Akiko Tonomura

Hitachi Aloka Medical, Ltd., Edo, Tōkyō, Japan

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Publications (16)37.02 Total impact

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    ABSTRACT: Although liver biopsy is the gold standard for viral liver disease management, it is invasive and the sampling error rate is problematic. Real-time tissue elastography (RTE), a recently developed method of ultrasound elastography, can be used to assess liver fibrosis noninvasively but the overlap between fibrosis stages limits its ability to assess liver fibrosis adequately when used alone. A multicenter collaborative study involving 542 patients with chronic viral hepatitis and cirrhosis who were scheduled to undergo liver biopsy compared the image features obtained from RTE image analysis, the liver fibrosis index (LFI), and pathological diagnosis. RTE and a blood test were performed on the same day as the liver biopsy. Data mining was also performed to construct a decision tree, and its diagnostic performance for assessing liver fibrosis was evaluated. The LFI was higher in patients with chronic hepatitis C (CHC) than in those with chronic hepatitis B (CHB). When a decision tree was constructed by data mining of RTE and serological findings, the diagnostic accuracy was very high for all fibrosis stages, with respective rates at F1, F2, F3, and F4 of 94.4, 54.1, 38.7, and 81.3% for patients with CHC and of 97.1, 50.0, 43.8, and 80.6% for patients with CHB. The variation in LFI values between the different etiologies appears to reflect the difference in the development style of liver fibrosis. The decision tree for assessing liver fibrosis constructed by data mining of both RTE and serological findings had a high diagnostic performance in assessing liver fibrosis and shows promising clinical utility. © 2014 S. Karger AG, Basel.
    Oncology 11/2014; 87 Suppl 1(s1):63-72. DOI:10.1159/000368147 · 2.42 Impact Factor
  • M. Mori · K. Fukuda · S. Hashimoto · A. Tonomura · T. Mitake
    Ultrasound in Medicine & Biology 08/2011; 37(8). DOI:10.1016/j.ultrasmedbio.2011.05.725 · 2.21 Impact Factor
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    ABSTRACT: The effect of scaffold shape on dentin regeneration is not well understood. In this study, porous hydroxyapatite/beta-tricalcium phosphate (HAp/beta-TCP), powdered HAp/beta-TCP, and polyglycolic acid (PGA) fiber mesh were used as scaffolds and transplanted with cultured porcine dental pulp-derived cells into the backs of nude mice. Samples were harvested after 6 weeks. Newly-formed hard tissue was observed in all transplants. When porous HAp/beta-TCP was used, dentin-like hard tissue was observed on the inner wall with minimum cell inclusions and odontoblast-like cells were aligned adjacent to the hard tissue. When HAp/beta-TCP powders or PGA were used, bone-like hard tissues showed cell inclusions and cell alignment was not observed. Hard tissue from the HAp/beta-TCP block group was positive for type I collagen, osteonectin, bone sialoprotein and dentin sialoprotein (DSP), which are markers for dentin. This result was confirmed by in situ hybridization with a dsp probe. Only the aligned cells were positive with an antisense probe. On the other hand, hard tissue from other scaffolds showed incomplete expression of both bone and dentin markers and they were negative for osteonectin and DSP. These results suggest that scaffold shape affects the type of tissue regenerated by dental pulp-derived cells.
    Annals of Biomedical Engineering 04/2010; 38(4):1664-71. DOI:10.1007/s10439-010-9910-z · 3.23 Impact Factor
  • Kanzo 01/2010; 51(9):539-541. DOI:10.2957/kanzo.51.539
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    ABSTRACT: The aim of this study was to investigate liver fibrosis using non-invasive Real-time Tissue Elastography (RTE) and transient elastography (FibroScan) methods. RTE, FibroScan and percutaneous liver biopsy were all performed on patients with chronic liver disease, particularly hepatitis C, to investigate liver fibrosis. FibroScan and RTE were compared for fibrous liver staging (F stage), which was pathologically classified using liver biopsy. In FibroScan, significant differences were observed between F1/F3 and F2/F4, but no such differences were observed between F1/F2, F2/F3 and F3/F4. In RTE, significant differences were observed between F1/F2, F2/F3 and F2/F4. But for F3/F4, no significant differences were observed. FibroScan and RTE correlated well with F staging of the liver. In particular RTE was more successful than FibroScan in diagnosing the degree of liver fibrosis.
    Intervirology 01/2010; 53(1):76-81. DOI:10.1159/000252789 · 1.68 Impact Factor
  • Ultrasound in Medicine & Biology 08/2009; 35(8). DOI:10.1016/j.ultrasmedbio.2009.06.587 · 2.21 Impact Factor
  • Ultrasound in Medicine & Biology 08/2009; 35(8). DOI:10.1016/j.ultrasmedbio.2009.06.211 · 2.21 Impact Factor
  • Gastroenterology 05/2009; 136(5). DOI:10.1016/S0016-5085(09)63848-8 · 16.72 Impact Factor
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    ABSTRACT: The purpose of this study was to investigate dentin-bridge formation in teeth following the transplantation of dental pulp-derived cells seeded on hydroxyapatite/tricalcium phosphate (HA/TCP) scaffolds. The dental pulp tissues were removed from the extracted first molar teeth of miniature pigs and single cell populations were subcultured. Second-passage cells that had alkaline phosphatase activity were combined with scaffolds. Cell-scaffold constructs were placed in contact with the exposed pulp tissue. The dimensions of the exposed pulp site were approximately 1-2.5 mm in diameter and 2-3 mm in depth from the tooth surface. After placing the constructs, the tooth was restored with composite resin. Six weeks after transplantation, hard tissue formation was observed on the pulp tissue in histology. Dentinal tubule-like structures were observed in most of the hard tissue generated, and columnar cells, which showed positive immunoreactions with dentin sialoprotein (DSP) and heat shock protein (HSP)-25, were aligned beneath the hard tissues. When only scaffolds were placed on the pulp tissues, particles of hard tissue were formed, however dentinal tubule-like structures and odontoblasts were not observed despite the formation of hard tissue. In conclusion, the implantation of dental pulp constructs into pulp exposed stimulates the formation of calcified dentin-like structures.
    Nagoya journal of medical science 03/2009; 71(1-2):51-62. · 0.75 Impact Factor
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    ABSTRACT: It is well known that as hepatic cirrhosis progresses, hepatocyte fibrosis spreads and nodule increases. However, it is not easy to diagnosis its early stage by conventional B-mode image because we have to read subtle change of speckle pattern which is not sensitive to the stage of fibrosis. Ultrasonic tissue elasticity imaging can provide us novel diagnostic information based on tissue hardness. We recently developed commercial-based equipment for tissue elasticity imaging. In this work, we investigated to develop the CAD system based on elasticity image for diagnosing defused type diseases such as hepatic cirrhosis. The results of clinical data analysis indicate that the CAD system is promising as means for diagnosis of diffuse disease with simple criterion. Key wordsHepatic cirrhosis-Elasticity imaging-CAD-Texture analysis
    12/2008: pages 451-456;
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    ABSTRACT: In the previous report [1], we have applied free-hand "Real-time Tissue Elastography" on the prostate cancer detection using transrectal probe and presented preliminary results to reveal its promising capability to realize high sensitivity for almost prostate diagnosis. It is also shown that free-hand method has some limitations come from ununiformity of compression and discontinuities between frame to frame. In this report, we present our latest clinical evaluation using balloon-inflation-based Elastography as proposed briefly in the previous paper [1].
    Ultrasonics Symposium, 2007. IEEE; 12/2007
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    ABSTRACT: A robust method for generating odontoblasts from cultured dental pulp cells has not been established. In this study, efficient methods for deriving odontoblasts from cultured human and porcine dental pulp-derived cells were investigated with special attention to species differences. Cultured human cells showed relatively low alkaline phosphatase (ALP) activity in the presence of dexamethasone (Dex) and beta-glycerophosphate (beta-Gly). In contrast, the addition of 1,25-dihydroxyvitaminD(3) (VitD3) significantly increased the ALP activity. In porcine cells, beta-Gly alone or a combination of Dex and beta-Gly significantly increased ALP activity; however, addition of VitD3 reduced this activity. RT-PCR and Western blotting analysis revealed that the combination of three induction reagents on human cells significantly upregulates the expression of osteocalcin mRNA, and dentin sialoprotein. We propose that the combination of Dex, beta-Gly, and VitD3 is critical for differentiation of human dental pulp-derived cells into odontoblasts. In addition, the inducibility of dental pulp-derived cells presented remarkable species differences.
    Connective Tissue Research 02/2007; 48(5):229-38. DOI:10.1080/03008200701507909 · 1.61 Impact Factor
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    ABSTRACT: With increasing age venous clots undergo an organization process during which they become adherent to the vessel wall. Therefore, one important factor influencing the decision whether or not to perform thrombolysis or thrombectomy for venous thrombosis is the age of the thrombus. The aim of this study was to examine the diagnostic ability and an appropriate assessment procedure of this method for venous thrombus. Methods: Conventional Ultrasonography (US) and Elastography were performed on 25 patients diagnosed with venous thrombosis in the lower extremities. All images were obtained with an Ultrasound Scanner EUB-8500 (HITACHI Medical Corporation) and analyzed by an external personal computer. First of all, we examined elasticity images obtained with differ- ent methods of compression and drew up a certain assessment procedure for evaluating venous thrombi. Secondly, we observed the venous thrombi with B-mode images, Color Doppler images and elasticity images. We estimated the age of thrombi by their appearance in conventional ultrasonographic images and divided them into three phases as follows: acute, sub-acute and chronic. Results: 25 patients, 30 lesions were assessed. We could obtain stable images by vibrating the area of the thrombus after initial compression. It was recommended that the range of the region of interest (ROI) include muscle, and exclude bone and arteries. In general, thrombi in the acute phase were represented as soft elasticity images, and venous thrombi in the chronic phase were represented as hard elasticity images. Meanwhile, thrombi in the acute phase presenting anechoic lesions were not imaged clearly, and with mixed thrombi with a small amount of venous flow it was difficult to differentiate between fresh thrombi and venous flow. Conclusion: Venous thrombi were imaged clearly with appropriate compression by Elastography. We will continue to improve elasticity imaging for assessing venous thrombus.
  • M J Honda · Y Shinohara · Y Sumita · A Tonomura · H Kagami · M Ueda
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    ABSTRACT: Numerous studies have demonstrated the effect of shear stress on osteoblasts, but its effect on odontogenic cells has never been reported. In this study, we focused on the effect of shear stress on facilitating tissue-engineered odontogenesis by dissociated single cells. Cells were harvested from the porcine third molar tooth at the early stage of crown formation, and the isolated heterogeneous cells were seeded on a biodegradable polyglycolic acid fiber mesh. Then, cell-polymer constructs with and without exposure to shear stress were evaluated by in vitro and in vivo studies. In in vitro studies, the expression of both epithelial and mesenchymal odontogenic-related mRNAs was significantly enhanced by shear stress for 2 h. At 12 h after exposure to shear stress, the expression of amelogenin, bone sialoprotein and vimentin protein was significantly enhanced compared with that of control. Moreover, after 7 days, alkaline phosphatase activity exhibited a significant increase without any significant effect on cell proliferation in vitro. In vivo, enamel and dentin tissues formed after 15 weeks of in vivo implantation in constructs exposure to in vitro shear stress for 12 h. Such was not the case in controls. We concluded that shear stress facilitates odontogenic cell differentiation in vitro as well as the process of tooth tissue engineering in vivo.
    Bone 07/2006; 39(1):125-33. DOI:10.1016/j.bone.2005.12.005 · 3.97 Impact Factor
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    ABSTRACT: Tissue elasticity imaging is a technology for imaging tissue hardness information using ultrasound. We have investigated the use of this method in cases of breast cancer, prostate cancer, etc. [Yamakawa, et. al., 2003; Yamakawa, et. al., 2003; Ito, et. al., 2006] However, tissue hardness provides important information for many diseases besides breast cancer and prostate cancer. For example, in deep venous thrombosis (DVT), the freshness of a thrombus can be determined from its hardness, and this information is very important for the treatment. However, the hardness of a thrombus that has an anechoic region cannot be measured correctly using conventional methods. Therefore, in this paper, we propose a new tissue elasticity imaging method for disease in anechoic regions. The results of a simulation and a phantom experiment verified that the proposed method is effective for detecting disease in an anechoic region. Moreover, we demonstrate that the proposed method can measure the hardness of a thrombus
    Proceedings of the IEEE Ultrasonics Symposium 01/2006; DOI:10.1109/ULTSYM.2006.316
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    ABSTRACT: "Real-time Tissue Elastography" has been implemented on our commercial ultrasound scanner (HITACHI EUB-8500) in 2004 [Matsumura, T, et al., 2004] based on our study of the ultrasonic elasticity imaging method since 2002 [Matsumura, T, et al., 2002]. As the first clinical applications, we have reported preliminary results for prostate cancer detection in 2003 [Yamakawa, M, et al., 2003]. In that report, we could suggest that this method is clinically useful for biopsy support technology. In this paper, we present our latest diagnostic results using ultrasonic probe capable of transrectal biopsy, and discuss the limitation of applicability of our method and future prospects
    Proceedings of the IEEE Ultrasonics Symposium 01/2006; DOI:10.1109/ULTSYM.2006.318