional MRI in such analysis is still quite limited.

Adenoma↗
PubMed1991

Magnetic resonance imaging of the muscles in patients with polymyositis and dermatomyositis.

Magnetic resonance imaging (MRI) of the muscles was performed in patients with polymyositis and dermatomyositis. Lesions with high intensity on T2-weighted image, but normal intensity on T1-weighted image, were observed in 7 of 8 patients in the active stage of the disease. Following clinical improvement with corticosteroid therapy in 4 patients, the high intensity lesions reverted to normal. The high intensity lesions seen on T2-weighted image in the active stage may represent edema and inflammation of the muscle. MRI of the muscle may serve as a diagnostic tool and be useful for follow-up of the patients with polymyositis or dermatomyositis.

Adult↗
PubMed1991

Differentiation of central lung tumor from postobstructive lobar collapse by rapid sequence computed tomography.

When central lung tumor is associated with lobar collapse, discrimination of tumor from atelectasis is important for determining operability or for field planning should radiation therapy be utilized. Because tumor and collapsed lung have similar attenuation values, they cannot always be distinguished with usual contrast-enhanced CT. The article describes separation of tumor from collapsed lung by means of RSCT with bolus injection of nonionic contrast medium. With this technique collapsed lung is appreciably enhanced, but tumor enhancement is slow and minimal. The difference is most marked from 40 seconds to 2 minutes after scanning begins. This phenomenon is probably related to the marked increase in blood flow per unit area of collapsed lung due to crowding of relatively large pulmonary arteries compared to tumor blood supply through small bronchial arteries. Tumor can also be delineated from atelectasis by differences in internal structure with this technique.

Aged↗