Publications by authors named "Masatoshi Hori"

Purpose: To retrospectively compare the accuracy in detection of hepatic metastases among contrast material-enhanced multi-detector row computed tomography (CT) alone, superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging alone, and a combination of contrast-enhanced CT and SPIO-enhanced MR imaging.

Materials And Methods: The ethics committee did not require its approval or informed consent for this retrospective study, which was compliant with Declaration of Helsinki principles. Data in 38 patients (22 men, 16 women; mean age, 64.

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The purpose of this article is to provide an update on imaging techniques useful for detection and characterization of fat in the liver. Imaging findings of liver steatosis, both diffuse steatosis and focal fatty change, as well as focal fatty sparing, are presented. In addition, we will review computed tomography (CT) and magnetic resonance (MR) findings of focal liver lesions with fatty metamorphosis, including hepatocellular carcinoma, hepatocellular adenoma, focal nodular hyperplasia, angiomyolipoma, lipoma, and metastases.

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Objective: The objective of our study was to assess the value of two-way interpretation (i.e., from rectum to cecum and vice versa) compared with one-way interpretation (i.

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Purpose: There has been one report that tissue blood flow (TBF) quantification with xenon CT was effective in predicting the therapeutic response to an anticancer drug in pancreatic cancer. The purpose of this study was to evaluate the correlation between the TBF of pancreatic tumors calculated with xenon CT and those with perfusion CT, in order to evaluate whether perfusion CT could replace xenon CT.

Materials And Methods: Nine patients with pathologically proved pancreatic tumors who underwent both xenon CT and perfusion CT were included.

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Uterine myometrial contractility remains a poorly characterized area of research in reproductive physiology. Rnd1, a novel member of the GTP-binding Rho protein family, inhibits Ca(2+)-sensitization by specifically interfering with a RhoA/Rho-activated kinases-dependent mechanism in smooth muscle. In addition to Rnd1, there are two other members, Rnd2 and Rnd3, in the Rnd family of Rho proteins.

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Purpose: To prospectively evaluate the diagnostic accuracy of low-radiation-dose computed tomographic (CT) colonography for detection of colorectal polyps by using two sequential colonoscopies, with the second colonoscopy as the reference standard.

Materials And Methods: The study was local ethics committee approved, and all patients gave written informed consent. Colonographic images were acquired by using a low-dose multi-detector row CT protocol (effective milliampere-second setting, 10 mAs).

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So far it has proven difficult to identify a causative gene(s) or gene product initiating the events that lead to inflammation of the intestinal mucosa and, ultimately, progression to Crohn's disease (CD), an inflammatory bowel disease. However, gene transcripts identified in the intestine of trinitrobenzene sulfonic acid (TNBS)-treated mice might suggest a clue, and even represent candidate genes leading to inflammation and mucosal damage, and to subsequent fibrosis. In the present study, DNA microarray (13000 transcripts) methodology was applied to mucosal RNA extracted from TNBS-treated mice, some transcripts of which were validated via cDNA subtraction and RT-PCR analyses.

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Inflammation suppresses intestinal motility, which secondarily induces abnormal growth of intestinal flora. Disturbance of this flora plays a role in the pathogenesis of mucosal inflammation, which in turn aggravates the intestinal dysmotility. Therefore, it is important to know the mechanism of alteration in motor function in the inflamed intestine.

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Purpose: To evaluate retrospectively the accuracy of multi-detector row computed tomography (CT) in the assessment of serosal invasion in patients with gastric cancer.

Materials And Methods: The Ethics Committee does not require approval or informed consent for retrospective studies. Forty-one consecutive patients (24 men, 17 women; mean age, 68 years) with gastric cancer were included in this study.

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Background: A new Xenon computed tomography (CT) system was developed to measure both hepatic arterial and portal venous tissue blood flow (HATBF/PVTBF) non-invasively. Despite its clinical trial, the effect of prostaglandin E1 (PGE1) on hepatic hemodynamics is not well investigated. In a rabbit model, we evaluated the accuracy of this system by comparing it with the electromagnetic blood flowmeter (EMBF), the pharmacological effect of PGE1 on the fractional hepatic hemodynamics.

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Objective: We investigated the effects of fluvastatin on hypoxia-induced (1 to 3 weeks, 10% O2) pulmonary hypertension with focus on endothelial nitric oxide synthase (eNOS) activity.

Methods And Results: Oral fluvastatin treatment (1 mg/kg daily) prevented the causing and progression of pulmonary hypertension as determined by the right ventricular pressure, right ventricular hypertrophy, and muscularization of pulmonary artery. We also revealed that fluvastatin treatments prevented the hypoxia-induced decrease in cGMP production in the rat lung and restored the endothelium-dependent relaxation in the pulmonary artery.

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Objective: Although adenovirus is a powerful tool for vascular research and therapy, endothelial impairment after infection has been reported. We investigated the mechanisms of this impairment and the effect of dexamethasone (DEX) on gene transfer into the vascular endothelial cells.

Methods And Results: Beta-galactosidase gene encoding adenovirus vector (beta-gal-Ad) (7.

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In the present study, we assessed the effects of dexamethasone on fetal bovine serum-induced dysfunction of mesenteric endothelial cells using an organ culture procedure. In rabbit mesenteric arteries cultured in the presence of 10% fetal bovine serum for 7 days, the endothelium-dependent, nitric oxide (NO)-mediated relaxations caused by substance P and ionomycin were decreased as compared to those in non-treated arteries. Dexamethasone (3 microM) inhibited the proliferative stimuli-induced endothelial dysfunction without affecting the contractility or NO susceptibility of smooth muscle cells.

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Rationale And Objectives: The purpose of this study is to assess the diagnostic impact of double phase computed tomography during hepatic arteriography for hepatocellular carcinoma.

Materials And Methods: 118 hepatocellular carcinomas in 73 cirrhotic patients who underwent double phase computed tomography during hepatic arteriography were enrolled in this study. Double phase computed tomography during hepatic arteriography consisted of computed tomography images obtained at 5-10 s (first phase) and 40-50 s (second phase) after the initiation of an intraarterial administration of 40-60 ml of contrast medium through the hepatic artery.

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Mast cells are secretory cells that release their granules, which contain inflammatory mediators. Some recent data suggested that cytoskeletons play a role in this process. However, the role of microtubules in Ca2+ signaling has not yet been well defined.

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Purpose: To determine, by using multi-detector row helical computed tomography (CT), the added value of obtaining unenhanced and delayed phase scans in addition to biphasic (hepatic arterial and portal venous phases) scans in the detection of hepatocellular carcinoma (HCC) in patients with cirrhosis.

Materials And Methods: Local ethical committee approval and patient consent were obtained. One hundred ninety-five patients (129 men, 66 women; mean age, 61 years; age range, 39-78 years) with 250 HCCs underwent multi-detector row helical CT of the liver.

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The time courses of changes in cardiovascular and autonomic nervous functions during acclimatization to hypoxia were studied in conscious Sprague-Dawley rats. The animals were kept under a 12:12-h light-dark cycle and exposed to hypoxia (1 atm, 10% O2). Implanted telemetry transmitters were used to record blood pressure (BP).

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Objective: We examined the inhibitory mechanisms of fluvastatin on FBS-induced vascular hypertrophy assessed by organ-cultured rat tail artery.

Methods And Results: After 5 days of culture with 10% FBS, hyperplastic morphological changes in the media layer were induced. Treatment with 1 mumol/L fluvastatin significantly inhibited these changes.

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Rationale And Objectives: The purpose of this study was to evaluate the utility of magnetic resonance (MR) imaging for indicating the extent of true tissue necrosis of the liver after radiofrequency (RF) ablation in comparison with histopathologic findings in dog models and an autopsy case.

Materials And Methods: RF ablation of the liver parenchyma was performed on three dogs under general anesthesia. MR appearances of the RF-ablated regions on T1-weighted fast-low angle shot (FLASH; repetition time/echo time [TR/TE]/flip angle: 120/3.

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Background And Aims: We prospectively compared the performance of low-dose multidetector computed tomographic colonography (CTC) without cathartic preparation with that of colonoscopy for the detection of colorectal polyps.

Methods: A total of 203 patients underwent low-dose CTC without cathartic preparation followed by colonoscopy. Before CTC, fecal tagging was achieved by adding diatrizoate meglumine and diatrizoate sodium to regular meals.

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Objective: We reviewed the medical records including pathologic descriptions, CT images, MR images, and digital subtraction angiograms of three patients with hepatic lesions that were associated with abnormal development of the portal vein-patent ductus venosus or congenital absence of the portal vein-to clarify the imaging characteristics of these abnormalities.

Conclusion: Two-phase helical CT and MRI, including MR angiography and dynamic studies, are useful for the diagnosis of patent ductus venosus and congenital absence of the portal vein. MRI may more effectively reveal hepatic lesions than two-phase helical CT under such abnormal conditions in which the liver has only the arterial but not the portal blood supply.

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It is important to diagnose hepatocellular carcinoma (HCC) correctly and in early stage, because viral hepatitis and liver cirrhosis are often complicated by HCC. Noncontrast and enhanced CT and MRI are very useful to visualize and diagnose HCC objectively. Especially, CT and MR imaging with dynamic study is essential to diagnose HCC, because it is usually hypervascular.

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Computed tomography (CT) and magnetic resonance imaging (MRI) are useful for detection and characterization of liver tumors, and widely used in clinical practice. By using dynamic CT and MRI with extracellular contrast material or MRI with liver-specific contrast material, we can investigate the morphological, hemodynamical and functional nature of focal hepatic lesions. Tumors often show characteristic findings on CT and MRI.

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We assessed the effects of dexamethasone (DEX) on hypoxia-induced dysfunction of the pulmonary endothelium using organ-cultured rabbit intrapulmonary arteries; 3-microM DEX inhibited the 7-day hypoxia (5% oxygen)-induced impairments of endothelial-dependent relaxation, cGMP accumulation, and increase in intracellular Ca(2+) level under substance P-stimulated conditions. Treatment with DEX over the final 3 days of the 7-day hypoxic exposure period also restored the decreased endothelium-dependent relaxation. Although chronic hypoxia did not change the mRNA expression of endothelial nitric oxide synthase (eNOS), 3 microM of DEX increased eNOS mRNA expression in both the hypoxic and normoxic (20% oxygen) pulmonary endothelium.

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Objective: The purpose of this study was to assess the efficacy of contrast enhanced multi-slice helical CT (MSCT) venography for the diagnosis of deep venous thrombosis (DVT) in comparison with venous sonography.

Materials And Methods: MSCT was used to obtain contiguous, 5-mm thick axial CT images from the diaphragm to the ankles of 27 patients after intravenous injection of contrast material. These patients were clinically suspected of having DVT.

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