Publications by authors named "Masayuki Yokoyama"

80 Publications

Analysis of circulating cell-free DNA after endoscopic ultrasound-guided fine needle aspiration in pancreatic ductal adenocarcinoma.

Pancreatology 2021 Apr 15. Epub 2021 Apr 15.

Department of Gastroenterology, Graduate School of Medicine, Chiba University, Chiba, Japan.

Background/objectives: Recently, increase in cell-free DNA (cfDNA) concentration or newly detected KRAS mutation after endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) biopsy were reported to be related to the occurrence of new distant metastasis. In this study, we investigated whether cfDNA concentration increased with the release of tumor components into the blood after EUS-FNA and whether its increase was related to prognosis.

Methods: Sixty-eight patients underwent EUS-FNA and were pathologically confirmed as having pancreatic ductal adenocarcinoma (PDAC). We measured plasma cfDNA concentration and the copy number of KRAS mutation in 68 patients and circulating tumor cells in 8 before and after EUS-FNA.

Results: The average cfDNA concentration after EUS-FNA (672.5 ± 919.6 ng/mL) was significantly higher than that before EUS-FNA (527.7 ± 827.3 ng/mL) (P < 0.001). KRAS mutation in plasma was detected in 8 patients (11.8%), however a significant increase in cfDNA concentration after EUS-FNA was not related to the change in KRAS-mutant copy number. Minimal increase in circulating tumor cells was observed in 3 of 8 patients. New distant metastasis was observed within 286 days to initial metastasis detection in 6 of 12 patients with ≥2-fold increase in cfDNA concentration and 26 of 56 patients with <2-fold increase within 185 days. In 32 patients who underwent surgery, ≥2-fold increase in cfDNA did not affect early recurrence.

Conclusions: The increase in cfDNA concentration after EUS-FNA was not caused by tumor cell components released into blood vessels. Hence, the risk of seeding via the blood stream after EUS-FNA may need not be considered.
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http://dx.doi.org/10.1016/j.pan.2021.04.001DOI Listing
April 2021

Propofol midazolam for sedation during radiofrequency ablation in patients with hepatocellular carcinoma.

JGH Open 2021 Feb 22;5(2):273-279. Epub 2020 Dec 22.

Departmetn of Anesthesiology, Graduate School of Medicine Chiba University Chiba Japan.

Background And Aim: Standardization of the sedation protocol during radiofrequency ablation (RFA) in patients with hepatocellular carcinoma (HCC) is needed. This randomized, single-blind, investigator-initiated trial compared clinical outcomes during and after RFA using propofol and midazolam, respectively, in patients with HCC.

Methods: Few- and small-nodule HCC patients (≤3 nodules and ≤3 cm) were randomly assigned to either propofol or midazolam. Patient satisfaction was assessed using a 100-mm visual analog scale (VAS) (1 mm = not at all satisfied, 100 mm = completely satisfied). Sedation recovery rates 1, 2, 3, and 4 h after RFA were evaluated based on Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scores; full recovery was defined as a MOAA/S score of 5.

Results: Between July 2013 and September 2017, 143 patients with HCC were enrolled, and 135 patients were randomly assigned to the treatment group. Compared with midazolam, propofol exhibited similar median procedural satisfaction (propofol: 73.1 mm, midazolam: 76.9 mm, = 0.574). Recovery rates 1 and 2 h after RFA were higher in the propofol group than in the midazolam group. Meanwhile, recovery rates observed 3 and 4 h after RFA were similar in the two groups. The safety profiles during and after RFA were almost identical in the two groups.

Conclusion: Patient satisfaction was almost identical in patients receiving propofol and midazolam sedation during RFA. Propofol sedation resulted in reduced recovery time compared with midazolam sedation in patients with HCC. The safety profiles of both propofol and midazolam sedation during and after RFA were acceptable.
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http://dx.doi.org/10.1002/jgh3.12483DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7857294PMC
February 2021

Efficacy and safety of upadacitinib over 84 weeks in Japanese patients with rheumatoid arthritis (SELECT-SUNRISE).

Arthritis Res Ther 2021 01 6;23(1). Epub 2021 Jan 6.

The First Department of Internal Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi Ward, Kitakyushu, Fukuoka, 807-8555, Japan.

Background: The objective of the study was to evaluate the efficacy and safety of upadacitinib over 84 weeks in Japanese patients with active rheumatoid arthritis (RA) and an inadequate response to conventional synthetic disease-modifying anti-rheumatic drugs.

Methods: All patients completing a 12-week, randomized, double-blind treatment period entered a blinded extension and continued upadacitinib 7.5, 15, or 30 mg once daily (QD), or were switched from placebo to upadacitinib 7.5, 15, or 30 mg QD. Efficacy and safety were assessed over 84 weeks.

Results: Of 197 randomized patients, 187 (94.9%) completed the 12-week period and entered the blinded extension; 152 (77.2%) patients were ongoing at week 84. At week 84, the proportions of patients achieving a 20% improvement in American College of Rheumatology criteria (ACR20) were 85.7%, 77.6%, and 58.0% with continued upadacitinib 7.5, 15, and 30 mg, respectively (nonresponder imputation), and were similar in patients who had switched from placebo. Favorable response rates were also observed for more stringent measures of response (ACR50/70) and remission (defined by the Disease Activity Score of 28 joints with C-reactive protein, Clinical Disease Activity Index, or Simplified Disease Activity Index). The 15 mg and 30 mg doses of upadacitinib were associated with more rapid and numerically higher initial responses for some measures of disease activity and remission compared with the 7.5 mg dose. Rates of adverse events, infection, opportunistic infection, serious infection, and herpes zoster were lower with upadacitinib 7.5 and 15 mg versus 30 mg.

Conclusions: Upadacitinib demonstrated sustained efficacy and was well tolerated over 84 weeks in Japanese patients with RA, with upadacitinib 15 mg offering the most favorable benefit-risk profile.

Trial Registration: ClinicalTrials.gov NCT02720523 . Registered on March 22, 2016.
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http://dx.doi.org/10.1186/s13075-020-02387-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7789301PMC
January 2021

Single intratracheal administration of cross-linked water-soluble acrylic acid polymer causes acute alveolo-interstitial inflammation and the subsequent fibrotic formation possibly via the TGF-β1 pathway in the lung of rats.

Toxicology 2021 01 28;448:152647. Epub 2020 Nov 28.

Department of Public Health and Environmental Medicine, The Jikei University School of Medicine, Japan. Electronic address:

In a Japanese chemical factory, a lung disease like pneumoconiosis appeared at a high rate among workers handling cross-linked water-soluble acrylic acid polymer (CWAAP). To our knowledge, no such case was known in the world until very recently. The present study was designed to elucidate the effect of single intratracheal CWAAP instillation on the lung of rats. The CWAAP group had a significant increase in relative lung weight accompanied by a significant elevation in the number of total cells, total protein concentrations, and myeloperoxidase concentrations in bronchoalveolar lavage fluid when compared to the control group. The histopathological study revealed acute lung inflammation with the destruction of alveoli. The factors promoting fibrosis, macrophages, TGF-β1, collagen and fibronectin vs. the factors suppressing fibrosis, matrix metalloproteinases were more powerfully driven in the CWAAP group, resultantly leading to fibrotic formation. In turn, we examined if acute lung inflammation and the subsequent fibrotic formation seen in the CWAAP group appeared in the other water-soluble polymer groups. Their histopathological findings were observed only in the polyacrylic acid sodium (PAAS), a monomer of CWAAP, group. The degree of inflammation and fibrogenesis was stronger in the CWAAP group than in the PAAS group. In conclusion, the present study demonstrated the induction of acute lung inflammation and the subsequent fibrotic formation by single intratracheal CWAAP instillation. The structural features of CWAAP that contains many carboxyl groups and cross-linked chains may be responsible for enhanced inflammation and fibrogenesis in the lung.
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http://dx.doi.org/10.1016/j.tox.2020.152647DOI Listing
January 2021

Analyses of Intermediate-Stage Hepatocellular Carcinoma Patients Receiving Transarterial Chemoembolization prior to Designing Clinical Trials.

Liver Cancer 2020 Sep 22;9(5):596-612. Epub 2020 Jul 22.

Department of Gastroenterology, Graduate School of Medicine, Chiba University, Chiba, Japan.

Background: Intermediate-stage hepatocellular carcinoma (HCC) has a high frequency of recurrence and progression to advanced stage after transarterial chemoembolization (TACE), particularly in patients with high tumor burden. Promising new results from immune checkpoint inhibitors (ICIs) and ICI-based therapies are expected to replace TACE, especially in HCC patients with high tumor burden.

Aims: The present study aimed to evaluate the effectiveness of TACE with a view to design clinical trials comparing TACE and ICIs.

Methods: We retrospectively identified intermediate-stage HCC patients undergoing TACE from our database and subdivided patients into low- and high-burden groups based on three subclassification models using the diameter of the maximum tumor and the number of tumors. Clinical outcomes were compared between low- and high-burden intermediate-stage HCC.

Results: Of 1,161 newly diagnosed HCC patients, 316 were diagnosed with intermediate-stage disease and underwent TACE. The median overall survival from high-burden intermediate-stage disease was not significantly different by clinical course, reaching high tumor burden in all subclassification models. The prognosis of high-burden patients after initial TACE was poor compared with low-burden patients for two models (except for the up-to-seven criteria). In all three models, high-burden patients showed a poor durable response rate (DRR) both ≥3 months and ≥6 months and poor prognosis after TACE. Moreover, patients with confirmed durable response ≥3 months and ≥6 months showed better survival outcomes for high-burden intermediate-stage HCC.

Conclusions: Our results demonstrate the basis for selecting a population that would not benefit from TACE and setting DRR ≥3 months or ≥6 months as alternative endpoints when designing clinical trials comparing TACE and ICIs.
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http://dx.doi.org/10.1159/000508809DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7548915PMC
September 2020

Long-term analysis of adalimumab in Japanese patients with moderate to severe hidradenitis suppurativa: Open-label phase 3 results.

J Dermatol 2021 Jan 7;48(1):3-13. Epub 2020 Oct 7.

Nihon University School of Medicine, Tokyo, Japan.

This phase 3, multicenter, open-label single-arm study evaluated adalimumab (ADA) in Japanese patients with moderate to severe hidradenitis suppurativa (HS). Fifteen patients received ADA 160 mg s.c. at week 0, 80 mg at week 2 and 40 mg at week 4 and every week thereafter. At any time after week 52, patients were given the option to receive 80 mg ADA every other week or remain on 40 mg every week. The primary end-point (achievement of HS Clinical Response [HiSCR] at week 24) and results up to week 24 were published previously. Secondary end-points included total abscess and inflammatory nodule (AN) count, 30% or more and 1 unit or more reduction in Patient's Global Assessment of Skin Pain Numeric Rating Scale (NRS30), modified Sartorius score and quality of life (QoL). After 12 weeks of ADA treatment, the achievement rate in HiSCR was 86.7%; HiSCR achievement rate was sustained through week 52 at 66.7%. Improvements at week 12 were also seen in the proportion of patients achieving an AN count of 0-2; NRS30 response rate among the nine patients with a baseline NRS of 3 or more; mean decrease in modified Sartorius score (61.4); and QoL as assessed by Dermatology Life Quality Index and Treatment Satisfaction Questionnaire; these improvements were maintained through 52 weeks. Similar efficacy was observed when patients switched dosing from ADA 40 mg every week to ADA 80 mg every other week. There were no new safety findings with ADA 40 mg weekly dosing during the study, and no differences in safety were found between patients who switched to 80 mg ADA every other week and patients who remained on 40 mg every week. The results of this study indicate that long-term ADA treatment is effective and well tolerated in Japanese patients with moderate to severe HS.
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http://dx.doi.org/10.1111/1346-8138.15605DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7821142PMC
January 2021

Stability evaluation of Gd chelates for macromolecular MRI contrast agents.

MAGMA 2020 Aug 10;33(4):527-536. Epub 2019 Dec 10.

Division of Medical Engineering, Research Center for Medical Sciences, The Jikei University School of Medicine, 163-1, Kashiwashita, Kashiwa-shi, Chiba, 277-8567, Japan.

Objective: We try to establish designs for the macromolecular agents possessing high Gd-chelating stability, because free Gd ion released from Gd chelates is known as a risk factor to cause toxic side effects and a safety concern.

Materials And Methods: We prepared three types of Gd-based macromolecular MRI contrast agents from a synthetic polymer (poly(glutamic acid) homopolymer or poly(ethylene glycol)-b-poly(lysine) block copolymer) and a chelating moiety (DO3A or DOTA) having two strategic designs for high chelate stability. Then, we examine the in vitro Gd-chelate stability of these macromolecular MRI contrast agents.

Results: The prepared macromolecular agents exhibited the same or higher Gd-chelate stability as/than did Gd-DOTA that possesses the highest Gd-chelate stability among the approved small-MW Gd-chelate MRI contrast agent.

Discussion: Our macromolecular design was considered to work well for high Gd-chelate stability.
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http://dx.doi.org/10.1007/s10334-019-00805-8DOI Listing
August 2020

Twenty-four-week interim analysis from a phase 3 open-label trial of adalimumab in Japanese patients with moderate to severe hidradenitis suppurativa.

J Dermatol 2019 Sep 8;46(9):745-751. Epub 2019 Jul 8.

Nihon University School of Medicine, Tokyo, Japan.

Hidradenitis suppurativa (HS) is a chronic skin disease characterized by recurrent painful inflamed nodules/abscesses and draining fistulas that negatively impact quality of life. Adalimumab, a monoclonal antibody against tumor necrosis factor-α, has been approved in the EU, USA and Japan for the treatment of moderate to severe HS. This is an interim analysis of an ongoing phase 3, multicenter, open-label, single-arm study of the safety and efficacy of adalimumab weekly dosing in Japanese patients with moderate to severe HS. Fifteen patients received adalimumab 160 mg at week 0, 80 mg at week 2 and 40 mg every week thereafter starting at week 4. The fulfillment of Hidradenitis Suppurativa Clinical Response was assessed under adalimumab treatment; clinical response was assessed by skin pain, total abscess and inflammatory nodule count and modified Sartorius score; and quality of life and safety were assessed. At week 12, 86.7% of patients achieved clinical response, with improvements at week 12 across the primary and secondary end points generally sustained through week 24. Adalimumab weekly dosing was generally safe and well tolerated with no new safety findings through week 24. These results suggest that adalimumab is effective and well tolerated in Japanese patients with moderate to severe HS.
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http://dx.doi.org/10.1111/1346-8138.14997DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771639PMC
September 2019

Sequential therapy with sorafenib and regorafenib for advanced hepatocellular carcinoma: a multicenter retrospective study in Japan.

Invest New Drugs 2020 02 6;38(1):172-180. Epub 2019 Jun 6.

Department of Gastroenterology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.

Background Conversion from sorafenib to regorafenib is primarily an evidence-based treatment strategy in patients with advanced hepatocellular carcinoma (HCC). This study aimed to assess the safety and efficacy of sequential therapy with sorafenib and regorafenib in patients with advanced HCC by analysis of outcomes in clinical practice with the aim to complement phase III findings. Methods The medical records of patients with advanced HCC receiving regorafenib were retrieved to collect data on sorafenib administration at seven Japanese institutions. Radiological responses and adverse events were evaluated using the Response Evaluation Criteria in Solid Tumors version 1.1 and the Common Terminology Criteria for Adverse Events version 4.0, respectively. Results Before March 2018, 44 patients were administered regorafenib for advanced HCC. The median sorafenib treatment duration was 8.4 months. The most common adverse events were similar to those reported by the RESORCE trial. The median overall survival (OS) was 17.3 months (95% confidence interval [CI] 11.4-22.9), and 17 of 37 patients (45.9%) discontinued regorafenib and received sequential systemic therapy after regorafenib. These patients had significantly longer OS than those who were treated by the best supportive care or sub-optimal therapy (not reached versus 8.7 months [95% CI 5.8-11.7]; P < 0.001). Conclusion The results based on Japanese clinical practices verified the tolerability of regorafenib in advanced HCC. Major regorafenib-associated adverse events were similar to those related to sorafenib. OS was significantly longer than expected, which might be associated with the sequential systemic therapies after regorafenib, mainly lenvatinib.
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http://dx.doi.org/10.1007/s10637-019-00801-8DOI Listing
February 2020

Toxicity and immunogenicity concerns related to PEGylated-micelle carrier systems: a review.

Sci Technol Adv Mater 2019 15;20(1):324-336. Epub 2019 Apr 15.

Division of Medical Engineering, Research Center for Medical Sciences, The Jikei University School of Medicine, Kashiwa, Chiba, Japan.

Polymeric-micelle carrier systems have emerged as a novel drug-carrier system and have been actively studied for anticancer drug targeting. In contrast, toxicological and immunological concerns related to not only polymeric-micelle carrier systems, but also other nanocarrier systems, have received little attention owing to researchers' focus on therapeutic effects. However, in recent clinical contexts, biopharmaceuticals' effects on immune responses have come to light, requiring that researchers substantively explore the potential negative side effects of nanocarrier systems and of therapeutic proteins in order to develop nanocarrier systems suitable for clinical use. The present review describes current insights into both toxicological and immunological issues regarding polymeric-micelle carrier systems. The review focuses on immunogenicity issues of polymeric-micelle carrier systems possessing poly(ethylene glycol) (PEG). We conclude that PEG-related immunogenicity is deeply related to characteristics of a counterpart block of PEG-conjugates, and we propose future directions for addressing this unresolved issue.
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http://dx.doi.org/10.1080/14686996.2019.1590126DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6493319PMC
April 2019

Logistic regression analysis of multiple interosseous hand-muscle activities using surface electromyography during finger-oriented tasks.

J Electromyogr Kinesiol 2019 Feb 23;44:117-123. Epub 2018 Dec 23.

Department of Computer Science and Communications Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.

Intrinsic hand muscles are densely located in the hand, and the myoelectric observation from the surface is sometimes unreliable because of some outside influences that may interfere with the signals. In the present study, we evaluated the activities of multiple interosseous hand-muscles which densely located in the hand, through analyzing the surface electromyographic signals during finger-oriented tasks using univariate and multivariate logistic regression models. Ten healthy subjects participated in our experiment, and isometrically exercised each finger one by one in flexed form. The result of a univariate analysis with the power and amplitude domain predictor variables of the surface electromyographic signals showed significant consistency between the activated finger and the inserted finger of the dorsal interosseous muscles to the proximal phalanx (P < 0.001). Meanwhile, the results of a multivariate analysis showed a higher correlation of the regression model of the fourth dorsal interosseous muscle during the action of the ring finger using frequency-domain variables (the Nagelkerke R = 0.716 when the median frequency was used), compared to the model without the frequency-domain variables (the Nagelkerke R = 0.583). Our result showed that the logistic regression models have a particular possibility for the analysis of the surface electromyographic signals of densely located hand-muscle activities related to the finger-oriented tasks.
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http://dx.doi.org/10.1016/j.jelekin.2018.12.006DOI Listing
February 2019

Trifluoromethane modification of thermally activated delayed fluorescence molecules for high-efficiency blue organic light-emitting diodes.

Chem Commun (Camb) 2018 Jul;54(59):8261-8264

Department of Chemistry and Biochemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.

Highly efficient blue and green thermally activated delayed fluorescence (TADF) molecules bearing trifluoromethane-modified carbazole groups were developed. The trifluoromethane groups on carbazole induced blue-shifted emission and improved the photoluminescence quantum yield. The photostability of the TADF molecules was strongly related to the modification position of trifluoromethane on carbazole.
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http://dx.doi.org/10.1039/c8cc03425gDOI Listing
July 2018

Transarterial chemoembolization as a substitute to radiofrequency ablation for treating Barcelona Clinic Liver Cancer stage 0/A hepatocellular carcinoma.

Oncotarget 2018 Apr 20;9(30):21560-21568. Epub 2018 Apr 20.

Department of Gastroenterology, Graduate School of Medicine, Chiba University, Chiba, Japan.

Background And Aim: Transarterial chemoembolization (TACE) is the standard procedure for treating Barcelona clinic liver cancer (BCLC) stage B hepatocellular carcinoma (HCC). However, it is often carried out in the treatment of BCLC stage 0/A HCC for various reasons. This study aimed to elucidate the prognosis for BCLC stage 0/A HCC patients treated with TACE or with radiofrequency ablation (RFA).

Materials And Methods: The prognosis of 242 BCLC stage 0/A HCC patients within Milan criteria who underwent initially TACE or RFA were retrospectively analyzed using propensity score matching analysis.

Results: The analyses of baseline patient characteristics revealed that the maximum tumor size and the proportion of BCLC stage A patients were significantly higher in patients treated with TACE than in those treated with RFA (<0.001 and 0.047, respectively). After adjusting these factors using propensity score matching (1:3 matching), patients treated with TACE (n=32) and those treated with RFA (n=96) were further analyzed. The local recurrence rate was significantly higher in the TACE group than in the RFA group (<0.001). However, the overall survival (OS) in HCC patients treated with TACE was comparable to that in HCC patients treated with RFA (1 year, 93.5 vs. 95.8%; 3 years, 75.4 vs. 85.8%; 5 years, 61.8 vs. 70.7%; =0.196). Multivariate analyses followed by univariate analyses revealed that serum bilirubin level (=0.032), serum albumin level (=0.008), HBV-DNA (=0.013), and tumor number (=0.021) were independent predictors of OS.

Conclusion: TACE can substitute RFA at least in some patients with BCLC 0/A HCC.
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http://dx.doi.org/10.18632/oncotarget.25108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5940395PMC
April 2018

Safety and efficacy of levodopa-carbidopa intestinal gel: results from an open-label extension study in Japanese, Korean and Taiwanese patients with advanced Parkinson's disease.

Ther Adv Neurol Disord 2018 26;11:1756286418759315. Epub 2018 Feb 26.

AbbVie Inc., North Chicago, Illinois, USA.

Objectives: Levodopa-carbidopa intestinal gel (LCIG) was developed to reduce motor complications in Parkinson's disease (PD) caused by pulsatile levodopa plasma concentrations following oral levodopa administration. Dyskinesia and 'wearing off' symptoms can vary between Asian and Caucasian patients with PD, thus highlighting the importance of assessing the effectiveness of LCIG in an Asian population. Efficacy and safety of LCIG were previously assessed in a 12-week open-label study; we report the efficacy and safety of at least 52 weeks of LCIG treatment in Japanese, Taiwanese, and Korean patients with advanced PD in the ongoing extension study.

Methods: In this interim analysis of a phase III, open-label, multicenter extension study in Japan, South Korea, and Taiwan [ClinicalTrials.gov identifier: NCT02082249/JapiCTI-142482], the mean change from baseline to final visit in 'off' time, as reported in the PD symptom diary, was normalized to a 16-h waking day. Changes in Parkinson's Disease Questionnaire-39 (PDQ-39) summary index and domains scores were also analyzed. Adverse events (AEs) were recorded.

Results: Of the 28 patients enrolled (21 Japanese, 3 Taiwanese, 4 Korean), 27 completed at least 52 total weeks of treatment, and 25 patients were continuing in the study at data cutoff. The mean [standard deviation (SD)] 'off' time was significantly reduced by 4.6 (3.1) h/day ( < 0.001, = 28). Patients experienced significant improvements in quality of life, as recorded by the mean change from baseline in PDQ-39 summary index ( < 0.001). All patients had at least one AE; three patients (11%) discontinued due to an AE. There were two deaths (sepsis and drowning), both of which the investigator considered unrelated to LCIG treatment.

Conclusions: These data suggest that LCIG treatment is efficacious, safe, and well tolerated in Japanese, Taiwanese, and Korean patients with advanced PD, thus confirming the consistency of LCIG treatment in patients with advanced PD.
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http://dx.doi.org/10.1177/1756286418759315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5833238PMC
February 2018

Chemotherapeutic Effect of CD147 Antibody-labeled Micelles Encapsulating Doxorubicin Conjugate Targeting CD147-Expressing Carcinoma Cells.

Anticancer Res 2018 03;38(3):1311-1316

Department of Biochemistry, Jikei University School of Medicine, Tokyo, Japan.

Background: CD147 (basigin/emmprin) is expressed on the surface of carcinoma cells.

Materials And Methods: For studying the efficacy of CD147-targeting medicine on CD147-expressing cells, we studied the effect of anti-CD147-labeled polymeric micelles (CD147ab micelles) that encapsulated a conjugate of doxorubicin with glutathione (GSH-DXR), with specific accumulation and cytotoxicity against CD147-expressing A431 human epidermoid carcinoma cells, Ishikawa human endometrial adenocarcinoma cells, and PC3 human prostate carcinoma cells.

Results: By treatment of each cell type with CD147ab micelles for 1 h, a specific accumulation of CD147ab micelles in CD147-expressing cells was observed. In addition, the cytotoxicity of GSH-DXR-encapsulated micelles against each cell type was measured by treatment of the micelles for 1 h. The cytotoxic effect of CD147ab micelles carrying GSH-DXR was 3- to 10-fold higher for these cells than that of micelles without GSH-DXR.

Conclusion: These results suggest that GSH-DXR-encapsulated CD147ab micelles could serve as an effective drug delivery system to CD147-expressing carcinoma cells.
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http://dx.doi.org/10.21873/anticanres.12353DOI Listing
March 2018

Photo Irradiation-Induced Core Crosslinked Poly(ethylene glycol)-block-poly(aspartic acid) Micelles: Optimization of Block Copolymer Synthesis and Characterization of Core Crosslinked Micelles.

Polymers (Basel) 2017 Dec 14;9(12). Epub 2017 Dec 14.

Medical Engineering Laboratory, Research Center for Medical Sciences, The Jikei University School of Medicine, 163-1, Kashiwashita, Kashiwa, Chiba 277-0004, Japan.

We used photo irradiation to design core crosslinked polymeric micelles whose only significant physico-chemical change was in their physico-chemical stability, which helps elucidate poly(ethylene glycol) (PEG)-related immunogenicity. Synthetic routes and compositions of PEG--poly(aspartic acid) block copolymers were optimized with the control of -alkyl chain length and photo-sensitive chalcone moieties. The conjugation ratio between -alkyl chain and the chalcone moieties was controlled, and upon the mild photo irradiation of polymeric micelles, permanent crosslink proceeded in the micelle cores. In the optimized condition, the core crosslinked (CCL) micelles exhibited no dissociation while the non-CCL micelles exhibited dissociation. These results indicate that the photo-crosslinking reactions in the inner core were successful. A gel-permeation chromatography (GPC) measurement revealed a difference between the micellar-formation stability of CCL micelles and that of the non-CCL micelles. GPC experiments revealed that the CCL micelles were more stable than the non-CCL micelles. Our research also revealed that photo-crosslinking reactions did not change the core property for drug encapsulation. In conclusion, the prepared CCL micelles exhibited the same diameter, the same formula, and the same inner-core properties for drug encapsulation as did the non-CCL micelles. Moreover, the CCL micelles exhibited non-dissociable micelle formation, while the non-CCL micelles exhibited dissociation into single block copolymers.
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http://dx.doi.org/10.3390/polym9120710DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6418968PMC
December 2017

Henoch-Schönlein Purpura Complicated by Hepatocellular Carcinoma.

Intern Med 2017 Nov 25;56(22):3041-3045. Epub 2017 Sep 25.

Department of Gastroenterology and Nephrology, Graduate School of Medicine, Chiba University, Japan.

Although Henoch-Schönlein purpura (HSP) is known to be accompanied by malignancies, cases with hepatobiliary cancer are extremely rare. A 62-year-old man with palpable purpura rapidly extending to both lower legs was admitted to our hospital. He was undergoing follow-up for cirrhosis caused by chronic hepatitis B virus infection and hepatocellular carcinoma (HCC). He had renal dysfunction with hematuria and proteinuria and abdominal pain. Based on the clinical presentation and skin biopsy findings, he was diagnosed with HSP. The administration of steroids resulted in the rapid improvement of the patient's symptoms and he was discharged 12 days after admission.
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http://dx.doi.org/10.2169/internalmedicine.8885-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5725858PMC
November 2017

Characteristics of patients with sorafenib-treated advanced hepatocellular carcinoma eligible for second-line treatment.

Invest New Drugs 2018 04 11;36(2):332-339. Epub 2017 Sep 11.

Department of Gastroenterology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.

Background Regorafenib has been investigated for its efficacy and safety as a second-line treatment in patients with advanced hepatocellular carcinoma (HCC). We assessed the characteristics of patients with HCC treated with sorafenib who might be eligible for second-line treatment in general and regorafenib in particular. Methods Patients with HCC treated with sorafenib were retrospectively analyzed. We defined second-line candidate patients as maintaining Child-Pugh A and ECOG-PS ≤1 at the time of sorafenib failure. We also defined regorafenib candidate patients as follows: 1) continuing sorafenib at the time of radiological progression, 2) maintaining Child-Pugh A and ECOG-PS ≤ 1 at the time of sorafenib failure, and 3) continuing sorafenib 400 mg or more without intolerable adverse events at least 20 days of the last 28 days of treatment. Results Of 185 patients, 130 (70%) and 69 (37%) were candidates for second-line treatment and regorafenib. Child-Pugh score 6 and ECOG-PS 1 at the time of starting sorafenib were significantly lower in both second-line treatment and regorafenib candidate patients. Moreover, hand-foot skin reaction and liver failure during sorafenib treatment were associated with significantly low and high probabilities, respectively, of both Child-Pugh score > 6 and ECOG-PS > 1 at the time of sorafenib failure. Conclusion Regorafenib candidate patients after sorafenib failure are limited, and generally fewer than those who are candidates for second-line treatment. A lower Child-Pugh score and a better ECOG-PS were predictors of eligibility for second-line therapy and regorafenib treatment in sorafenib-treated patients with advanced HCC patients.
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http://dx.doi.org/10.1007/s10637-017-0507-3DOI Listing
April 2018

Efficacy and safety of levodopa-carbidopa intestinal gel from a study in Japanese, Taiwanese, and Korean advanced Parkinson's disease patients.

NPJ Parkinsons Dis 2016 3;2:16020. Epub 2016 Nov 3.

AbbVie Inc, North Chicago, IL, USA.

In a previous multinational, randomized, double-blind, double-dummy study, levodopa-carbidopa intestinal gel (LCIG) was tolerable and significantly improved 'off' time in advanced Parkinson's disease (PD) patients. However, efficacy and safety in the Asian population has not yet been demonstrated. In this open-label study, efficacy and safety of LCIG were assessed in Japanese, Korean, and Taiwanese advanced PD patients with motor complications not adequately controlled by available PD medication. The patients were treated with LCIG monotherapy for 12 weeks. The primary end point was the mean change from baseline to week 12 in 'off' time, as reported in the PD Symptom Diary, normalized to a 16 h waking day and analyzed by a mixed-model repeated-measures analysis. Adverse events (AEs) were recorded. Thirty-one patients were enrolled (23 Japanese, 4 Taiwanese, 4 Korean) and 28 (90%) completed the study. For those who completed the study, the mean (s.d.) total daily levodopa dose from LCIG was 1,206.3 (493.6) mg/day at final visit (=28); last observation carried forward (=30) was 1,227.6 (482.8) mg/day. There was a significant mean change (s.d.) of -4.6 (3.0) hours of 'off' time from baseline (mean (s.d.)=7.4 (2.3)) to week 12 (=29), <0.001. All the patients had an AE, with the most frequently reported being incision site pain (42%); 1 (3.2%) discontinued treatment because of an AE and later died because of sepsis, which the investigator considered unrelated to LCIG treatment. These results suggest that LCIG is efficacious and tolerable in Japanese, Taiwanese, and Korean advanced PD patients.
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http://dx.doi.org/10.1038/npjparkd.2016.20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5516619PMC
November 2016

Histone lysine methyltransferase G9a is a novel epigenetic target for the treatment of hepatocellular carcinoma.

Oncotarget 2017 Mar;8(13):21315-21326

Department of Cellular and Molecular Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.

Histone H3 lysine 9 dimethylation (H3K9me2) is mainly regulated by the histone lysine methyltransferase G9a and is associated with the repression of transcription. However, both the role of G9a and the significance of H3K9me2 in hepatocellular carcinoma (HCC) cells remain unclear. In this study, we conducted loss-of-function assay of G9a using short-hairpin RNA and pharmacological interference. Knockdown of G9a reduced H3K9me2 levels and impaired both HCC cell growth and sphere formation. However, transforming growth factor β1-induced epithelial mesenchymal transition (EMT) was not suppressed by G9a knockdown. Combined analyses of chromatin immunoprecipitation followed by sequencing and RNA-sequencing led to successful identification of 96 candidate epigenetic targets of G9a. Pharmacological inhibition of G9a by BIX-01294 resulted in both cell growth inhibition and induction of apoptosis in HCC cells. Intraperitoneal administration of BIX-01294 suppressed the growth of xenograft tumors generated by implantation of HCC cells in non-obese diabetic/severe combined immunodeficient mice. Immunohistochemical analyses revealed high levels of G9a and H3K9me2 in 36 (66.7%) and 35 (64.8%) primary HCC tissues, respectively. G9a expression levels were significantly positively correlated with H3K9me2 levels in tumor tissues. In contrast, in non-tumor tissues, G9a and H3K9me2 were only observed in biliary epithelial cells and periportal hepatocytes. In conclusion, G9a inhibition impairs anchorage-dependent and -independent cell growth, but not EMT in HCC cells. Our data indicate that pharmacological interference of G9a might be a novel epigenetic approach for the treatment of HCC.
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http://dx.doi.org/10.18632/oncotarget.15528DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5400586PMC
March 2017

PEG-poly(L-lysine)-based polymeric micelle MRI contrast agent: Feasibility study of a Gd-micelle contrast agent for MR lymphography.

J Magn Reson Imaging 2018 01 17;47(1):238-245. Epub 2017 Apr 17.

Department of Radiology, Institute of Medical Science, University of Tokyo, Tokyo, Japan.

Purpose: To investigate the feasibility of polymeric micelle of poly(ethyleneglycol) (PEG)-b-poly(L-lysine-DOTA) (Gd-micelle) as a contrast agent for magnetic resonance lymphography (MRL).

Materials And Methods: Twenty-four female BALB/c mice were randomly divided into four groups of six mice each. Among them, mice of two groups were injected of complete Freund's adjuvant to obtain inflamed lymph nodes. We subcutaneously injected 0.5 μmol Gd per mouse of Gd-micelle or gadofluorine P in the right rear footpad. Identical 3D T -weighted gradient-echo imaging (1T MRI system) were subsequently obtained to create time-intensity curves of the right popliteal, sacral, and lumbar-aortic lymph nodes and to measure the contrast ratios (CRs). The peak CR, area under the curve (AUC), and elimination half-life (T ) of CR of the popliteal lymph node were assessed by two-way factorial analysis of variance. We also performed a qualitative assessment of normal and inflamed lymph node at three timepoints.

Results: The mean peak CR of Gd-micelle was 2.64 and 1.89 for gadofluorine P in normal mice, and 3.48 and 2.73 in the inflamed lymph node. Statistically, peak CR was higher for Gd-micelle (P = 0.004). In addition, the AUC was larger (P < 0.001) and T was longer (P < 0.001) for Gd-micelle. In qualitative assessment, Gd-micelle demonstrated the same or higher scores in every lymph node, and demonstrated a higher score in lumbar-aortic lymph node of a 360-minute image (P = 0.006) and in inflamed lymph node of a 360-minute image (P = 0.009).

Conclusion: Compared to gadofluorine P, Gd-micelle showed higher and more prolonged enhancement in MRL imaging in normal and inflamed lymph nodes.

Level Of Evidence: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:238-245.
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http://dx.doi.org/10.1002/jmri.25740DOI Listing
January 2018

A polymeric micelle magnetic resonance imaging (MRI) contrast agent reveals blood-brain barrier (BBB) permeability for macromolecules in cerebral ischemia-reperfusion injury.

J Control Release 2017 05 18;253:165-171. Epub 2017 Mar 18.

Medical Engineering Laboratory, Research Center for Medical Sciences, The Jikei University School of Medicine, Nishi-shinbashi 3-25-8, Minato-ku, Tokyo 105-8461, Japan. Electronic address:

Blood-brain barrier (BBB) opening is a key phenomenon for understanding ischemia-reperfusion injuries that are directly linked to hemorrhagic transformation. The recombinant human tissue-type plasminogen activator (rtPA) increases the risk of symptomatic intracranial hemorrhages. Recent imaging technologies have advanced our understanding of pathological BBB disorders; however, an ongoing challenge in the pre-"rtPA treatment" stage is the task of developing a rigorous method for hemorrhage-risk assessments. Therefore, we examined a novel method for assessment of rtPA-extravasation through a hyper-permeable BBB. To examine the image diagnosis of rtPA-extravasation for a rat transient occlusion-reperfusion model, in this study we used a polymeric micelle MRI contrast-agent (Gd-micelles). Specifically, we used two MRI contrast agents at 1h after reperfusion. Gd-micelles provided very clear contrast images in 15.5±10.3% of the ischemic hemisphere at 30min after i.v. injection, whereas a classic gadolinium chelate MRI contrast agent provided no satisfactorily clear images. The obtained images indicate both the hyper-permeable BBB area for macromolecules and the distribution area of macromolecules in the ischemic hemisphere. Owing to their large molecular weight, Gd-micelles remained in the ischemic hemisphere through the hyper-permeable BBB. Our results indicate the feasibility of a novel clinical diagnosis for evaluating rtPA-related hemorrhage risks.
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http://dx.doi.org/10.1016/j.jconrel.2017.03.020DOI Listing
May 2017

An uncovered risk factor of sonothrombolysis: Substantial fluctuation of ultrasound transmittance through the human skull.

Ultrasonics 2017 05 16;77:168-175. Epub 2017 Feb 16.

Division of Medical Engineering, Research Center for Medical Sciences, The Jikei University School of Medicine, 3-25-8, Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan. Electronic address:

Sonothrombolysis is one of the most feasible methods for enhancing clot lysis with a recombinant tissue plasminogen activator (rt-PA) in cases of acute ischemic strokes. For safe and efficient clinical practices of sonothrombolysis, accurate estimation of ultrasound transmittance through the human skull is critical. Previously, we reported substantial and periodic fluctuation of ultrasound transmittance through a bone-phantom plate following changes to ultrasound frequency, the thickness of the bone-phantom plate, and the distance between a transducer and the bone-phantom plate. In the present study, we clarify the transmittance behavior of medium-frequency ultrasound (from 400kHz to 600kHz) through the human skull, and examine reduction of the transmittance fluctuation. For the study, we measured transmittance of sinusoidal ultrasound waves at 400kHz, 500kHz, and 600kHz at 13 temple spots on 3 human skulls by changing the distance between a transducer and the skull bone, and found substantial and periodic fluctuation in the transmittance behaviors for these sinusoidal voltage excitations. Degrees of the fluctuation varied depending on the measurement spots. A fluctuation ratio between the maximum transmittance and the minimum transmittance reached 3 in some spots. This large transmittance fluctuation is considered to be a risk factor for sonothrombolysis therapies. We examined a modulated ultrasound wave to reduce the fluctuation, and succeeded in obtaining considerable reduction. The average fluctuation ratios for 400-kHz, 500-kHz, and 600-kHz waves were 2.38, 2.38, and 2.07, respectively. We successfully reduced the ratio to 1.72 by using a periodic selection of random frequency (PSRF)-type of modulation wave. The thus obtained results indicate that attention to the fluctuation in ultrasound transmittance through the skull is necessary for safe and effective sonothrombolysis therapies, and that modulated ultrasound waves constitute a powerful method for reducing the risk of fluctuation.
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http://dx.doi.org/10.1016/j.ultras.2017.02.012DOI Listing
May 2017

Successful Treatment of Hepatocellular Carcinoma Complicated by Fanconi Anemia.

Case Rep Gastroenterol 2017 Jan-Apr;11(1):29-35. Epub 2017 Jan 27.

Department of Gastroenterology and Nephrology, Graduate School of Medicine, Chiba University, Chiba, Japan.

A 42-year-old woman with liver tumors was referred to our hospital. Her condition was complicated by Fanconi anemia, and she had undergone total laryngectomy 8 years ago. On admission, contrast-enhanced computed tomography revealed hypervascular tumors in the right hepatic lobe. Ultrasound-guided tumor biopsy revealed that the tumor comprised moderately differentiated hepatocellular carcinoma. Although the patient exhibited preserved liver function (Child-Pugh A), complete blood count revealed severe pancytopenia. Eventually, the tumor was successfully treated by transcatheter arterial embolization (TAE). Both platelet transfusion and systemic administration of antibiotics were performed. She was discharged 35 days after TAE.
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http://dx.doi.org/10.1159/000454710DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5301094PMC
January 2017

An In Vitro Assay for Sonothrombolysis Based on the Spectrophotometric Measurement of Clot Thickness.

J Ultrasound Med 2017 Apr 2;36(4):681-698. Epub 2017 Feb 2.

Division of Medical Engineering, Research Center for Medical Sciences, the Jikei University School of Medicine, Tokyo, Japan.

Objectives: For improved thrombolysis therapy based on ultrasound irradiation, researchers and practitioners would strongly benefit from an easy and efficient in vitro assay system of thrombolysis activity involving irradiated ultrasound. For the present study, we designed a new in vitro sonothrombolysis assay system using a sheet-type clot.

Methods: We designed a cell for clot assay, and we confirmed that this clot cell did not significantly intervene in the acoustic field. Using human plasma, we made a sheet-type clot in the cell. Clot thicknesses at 100 points along 4 directions were measured photometrically at a rate of approximately 4 points/s.

Results: The sonothrombolysis effects at 13 levels of ultrasonic intensity were obtained with only one sheet-type clot. With this method, we used a clinically oriented probe at 0.7 and 0.3 W/cm to confirm that sonothrombolysis took place.

Conclusions: We successfully established a new, easy, and efficient method for conducting in vitro sonothrombolysis assays. This method involves little intervention of either ultrasound reflection or standing waves in the clot cell. We believe that this new assay method is very useful for fundamental analyses of ultrasound's thrombolysis effects.
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http://dx.doi.org/10.7863/ultra.15.11018DOI Listing
April 2017

Impact of Radiofrequency Ablation-Induced Glisson's Capsule-Associated Complications in Patients with Hepatocellular Carcinoma.

PLoS One 2017 18;12(1):e0170153. Epub 2017 Jan 18.

Department of Gastroenterology and Nephrology, Graduate School of Medicine, Chiba University, Chiba, Japan.

Background: Radiofrequency ablation (RFA) is commonly used to locally treat hepatocellular carcinoma (HCC). However, when tumors are close to the Glisson's capsule, RFA may induce injury in this region, complicating therapeutic efforts. We investigated the impact of RFA-induced Glisson's capsule-associated complications on liver function and prognosis of HCC patients.

Methods: We retrospectively reviewed our patient database and found 170 early-stage HCC patients treated via RFA from April 2004 to December 2012. We defined RFA-induced Glisson's capsule-associated complication as lasting hepatic arterioportal (AP) fistula, major intrahepatic bile-duct dilatation (affecting two or more subsegments), or hepatic infarction. We also defined liver failure as initial occurrence of either total bilirubin increase (>3.0 mg/dL), uncontrolled ascites, or encephalopathy.

Results: In our cohort, 15 patients had RFA-induced Glisson's capsule-associated complications (incidence of related complications, with some overlap: lasting AP fistula, n = 9; major intrahepatic bile-duct dilatation, n = 7; and hepatic infarction, n = 2). The cumulative incidence of liver failure before stage progression was significantly higher and the median overall survival (OS) was significantly lower (52.3 months) in HCC patients with Glisson's capsule-associated complications than in those without Glisson's capsule-associated complications (95.0 months). In addition, multivariate analysis demonstrated that Glisson's capsule-associated complication was a significant independent factor associated with OS.

Conclusions: In this study, we have shown that early-stage HCC patients with RFA-induced Glisson's capsule-associated complications may have higher risks in poor prognosis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0170153PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5242538PMC
August 2017

Successful Management of Graft Reinfection of HCV Genotype 2 in Living Donor Liver Transplantation from a Hepatitis B Core Antibody-Positive Donor with Sofosbuvir and Ribavirin.

Case Rep Gastroenterol 2016 May-Aug;10(2):366-372. Epub 2016 Jul 20.

Department of General Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.

Direct-acting antivirals (DAAs) are relatively safe and highly effective for the eradication of hepatitis C virus (HCV) in liver transplant recipients. In this case study, we present a female with a graft reinfected with HCV genotype 2 who was treated with a combination of sofosbuvir and ribavirin after living donor liver transplantation (LDLT). Because the graft was from a hepatitis B core antibody-positive donor, passive immunization with hyperimmune hepatitis B immunoglobulin (HBIG) and entecavir were also provided to prevent hepatitis B virus (HBV) reactivation. It became clear that the combination of sofosbuvir and ribavirin promptly led to a sustained virologic response and that this combination was safe to treat graft reinfection with HCV genotype 2 after LDLT. Adverse events caused by DAAs were not observed, except for slight anemia. HBIG and entecavir were useful in the prevention of HBV reactivation. In conclusion, the present case indicated that DAA treatment for graft reinfection with HCV is safe and effective in LDLT from hepatitis B core antibody-positive donors.
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http://dx.doi.org/10.1159/000447423DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5043295PMC
July 2016

Exploring the relationship between anti-PEG IgM behaviors and PEGylated nanoparticles and its significance for accelerated blood clearance.

J Control Release 2016 07 6;234:59-67. Epub 2016 May 6.

Medical Engineering Laboratory, Research Center for Medical Sciences, Jikei University School of Medicine, 3-25-8, Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan. Electronic address:

Surface PEGylation on nanoparticles has greatly helped prolong their blood circulation half-lives. However, The injection of PEGylated nanoparticles into mice induced poly(ethylene glycol) (PEG)-specific IgM antibodies (anti-PEG IgMs), significantly changing PEG-liposomes' pharmacokinetics. In this study, we used various PEG-conjugates to conduct a mechanistic study of anti-PEG IgMs' binding behavior. The conventional belief has been that anti-PEG IgMs bind to PEG main chains; however, our findings reveal that anti-PEG IgMs did not bind to PEG main chains, whereas anti-PEG IgMs did bind to PEG-hydrophobic polymer blocks. The insertion of a hydrophilic polymer between each PEG chain and each hydrophobic polymer block suppressed anti-PEG IgMs' binding. We prove here that hydrophobic blocks are essential to anti-PEG IgMs' binding, and also that anti-PEG IgMs do not bind to intact PEGs without hydrophobic moiety. These results support our conclusion that anti-PEG IgMs exhibit specificity to PEG; however, the presence of a hydrophobic block at a proximity position from each PEG chain is essential for the binding. Also in the present study, we elucidate relations between anti-PEG IgMs and PEGylated nanoparticles. In one of our previous studies, anti-PEG IgMs scarcely affected the pharmacokinetics of PEG-b-poly(β-benzyl l-aspartate) block copolymer (PEG-PBLA) micelles, whereas anti-PEG IgMs significantly decreased PEG-liposomes' blood circulation half-life. Finally, we found that the ratio of anti-PEG IgM molecules to PEG-liposome particles is critical to these pharmacokinetic changes, and that a 10-fold increase in the number of anti-PEG IgM molecules permitted them to capture the PEG-liposome particles, thus leading to the aforementioned changes.
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http://dx.doi.org/10.1016/j.jconrel.2016.05.010DOI Listing
July 2016

Substantial fluctuation of acoustic intensity transmittance through a bone-phantom plate and its equalization by modulation of ultrasound frequency.

Ultrasonics 2015 May 7;59:94-101. Epub 2015 Feb 7.

Division of Medical Engineering, Research Center for Medical Sciences, The Jikei University School of Medicine, 3-25-8, Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan. Electronic address:

For safe and efficient sonothrombolysis therapies, accurate estimation of ultrasound transmittance through the human skull is essential. The present study clarifies uncertainty surrounding this transmittance and experimentally verifies the equalization of transmittance through the modulation of ultrasound frequency. By changing three factors (ultrasound frequency, the thickness of a bone-phantom plate, and the distance between a transducer and a bone-phantom plate), we measured the intensity of ultrasound passing through the plate. Two activating methods, sinusoidal waves at 500 kHz and modulated waves, were compared. When we changed (1) the distance between a transducer and a bone-phantom plate and (2) the thickness of the bone-phantom plate, ultrasound transmittance through the plates substantially fluctuated. The substantial fluctuation in transmittance was observed also for a cut piece of human temporal skull bone. This fluctuation significantly declined for the modulated wave. In conclusion, modulation of ultrasound frequency can equalize the transmittance with an approximately 30-65% fluctuation drop and an approximately 40% fluctuation drop for a bone-phantom plate and for a cut piece of skull bone, respectively. By using modulated waves, we can develop safer and more effective sonothrombolysis therapies.
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http://dx.doi.org/10.1016/j.ultras.2015.01.017DOI Listing
May 2015

Determination of polymeric micelles' structural characteristics, and effect of the characteristics on pharmacokinetic behaviors.

J Control Release 2015 Apr 14;203:77-84. Epub 2015 Feb 14.

Medical Engineering Laboratory, Research Center for Medical Sciences, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan. Electronic address:

We evaluated structural factors characterizing PEG-b-P(Asp-Bzl) micelles including core size, aggregation number (Nagg), and core surface PEG density by means of small-angle X-ray scattering (SAXS), field flow fractionation with multi-angle light scattering (FFF-MALS) analysis, and DLS. Furthermore, we evaluated the stability of PEG-b-P(Asp-Bzl) micelles by means of GPC. This paper reports the correlation between the evaluated micelles' structural factors and the micelles' behaviors including the micelles' in vivo pharmacokinetic behaviors. One micelle PEG(12)-b-P(Asp-Bzl) (PEG=12,000) exhibited a high core surface density (~0.99 chain/nm(2)). In these circumstances, PEG(12)-b-P(Asp-Bzl) micelles exhibited a highly stretched PEG brush form. However, the evaluated core surface PEG densities could not fully explain the micelles' in vivo pharmacokinetic behaviors. In contrast, GPC will become a strong tool for predicting PEG(12)-b-P(Asp-Bzl) micelles' in vivo behaviors, as well as the micelles' in vitro behaviors. The stability results correlated strongly with the area-under-the-curve (AUC) values of PEG-b-P(Asp-Bzl) micelles' in vivo pharmacokinetics. Finally, we evaluated PEG(12)-b-P(Asp-Bzl) micelles' most effective structural factor for determining the micelles' behaviors, and the micelles' outermost shell surface's PEG density (DOS, PEG) correlated with the micelles' behaviors. We revealed that the evaluated DOS, PEG is the most important factor for understanding PEG(12)-b-P(Asp-Bzl) micelles' behaviors.
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http://dx.doi.org/10.1016/j.jconrel.2015.02.017DOI Listing
April 2015