35 results on '"Ryota Saito"'
Search Results
2. Detection of multiple druggable mutations of lung cancer from cytology specimens by <scp>MINtS</scp> : An advanced medicine A trial
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Kazutaka Fujita, Ryo Arai, Satoshi Shoji, Ryota Saito, Motoko Nomura, Takamasa Hotta, Hajime Asahina, Masanori Kawakami, Ichiro Nakachi, Yukihiro Hasegawa, Kohei Okafuji, Aya Suzuki, Akihiko Miyanaga, Noriaki Sunaga, Hiromi Nagashima, Naoya Ikeda, Satoshi Watanabe, Yoshiaki Nagai, Megumi Furuta, Hidenori Kage, Daisuke Arai, Tatsuro Fukuhara, Masayuki Nakayama, Satoshi Morita, Kunihiko Kobayashi, and Koichi Hagiwara
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Cancer Research ,Oncology ,General Medicine - Published
- 2023
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3. Phase I/II study of biweekly nab‐paclitaxel in patients with platinum‐pretreated non‐small cell lung cancer: NJLCG1402
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Toshiyuki Harada, Daisuke Jingu, Mami Morita, Akira Inoue, Hisashi Tanaka, Atsushi Nakamura, Shunichi Gamou, Taku Nakagawa, Eisaku Miyauchi, Ryota Saito, and Tomoya Kuda
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Pulmonary and Respiratory Medicine ,Male ,non‐small cell lung cancer ,medicine.medical_specialty ,Lung Neoplasms ,Paclitaxel ,phase I/II trial ,Gastroenterology ,chemistry.chemical_compound ,Internal medicine ,Albumins ,Carcinoma, Non-Small-Cell Lung ,nab‐PTX monotherapy ,Antineoplastic Combined Chemotherapy Protocols ,medicine ,Clinical endpoint ,Humans ,In patient ,Lung cancer ,Adverse effect ,RC254-282 ,Nab-paclitaxel ,Aged ,Platinum ,Aged, 80 and over ,business.industry ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,General Medicine ,Original Articles ,Middle Aged ,medicine.disease ,Progression-Free Survival ,Phase i ii ,Oncology ,chemistry ,Original Article ,Female ,Non small cell ,business - Abstract
Background NJLCG1402 was a phase I/II trial investigating biweekly nanoparticle albumin‐bound paclitaxel (nab‐PTX) in patients with advanced non‐small cell lung cancer (NSCLC). Methods The study included patients aged ≥20 years with previously treated NSCLC. Nab‐PTX (100–150 mg/m2) was administered biweekly in a 28‐day cycle. The phase I portion was performed to determine the recommended phase II dose of nab‐PTX. In the phase II portion, the primary endpoint was the objective response rate. Secondary endpoints were disease control rate, progression‐free survival, overall survival, and safety. Results A total of 15 patients received biweekly nab‐PTX (100–150 mg/m2) and 12 patients in phase II were treated with 150 mg/m2. In the phase I portion, 150 mg/m2 was determined as the recommended dose. Among those treated with 150 mg/m2, the objective response rate was 22%, and the median progression‐free and overall survival was 3.6 and 11.2 months, respectively. Adverse events grade ≥3 were observed in 39% of patients. Conclusions Biweekly nab‐PTX monotherapy was well tolerated and exhibited favorable antitumor activity in patients with previously treated NSCLC., We conducted the first prospective multicenter phase I/II trial to evaluate the efficacy and safety of biweekly nab‐PTX treatment in patients with previously treated advanced NSCLC. In phase I portion, 150 mg/m2 was determined as the recommended dose. Among those treated with 150 mg/m2, the objective response rate was 22%; median progression‐free and overall survival was 3.6 and 11.2 months, respectively.
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- 2021
4. Osimertinib in poor performance status patients with T790M-positive advanced non-small-cell lung cancer after progression of first- and second-generation EGFR-TKI treatments (NEJ032B)
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Kiyotaka Miura, Ryota Saito, Kensuke Nakazawa, Takeshi Isobe, Ryoichi Honda, Yuki Akazawa, Nobuhiro Kanaji, Susumu Takeuchi, Yukari Tsubata, Kana Watanabe, Satoshi Morita, Kunihiko Kobayashi, Taku Nakagawa, Atsushi Nakamura, Naoki Furuya, Daisuke Jingu, Eiki Ichihara, Atsuto Mouri, Satoshi Ohizumi, Makoto Maemondo, Mami Morita, and Hiroshige Yoshioka
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Oncology ,medicine.medical_specialty ,Afatinib ,Phases of clinical research ,EGFR T790M ,T790M ,Gefitinib ,Internal medicine ,medicine ,Clinical endpoint ,Osimertinib ,Lung cancer ,Poor performance status ,business.industry ,Hematology ,General Medicine ,medicine.disease ,Phase II ,respiratory tract diseases ,Surgery ,Original Article ,Erlotinib ,business ,Non-small-cell lung cancer ,medicine.drug - Abstract
Background Osimertinib is effective in patients with T790M mutation-positive advanced non-small-cell lung cancer (NSCLC) resistant to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). However, its effectiveness and safety in patients with poor performance status (PS) are unknown. Methods Enrolled patients showed disease progression after treatment with gefitinib, erlotinib, or afatinib; T790M mutation; stage IIIB, IV, or recurrent disease; and PS of 2–4. Osimertinib was orally administered at a dose of 80 mg/day. The primary endpoint of this phase II study (registration, jRCTs061180018) was response rate and the secondary endpoints were progression-free survival (PFS), overall survival (OS), disease control rate, and safety. Results Thirty-three patients were enrolled, of which 69.7% and 24.2% had PS of 2 and 3, respectively. One patient was excluded due to protocol violation; in the remaining 32 patients, the response rate was 53.1%; disease control rate was 75.0%; PFS was 5.1 months; and OS was 10.0 months. The most frequent adverse event of grade 3 or higher severity was lymphopenia (12.1%). Interstitial lung disease (ILD) was observed at all grades and at grades 3–5 in 15.2% (5/33) and 6.1% (2/33) of patients, respectively. Treatment-related death due to ILD occurred in one patient. Patients negative for activating EGFR mutations after osimertinib administration had longer median PFS than those positive for these mutations. Conclusion Osimertinib was sufficiently effective in EGFR-TKI-resistant, poor PS patients with T790M mutation-positive advanced NSCLC. Plasma EGFR mutation clearance after TKI treatment could predict the response to EGFR-TKIs.
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- 2021
5. Clinical efficacy of amrubicin in patients with small cell lung cancer relapse after first-line treatment including immune checkpoint inhibitors: A retrospective multicenter study (TOPGAN 2021-01)
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Shinya Uematsu, Satoru Kitazono, Hisashi Tanaka, Ryota Saito, Yosuke Kawashima, Fumiyoshi Ohyanagi, Takehiro Tozuka, Tsugitomi Ryosuke, Toshio Sakatani, Atsushi Horiike, Takahiro Yoshizawa, Masafumi Saiki, Yuichi Tambo, Junji Koyama, Masaki Kanazu, Keita Kudo, Yuko Tsuchiya‐Kawano, Noriko Yanagitani, and Makoto Nishio
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Pulmonary and Respiratory Medicine ,Oncology ,General Medicine - Abstract
The therapeutic efficacy of cytotoxic anticancer drugs has been reported to be enhanced after immune checkpoint inhibitors (ICI) in non-small cell lung cancer; however, it is unclear whether the same is applicable for small cell lung cancer (SCLC). We evaluated the efficacy of second-line amrubicin (AMR) following first-line platinum-based chemotherapy and ICI combination therapy (chemo-ICI) in SCLC.We retrospectively enrolled consecutive patients with SCLC treated with AMR as a second-line following chemo-ICI as first-line between July 2019 and April 2021 from 16 institutions throughout Japan. We investigated the therapeutic effectiveness, safety, and efficacy-enhancing variables of AMR.Overall, 89 patients treated with AMR after first-line chemo-ICI were analyzed. The overall response rate (ORR) was 29.2% (95% confidence intervals [CI], 20.1-39.8) and median PFS (m PFS) was 2.99 months (95% CI, 2.27-3.65). Patients who relapsed more than 90 days after receiving first-line platinum combination therapy (sensitive relapse) exhibited greater ORR (58.3% vs. 24.7%, p = 0.035) and m PFS (5.03 vs. 2.56 months, p = 0.019) than patients who relapsed in90 days (refractory relapse). Grade 3 or higher adverse events were mainly hematological toxicity.Our study suggested that the therapeutic effect of AMR was not enhanced after ICI on SCLC. However, AMR may be effective in cases of sensitive relapse after chemo-ICI. There was no increase in severe toxicity associated with AMR after ICI.
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- 2022
6. Randomized phase 2 study comparing irinotecan versus amrubicin as maintenance therapy after first‐line induction therapy for extensive disease small cell lung cancer (HOT1401/NJLCG1401)
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Keita Kudo, Tomomi Masuda, Toshiyuki Harada, Kazuhiro Usui, Eiki Kikuchi, Yukihiro Hasegawa, Akira Inoue, Satoshi Oizimi, Atsushi Nakamura, Makoto Maemondo, Tatsuro Fukuhara, Yuka Fujita, Ryoichi Honda, Hiroshi Yokouchi, Hiroshi Watanabe, Naomi Watanabe, Hisashi Tanaka, Ryota Saito, Naoto Morikawa, and Yasutaka Kawai
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Adult ,Male ,0301 basic medicine ,Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Lung Neoplasms ,cisplatin ,Antineoplastic Agents ,Gastroenterology ,maintenance ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Maintenance therapy ,Internal medicine ,Humans ,Medicine ,Anthracyclines ,Prospective Studies ,neoplasms ,irinotecan ,RC254-282 ,Aged ,business.industry ,Induction chemotherapy ,small‐cell lung cancer ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,Original Articles ,Induction Chemotherapy ,General Medicine ,Middle Aged ,medicine.disease ,amrubicin ,Small Cell Lung Carcinoma ,Irinotecan ,Regimen ,030104 developmental biology ,Oncology ,030220 oncology & carcinogenesis ,Every Three Weeks ,Original Article ,Drug Therapy, Combination ,Female ,Topoisomerase I Inhibitors ,Every Four Weeks ,business ,Amrubicin ,Progressive disease ,medicine.drug - Abstract
Background A cisplatin plus irinotecan (CPT‐11) regimen is used for patients with extensive disease small cell lung cancer (ED‐SCLC). Amrubicin (AMR) is primarily used for relapsed SCLC. The HOT1401/NJLCG1401 trial, an open‐label randomized phase II trial, was designed to assess the benefit of maintenance therapy in patients with ED‐SCLC who responded to induction therapy. Methods Patients with histologically‐ or cytologically‐confirmed ED‐SCLC were included and were treated with an induction therapy of four cycles of cisplatin (60 mg/m2 on day 1) plus CPT‐11 (60 mg/m2 on days 1, 8, and 15) every four weeks. After induction therapy, patients who had nonprogressive disease were randomized to receive either maintenance CPT‐11 (60 mg/m2 on days 1 and 8) every three weeks, or AMR (35 mg/m2 on days 1–3) every three weeks. Results A total of 34 patients were enrolled; 20 patients had progressive disease or received incomplete induction chemotherapy. Finally, 14 patients were randomly assigned to receive CPT‐11 (n = 7) or AMR (n = 7). This study was terminated prematurely because of low patient accrual. The overall objective response rate was 73%, the median PFS was 5.7 months (95% confidence interval [CI]: 3.6–11.8), and the median overall survival was 20.1 months (95% CI: 13.7–not reached). No statistically significant difference in progression‐free survival (PFS) were noted between patients treated with CPT‐11 and those treated with AMR. There were no treatment‐related deaths in this study. Conclusions Maintenance therapy with CPT‐11 or AMR after induction therapy might be effective in some patients., There were some patients who achieved long disease control. Maintenance therapy with CPT‐11 or AMR after induction therapy could have potential for treating ED‐SCLC.
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- 2021
7. Identification of risk factors for venous thromboembolism and validation of the Khorana score in patients with advanced lung cancer: based on the multicenter, prospective Rising-VTE/NEJ037 study data
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Yukari Tsubata, Keita Kawakado, Kosuke Hamai, Naoki Furuya, Toshihide Yokoyama, Ryota Saito, Atsushi Nakamura, Takeshi Masuda, Megumi Hamaguchi, Shoichi Kuyama, Ryoichi Honda, Tadashi Senoo, Masamoto Nakanishi, Takamasa Hotta, Masahiro Yamasaki, Nobuhisa Ishikawa, Kazunori Fujitaka, Tetsuya Kubota, Kunihiko Kobayashi, and Takeshi Isobe
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Oncology ,Surgery ,Hematology ,General Medicine - Abstract
Background Management of cancer-associated venous thromboembolism (VTE) is essential in cancer treatment selection and prognosis. However, currently, no method exists for assessing VTE risk associated with advanced lung cancer. Therefore, we assessed VTE risk, including driver gene mutation, in advanced lung cancer and performed a Khorana score validation. Methods The Rising-VTE/NEJ037 study was a multicenter prospective observational study that included patients with advanced lung cancer. In the Rising-VTE/NEJ037 study, the Khorana score was calculated for enrolled patients with available data on all Khorana score components. The modified Khorana score was based on the body mass index of ≥ 25 kg/m2, according to the Japanese obesity standard. A multivariate logistic regression analysis, including patient background characteristics, was performed to evaluate the presence of VTE 2 years after the lung cancer diagnosis. Results This study included 1008 patients with lung cancer, of whom 100 (9.9%) developed VTE. From the receiver operating characteristic curve analysis, VTE risk could not be determined because both the Khorana score (0.518) and modified Khorana score (0.516) showed very low areas under the curve. The risk factors for VTE in the multivariate analysis included female sex, adenocarcinoma, performance status, N factor, lymphocyte count, platelet count, prothrombin fragment 1 + 2 and diastolic blood pressure. Conclusion The Khorana score, which is widely used in cancer-VTE risk assessment, was less useful for Japanese patients with advanced lung cancer. Prothrombin fragment 1 + 2, a serum marker involved in coagulation, was more suitable for risk identification. Clinical trial information jRCTs061180025.
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- 2022
8. Improving E. coli organic solvent tolerance by 1,4-dihydroxy-2-naphthoic acid
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Noriyuki Doukyu, Hideyuki Fujisawa, and Ryota Saito
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Escherichia coli Proteins ,Organic Chemistry ,General Medicine ,Gene Expression Regulation, Bacterial ,Naphthols ,Applied Microbiology and Biotechnology ,Biochemistry ,Analytical Chemistry ,Bacterial Proteins ,Escherichia coli ,Solvents ,Trans-Activators ,Molecular Biology ,Biotechnology - Abstract
Improving the organic solvent tolerance of bacteria is beneficial for the bioproduction of various valuable chemicals. In this study, we found that 1,4-dihydroxy-2-naphthoic acid (DHNA), known as a prebiotic, increased organic solvent tolerance in Escherichia coli. The AcrAB‒TolC multidrug efflux pump contributes to the intrinsic organic solvent tolerance of E. coli. The addition of DHNA increased this pump's expression level. Transcriptional activators MarA, SoxS, and Rob proteins are known to control the expression of marA/soxS/rob regulon genes, including acrAB and tolC. Evaluation of the organic solvent tolerances of DmarA mutant, DsoxS mutant, and Drob mutant showed that DmarA mutant and DsoxS mutant did not improve organic solvent tolerance by the addition of DHNA. In addition, DHNA increased the promoter activities of both marA and soxS. These results indicated that DHNA induces the AcrAB‒TolC pump through both the marRAB system and the soxRS system.
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- 2022
9. Artificial control of the multistep oxidation reactions catalyzed by the cytochrome P450 enzyme RosC
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Hiroshi Kanai, Yuna Maruyama, Ryota Saito, Yohei Iizaka, Momoho Sano, Yojiro Anzai, Tomoko Suzuki, Arisa Watanabe, Atsushi Fukumoto, and Misa Kurita
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Stereochemistry ,Mutant ,Leucomycins ,Micromonospora ,Applied Microbiology and Biotechnology ,Aldehyde ,Redox ,Catalysis ,03 medical and health sciences ,chemistry.chemical_compound ,Bacterial Proteins ,Cytochrome P-450 Enzyme System ,Biosynthesis ,Escherichia coli ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,biology ,030306 microbiology ,Cytochrome P450 ,General Medicine ,Monooxygenase ,Amino acid ,Amino Acid Substitution ,chemistry ,Alcohol oxidation ,Mutation ,biology.protein ,Oxidation-Reduction ,Biotechnology - Abstract
The cytochrome P450 monooxygenase RosC catalyzes the three-step oxidation reactions, which leads to the formation of a hydroxy, formyl, and carboxy group at C-20 during rosamicin biosynthesis in Micromonospora rosaria IFO13697. To determine if amino acid substitutions in RosC could allow for the control of the multistep oxidation reactions, we screened RosC random mutants. The RosC mutant RM30, with five amino acid substitutions (P107S, L176Q, S254N, V277A, and I319N), catalyzed only the first step of the oxidation reaction. Whole-cell assays using Escherichia coli cells expressing RosC mutants with single and double amino acid substitutions derived from RM30 indicated that P107S/L176Q, P107S/V277A, P107S/I319N, L176Q/V277A, L176Q/I319N, and S254N/V277A significantly reduced the catalytic activity of the second reaction, which is alcohol oxidation. Of the previously mentioned mutants, double mutants containing L176Q, which was presumed to occur in the FG loop region, lost the total catalytic activity of the third reaction (aldehyde oxidation). Additionally, an engineered M. rosaria strain with rosC disruption, which introduced the gene encoding the RosC mutants P107S/L176Q and P107S/V277A preferentially produced 20-dihydrorosamicin, which is formed after the first oxidation reaction of RosC.
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- 2020
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10. Correction to: Osimertinib in poor performance status patients with T790M‑positive advanced non‑small‑cell lung cancer after progression of first- and second‑generation EGFR‑TKI treatments (NEJ032B)
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Yukari Tsubata, Kana Watanabe, Ryota Saito, Atsushi Nakamura, Hiroshige Yoshioka, Mami Morita, Ryoichi Honda, Nobuhiro Kanaji, Satoshi Oizumi, Daisuke Jingu, Taku Nakagawa, Kensuke Nakazawa, Atsuto Mouri, Susumu Takeuchi, Naoki Furuya, Yuki Akazawa, Kiyotaka Miura, Eiki Ichihara, Makoto Maemondo, Satoshi Morita, Kunihiko Kobayashi, and Takeshi Isobe
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ErbB Receptors ,Acrylamides ,Aniline Compounds ,Lung Neoplasms ,Oncology ,Carcinoma, Non-Small-Cell Lung ,Mutation ,Correction ,Humans ,Surgery ,Hematology ,General Medicine ,Protein Kinase Inhibitors - Abstract
Osimertinib is effective in patients with T790M mutation-positive advanced non-small-cell lung cancer (NSCLC) resistant to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). However, its effectiveness and safety in patients with poor performance status (PS) are unknown.Enrolled patients showed disease progression after treatment with gefitinib, erlotinib, or afatinib; T790M mutation; stage IIIB, IV, or recurrent disease; and PS of 2-4. Osimertinib was orally administered at a dose of 80 mg/day. The primary endpoint of this phase II study (registration, jRCTs061180018) was response rate and the secondary endpoints were progression-free survival (PFS), overall survival (OS), disease control rate, and safety.Thirty-three patients were enrolled, of which 69.7% and 24.2% had PS of 2 and 3, respectively. One patient was excluded due to protocol violation; in the remaining 32 patients, the response rate was 53.1%; disease control rate was 75.0%; PFS was 5.1 months; and OS was 10.0 months. The most frequent adverse event of grade 3 or higher severity was lymphopenia (12.1%). Interstitial lung disease (ILD) was observed at all grades and at grades 3-5 in 15.2% (5/33) and 6.1% (2/33) of patients, respectively. Treatment-related death due to ILD occurred in one patient. Patients negative for activating EGFR mutations after osimertinib administration had longer median PFS than those positive for these mutations.Osimertinib was sufficiently effective in EGFR-TKI-resistant, poor PS patients with T790M mutation-positive advanced NSCLC. Plasma EGFR mutation clearance after TKI treatment could predict the response to EGFR-TKIs.
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- 2022
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11. Severe gastrointestinal hemorrhage related to everolimus: a case report
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Masataka Masubuchi, Koichiro Haruki, Masashi Tsunematsu, Ryota Saito, Michiaki Watanabe, and Katsuhiko Yanaga
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Male ,Sorafenib ,medicine.medical_specialty ,medicine.medical_treatment ,Cautery ,Stomach Diseases ,Antineoplastic Agents ,Argon plasma coagulation ,03 medical and health sciences ,0302 clinical medicine ,Renal cell carcinoma ,medicine ,Humans ,Billroth I ,Everolimus ,Carcinoma, Renal Cell ,Aged ,Argon Plasma Coagulation ,Drug Substitution ,business.industry ,Sunitinib ,Gastroenterology ,Gastric antral vascular ectasia ,Hematemesis ,General Medicine ,medicine.disease ,Kidney Neoplasms ,Surgery ,030220 oncology & carcinogenesis ,Therapeutic endoscopy ,030211 gastroenterology & hepatology ,business ,medicine.drug - Abstract
Everolimus is an mTOR (the mammalian target of rapamycin) inhibitor, which is used for the treatment of advanced renal cell carcinoma. Life-threatening hemorrhages are extremely rare adverse effect of everolimus. We herein report a successfully treated case of severe everolimus-related gastrointestinal hemorrhage by emergency surgical resection for patient with advanced renal cell carcinoma. A 72-year-old male was diagnosed with renal cell carcinoma, for which everolimus was administered after unsuccessful treatment with sunitinib and sorafenib. The patient suddenly developed hematemesis 4 weeks after administration. Upper gastrointestinal endoscopy showed gastric antral vascular ectasia. Once the hemorrhage was successfully cauterized by argon plasma coagulation, everolimus was discontinued. However, the patient after re-administration of everolimus developed hematemesis again and exhibited hemorrhage shock. Since therapeutic endoscopy could not achieve hemostasis, the patient underwent emergency distal gastrectomy with Billroth I reconstruction. The patient's vital signs and hemoglobin level stabilized after the surgery. Thereafter, the patient made a satisfactory recovery, and was discharged on postoperative day 10.
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- 2019
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12. Cytotoxicity comparison of 35 developmental neurotoxicants in human induced pluripotent stem cells (iPSC), iPSC-derived neural progenitor cells, and transformed cell lines
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Isao Ishii, Akihiro Honda, Yasumi Anan, Issei Ohkubo, Yasunari Kanda, Hiroto Hana-ika, Reina Hashiyama, Shotaro Kamata, Ryota Saito, Noriyuki Akahoshi, and Kohji Noguchi
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0301 basic medicine ,Insecticides ,Cell Survival ,Induced Pluripotent Stem Cells ,Drug Evaluation, Preclinical ,Biology ,Toxicology ,Marker gene ,Cell Line ,03 medical and health sciences ,0302 clinical medicine ,Neural Stem Cells ,Chlorocebus aethiops ,Toxicity Tests ,Animals ,Humans ,Luciferase ,Viability assay ,Human Induced Pluripotent Stem Cells ,Induced pluripotent stem cell ,Cytotoxicity ,Gene ,Cell Differentiation ,General Medicine ,Neural stem cell ,Cell biology ,030104 developmental biology ,030220 oncology & carcinogenesis ,Neurotoxicity Syndromes - Abstract
The Organization for Economic Co-operation and Development (OECD) test guideline 426 for developmental neurotoxicity (DNT) of industrial/environmental chemicals depends primarily on animal experimentation. This requirement raises various critical issues, such as high cost, long duration, the sacrifice of large numbers of animals, and interspecies differences. This study demonstrates an alternative protocol that is simple, quick, less expensive, and standardized to evaluate DNT of many chemicals using human induced pluripotent stem cells (iPSC) and their differentiation to neural progenitor cells (NPC). Initially, concentration-dependent cytotoxicity of 35 DNT chemicals, including industrial materials, insecticides, and clinical drugs, were compared among iPSC, NPC, and two transformed cells, Cos-7 and HepG2, using tetrazolium dye (MTS)-reducing colorimetric and ATP luciferase assays, and IC50 values were calculated. Next, inhibitory effects of the 14 representative chemicals (mainly insecticides) on iPSC differentiation to NPC were evaluated by measuring altered expression of neural differentiation and undifferentiation marker genes. Results show that both iPSC and NPC were much more sensitive to most DNT chemicals than the transformed cells, and 14 chemicals induced differential patterns of marker gene expression, highlighting the validity and utility of the protocol for evaluation and classification of DNT chemicals and preclinical DNT tests for safety assessment.
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- 2020
13. Enucleation of solid pseudopapillary tumor with a preoperative nasopancreatic drainage stent in a child
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Tadashi Akiba, Keiichiro Tanaka, Ryota Saito, Koichiro Haruki, Takeyuki Misawa, and Takeshi Gocho
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Pancreatic duct ,medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Enucleation ,Stent ,General Medicine ,Malignancy ,medicine.disease ,Surgery ,Solid pseudopapillary tumor ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Pancreatic tumor ,030220 oncology & carcinogenesis ,Laparotomy ,medicine ,030211 gastroenterology & hepatology ,Complication ,business - Abstract
Solid pseudopapillary tumor (SPT) is a rare pancreatic tumor with low-grade malignancy in children. A complete surgical resection can achieve a favorable prognosis. Although several reports have indicated that enucleation is considered a safe and effective treatment, the most significant complication is injury to the main pancreatic duct. The usefulness and safety of tumor enucleation after preoperative placement of an endoscopic nasopancreatic drainage stent (NPDS) has recently been reported. We present the case of SPT in a 10-year-old girl. To avoid and detect injury to the main pancreatic duct during operation, an NPDS was endoscopically placed before laparotomy. The patient underwent a complete enucleation of the tumor with the guidance of an NPDS. Our case is the first report of a successful enucleation of an SPT with a preoperative placement of an NPDS. This procedure may lead to safe enucleation of a pancreatic tumor with low malignancy, such as SPT, in children.
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- 2017
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14. Green fluorescent protein chromophore derivatives as a new class of aldose reductase inhibitors
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Akihiro Kato, Toshiya Komatsu, Chikako Ishikawa, Maiko Hoshi, and Ryota Saito
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Models, Molecular ,Stereochemistry ,Green Fluorescent Proteins ,010402 general chemistry ,01 natural sciences ,Green fluorescent protein ,Diabetes Complications ,Inhibitory Concentration 50 ,Structure-Activity Relationship ,chemistry.chemical_compound ,Aldehyde Reductase ,Drug Discovery ,medicine ,Humans ,Enzyme Inhibitors ,Pharmacology ,Aldose reductase ,biology ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,Imidazoles ,General Medicine ,Chromophore ,biology.organism_classification ,Aldose reductase inhibitor ,0104 chemical sciences ,Molecular Docking Simulation ,Biochemistry ,Docking (molecular) ,Sorbinil ,Target protein ,Aequorea ,medicine.drug - Abstract
A number of (Z)-4-arylmethylene-1H-imidazol-5(4H)-ones, which are related to the fluorescent chromophore of the Aequorea green fluorescent protein (GFP), have been synthesized and evaluated their in vitro inhibitory activity against recombinant human aldose reductase for the first time. The GFP chromophore model 1a, with a p-hydroxy group on the 4-benzylidene and a carboxymethyl group on the N1 position, exhibited strong bioactivity with an IC50 value of 0.36 μM. This efficacy is higher than that of sorbinil, a known highly potent aldose reductase inhibitor. Compound 1h, the 2-naphtylmethylidene analogue of 1a, exhibited the best inhibitory effect among the tested copounds with an IC50 value of 0.10 μM. Structure-activity relationship studies combined with docking simulations revealed the interaction mode of the newly synthesized inhibitors toward the target protein as well as the structural features required to gain a high inhibitory activity. In conclusion, the GFP chromophore model compounds synthesized in this study have proved to be potential drugs for diabetic complications.
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- 2017
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15. Inter-strain expression of sequence-diverse HET domain genes severely inhibits growth of Aspergillus oryzae
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Ryota Saito, Kazuhiro Iwashita, Noriko Mori, Takuya Katayama, and Jun-ichi Maruyama
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0301 basic medicine ,Genetics ,Heterokaryon ,animal structures ,Cell growth ,Strain (biology) ,030106 microbiology ,Organic Chemistry ,Nucleic acid sequence ,General Medicine ,Biology ,biology.organism_classification ,Applied Microbiology and Biotechnology ,Biochemistry ,Genome ,Analytical Chemistry ,03 medical and health sciences ,030104 developmental biology ,Aspergillus oryzae ,Molecular Biology ,Gene ,Pezizomycotina ,Biotechnology - Abstract
In the Pezizomycotina (filamentous ascomycete) species, genes that encode proteins with an HET domain (Pfam: PF06985) are reportedly involved in heterokaryon incompatibility (HI) in which cell death or growth defects are induced after fusion of cells that are genetically incompatible owing to diversities in their nucleotide sequence. HET domain genes are commonly found in Pezizomycotina genomes and are functionally characterized in only a few species. Here, we compared 44 HET domain genes between an incompatible strain pair of Aspergillus oryzae RIB40 and RIB128 and performed inter-strain expression of 37 sequence-diverse genes for mimicking HI. Four HET domain genes were identified to cause severe growth inhibition in a strain- or sequence-specific manner. Furthermore, SNPs responsible for the inhibition of cell growth were identified. This study provides an important insight into the physiological significance of sequence diversity of HET domain genes and their potential functions in HI of A. oryzae. Inter-strain expression of sequence-diverse HET domain genes severely inhibited growth in an incompatible strain pair of Aspergillus oryzae, and SNPs responsible for the growth inhibition were identified.
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- 2019
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16. Hepatocellular carcinoma with gastric metastasis treated by simultaneous hepatic and gastric resection: report of a case
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Ryota Saito, Takeshi Gocho, Koichiro Haruki, Tadashi Akiba, Katsuhiko Yanaga, Hiroaki Shiba, and Takeyuki Misawa
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Male ,medicine.medical_specialty ,Carcinoma, Hepatocellular ,Liver tumor ,medicine.medical_treatment ,Gastroenterology ,Metastasis ,03 medical and health sciences ,0302 clinical medicine ,Gastrectomy ,Stomach Neoplasms ,Surgical oncology ,Internal medicine ,Laparotomy ,medicine ,Left Hemihepatectomy ,Hepatectomy ,Humans ,Aged ,business.industry ,Stomach ,Liver Neoplasms ,digestive, oral, and skin physiology ,General Medicine ,Hepatology ,medicine.disease ,Magnetic Resonance Imaging ,digestive system diseases ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Hepatocellular carcinoma ,030211 gastroenterology & hepatology ,Tomography, X-Ray Computed ,business - Abstract
Hepatocellular carcinoma (HCC) with gastric metastasis is extremely rare. There have been few reports on curative surgical resection for gastric metastasis of HCC. We herein report such a case successfully treated by simultaneous surgical resection. A 73-year-old male was admitted for evaluation and treatment of a liver tumor. Computed tomography showed an exophytic tumor of 170 mm in diameter located in the left lobe of the liver with poor delineation to the gastric wall. Upper gastrointestinal endoscopy revealed a submucosal tumor with ulceration in the antrum of the stomach. With a diagnosis of HCC with invasion to the gastric wall, an en bloc resection was planned, and the patient underwent laparotomy. The patients underwent left hemihepatectomy with partial resection of the stomach for adhesion and distal gastrectomy for the tumor. Pathological examination of the liver tumor revealed poorly differentiated HCC, and pathological diagnosis of the tumor in the submucosal and muscular layer of the stomach was compatible with metastasis from HCC, which was separate from the liver tumor. Therefore, we diagnosed the tumor as HCC with hematogenous gastric metastasis. The patient remains well with no evidence of tumor recurrence as of 13 months after resection.
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- 2016
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17. Impact in stability during sequential CDR grafting to construct camelid VHH antibodies against zinc oxide and gold
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Mitsuo Umetsu, Yutaro Saito, Hikaru Nakazawa, Koki Makabe, Izumi Kumagai, Ryota Saito, and Takamitsu Hattori
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0301 basic medicine ,Surface Properties ,Grafting (decision trees) ,Stability (learning theory) ,chemistry.chemical_element ,02 engineering and technology ,Zinc ,Complementarity determining region ,Biochemistry ,03 medical and health sciences ,Protein stability ,Cdr grafting ,Animals ,Molecular Biology ,biology ,Protein Stability ,General Medicine ,Single-Domain Antibodies ,021001 nanoscience & nanotechnology ,Complementarity Determining Regions ,030104 developmental biology ,chemistry ,Biophysics ,biology.protein ,Inorganic materials ,Gold ,Antibody ,Zinc Oxide ,0210 nano-technology ,Camelids, New World - Abstract
Biomolecules which recognize inorganic materials and metal surfaces gain much attention for creating new type of nanomaterials and sensors. 4F2, a camelid VHH antibody, recognizes ZnO surface and has been applied for sensor applications. 4F2 was constructed sequential complementarity determining region (CDR) replacement on the parental VHH antibody, termed the Construction of Antibody by Integrating Grafting and Evolution Technology; CAnIGET procedure. Here, we evaluate the influence of CDR replacements during 4F2 generation using calorimetric technique. We found that the initial peptide grafting at CDR1 results in the stability reduction and subsequent CDR3 randomize and selection restore the stability during the construction of 4F2. Further examination using anti-gold VHH, AuE32, revealed that the final CDR3 randomize and selection step has little effect in stability while the initial CDR1 grafting reduces the stability as same as the case for 4F2. Our results showing here provide the detailed view of the stability alteration during the CAnIGET procedure.
- Published
- 2017
18. Acrolein, an α,β-Unsaturated Carbonyl, Inhibits Both Growth and PSII Activity in the CyanobacteriumSynechocystissp. PCC 6803
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Tomohito Mabuchi, Tatsuya Iwamoto, Ginga Shimakawa, Amane Makino, Chikahiro Miyake, Hiroshi Yamamoto, Toshio Sugimoto, Katsumi Amako, and Ryota Saito
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Photosynthetic reaction centre ,Photosystem II ,macromolecular substances ,Photosynthesis ,Photosystem I ,Photochemistry ,Applied Microbiology and Biotechnology ,Biochemistry ,Analytical Chemistry ,chemistry.chemical_compound ,Benzoquinones ,Acrolein ,Molecular Biology ,P700 ,Chemistry ,Organic Chemistry ,Synechocystis ,Photosystem II Protein Complex ,food and beverages ,General Medicine ,Carbon Dioxide ,Benzoquinone ,Oxygen ,Thylakoid ,Biotechnology - Abstract
In this study, we sought to determine whether and how an α,β-unsaturated carbonyl, acrolein, can inhibit the growth of the cyanobacterium Synechocystis sp. PCC6803 (S. 6803). Treatment of S. 6803 with 200 µM acrolein for 3 d significantly and irreversibly inhibited its growth. To elucidate the inhibitory mechanism, we examined the effects of acrolein on photosynthesis. In contrast to dark conditions, the addition of acrolein to S. 6803 under conditions of illumination lowered the CO₂-dependent O₂ evolution rate (photosynthetic activity). Furthermore, treatment with acrolein lowered the activity reducing dimethyl benzoquinone in photosystem II (PSII). Acrolein also suppressed the reduction rate for the oxidized form of the reaction center chlorophyll of photosystem I (PSI), P700. These results indicate that acrolein inhibited PSII activity in thylakoid membranes. The addition of 200 µM acrolein to the illuminated S. 6803 cells gradually increased the steady-state level (Fs) of Chl fluorescence and decreased the quantum yield of PSII. These results suggested that acrolein damaged the acceptor side of PSII. On the other hand, acrolein did not inhibit respiration. From the above results, we gained insight into the metabolism of acrolein and its physiological effects in S. 6803.
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- 2013
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19. Transplantation of Liver Organoids in the Omentum and Kidney
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Ryusuke Ito, Ryota Saito, Keisuke Nagatsuma, Tomokazu Matsuura, Hiroshi Mano, Ken Tanaka, Mamoru Aizawa, Haruka Maehashi, Hideki Nomoto, Kiyoshi Ohkawa, Yuji Ishii, Hiroshi Hano, Masaya Saito, and Katsuhiko Yanaga
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Kidney ,Pathology ,medicine.medical_specialty ,Liver cytology ,Biomedical Engineering ,Medicine (miscellaneous) ,Bioengineering ,General Medicine ,Biology ,Biomaterials ,Transplantation ,Hepatocyte nuclear factors ,surgical procedures, operative ,Tyrosine aminotransferase ,medicine.anatomical_structure ,Cell culture ,Hepatic stellate cell ,Organoid ,medicine - Abstract
Liver organoids were reconstructed by mouse-immortalized hepatocytes and nonparenchymal cells (sinusoidal endothelial cells and hepatic stellate cells) in a radial-flow bioreactor (RFB). A biodegradable apatite-fiber scaffold (AFS) was used as a scaffold packed in the RFB, which enables three-dimensional cell cultures. The organoids cocultured in the RFB showed a liver-like structure with high-density layers of hepatocytes and the formation of vessel-like structures. A liver organoid consisting of three cocultured cells was transplanted under the kidney capsule (kidney group) or into the omentum (omentum group) using BALB/c nude mice. Transplanted liver organoids survived in the kidney or omentum. The expression of mRNAs of albumin, connexin 26 and 32, hepatocyte nuclear factor 4α, and glucose-6-phosphatase was increased in both groups at 8 weeks after transplantation in comparison to the pretransplant status. Tyrosine aminotransferase appeared only in the omentum group. The results suggested that the functions of liver organoids differed depending on the transplanted site in the recipient animals.
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- 2010
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20. Efficacy of a half-grip technique using a fine tip LigaSure™, Dolphin Tip Sealer/Divider, on liver dissection in swine model
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Norimitsu Okui, Seiya Yoshida, Katsuhiko Yanaga, Ryota Iwase, Michinori Matsumoto, Yoichi Toyama, Ryota Saito, Hiroaki Kitamura, Koichiro Haruki, and Junichi Shimada
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Liver surgery ,medicine.medical_specialty ,Liver dissection ,Swine ,Blood Loss, Surgical ,Dolphin Tip Sealer/Divider ,Dissection (medical) ,Anesthesia, General ,Fine tip LigaSure ,General Biochemistry, Genetics and Molecular Biology ,Blood loss ,Statistical analyses ,Statistical significance ,Hand strength ,medicine ,Animals ,Digestive System Surgical Procedures ,Medicine(all) ,Half-grip technique ,Hand Strength ,Biochemistry, Genetics and Molecular Biology(all) ,business.industry ,Dissection ,Less bleeding ,Equipment Design ,General Medicine ,medicine.disease ,Surgery ,Liver ,Mann–Whitney U test ,business ,Liver parenchyma ,Research Article - Abstract
Background Recently, a lot of energy devices in the surgical field, especially in the liver surgery, have been developed, and a fine tip LigaSure™, Dolphin Tip Sealer/Divider (DT-SD) also has been used frequently to dissect liver parenchyma as well as ultrasonically activated device (USAD). However, the utility of this instrument for liver dissection (LD) is still unknown. Moreover, to reduce bleeding during LD, a half-grip technique (HGT) was contrived. We herein report an experimental study in swine model to evaluate the feasibility and effectiveness of HGT using DT-SD for LD. Methods The swine model experiment was carried out under general anesthesia by veterinarians. LD was performed repeatedly by DT-SD with the HGT (Group A, n = 6), or the conventional clamp-crush technique (CCT) (Group B, n = 6), and by variable mode USAD (Group C, n = 6). The dissection length and depth (cm) as well as bleeding volume (g) were measured carefully, and the dissection area (cm2) and speed (cm2/min) were calculated precisely. Histological examinations of the dissection surfaces were also executed. Mann–Whitney’s U test was used for Statistical analyses with variance at a significance level of 0.05. Results Among the three groups, the three averages of dissection lengths were unexpectedly equalized to 8.3 cm. The dissection area (cm2) was 9.9 ± 5.1 in Group A, 9.8 ± 4.7 in Group B, and 9.9 ± 4.5 in Group C. The mean blood loss during LD was 10.6 ± 14.8 g in Group A, 41.4 ± 39.2 g in Group B, and 34.3 ± 39.2 g in Group C. For Group A, the bleeding rate was the least, 0.9 ± 1.0 g/cm2, and the average depth of coagulation was the thickest, 1.47 ± 0.29 mm, among the three groups (p
- Published
- 2015
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21. RNA LEGO
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Ryota Saito, Satoru Horiya, Kazuo Harada, Koh Kobayashi, Xianglan Li, Akira Katoh, and Gota Kawai
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Pharmacology ,Clinical Biochemistry ,RNA ,Nanotechnology ,General Medicine ,Biology ,Biochemistry ,Nucleic acid secondary structure ,Complementarity (molecular biology) ,Drug Discovery ,Biophysics ,Nucleic acid ,Molecular Medicine ,Rna folding ,Linker ,Molecular Biology ,Macromolecule - Abstract
The high affinity and specificity of nucleic acid base complementarity has been proven to be a powerful method for constructing specific molecular assemblies. On the other hand, recent structural studies of RNA have revealed the wide range of tertiary interactions utilized in RNA folding, which may potentially be used as tools for the design of specific macromolecular assemblies. Here, RNA building blocks containing two hairpin loops, based on the dimerization initiation site (DIS) of HIV RNA, connected by a short linker were used to construct large RNA assemblies through hairpin loop-loop ("kissing") interactions. We show that specific linear and circular assemblies can be constructed in a magnesium-dependent manner using several non-self-complementary loop-loop interactions designed in this study. These results show that the use of RNA tertiary interactions may broaden the reportoire of nucleic acid-based nanostructures.
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- 2003
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22. Severe Peters Plus syndrome-like phenotype with anterior eye staphyloma and hypoplastic left heart syndrome: Proposal of a new syndrome
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Ryota Saito, Makiko Osawa, Kiyoshi Ogawa, Jiro Nishimura, Norimasa Mitsui, Kenji Hoshino, Takashi Negishi, Hirofumi Ohashi, and Reiko Shimizu
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Embryology ,Fatal outcome ,Staphyloma ,General Medicine ,Anatomy ,Biology ,medicine.disease ,Phenotype ,Hypoplastic left heart syndrome ,Pediatrics, Perinatology and Child Health ,Female patient ,medicine ,Peters-plus syndrome ,Anterior staphyloma ,Developmental Biology - Abstract
Peters Plus syndrome is a very rare autosomal recessive condition characterized by ocular defects (typically Peters anomaly) and other systemic major/minor anomalies. Mutations in the B3GALTL gene encoding beta 1,3-glucosyltransferase have been found in virtually all patients with typical Peters Plus syndrome. We report on a female patient with unusually severe manifestations of Peters Plus syndrome, including anterior eye staphyloma, cleft lip and palate, and hypoplastic left heart syndrome (HLHS). Analysis of the B3GALTL gene revealed no mutation in the patient. To our knowledge, HLHS has not previously been reported in Peters Plus syndrome so far, and anterior staphyloma, a most severe defect of the anterior eye chamber, is also apparently rare in the syndrome. Our patient might represent a new syndrome of severe Peters Plus syndrome-like phenotype with anterior eye staphyloma and HLHS.
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- 2010
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23. Scavenging systems for reactive carbonyls in the cyanobacterium Synechocystis sp. PCC 6803
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Ryota Saito, Mayumi Suzuki, Katsuhiko Sakamoto, Chikahiro Miyake, Ginga Shimakawa, Eriko Yamamoto, Amane Makino, Hiroshi Yamamoto, and Akiko Nishi
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Molecular Sequence Data ,Aldo-Keto Reductases ,Dehydrogenase ,macromolecular substances ,Reductase ,Applied Microbiology and Biotechnology ,Biochemistry ,Analytical Chemistry ,chemistry.chemical_compound ,Bacterial Proteins ,Aldehyde Reductase ,Amino Acid Sequence ,Molecular Biology ,Aldehydes ,Organic Chemistry ,Methylglyoxal ,Acrolein ,Synechocystis ,Hemithioacetal ,Propionaldehyde ,General Medicine ,Glutathione ,Ketones ,chemistry ,Biotechnology ,Glyoxalase system - Abstract
To elucidate the scavenging systems of sugar- and lipid-derived reactive carbonyls (RCs) in the cyanobacterium Synechocystis sp. PCC 6803 (S. 6803), we selected proteins from S. 6803 based on amino-acid (AA) sequence similarities with proteins from Arabidopsis thaliana, and characterized the properties of the GST-fusion proteins expressed. Slr0942 catalyzed the aldo-keto reductase (AKR) reaction scavenging mainly sugar-derived RCs, methylglyoxal (MG). Slr1192 is the medium-chain dehydrogenase/redutase (MDR). It catalyzed the AKR reaction scavenging several lipid-derived RCs, acrolein, propionaldehyde, and crotonaldehyde. Slr0315 is a short-chain dehydrogenase/redutase (SDR), and it catalyzed only the reduction of MG in the AKR reaction. Slr0381 catalyzed the conversion of hemithioacetal to S-lactoylglutahione (SLG) in the glyoxalase (GLX) 1 reaction. Sll1019 catalyzed the conversion of SLG to glutathione and lactate in the GLX2 reaction. GLX1 and GLX2 compose the glyoxalase system, which scavenges MG. These enzymes contribute to scavenging sugar- and lipid-derived RCs as scavenging systems.
- Published
- 2013
24. Functional analysis of the AKR4C subfamily of Arabidopsis thaliana: model structures, substrate specificity, acrolein toxicity, and responses to light and [CO(2)]
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Ginga Shimakawa, Amane Makino, Hiroshi Yamamoto, Tatsuya Iwamoto, Katsuhiko Sakamoto, Chikahiro Miyake, Akiko Nishi, Katsumi Amako, and Ryota Saito
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Models, Molecular ,Subfamily ,Light ,Protein Conformation ,Aldo-Keto Reductases ,Arabidopsis ,Reductase ,Biology ,Applied Microbiology and Biotechnology ,Biochemistry ,Analytical Chemistry ,Substrate Specificity ,chemistry.chemical_compound ,Protein structure ,Aldehyde Reductase ,Stress, Physiological ,DHAP ,Acrolein ,Molecular Biology ,Dihydroxyacetone phosphate ,chemistry.chemical_classification ,Organic Chemistry ,Methylglyoxal ,Temperature ,Dose-Response Relationship, Radiation ,General Medicine ,Carbon Dioxide ,Hydrogen-Ion Concentration ,Pyruvaldehyde ,Enzyme Activation ,Enzyme ,chemistry ,Carbohydrate Metabolism ,Biotechnology - Abstract
In Arabidopsis thaliana, the aldo-keto reductase (AKR) family includes four enzymes (The AKR4C subfamily: AKR4C8, AKR4C9, AKR4C10, and AKR4C11). AKR4C8 and AKR4C9 might detoxify sugar-derived reactive carbonyls (RCs). We analyzed AKR4C10 and AKR4C11, and compared the enzymatic functions of the four enzymes. Modeling of protein structures based on the known structure of AKR4C9 found an (α/β)8-barrel motif in all four enzymes. Loop structures (A, B, and C) which determine substrate specificity, differed among the four. Both AKR4C10 and AKR4C11 reduced methylglyoxal. AKR4C10 reduced triose phosphates, dihydroxyacetone phosphate (DHAP), and glyceraldehydes 3-phosphate (GAP), the most efficiently of all the AKR4Cs. Acrolein, a lipid-derived RC, inactivated the four enzymes to different degrees. Expression of the AKR4C genes was induced under high-[CO2] and high light, when photosynthesis was enhanced and photosynthates accumulated in the cells. These results suggest that the AKR4C subfamily contributes to the detoxification of sugar-derived RCs in plants.
- Published
- 2013
25. Detection of epidermal growth factor receptor T790M mutation in plasma DNA from patients refractory to epidermal growth factor receptor tyrosine kinase inhibitor
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Darryl Irwin, Noriko Yanagitani, Fumiyoshi Ohyanagi, Kyohei Kaburaki, Keita Kudo, Azusa Tanimoto, Yoshihiko Fujita, Kazuko Sakai, Toshio Sakatani, Ryota Saito, Makoto Nishio, Atsushi Horiike, and Kazuto Nishio
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Adult ,Male ,Cancer Research ,Lung Neoplasms ,Biology ,Sensitivity and Specificity ,Disease-Free Survival ,Cohort Studies ,chemistry.chemical_compound ,T790M ,Erlotinib Hydrochloride ,Gefitinib ,Carcinoma, Non-Small-Cell Lung ,medicine ,Humans ,Epidermal growth factor receptor ,Protein Kinase Inhibitors ,Alleles ,Aged ,Methionine ,Kinase ,General Medicine ,DNA, Neoplasm ,Original Articles ,Middle Aged ,Molecular biology ,respiratory tract diseases ,ErbB Receptors ,Subcloning ,Oncology ,chemistry ,Mutation (genetic algorithm) ,Mutation ,biology.protein ,Quinazolines ,Female ,Erlotinib ,medicine.drug - Abstract
A secondary epidermal growth factor receptor (EGFR) mutation, the substitution of threonine 790 with methionine (T790M), leads to acquired resistance to reversible EGFR-tyrosine kinase inhibitors (EGFR-TKIs). A non-invasive method for detecting T790M mutation would be desirable to direct patient treatment strategy. Plasma DNA samples were obtained after discontinuation of gefitinib or erlotinib in 75 patients with non-small cell lung cancer (NSCLC). T790M mutation was amplified using the SABER (single allele base extension reaction) technique and analyzed using the Sequenom MassARRAY platform. We examined the T790M mutation status in plasma samples obtained after treatment with an EGFR-TKI. The SABER assay sensitivity using mixed oligonucleotides was determined to be 0.3%. The T790M mutation was detected in 21 of the 75 plasma samples (28%). The presence of the T790M mutation was confirmed by subcloning into sequencing vectors and sequencing in 14 of the 21 samples (66.6%). In this cohort of 75 patients, the median progression-free survival (PFS) of the patients with the T790M mutation (n = 21) was not statistically different from that of the patients without the mutation (n = 54, P = 0.94). When patients under 65 years of age who had a partial response were grouped according to their plasma T790M mutation status, the PFS of the T790M-positive patients (n = 11) was significantly shorter than that of the T790M-negative patients (n = 29, P = 0.03). The SABER method is a feasible means of determining the plasma T790M mutation status and could potentially be used to monitor EGFR-TKI therapy.
- Published
- 2013
26. ChemInform Abstract: An Extremely High Insulin-Mimetic Activity of Bis(1,4-dihydro-2-methyl-1-phenyl-4-thioxo-3-pyridinolato)zinc(II) Complex
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Yoshitane Kojima, Kallol K. Ghosh, Hiromu Sakurai, Asuka Tamura, Takeshi Tsukahara, Akira Katoh, Ryota Saito, and Yutaka Yoshikawa
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chemistry ,chemistry.chemical_element ,High insulin ,Positive control ,General Medicine ,Zinc ,Medicinal chemistry - Abstract
Vanadyl and zinc(II) complexes with VO(O2S2) and Zn(O2S2) coordination mode, respectively, were synthesized. Among them, bis(1,4-dihydro-2-methyl-1-phenyl-4-thioxo-3-pyridinolato)zinc(II) complex exhibited an extremely high insulin-mimetic activity (IC50=0.04 mM when IC50 value of a positive control, VOSO4 was estimated to be 1.0 mM) compared to vanadyl and zinc(II) complexes reported previously.
- Published
- 2010
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27. ChemInform Abstract: First Asymmetric Photosensitization in Supercritical Fluid. Exceptionally High Pressure/Density Dependence of Optical Yield in Photosensitized Enantiodifferentiating Isomerization of Cyclooctene
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Akira Katoh, Yoshihisa Inoue, Takehiko Wada, Masayuki Kaneda, and Ryota Saito
- Subjects
chemistry.chemical_compound ,Supercritical carbon dioxide ,Chemistry ,Cyclooctene ,Yield (chemistry) ,High pressure ,General Medicine ,Enantiomer ,Photochemistry ,Isomerization ,Supercritical fluid - Abstract
The photosensitized enantiodifferentiating isomerization of (Z)-cyclooctene (1Z) in supercritical carbon dioxide has been performed for the first time. The critical control of the enantiomeric exce...
- Published
- 2010
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28. Pax6-5a promotes neuronal differentiation of murine embryonic stem cells
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Jinzhan Wu, Takumi Era, Hajime Watanabe, Ryota Saito, Takeshi Iwatsubo, Sachiko Nishina, Takashi Watanabe, Hiroshi Nishina, Junko Kubota, Tadashi Yokoi, Toshiaki Katada, Noriyuki Azuma, and Nao Shimizu
- Subjects
Gene isoform ,endocrine system ,PAX6 Transcription Factor ,Immunoblotting ,Pharmaceutical Science ,Biology ,Cell Line ,Mice ,Animals ,Humans ,Immunoprecipitation ,Paired Box Transcription Factors ,Protein Isoforms ,Eye Proteins ,Gene ,Transcription factor ,Embryonic Stem Cells ,Oligonucleotide Array Sequence Analysis ,Pharmacology ,Homeodomain Proteins ,Neurons ,Microscopy, Confocal ,Reverse Transcriptase Polymerase Chain Reaction ,Neurogenesis ,Cell Differentiation ,General Medicine ,Tetracycline ,Embryonic stem cell ,Molecular biology ,eye diseases ,Repressor Proteins ,BHLHB2 ,Cell culture ,sense organs ,PAX6 ,Plasmids - Abstract
Pax6 genes are highly conserved and important for eye development. Vertebrates predominantly produce two alternatively spliced Pax6 isoforms, Pax6 and Pax6-5a. Pax6-5a differs from Pax6 by the presence of 14 additional amino acids encoded by exon 5a. These additional amino acids occur in the Pax6 paired domain and thus influence its DNA-binding properties. However, little is known about Pax6-5a's physiological functions. Here we establish murine embryonic stem (ES) cell lines in which expression of either the human Pax6 or Pax6-5a isoform is negatively controlled by tetracycline. We report that, in contrast to Pax6 expression, Pax6-5a expression strongly induces ES cells to differentiate into neurons. Moreover, using DNA microarray analysis, we have identified the transcription factor basic helix loop-helix domain containing, class b2 (bHLHb2) in Pax6-5a-expressing ES cells. Our Pax6 isoform-expressing ES cell lines may serve as useful models for identifying Pax6-regulated genes that are important for neurogenesis and/or eye development.
- Published
- 2009
29. ChemInform Abstract: Determination of the Absolute Structure of Albaconol
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Mikio Fujii, Sadayuki Ishii, Ryota Saito, Hiroyuki Akita, and et al. et al.
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Absolute structure ,Terpene ,Chemistry ,Computational chemistry ,Stereochemistry ,General Medicine - Published
- 2008
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30. ChemInform Abstract: Synthesis and Spectroscopic Properties of 2,5-Bis(benzoazol-2-yl)pyrazines
- Author
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Saori Suzuki, Ryota Saito, Shinnosuke Machida, and Akira Katoh
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chemistry.chemical_classification ,chemistry.chemical_compound ,Base (chemistry) ,chemistry ,Pyrazine ,Chemical modification ,Organic chemistry ,General Medicine ,Combinatorial chemistry ,Fluorescence ,Ion - Abstract
A class of π-conjugated 2,5-bis(benzoazol-2-yl)pyrazine dyes have been synthesized in which 2,5-bis(benzimidazol-2-yl)pyrazine (1) exhibits strong fluorescence in solution. The enhanced fluorescence of 1 with a base leads to future applications such as anion sensing feasible upon chemical modification.
- Published
- 2008
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31. Facile detection of specific RNA-polypeptide interactions by MALDI-TOF mass spectrometry
- Author
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Yuriko Matsumura, Maki Sugaya, Ryota Saito, Akira Katoh, and Kazuo Harada
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Models, Molecular ,Aptamer ,Molecular Sequence Data ,Peptide ,Response Elements ,Biochemistry ,Binding, Competitive ,Bacteriophage ,Structure-Activity Relationship ,Structural Biology ,Peptide Library ,Drug Discovery ,Combinatorial Chemistry Techniques ,Viral Regulatory and Accessory Proteins ,Amino Acid Sequence ,Binding site ,Peptide library ,Molecular Biology ,Peptide sequence ,Pharmacology ,chemistry.chemical_classification ,Binding Sites ,biology ,Peptide chemical synthesis ,Organic Chemistry ,RNA ,rev Gene Products, Human Immunodeficiency Virus ,General Medicine ,biology.organism_classification ,Combinatorial chemistry ,Bacteriophage lambda ,chemistry ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,Molecular Medicine ,RNA, Viral ,Peptides ,Aptamers, Peptide - Abstract
A simple method for the detection of specific RNA-polypeptide interactions using MALDI-TOF mass spectroscopy is described. Instead of direct observation of the RNA-polypeptide complex, we attempted the indirect observation of the binding event by focusing on the disappearance of the free polypeptide signal upon interaction with RNA. As a result, specific binding of the Rev-response element (RRE) RNA of the HIV with two RRE-binding peptide aptamers, DLA and RLA peptides, as well as the bacteriophage lambda boxB RNA with the lambda N peptide was observed. We also show that specific RNA-binding peptides can be identified from a mixture of peptides with varying RNA-binding affinity, showing that the method could be applied to high-throughput screening from simple peptide libraries. The method described in this study provides a quick and simple method for detecting specific RNA-polypeptide interactions that avoids difficulties associated with direct observation of RNA and RNA-polypeptide complexes, which may find various applications in the analysis of RNA-polypeptide interactions and in the identification of novel RNA-binding polypeptides.
- Published
- 2008
32. Insulinomimetic Vanadyl?Hydroxythiazolethione Complexes with VO(S2O2) Coordination Mode: The Correlation Between the Activity and Hammett?s Substituent Constant
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Hiromu Sakurai, Yusuke Adachi, Akira Katoh, Mika Yamaguchi, and Ryota Saito
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chemistry.chemical_compound ,Crystallography ,chemistry ,Substituent ,Mode (statistics) ,General Medicine ,Constant (mathematics) - Abstract
Four kinds of vanadyl–hydroxythiazolethione complexes with VO(S2O2) coordination mode were newly synthesized, and demonstrated for the first time that the insulinomimetic activity apparently correl...
- Published
- 2005
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33. Synthesis of Azine-Type Heterocyclic Compounds and Their Conversion into Functional Molecules
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Akira Katoh and Ryota Saito
- Subjects
Ligand ,Stereochemistry ,Electrospray ionization ,Organic Chemistry ,Absolute configuration ,chemistry.chemical_element ,General Medicine ,Zinc ,Medicinal chemistry ,Azine ,chemistry.chemical_compound ,chemistry ,Stability constants of complexes ,Reagent ,Cyclic voltammetry - Abstract
We have focused on the synthesis of azine-type heterocyclic compounds and their conversion into useful functional molecules. In this article, the following points were reviewed. 1) 6-Amino-2, 3-dimorpholinoquinoxalines bearing the amino acid residues at C-6 position were found to be highly-sensitive fluorescent chiral derivatization reagents. 2) A new tripodal heterocyclic hexadentate ligand, in which three sets of 3-hydroxy-4 (1H) -pyridinone and ethyleneoxy chain are linked to tris (carboxyethoxymethyl) ethane was synthesized. The allosteric binding of alkali metal ions to a pseudocryptand formed by the ligand and Ga (III) was discussed. 3) Hydroxyazine-type linear and cyclic hexapeptides were newly synthesized. The iron (M) complex-forming tendency, the absolute configuration, the stability constant, the iron (III) removal from human transferrin, and the growth-promotion activity were discussed. 4) Oxovanadium complexes of 3-hydroxy-4 (1H) -pyridinones were synthesized. The spectroscopic characterization of the complexes was carried out on the basis of 1H-, 51V-NMR, IR, UV-VIS, FAB MS, ESI MS and ESR spectra, and cyclic voltammetry (CV). Further, an extremely high insulin-mimetic activity of bis (1, 4-dihydro-2-methyl-1-phenyl-4-thioxo-3-pyridinolato) zinc (II) complex was also discussed.
- Published
- 2004
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34. RNA LEGO: magnesium-dependent assembly of RNA building blocks through loop-loop interactions
- Author
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Ryota Saito, Satoru Horiya, Gota Kawai, Xianglan Li, Kazuo Harada, Koh Kobayashi, and Akira Katoh
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chemistry.chemical_classification ,Circular dichroism ,Base Sequence ,Stereochemistry ,Magnesium ,Base pair ,Molecular Sequence Data ,RNA ,chemistry.chemical_element ,General Medicine ,Biology ,Molecular biology ,Loop (topology) ,chemistry ,Nucleic Acid Conformation ,Nucleotide ,Electrophoresis, Polyacrylamide Gel ,Polyacrylamide gel electrophoresis ,Linker - Abstract
We describe the construction of nano-molecular assemblies using RNA building blocks the human immunodeficiency virus type 1 (HIV-1) dimerization initiation site (DIS) RNA, that forms stable base pairing through a magnesium-depe ndent loop-loop interaction ("kissing"). RNA building blocks containing two DIS or DIS-like hairpins connected by a two nucleotide linker self-assembled to form specific structures as observed by non-denaturin g polyacrylamide gel electrophoresis (PAGE). Furthermore, observation of "real time" formation of the molecular assemblies by circular dichroism (CD) spectroscopy was attempted.
- Published
- 2003
35. Hepatic reconstruction from fetal porcine liver cells using a radial flow bioreactor
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Ryusuke Ito, Taro Sakamoto, Katsuhiko Yanaga, Ryota Saito, Hideki Marushima, and Yuji Ishii
- Subjects
medicine.medical_specialty ,Pathology ,Time Factors ,Swine ,Cell Culture Techniques ,Gestational Age ,Biology ,Connexins ,Tight Junctions ,Bioreactors ,Oxygen Consumption ,Microscopy, Electron, Transmission ,Ammonia ,Transplantation medicine ,Porcine liver ,Internal medicine ,medicine ,Bioreactor ,Animals ,Urea ,Cell Shape ,Cell Proliferation ,Fetus ,Hepatocyte Growth Factor ,fungi ,Gastroenterology ,food and beverages ,Cell Differentiation ,General Medicine ,respiratory system ,Liver, Artificial ,respiratory tract diseases ,Organoids ,Basic Research ,surgical procedures, operative ,Endocrinology ,Liver metabolism ,Liver ,Cell culture ,Hepatocytes ,Swine, Miniature ,Hepatocyte growth factor ,Radial flow ,Bile Ducts ,Rheology ,medicine.drug - Abstract
To examine the efficacy of the radial flow bioreactor (RFB) as an extracorporeal bioartificial liver (BAL) and the reconstruction of liver organoids using embryonic pig liver cells.We reconstructed the liver organoids using embryonic porcine liver cells in the RFB. We also determined the gestational time window for the optimum growth of embryonic porcine liver cells. Five weeks of gestation was designated as embryonic day (E) 35 and 8 wk of gestation was designated as E56. These cells were cultured for one week before morphological and functional examinations. Moreover, the efficacy of pulsed administration of a high concentration hepatocyte growth factor (HGF) was examined.Both cell growth and function were excellent after harvesting on E35. The pulsed administration of a high concentration of HGF promoted the differentiation and maturation of these fetal hepatic cells. Microscopic examination of organoids in the RFB revealed palisading and showed that bile duct-like structures were well developed, indicating that the organoids were mini livers. Transmission electron microscopy revealed microvilli on the luminal surfaces of bile duct-like structures and junctional complexes, which form the basis of the cytoskeleton of epithelial tissues. Furthermore, strong expression of connexin (Cx) 32, which is the main protein of hepatocyte gap junctions, was observed. With respect to liver function, ammonia detoxification and urea synthesis were shown to be performed effectively.Our system can potentially be applied in the fields of BAL and transplantation medicine.
- Published
- 2008
- Full Text
- View/download PDF
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