Publications by authors named "Takeo Miyahara"

Aim: To investigate the diagnosis of nonalcoholic steatohepatitis (NASH) using contrast ultrasonography in the NASH rat model.

Methods: The liver in methionine choline-deficient diet (MCDD) rats, a NASH model constructed by feeding an MCDD, was examined by contrast ultrasonography at weeks 2, 4, 8, 12 and 16, with late phase images of contrast ultrasonography (Kupffer imaging) in which contrast enhancement was achieved by incorporation of a contrast agent by Kupffer cells (KCs), and images were compared to those in rats taking a regular chow.

Results: Decrease in contrast enhancement was observed first in MCDD rats at week 2.

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A 74-year-old woman underwent abdominal echography at a local clinic and a splenic mass was found. She was hospitalized for detailed examinations and treatment. Splenectomy was performed to make a definite diagnosis and for treatment because a definitive diagnosis could not be made, despite various examinations.

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Delayed parenchymal phase images of the liver more than 5 min after IV injection of ultrasound contrast agents are thought to be related to the phagocytosis of contrast agent microbubbles by macrophages. In this study, we examined whether liver-specific macrophages, Kupffer cells, phagocytosed the microbubbles and whether their elimination affected the delayed parenchymal images of the liver. Phase-contrast microscope observations showed that Kupffer cells phagocytosed various contrast agents in vitro.

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We developed a computed tomography (CT) virtual ultrasound system (CVUS) as an imaging system to support treatment under percutaneous ultrasound (US) guidance. This prototype clinical system, produced in collaboration with Tokyo Medical University, uses display software developed by Toshiba Medical Systems. We examined the utility of this system by scheduling treatment plans preoperatively and simulating puncture and radiofrequency ablation (RFA) for liver cancer.

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Cirrhosis is the most important consequence of alcoholic liver disease for which liver transplantation is the only treatment option available. Transdifferentiation of hepatic stellate cells (HSC) to myofibroblastic cells (MF) is a central event in liver fibrogenesis, and understanding molecular mechanisms that underlie this cellular event provides pivotal insights into development of new therapeutic modalities for cirrhosis. To this end, the authors proposed several years ago that transdifferentiation of quiescent HSC to MF may be causally associated with transcriptional regulation known for adipocyte-preadipocytic fibroblast dedifferentiation.

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Phase contrast microscopy showed that Levovist microbubbles were phagocytosed by cultured Kupffer cells and moved gradually toward the nucleus from the cell surface. They were diminished in size and disappeared within 30min by diffusion of the gas contained within the microbubbles. In an in vivo study, confocal laser scanning microscopy demonstrated that Levovist microbubbles were trapped and phagocytosed by Kupffer cells.

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Background And Aims: Non alcoholic steatohepatitis (NASH) is one of the representative liver diseases in the developed countries. Diagnosis of NASH is dependent on histological findings from liver biopsy. Usefulness of contrast ultrasound with Levovist for diagnosis of NASH is described.

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T2-weighted fast spin echo images and T2*-weighted gradient-echo images of superparamagnetic iron oxide magnetic resonance imaging (SPIO-MRI) have been reported to reflect the number and function of macrophages in reticuloendothelial organs and be useful to differentiate malignant tumors from benign nodules of liver. We tried to prove that contrast-enhanced ultrasound can diagnose hepatocellular carcinoma (HCC) by comparing the findings of SPIO-MRI and the findings of the liver parenchyma on the delayed parenchymal phase of ultrasound imaging using the intravenous contrast agent Levovist, not through the evaluation of vascular imaging. Forty-six patients (52 nodules) with histopathological diagnosis of hepatic tumors were studied.

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Activation of Hepatic stellate cells (HSC) in fibrogenesis involves distinct morphological and biochemical changes. This activation requires the coordinated changes in activity of several transcription factors. Peroxisome proliferator-activated receptor gamma (PPAR gamma) is one such factor whose activity is decreased in activated HSC.

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Interleukin (IL)-10 expression is induced in activated hepatic stellate cells (HSC) in vitro and in vivo. We analyzed expression of IL-10 receptor (IL-10R) and coreceptor cytokine receptor family (CRF2-4) in HSC. We aimed to clone and sequence partial cDNA for rat IL-10R and CRF2-4, determine their expression in activated rat HSC in vivo and in vitro, and examine the biological responsiveness of HSC to exogenous IL-10.

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