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Gamada H, Funayama T, Yamaji A, Okuwaki S, Asada T, Izawa S, Kumagai H, Fujii K, Amano K, Shiina I, Tatsumura M, Uesugi M, Nakagawa T, Yamazaki M, Koda M. Treatment of Thoracolumbar Pyogenic Spondylitis with Minimally Invasive Posterior Fixation without Anterior Lesion Debridement or Bone Grafting: A Multicenter Case Study. J Clin Med 2023; 12:jcm12030932. [PMID: 36769580 PMCID: PMC9918103 DOI: 10.3390/jcm12030932] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/20/2023] [Accepted: 01/22/2023] [Indexed: 01/27/2023] Open
Abstract
The usefulness of minimally invasive posterior fixation without debridement and autogenous bone grafting remains unknown. This multicenter case series aimed to determine the clinical outcomes and limitations of this method for thoracolumbar pyogenic spondylitis. Patients with thoracolumbar pyogenic spondylitis treated with minimally invasive posterior fixation alone were retrospectively evaluated at nine affiliated hospitals since April 2016. The study included 31 patients (23 men and 8 women; mean age, 73.3 years). The clinical course of the patients and requirement of additional anterior surgery constituted the study outcomes. The postoperative numerical rating scale score for lower back pain was significantly smaller than the preoperative score (5.8 vs. 3.6, p = 0.0055). The preoperative local kyphosis angle was 6.7°, which was corrected to 0.1° after surgery and 3.7° at the final follow-up visit. Owing to failed infection control, three patients (9.6%) required additional anterior debridement and autogenous bone grafting. Thus, in this multicenter case series, a large proportion of patients with thoracolumbar pyogenic spondylitis could be treated with minimally invasive posterior fixation alone, thereby indicating it as a treatment option for pyogenic spondylitis.
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Affiliation(s)
- Hisanori Gamada
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
- Department of Orthopaedic Surgery, Ibaraki Western Medical Center, 555 Otsuka, Chikusei 308-0813, Japan
- Correspondence: ; Tel.: +81-29-853-3219
| | - Toru Funayama
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Akihiro Yamaji
- Department of Orthopaedic Surgery, Ichihara Hospital, 3691 Osone, Tsukuba 300-3253, Japan
| | - Shun Okuwaki
- Department of Orthopaedic Surgery, Kenpoku Medical Center, Takahagi Kyodo Hospital, 1006-9 Kamiteduna-Agehocho, Takahagi 318-0004, Japan
| | - Tomoyuki Asada
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Shigeo Izawa
- Department of Orthopaedic Surgery, Tsukuba Central Hospital, 1589-3 Kashiwada-Cho, Ushiku 300-1211, Japan
| | - Hiroshi Kumagai
- Department of Orthopaedic Surgery, Ichihara Hospital, 3691 Osone, Tsukuba 300-3253, Japan
| | - Kengo Fujii
- Department of Orthopaedic Surgery, Showa General Hospital, 8-1-1 Hanakonagei, Kodaira 187-0002, Japan
| | - Kuniaki Amano
- Department of Orthopaedic Surgery, Tsukuba Central Hospital, 1589-3 Kashiwada-Cho, Ushiku 300-1211, Japan
| | - Itsuo Shiina
- Department of Orthopaedic Surgery, Moriya Daiichi Hospital, 1-17 Matsumaedai, Moriya 302-0102, Japan
| | - Masaki Tatsumura
- Department of Orthopaedic Surgery and Sports Medicine, Tsukuba University Hospital Mito Clinical Education and Training Center, Mito Kyodo General Hospital, 3-2-7 Miyamachi, Mito 310-0015, Japan
| | - Masafumi Uesugi
- Department of Orthopaedic Surgery, Ibaraki Seinan Medical Center Hospital, 2190 Sashima, Sakai 306-0433, Japan
| | - Tsukasa Nakagawa
- Department of Orthopaedic Surgery, Ibaraki Western Medical Center, 555 Otsuka, Chikusei 308-0813, Japan
| | - Masashi Yamazaki
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
| | - Masao Koda
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
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Funayama T, Tsukanishi T, Kumagai H, Noguchi H, Izawa S, Abe T, Miura K, Nagashima K, Mataki K, Shibao Y, Sato K, Koda M, Yamazaki M. A novel unidirectional porous β-tricalcium phosphate grafting for vertebral fracture in the elderly: preliminary case series. J Rural Med 2019; 14:211-215. [PMID: 31788144 PMCID: PMC6877923 DOI: 10.2185/jrm.3017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 06/28/2019] [Indexed: 01/06/2023] Open
Abstract
Objective: To treat vertebral fractures with posterior wall injury in the
elderly, vertebral bone grafting is generally performed through a posterior transpedicular
approach, combined with pedicle screw fixation. An autologous bone is ideal to treat this
disorder. However, harvesting autologous bones from the elderly with osteoporosis is
limited by the amount and quality of available autologous bone. Thus, we developed a
bone-grafting substitute. The newly developed unidirectional porous β-tricalcium
phosphate, with a porosity of 57% (UDPTCP; Affinos®, Kuraray Co., Ltd., Tokyo,
Japan), is used in the bone-grafting procedure. This is the first report of UDPTCP used as
an artificial bone graft in patients with an acute vertebral burst fracture. Materials and Methods: UDPTCP (mean: 4.2 g) was implanted through the
pedicle, and posterior instrumentation was achieved with pedicle screws in five elderly
patients. Resorption of UDPTCP and substitution with the autologous bone were evaluated on
computed tomography (CT) and plain X-ray performed immediately and at 3, 6, and 12 months
after the operation. Results: In case 1, the pedicle screws did not loosen, and UDPTCP was
completely resorbed and replaced with the autologous bone at 3 postoperative months. In
the other four cases, although the pedicle screws or the caudal part loosened because of
osteoporosis, resorption of UDPTCP was observed at 3 postoperative months. At 6
postoperative months, progressive substitution with the autologous bone was confirmed, and
at 12 postoperative months, formation of the good autologous bone was confirmed. Conclusion: This preliminary case series demonstrated that the newly
developed UDPTCP shows good clinical potential as a bone-graft substitute for acute
vertebral burst fractures in the elderly, including patients with osteoporosis.
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Affiliation(s)
- Toru Funayama
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Toshinori Tsukanishi
- Department of Orthopedic Surgery, Kenpoku Medical Center Takahagi Kyodo Hospital, Japan
| | - Hiroshi Kumagai
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Hiroshi Noguchi
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Shigeo Izawa
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Tetsuya Abe
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Kousei Miura
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Katsuya Nagashima
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Kentaro Mataki
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Yosuke Shibao
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Kosuke Sato
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Masao Koda
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Masashi Yamazaki
- Department of Orthopedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
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Noguchi H, Funayama T, Koda M, Iijima Y, Kumagai H, Ishikawa T, Aiba A, Abe T, Nagashima K, Miura K, Izawa S, Maki S, Furuya T, Yamazaki M. A unidirectional porous beta-tricalcium phosphate material (Affinos®) for reconstruction of bony defects after excision of fibular bone for spinal surgery graft. J Clin Neurosci 2019; 66:71-76. [PMID: 31174946 DOI: 10.1016/j.jocn.2019.05.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/22/2019] [Indexed: 10/26/2022]
Abstract
The aim of this study was to elucidate the bone regeneration-inducing capability of Affinos®, a newly developed, high-porosity unidirectional porous β-TCP artificial bone. We compared the ability of Affinos® and OSferion®, a commercially available β-TCP product, to induce bone regeneration following implantation into bony defects left after fibula harvesting for spinal fusion surgery. Study subjects underwent surgery to harvest non-vascularized fibula grafts for spinal fusion surgery and were implanted with either Affinos® (19 patients) or OSferion® (15 patients, control group) at the defect site. The minimal and mean follow up periods were 6 and 11 months after surgery, respectively. X-rays of the lower leg taken 1-2 weeks after surgery and at the final follow-up visit were used to evaluate fibular-β-TCP continuity and fibula defect filling ratio. There was no significant difference in radiographic continuity in the fibula between the two groups. The fibula defect filling ratio for the Affinos® group decreased from 0.94 ± 0.17 at 1-2 weeks to 0.77 ± 0.14 at 10 months. For the OSferion® control group, the fibula defect filling ratio decreased from 0.94 ± 0.14 at 1-2 weeks to 0.52 ± 0.27 at final follow-up. The Affinos® group showed a significantly higher fibula defect filling ratio compared to that for the OSferion® group (p = 0.003). These results indicate that Affinos® has slow absorption rates and significant defect filling activity compared with OSferion®. Thus, Affinos® could be a suitable substitute to fill bony defects induced by fibula harvesting for spinal reconstruction surgery.
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Affiliation(s)
- Hiroshi Noguchi
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Japan.
| | - Toru Funayama
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Masao Koda
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Yasushi Iijima
- Department of Orthopedic Surgery, Seirei Sakura Citizen Hospital, Chiba, Japan
| | - Hiroshi Kumagai
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | | | - Atsuomi Aiba
- Department of Orthopedic Surgery, Numazu City Hospital, Shizuoka, Japan
| | - Tetsuya Abe
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Katsuya Nagashima
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Kousei Miura
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Shigeo Izawa
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
| | - Satoshi Maki
- Department of Orthopedic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Takeo Furuya
- Department of Orthopedic Surgery, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Masashi Yamazaki
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Japan
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Hirose T, Hasegawa J, Izawa S, Enoki H, Suzuki Y, Kuzuya M. P-161: Geriatric conditions that predict mortality and hospitalization in dependent older people living in long term care facilities. Eur Geriatr Med 2015. [DOI: 10.1016/s1878-7649(15)30261-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Izawa S, Enoki H, Hasegawa J, Hirose T, Kuzuya M. Factors associated with deterioration of mini nutritional assessment-short form status of nursing home residents during a 2-year period. J Nutr Health Aging 2014; 18:372-7. [PMID: 24676317 DOI: 10.1007/s12603-013-0400-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE A number of other studies have been conducted to verify the Mini Nutritional Assessment (MNA) or the MNA short form (MNA-SF) as a nutritional assessment/screening tool in various clinical settings or communities. However, there are few longitudinal studies using these tools to analyze which factors affect the incidence of deteriorating nutritional status. We tried to identify the factors associated with deterioration of MNA-SF status of nursing home residents during a 2-year period. METHODS Participants were 392 people with a mean age of 84.3 in 12 nursing homes in Japan. The factors associated with deterioration in MNA-SF categories during the study period compared to stable/improved MNA-SF categories were identified. RESULTS At baseline, 19.9% of the participants were malnourished and 60.2% were at risk of malnutrition, according to the MNA-SF classification. After 2 years, 66.3% participants maintained and 6.1% participants improved their nutritional status according to the MNA-SF classification, while 27.6% showed deterioration in MNA-SF status. Stepwise logistic-regression procedure indicated that basic ADL impairment and hospitalization during the follow-up period were associated with declining MNA-SF status. CONCLUSIONS Poor basic ADL status and hospitalization during the follow-up period were associated with malnutrition and risk of malnutrition as assessed by MNA-SF of nursing homes residents during a 2-year period.
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Affiliation(s)
- S Izawa
- S. Izawa, Department of Health and Nutrition, Faculty of Psychological and Physical Science, Aichi Gakuin University,12 Araike, Iwasaki-cho, Nisshin, Aichi 470-0195, Japan. TEL: +81-561-73-1111; FAX: +81-561-73-1142. E-mail address:
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Hakamata Y, Izawa S, Sato E, Komi S, Murayama N, Moriguchi Y, Hanakawa T, Inoue Y, Tagaya H. 1603 – Stress hormone and neuropsychological functioning predict attention bias towards threat in healthy individuals. Eur Psychiatry 2013. [DOI: 10.1016/s0924-9338(13)76601-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Watanabe M, Kono K, Kawaguchi Y, Mizukami Y, Mimura K, Maruyama T, Izawa S, Fujii H. NK cell dysfunction with down-regulated CD16 and up-regulated CD56 molecules in patients with esophageal squamous cell carcinoma. Dis Esophagus 2010; 23:675-81. [PMID: 20545975 DOI: 10.1111/j.1442-2050.2010.01073.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
NK cells can be divided into two subsets, CD56(dim) and CD56(bright) NK cells, based on their expression of CD56 and CD16. In the present study, we analyzed NK cell dysfunction in patients with esophageal squamous cell carcinoma (ESCC), with a particular focus on the expression of CD16 and CD56 molecules. Expression of CD16 and CD56, and the distribution of CD56(dim) or CD56(bright) NK cells gated on CD56(+)CD3(-) NK cells were compared between ESCC patients (n= 40) and healthy donors (n= 38). Purified NK cells were evaluated for Cetuximab-mediated antibody-dependent cellular cytotoxicity (ADCC) against epidermal growth factor receptor (EGFR)-expressing ESCC cell lines. Although there were no significant differences in the distribution of CD56(dim) and CD56(bright) NK cells between ESCC patients and healthy donors, down-regulated CD16 and up-regulated CD56 were significantly observed on NK cells of ESCC patients, paralleling the impairment of Cetuximab-mediated ADCC, in comparison with healthy donors. After patients received curative resections of ESCC, the down-regulated CD16 and up-regulated CD56 were significantly restored to the levels of healthy donors. Moreover, TGF-beta1 partially contributed to down-regulation of CD16 on NK cells. Down-regulated CD16 and up-regulated CD56 molecules on NK cells were observed in ESCC patients, resulting in NK cell dysfunction.
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Affiliation(s)
- M Watanabe
- First Department of Surgery, University of Yamanashi, Yamanashi, Japan
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Maruyama T, Kono K, Izawa S, Mizukami Y, Kawaguchi Y, Mimura K, Watanabe M, Fujii H. CCL17 and CCL22 chemokines within tumor microenvironment are related to infiltration of regulatory T cells in esophageal squamous cell carcinoma. Dis Esophagus 2010; 23:422-9. [PMID: 20002703 DOI: 10.1111/j.1442-2050.2009.01029.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
It has been reported that an increased population of regulatory T cells (T-regs) is one of the reasons for impaired anti-tumor immunity. We investigated the frequency of Foxp3(+) T-regs in tumor-infiltrating lymphocytes (TILs) and peripheral blood lymphocytes (PBLs) of patients with esophageal squamous cell carcinoma (ESCC). Furthermore, in order to elucidate the mechanisms behind T-regs accumulation within tumors, we evaluated the relationship between CCL17 or CCL22 expression and the frequency of Foxp3(+) T-regs. CD4(+)CD25(+)Foxp3(+) T-regs as a percentage of CD4(+) cells were counted by flow cytometry. The frequency of CCL17(+) or CCL22(+) cells among CD14(+) cells in tumors was also evaluated by flow cytometry. Moreover, an in vitro migration assay using T-regs derived from ESCC was performed in the presence of CCL17 or CCL22. The frequency of Foxp3(+) T-regs in TILs was significantly higher than that in the normal esophageal mucosa (24.6 +/- 10.0 vs 7.1 +/- 5.9%, P < 0.01). The frequency of Foxp3(+) T-regs in PBLs of ESCC patients was significantly higher than that in normal healthy donors (7.0 +/- 4.2 vs 2.5 +/- 1.0%, P < 0.01). Furthermore, the frequency of CCL17(+) or CCL22(+) cells among CD14(+) cells within tumors was significantly higher than that of normal esophageal mucosa, and there was a significant correlation between the frequency of CCL17(+) or CCL22(+) cells and Foxp3(+) T-regs in TILs. In addition, the in vitro migration assay indicated that T-regs were significantly induced to migrate by CCL17 or CCL22. In conclusion, CCL17 and CCL22 within the tumor are related to the increased population of Foxp3(+) T-regs in ESCC.
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Affiliation(s)
- T Maruyama
- First Department of Surgery, University of Yamanashi, Chuo City, Yamanashi, Japan
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Akimoto T, Kim K, Yamauchi R, Izawa S, Hong C, Aizawa K, Lee H, Suzuki K. Exercise in, and adaptations to a cold environment have no effect on SIgA. J Sports Med Phys Fitness 2009; 49:315-319. [PMID: 19861939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
AIM The authors hypothesized that inconsistent SIgA response to exercise is caused by the different adaptative status of subjects to a cold environment. The purposes of the study were to examine whether moderate-intense exercise in a cold environment decreases SIgA and whether adaptation to a cold environment has any effect on SIgA. METHODS Young male skaters, short track (N=9) and inline (N=10), participated in this study. All subjects cycled for 60 min at 65% VO(2max) in cold (ambient temperature: 5 +or - 1 degrees Celsius, relative humidity 41 + or - 9%) and thermoneutral (ambient temperature: 21 + or - 1 degrees Celsius, relative humidity 35 + or - 5%) conditions. Saliva samples were collected as follows: before and after 1hour of environmental exposure; immediately, 30-min, 60-min and 120-min after the exercise. RESULTS AND CONCLUSIONS Salivary SIgA and saliva flow rate decreased after the exercise in both groups only in thermoneutral conditions. The SIgA secretion rate did not decrease after moderate-high intensity exercise in a cold environment, and the SIgA response to exercise was not affected by the different adaptative status of subjects to the cold environment.
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Affiliation(s)
- T Akimoto
- Laboratory of Regenerative Medical Engineering, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan.
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Kim KI, Kim SR, Sasase N, Taniguchi M, Harada S, Kinoshita K, Kim SH, Akimoto Y, Shikata M, Kimura N, Izawa S, Ohtani A, Nakao K, Motojima M, Kinoshita M, Hirai M, Ohzu M, Hirooka T, Nabeshima S, Ishii F, Tanaka K, Hotta H. 2'-,5'-Oligoadenylate synthetase response ratio predicting virological response to PEG-interferon-α2b plus ribavirin therapy in patients with chronic hepatitis C. J Clin Pharm Ther 2006; 31:441-6. [PMID: 16958821 DOI: 10.1111/j.1365-2710.2006.00761.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Although all the mechanisms of elimination of hepatitis C virus (HCV) by Interferon (IFN) have not been fully elucidated, the 2'-5'-oligoadenylate (2-5A) system is one of the mechanisms of the antiviral effect of IFN. Consequently, the measurement of 2'-5'-oligoadenylate synthetase (2-5AS) activity could be useful for the evaluation of IFN treatment. This retrospective study was aimed at assessing whether 2-5AS activity functions as a clinical marker of virological response to PEG-interferon-alpha2b (PEG-IFN) plus ribavirin therapy of chronic hepatitis C. METHODS The 32 patients included in this study had high viral loads of serum HCV-RNA of genotype 1b with chronic hepatitis C. All the patients received a regimen of PEG-IFN plus ribavirin for 48 weeks, and were then divided into two groups: one group (effective group) with undetectable serum HCV-RNA levels at 24 weeks (n = 22) of therapy, the other group (ineffective group) with persistent presence of HCV-RNA in serum at 24 weeks (n = 10). The 2-5AS activity in serum was measured 2, 8 and 12 weeks before initial administration. RESULTS The 2-5AS response ratio (measured value/measured value of baseline 2-5AS) at 2, 8 and 12 weeks after the administration in the effective group was significantly higher than that in the ineffective group. CONCLUSIONS These results suggest that the ratio of 2-5AS is closely related to the antiviral effect, and that the measurement of 2-5AS response ratio may be a useful clinical parameter of virological response to PEG-IFN plus ribavirin therapy of chronic hepatitis C.
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Affiliation(s)
- K-I Kim
- Department of Pharmacy, Kobe Asahi Hospital, Kobe, Japan
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Fukunishi Y, Sakai T, Sasaki K, Izawa S, Xiong AK. Feedback control of instability waves in a transitional flat-plate boundary layer. J Vis (Tokyo) 2006. [DOI: 10.1007/bf03181675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Takahashi M, Shimizu H, Murakami T, Enosawa S, Suzuki C, Takeno Y, Hakamata Y, Kudou S, Izawa S, Yasue T, Kobayashi E. A novel immunomodulator KRP-203 combined with cyclosporine prolonged graft survival and abrogated transplant vasculopathy in rat heart allografts. Transplant Proc 2005; 37:143-5. [PMID: 15808575 DOI: 10.1016/j.transproceed.2004.12.107] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
To find more effective and less toxic immunosuppressive strategies in long-term treatment for organ transplantation patients, we examined the effects on rat heart allograft survival of a novel sphigosine-1-phosphate receptor agonist, KRP-203, combined with a subtherapeutic dose of cyclosporine (CsA). Rat heart transplantation was performed across a major histocompatibility complex-incompatible (DA to LEW) rat combination. KRP-203 alone showed little or no effect on heart allograft survival. In contrast, KRP-203 combined with a subtherapeutic dose of CsA led to prolonged allograft survival. Histologic analyses showed that the combination completely suppressed acute rejection, as characterized by allograft vasculopathy, mononuclear cell infiltration, and myocardial necrosis in the heart allografts. RT-PCR analysis showed that the allografts treated with CsA or KRP-203 alone showed no suppression of IL-10, IFN-gamma, and TNF-alpha mRNA expression, but when combined with a subtherapeutic dose of CsA it completely suppressed their mRNA expressions. Furthermore, the combination treatment reduced donor-specific antibody production. KRP-203 combined with a subtherapeutic dose of CsA synergistically prolonged rat heart allograft survival. The combination of CsA with KRP-203 may provide an option to prevent allograft rejection and reduce adverse effects.
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Affiliation(s)
- M Takahashi
- Division of Organ Replacement Research, Center for Molecular Medicine, Jichi Medical School, Tochigi, Japan.
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Kim KI, Sasase N, Taniguchi M, Mita K, Kinoshita K, Togitani T, Shikata M, Kimura N, Izawa S, Ohtani A, Nakao K, Muramoto Y, Kim SR, Nabeshima S, Ishii F, Tanaka K, Hayashi Y. Interferon-beta induction/interferon-alpha2b plus ribavirin therapy in patients with chronic hepatitis C. Int J Clin Pharmacol Res 2005; 25:71-6. [PMID: 16060397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Treatment of chronic hepatitis C virus (HCV) infection with interferon (IFN) and ribavirin improves the rate of eradication of the virus by less than 20% in patients with genotype 1b and a high viral load. In this study we assessed whether IFN-beta induction/IFN-alpha2b plus ribavirin enhances the efficacy of the therapy in patients with chronic hepatitis C. The efficacy of IFN-beta induction/IFN-alpha2b plus ribavirin therapy (group A, n=7) was compared with that of IFN-alpha2b plus ribavirin (group B, n=7) in 14 patients with high levels of HCV-RNA (> 100 K/U/ml). No significant differences were observed in the clearance of HCV-RNA between the two groups (A and B, respectively) 2 weeks after the start of the treatment (0% and 14.3%), at the end of the treatment (71.4% and 100%) and 6 months after the end of the treatment (28.6% and 14.3%). Recovery was complete in 28.6% and 14.3%, transient in 42.9% and 85.7% and absent in 28.6% and 0% in groups A and B, respectively. Early log changes in the viral load from the baseline after 2 weeks of treatment were 2.41 +/- 0.91 and 2.77 +/- 0.20 in groups A and B, respectively, with no significant difference between the two groups. In the present study, we were not able to demonstrate that IFN-beta induction/IFN-alpha2b plus ribavirin therapy was superior to IFN-alpha2b plus ribavirin therapy in patients with genotype 1b and high viral loads.
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Affiliation(s)
- K I Kim
- Division of Molecular Medicine & Medical Genetics, International Center for Medical Research and Treatment, Kobe University Graduate School of Medicine, Kobe, Japan
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Izawa S, Kuroki N, Inoue Y. Nuclear thioredoxin peroxidase Dot5 in Saccharomyces cerevisiae: roles in oxidative stress response and disruption of telomeric silencing. Appl Microbiol Biotechnol 2004; 64:120-4. [PMID: 12925864 DOI: 10.1007/s00253-003-1421-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2003] [Revised: 07/06/2003] [Accepted: 07/18/2003] [Indexed: 10/26/2022]
Abstract
The DOT5 gene was originally cloned as one of the DOT (disrupter of telomeric silencing) genes; and later it was re-discovered as a nuclear thioredoxin peroxidase in Saccharomyces cerevisiae. Here, we demonstrate that the telomeric-silencing disruption activity of Dot5 is independent of thioredoxin peroxidase activity. In addition, Dot5 cannot suppress the increased susceptibility to peroxides of mutants defected in cytosolic thioredoxin peroxidase, even when Dot5 is expressed in the cytoplasm. Furthermore, Dot5 does not affect redox regulation of the Yap1 transcription factor. These results suggest that Dot5 is less important as an antioxidant in yeast cells.
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Affiliation(s)
- S Izawa
- Laboratory of Molecular Microbiology, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Uji, 611-0011 Kyoto, Japan
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15
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Izawa S, Inoue Y. A screening system for antioxidants using thioredoxin-deficient yeast: discovery of thermostable antioxidant activity from Agaricus blazei Murill. Appl Microbiol Biotechnol 2003; 64:537-42. [PMID: 14593506 DOI: 10.1007/s00253-003-1467-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2003] [Revised: 09/11/2003] [Accepted: 09/19/2003] [Indexed: 11/28/2022]
Abstract
Previously, we found that cytosolic thioredoxin is a negative regulator for an oxidative stress responsive transcription factor, Yap1p (yeast AP-1-like transcription factor), i.e., this transcription factor is constitutively concentrated in the nucleus in the thioredoxin-deficient mutant ( trx1delta trx2delta) due to an impairment of the reactive oxygen species-scavenging activity of this mutant [Izawa et al. (1999) J Biol Chem 274:28459-28465]. Based on these findings, we developed a screening method to discover substances that show antioxidant activity. With this method, antioxidant activity was evaluated by monitoring the subcellular localization of Yap1p. Since Yap1p is oxidized and accumulates in the nucleus in trx1delta trx2Delta cells, it is easy to identify antioxidant activity by observing the localization of green fluorescent protein (GFP)-tagged Yap1p. If exogenous substances taken in by trx1delta trx2Delta cells were able to function as antioxidants to reduce the oxidized form of Yap1p, GFP1-Yap1p would diffuse into the cytoplasm. We used this system to screen for antioxidant activity in mushrooms, and found that the edible mushroom Agaricus blazei Murill is an excellent source of antioxidants.
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Affiliation(s)
- S Izawa
- Laboratory of Molecular Microbiology, Graduate School of Agriculture, Kyoto University, Uji, 611-0011 Kyoto, Japan
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16
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17
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Kuge S, Arita M, Murayama A, Maeta K, Izawa S, Inoue Y, Nomoto A. Regulation of the yeast Yap1p nuclear export signal is mediated by redox signal-induced reversible disulfide bond formation. Mol Cell Biol 2001; 21:6139-50. [PMID: 11509657 PMCID: PMC87331 DOI: 10.1128/mcb.21.18.6139-6150.2001] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Yap1p, a crucial transcription factor in the oxidative stress response of Saccharomyces cerevisiae, is transported in and out of the nucleus under nonstress conditions. The nuclear export step is specifically inhibited by H(2)O(2) or the thiol oxidant diamide, resulting in Yap1p nuclear accumulation and induction of transcription of its target genes. Here we provide evidence for sensing of H(2)O(2) and diamide mediated by disulfide bond formation in the C-terminal cysteine-rich region (c-CRD), which contains 3 conserved cysteines and the nuclear export signal (NES). The H(2)O(2) or diamide-induced oxidation of the c-CRD in vivo correlates with induced Yap1p nuclear localization. Both were initiated within 1 min of application of oxidative stress, before the intracellular redox status of thioredoxin and glutathione was affected. The cysteine residues in the middle region of Yap1p (n-CRD) are required for prolonged nuclear localization of Yap1p in response to H(2)O(2) and are thus also required for maximum transcriptional activity. Using mass spectrometry analysis, the H(2)O(2)-induced oxidation of the c-CRD in vitro was detected as an intramolecular disulfide linkage between the first (Cys(598)) and second (Cys(620)) cysteine residues; this linkage could be reduced by thioredoxin. In contrast, diamide induced each pair of disulfide linkage in the c-CRD, but in this case the cysteine residues in the n-CRD appeared to be dispensable for the response. Our data provide evidence for molecular mechanisms of redox signal sensing through the thiol-disulfide redox cycle coupled with the thioredoxin system in the Yap1p NES.
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Affiliation(s)
- S Kuge
- Department of Microbiology, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku Tokyo 113-0033, Japan.
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19
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Abstract
The ZRC1 gene encodes a multicopy suppressor of zinc toxicity in Saccharomyces cerevisiae; however, previously we found that the expression of ZRC1 was induced when the intracellular zinc level was decreased. Zrc1 has six putative transmembrane domains and we determined that a Zrc1-GFP fusion protein was localized to the vacuolar membrane. The steady state level of intracellular zinc in a zrc1Delta mutant cultured in the zinc-abundant medium was lower than that in wild type. No distinct difference was observed in the basal activity of glyoxalase I, which is a cytosolic enzyme requiring zinc for catalytic function and is used here as a marker for cytosolic zinc-availability, between wild type and zrc1Delta mutant, although the activity was decreased much greater extent in the zrc1Delta mutant if the cells were exposed to the metal-limited medium. Similarly, the basal expression level of ZRC1-lacZ reporter gene in zrc1Delta mutant was the same as that in wild type; however, the fold of induction of ZRC1-lacZ expression in zrc1Delta mutant under the zinc-limited conditions was higher than that in the wild type. Based on these results, we present a tentative model for the function of Zrc1 as a mechanism to maintain the zinc homeostasis in yeast.
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Affiliation(s)
- S Miyabe
- Research Institute for Food Science, Kyoto University, Uji, Kyoto, 611-0011, Japan
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20
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Sugiyama K, Kawamura A, Izawa S, Inoue Y. Role of glutathione in heat-shock-induced cell death of Saccharomyces cerevisiae. Biochem J 2000; 352 Pt 1:71-8. [PMID: 11062059 PMCID: PMC1221433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Previously we reported that expression of GSH1 (gamma-glutamylcysteine synthetase) and GSH2 (glutathione synthetase) of the yeast Saccharomyces cerevisiae was increased by heat-shock stress in a Yap1p-dependent fashion and consequently intracellular glutathione content was increased [Sugiyama, Izawa and Inoue (2000) J. Biol. Chem. 275, 15535-15540]. In the present study, we discuss the physiological role of glutathione in the heat-shock stress response in this yeast. Both gsh1 and gsh2 mutants could acquire thermotolerance by mild heat-shock stress and induction of Hsp104p in both mutants was normal; however, mutant cells died faster by heat shock than their parental wild-type strain. After pretreatment at a sublethal temperature, the number of respiration-deficient mutants increased in a gsh1 mutant strain in the early stages of exposure to a lethal temperature, although this increase was partially suppressed by the addition of glutathione. These results lead us to suspect that an increase of glutathione synthesis during heat-shock stress is to protect mitochondrial DNA from oxidative damage. To investigate the correlation between mitochondrial DNA damage and glutathione, mitochondrial Mn-superoxide dismutase (the SOD2 gene product) was disrupted. As a result, the rate of generation of respiration-deficient mutants of a sod2 delta strain was higher than that of the isogenic wild-type strain and treatment of the sod2 delta mutant with buthionine sulphoximine, an inhibitor of glutathione synthesis, inhibited cell growth. These results suggest that glutathione synthesis is induced by heat shock to protect the mitochondrial DNA from oxidative damage that may lead to cell death.
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Affiliation(s)
- K Sugiyama
- Research Institute for Food Science, Kyoto University, Uji, Kyoto 611-0011, Japan
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21
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Miyabe S, Izawa S, Inoue Y. Expression of ZRC1 coding for suppressor of zinc toxicity is induced by zinc-starvation stress in Zap1-dependent fashion in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2000; 276:879-84. [PMID: 11027563 DOI: 10.1006/bbrc.2000.3580] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ZRC1 gene was cloned as a multicopy suppressor of zinc toxicity in Saccharomyces cerevisiae. Zrc1 belongs to CDF (cation diffusion facilitator) family. The transporters belonging to this family are thought to play an important role in metal detoxification. However, we found that cell growth of zrc1Delta mutant was lowered under the metal-limited conditions, which was restored by zinc. The Zap1 transcription factor is crucial for expression of several genes responsive to zinc-starvation stress. The expression of ZRC1 was induced in Zap1-dependent fashion when the intracellular zinc level was decreased and this induction was repressed by zinc. These results imply an important role of Zrc1 in the zinc-starvation stress.
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Affiliation(s)
- S Miyabe
- Research Institute for Food Science, Kyoto, 611-0011, Japan
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22
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Tsujimoto Y, Izawa S, Inoue Y. Cooperative regulation of DOG2, encoding 2-deoxyglucose-6-phosphate phosphatase, by Snf1 kinase and the high-osmolarity glycerol-mitogen-activated protein kinase cascade in stress responses of Saccharomyces cerevisiae. J Bacteriol 2000; 182:5121-6. [PMID: 10960096 PMCID: PMC94660 DOI: 10.1128/jb.182.18.5121-5126.2000] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We screened the genome of Saccharomyces cerevisiae for the genes responsive to oxidative stress by using the lacZ transposon-insertion library. As a result, we found that expression of the DOG2 gene coding for 2-deoxyglucose-6-phosphate phosphatase was induced by oxidative stress. The expression of DOG2 was also induced by osmotic stress. We found a putative cis element (STRE, a stress response element) in the DOG2 promoter adjacent to a consensus sequence to which the Mig1p repressor is known to bind. The basal levels of DOG2 gene expression were increased in a mig1Delta mutant, while the derepression of DOG2 was not observed in a snf1Delta mutant under glucose-deprived conditions. Induction of the DOG2 gene expression by osmotic stress was observed in any of the three disruptants pbs2Delta, hog1Delta, and snf1Delta. However, the osmotic induction was completely abolished in both the snf1Delta pbs2Delta mutant and the snf1Delta hog1Delta mutant. Additionally, these single mutants as well as double mutants failed to induce DOG2 expression by oxidative stress. These results suggest that Snf1p kinase and the high-osmolarity glycerol-mitogen-activated protein kinase cascade are likely to be involved in the signaling pathway of oxidative stress and osmotic stress in regulation of DOG2.
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Affiliation(s)
- Y Tsujimoto
- Research Institute for Food Science, Kyoto University, Uji, Japan
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23
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Abstract
Patch-clamp recordings were used to examine the osmosensitivity and mechanosensitivity of neurons in the caudal part of the nucleus tractus solitarius in coronal slices from rat brain. Firing rates and membrane potentials were measured as slices were exposed to perfusate which varied in its osmolality and/or sodium concentration. In all cells tested, the responses to change in the sodium concentration of perfusate were duplicated by osmolality changes of sucrose or mannitol. When nucleus tractus solitarius cells were tested with changes in pressure applied via the pipette, responses to positive or negative pressure paralleled their responses to osmotic stimulation. We suggest that a mechanosensitive receptor exists on osmosensitive neurons within the nucleus tractus solitarius, and this receptor may be responsible for changes in the firing rate and membrane potential which occur in the nucleus tractus solitarius neurons.
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Affiliation(s)
- S Izawa
- Department of Operative Dentistry, Okayama University Dental School, Japan
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24
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Abstract
Glutathione is synthesized in two sequential reactions catalyzed by gamma-glutamylcysteine synthetase (GSH1 gene product) and glutathione synthetase (GSH2 gene product). The expression of GSH1 in Saccharomyces cerevisiae has been known to be up-regulated by Yap1p, a critical transcription factor for the oxidative stress response in yeast. The present study demonstrates that GSH2 expression is also regulated by Yap1p under oxidative stress-induced conditions. In addition to oxidative stress, expression of GSH1 and GSH2 was induced by heat shock stress in a Yap1p-dependent manner with subsequent increases in intracellular glutathione content. Oxygen respiration rate increased when cells were exposed to higher temperatures, and as a result, intracellular oxidation levels were increased. The heat shock-induced expression of GSH1 and GSH2 did not occur under anaerobic conditions. Furthermore, even under aerobic conditions, the heat shock response of these genes was not observed when cells were pretreated with KCN to block oxygen respiration. We speculate that heat shock stress enhances oxygen respiration, which in turn results in an increase in the generation of reactive oxygen species in mitochondria. This signal may be mediated by Yap1p, resulting in the elevation of intracellular glutathione levels.
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Affiliation(s)
- K Sugiyama
- Research Institute for Food Science, Kyoto University, Uji, Kyoto 611-0011, Japan
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25
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Izawa S, Maeda K, Sugiyama K, Mano J, Inoue Y, Kimura A. Thioredoxin deficiency causes the constitutive activation of Yap1, an AP-1-like transcription factor in Saccharomyces cerevisiae. J Biol Chem 1999; 274:28459-65. [PMID: 10497208 DOI: 10.1074/jbc.274.40.28459] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Yap1 is a transcription factor that responds to oxidative stress in Saccharomyces cerevisiae. The activity of Yap1 is regulated at the level of its intracellular localization, and a cysteine-rich domain at the C terminus of Yap1 is involved in this regulation. We investigated the effects of redox-regulatory proteins, thioredoxin and glutaredoxin, on the regulation of Yap1, using the deficient mutants of these thiol-disulfide oxidoreductases. In the thioredoxin-deficient mutant (trx1Delta/trx2Delta), Yap1 was constitutively concentrated in the nucleus and the level of expression of the Yap1 target genes was high under normal conditions, while this was not the case for the glutaredoxin-deficient mutant (grx1Delta/grx2Delta). No distinct difference was observed in the levels of Yap1 protein between the wild type and trx1Delta/trx2Delta. The constitutive activation of Yap1 in trxDelta/trx2Delta was observed under aerobic conditions but not under anaerobic conditions. These findings suggest that thioredoxin has negative effects on this regulation via the redox states. We also show the synthetic lethality between yap1Delta and trx1Delta/trx2Delta mutation, but the yap1Delta/grx1Delta/grx2Delta triple mutant was viable, suggesting a difference of the functions between thioredoxin and glutaredoxin and a genetic interaction between Yap1 and thioredoxin in vivo.
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Affiliation(s)
- S Izawa
- Department of Molecular Breeding of Microorganisms, Research Institute for Food Science, Kyoto University, Uji, Kyoto 611-0011, Japan
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26
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Izawa S. [Status of patients on antidepressants or tranquilizing agents for extended periods--results of a survey conducted by Kitasato University Hospital]. Nihon Shinkei Seishin Yakurigaku Zasshi 1999; 19:223-6. [PMID: 10637833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
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27
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Inoue Y, Matsuda T, Sugiyama K, Izawa S, Kimura A. Genetic analysis of glutathione peroxidase in oxidative stress response of Saccharomyces cerevisiae. J Biol Chem 1999; 274:27002-9. [PMID: 10480913 DOI: 10.1074/jbc.274.38.27002] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Three glutathione peroxidase homologs (YKL026C, YBR244W, and YIR037W/HYR1) were found in the Saccharomyces Genome Database. We named them GPX1, GPX2, and GPX3, respectively, and we investigated the function of each gene product. The gpx3Delta mutant was hypersensitive to peroxides, whereas null mutants of the GPX1 and GPX2 did not show any obvious phenotypes. Glutathione peroxidase activity decreased approximately 57 and 93% in the gpx3Delta and gpx1Delta/gpx2Delta/gpx3Delta mutants, respectively, compared with that of wild type. Expression of the GPX3 gene was not induced by any stresses tested, whereas that of the GPX1 gene was induced by glucose starvation. The GPX2 gene expression was induced by oxidative stress, which was dependent upon the Yap1p. The TSA1 (thiol-specific antioxidant) gene encodes thioredoxin peroxidase that can reduce peroxides by using thioredoxin as a reducing power. Disruption of the TSA1 gene enhanced the basal expression level of the Yap1p target genes such as GSH1, GLR1, and GPX2 and that resulted in increases of total glutathione level and activities of glutathione reductase and glutathione peroxidase. However, expression of the TSA1 gene did not increase in the gpx1Delta/gpx2Delta/gpx3Delta mutant. Therefore, de novo synthesis and recycling of glutathione were increased in the tsa1Delta mutant to maintain the catalytic cycle of glutathione peroxidase reaction efficiently as a backup system for thioredoxin peroxidase.
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Affiliation(s)
- Y Inoue
- Research Institute for Food Science, Kyoto University, Uji, Kyoto 611-0011, Japan.
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Kim Y, Kikuchi M, Akiyama S, Sho K, Izawa S. Morphology and coarsening behavior in Polycarbonate/Nylon6-co-12 blends with and without compatibilizer. POLYMER 1999. [DOI: 10.1016/s0032-3861(98)00756-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Izawa S, Maeda K, Miki T, Mano J, Inoue Y, Kimura A. Importance of glucose-6-phosphate dehydrogenase in the adaptive response to hydrogen peroxide in Saccharomyces cerevisiae. Biochem J 1998; 330 ( Pt 2):811-7. [PMID: 9480895 PMCID: PMC1219210 DOI: 10.1042/bj3300811] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Glucose-6-phosphate dehydrogenase (G6PDH)-deficient cells of Saccharomyces cerevisiae showed increased susceptibility and were unable to induce adaptation to oxidative stress. Historically, mainly in human erythrocytes, it has been suggested and accepted that decreased cellular GSH, due to loss of the NADPH-dependent activity of glutathione reductase (GR), is responsible for the increased sensitivity to oxidative stress in G6PDH-deficient cells. In the present study we investigated whether the increased susceptibility and the inability to induce adaptation to H2O2 stress of G6PDH-deficient yeast is caused by incompleteness of glutathione recycling. We constructed G6PDH- and GR-deficient mutants and analysed their adaptive response to H2O2 stress. Although G6PDH-deficient cells contained comparable amounts of GSH and GR activity to wild-type cells, GSSG was not reduced efficiently, and intracellular GSSG levels and the ratio of GSSG to total glutathione (GSSG/tGSH) were higher in G6PDH-deficient cells than in wild-type. On the other hand, GR-deficient cells showed a susceptibility identical with that of wild-type cells and induced adaptation to H2O2 stress, even though the GSSG/tGSH ratio in GR-deficient cells was higher than in G6PDH-deficient cells. These results indicate that incompleteness of glutathione recycling alone is not sufficient to account for the increased sensitivity and inability to induce adaptation to H2O2 stress of G6PDH-deficient yeast cells. In S. cerevisiae, G6PDH appears to play other important roles in the adaptive response to H2O2 stress besides supplying NADPH to the GR reaction.
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Affiliation(s)
- S Izawa
- Department of Molecular Breeding of Microorganisms, Research Institute for Food Science, Kyoto University, Uji, Kyoto 611-0011, Japan
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Inoue Y, Sugiyama K, Izawa S, Kimura A. Molecular identification of glutathione synthetase (GSH2) gene from Saccharomyces cerevisiae. Biochim Biophys Acta 1998; 1395:315-20. [PMID: 9512666 DOI: 10.1016/s0167-4781(97)00199-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The hypothetical protein YOL049w on the chromosome XV was identified to be the structural gene for glutathione synthetase (GSH2) of Saccharomyces cerevisiae. Translational initiation site was identified by making the GSH2-lacZ fusion. The GSH2 gene contained an open reading frame (1473 bp) with 491 amino acids, and molecular weight of the GSH2 gene product was calculated to be 55,812. Glutathione synthetase activity in transformant carrying the GSH2 gene with multicopy plasmid increased approximately 4-fold. The GSH2 gene was not essential for growth of yeast cell, and glutathione was not detected from the gsh2 disrupter.
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Affiliation(s)
- Y Inoue
- Research Institute for Food Science, Kyoto University, Japan.
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31
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Izawa S, Inoue Y, Kimura A. Importance of catalase in the adaptive response to hydrogen peroxide: analysis of acatalasaemic Saccharomyces cerevisiae. Biochem J 1996; 320 ( Pt 1):61-7. [PMID: 8947468 PMCID: PMC1217898 DOI: 10.1042/bj3200061] [Citation(s) in RCA: 156] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Controversy about the importance of catalase in the detoxification of H2O2 in human erythrocytes continues. It has been suggested that catalase has no role in the clearance of H2O2 in erythrocytes. In the present study we investigated the role of catalase in the defence mechanism against oxidative stress using Saccharomyces cerevisiae. S. cerevisiae has two catalases, catalase A and catalase T. We constructed a double mutant (acatalasaemic mutant) unable to produce either catalase A or catalase T, and compared it with wild-type and single-mutant cells. The acatalasaemic mutant cells showed a similar growth rate to wild-type cells under non-oxidative stress conditions, and showed a similar susceptibility to H2O2 stress in the exponential growth phase. The acatalasaemic mutant cells at stationary phase were, however, much more sensitive to H2O2 stress than wild-type and single-mutant cells. Moreover, the ability of acatalasaemic and single-mutant cells to show adaptation to 2 mM H2O2 was distinctly inferior to that of wild-type cells. These results suggest that catalase is not essential for yeast cells under normal conditions, but plays an important role in the acquisition of tolerance to oxidative stress in the adaptive response of these cells.
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Affiliation(s)
- S Izawa
- Laboratory of Molecular Breeding of Microorganisms, Kyoto University, Japan
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32
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Inoue Y, Sugiyama K, Ueminami H, Izawa S, Kimura A. Modification of Escherichia coli B glutathione synthetase with polyethylene glycol for clinical application to enzyme replacement therapy for glutathione deficiency. Clin Diagn Lab Immunol 1996; 3:663-8. [PMID: 8914756 PMCID: PMC170428 DOI: 10.1128/cdli.3.6.663-668.1996] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Glutathione synthetase of Escherichia coli B was modified with polyethylene glycol, and the properties of the resultant modified enzyme were investigated. The thermal stability of the modified enzyme and its resistance against several proteases increased compared with those of the native enzyme. The modified enzyme was injected intravenously via the rat tail vein, and the circulating life of the enzyme in plasma was monitored. The half-life of the native enzyme was 50 min, whereas that of the modified enzyme was approximately 24 h. The systemic anaphylaxis reaction was tested by using rats intravenously injected with the native and modified enzymes. For the native enzyme, strong reactions such as dyspnea and tumble were observed; however, no symptom or only a very weak reaction, such as scratching, was observed with the modified enzyme.
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Affiliation(s)
- Y Inoue
- Research Institute for Food Science, Kyoto University, Japan
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33
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Miki T, Tsujimoto Y, Miyabe S, Sugiyama K, Izawa S, Inoue Y, Kimura A. Oxidative stress response in yeast: purification and characterization of glutathione reductase from Hansenula mrakii. Biosci Biotechnol Biochem 1996; 60:1207-9. [PMID: 8782419 DOI: 10.1271/bbb.60.1207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Glutathione reductase was purified from a yeast. Hansenula mrakii IFO 0895, to approximately 3500-fold with 59% activity yield. The enzyme was homogeneous on polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated to be 56 kDa by SDS-polyacrylamide gel electrophoresis, and 123 kDa by gel filtration using a calibrated Sephadex G-150 column. The Km values for glutathione disulfide and NADPH were 21.3 microM and 14.3 microM, respectively. The enzyme was most active at pH 7.5, 55 degrees C. The enzyme was stable up to 40 degrees C, and between pHs 4 and 10. The enzyme was inhibited by p-chloromercuribenzoate and metal ions such as Fe3+, Cd2+, Cu2+, and Zn2+.
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Affiliation(s)
- T Miki
- Research Institute for Food Science, Kyoto University, Japan
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34
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Kobayashi S, Miyabe S, Izawa S, Inoue Y, Kimura A. Correlation of the OSR/ZRCI gene product and the intracellular glutathione levels in Saccharomyces cerevisiae. Biotechnol Appl Biochem 1996; 23:3-6. [PMID: 8867889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The OSR (oxidative-stress-resistance) gene was cloned as the gene which enhances resistance against oxidative stress caused by lipid hydroperoxide in Saccharomyces cerevisiae. The nucleotide sequence of the gene was determined and found to be identical with the zinc-resistance-conferring (ZRCI) gene, which was cloned as the gene enhancing the resistance against zinc and cadmium. A knockout mutant of the OSR gene showed increased sensitivity to lipid hydroperoxide. The intracellular glutathione content in the knockout mutant decreased approx. 40% compared with that of wild-type cells, whereas it increased 3-fold in yeast overexpressing the OSR gene. Therefore the OSR/ZRCI gene product seems to regulate the intracellular glutathione content.
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Affiliation(s)
- S Kobayashi
- Research Institute for Food Science, Kyoto University, Japan
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Inoue Y, Tran LT, Kamakura M, Izawa S, Miki T, Tsujimoto Y, Kimura A. Oxidative stress response in yeast: glutathione peroxidase of Hansenula mrakii is bound to the membrane of both mitochondria and cytoplasm. Biochim Biophys Acta 1995; 1245:325-30. [PMID: 8541308 DOI: 10.1016/0304-4165(95)00117-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The yeast Hansenula mrakii IFO 0895 induces glutathione peroxidase (GPx) when the cells are exposed to the oxidative stress such as lipid hydroperoxide, superoxide- and hydroxy radical-generating conditions. To clarify the localization of GPx in H. mrakii cell, distribution of the enzyme was investigated. After centrifugation of the yeast protoplast homogenates at 2500 x g for 10 min, 67% of total GPx activity was recovered from the supernatant (Sup. 1) and 33% was from the pellet (Pellet 1). When the Sup. 1 was fractionated by sucrose density gradient ultracentrifugation, GPx activity was essentially recovered from the mitochondria fraction. Submitochondrial localization of the enzyme showed that 95% and 2.5% of the enzyme was recovered from the inner and outer membrane, respectively. No GPx activity was detected neither in intermembrane space nor in matrix of mitochondria. On the other hand, at least 12% of total GPx activity was recovered from the purified plasma membrane which was obtained from the Pellet 1 by successive sucrose density gradient centrifugation. Thus, the GPx of H. mrakii is present in the inner and outer membrane of mitochondria as well as the plasma membrane.
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Affiliation(s)
- Y Inoue
- Research Institute for Food Science, Kyoto University, Japan
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Takehara M, Ling F, Izawa S, Inoue Y, Kimura A. Molecular cloning and nucleotide sequence of purine nucleoside phosphorylase and uridine phosphorylase genes from Klebsiella sp. Biosci Biotechnol Biochem 1995; 59:1987-90. [PMID: 8534998 DOI: 10.1271/bbb.59.1987] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Klebsiella sp. LF 1202 was isolated as a bacterium that can assimilate adenosine as a sole source of carbon and nitrogen [F. Ling et al., Agric. Biol. Chem., 55, 573-575 (1991)] from a soil sample. Both the purine nucleoside phosphorylase (PNPase) and uridine phosphorylase (UPase) of this bacterium were induced simultaneously when the bacterium was cultured in a medium containing adenosine or uridine as a sole source of carbon and nitrogen. This induction profile is different from that of Escherichia coli. Here we cloned and sequenced the gene corresponding to each enzyme. The open reading frame (ORF) of the PNPase gene consisted of 717 bp that encoded a polypeptide of 239 amino acids with a molecular weight of 26,198. The ORF of the UPase gene consisted of 834 bp that encoded a polypeptide of 278 amino acids with a molecular weight of 28,912.
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Affiliation(s)
- M Takehara
- Research Institute for Food Science, Kyoto University, Japan
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Izawa S, Inoue Y, Kimura A. Oxidative stress response in yeast: effect of glutathione on adaptation to hydrogen peroxide stress in Saccharomyces cerevisiae. FEBS Lett 1995; 368:73-6. [PMID: 7615092 DOI: 10.1016/0014-5793(95)00603-7] [Citation(s) in RCA: 171] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Role of intracellular glutathione in the response of Saccharomyces cerevisiae to H2O2 was investigated. Depletion of cellular glutathione or inhibition of gamma-glutamylcysteine synthetase (GSH-I) enhanced the sensitivity to H2O2 and suppressed the adaptation to H2O2. A mutant deficient in GSH-I also showed the hypersensitivity and could not adapt to H2O2. Incubation of the cell with amino acids constituting glutathione (L-Glu, L-Cys, Gly) increased the intracellular glutathione content, and subsequently the cell acquired resistance against H2O2. These results strongly suggest that intracellular glutathione plays an important role in the adaptive response in S. cerevisiae to oxidative damage.
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Affiliation(s)
- S Izawa
- Research Institute for Food Science, Kyoto University, Japan
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Abstract
Regulation of the activity of neuraminidase of Streptococcus sp. (group K) was evaluated by examining the effects of alcohols on the hydrolysis of colominic acids catalyzed by the neuraminidase. Two kinds of alcohol binding site, activation and inhibition sites, were proposed to exist. Competitive inhibition was observed with alcohols smaller than polyethylene glycol #300 (average molecular weight: 300), so the inhibition site is considered to be the substrate binding site, the size of which was estimated to be 10 A in diameter. On the contrary, polyethylene glycols larger than this size activated the enzyme by 1.5-1.8 times. The activity could be raised by binding of the polyethylene glycols to the activation site. This activation was shown to be due solely to the decrease in the Michaelis constant, Km. The smaller polyethylene glycols (#200 and #300) were also considered to bind to the activation site, although activation was not clearly observed due to compensation with inhibition. Strong substrate inhibition by colominic acid was also observed. The activity of Streptococcus neuraminidase was shown to be regulated intricately by the substrate colominic acid and alcohols contained in the reaction medium.
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Affiliation(s)
- K Inouye
- Department of Food Science and Technology, Faculty of Agriculture, Kyoto University
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Endo A, Kikuchi M, Izawa S, Ikezawa Y. Characteristics of the chemical forms of 11C, 13N, and 15O induced in air by the operation of a 100 MeV electron linear accelerator. Health Phys 1995; 68:80-88. [PMID: 7989199 DOI: 10.1097/00004032-199501000-00010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To characterize airborne radioactivity induced by the operation of high-energy accelerators, the fractions of aerosol and gaseous components, and the chemical forms of 11C, 13N, and 15O produced in the air of a target room of a 100 MeV electron linear accelerator were studied. Measurements of radioactivity using a particulate air sampling filter and a gas flow-through ionization chamber showed that more than 98% of 11C, 13N, and 15O were present as gaseous forms. Their chemical forms, detected by means of radio-gas chromatography, were 11C as CO2; 13N as N2 and NO; and 15O as O2 and NO. Machine operating conditions, which affect the compositions of the induced radionuclides and of their chemical forms, and the resulting effect on the estimation of internal doses are discussed.
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Affiliation(s)
- A Endo
- Department of Health Physics, Japan Atomic Energy Research Institute, Ibaraki-ken
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Ogawa W, Izawa S, Sakai-Tomita Y, Moritani C, Tsuda M, Kinomura K, Kitazawa S, Tsuchiya T. F0F1-ATPase of Vibrio parahaemolyticus: purification using new detergents and characterization. Biochim Biophys Acta 1994; 1188:69-74. [PMID: 7947906 DOI: 10.1016/0005-2728(94)90023-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Previous attempts to isolate a stable F0F1-ATPase complex (H(+)-translocating ATPase) from Vibrio parahaemolyticus have been unsuccessful. Using new non-ionic detergents (alkyl thiomaltosides), a stable F0F1 complex with a high specific activity (15-25 units/mg protein) was purified and characterized. The purified F0F1-ATPase consists of eight subunits (alpha, beta, gamma, delta, epsilon, a, b and c). The new detergents, in combination with sucrose (or glycerol), lipid, dithiothreitol and phenylmethylsulfonyl fluoride, effectively stabilized the F0F1 complex. The ATPase activity of the F0F1 complex was greatly increased by anions, such as SO4(2-) and SO3(2-). Sodium ion increased the activity by about 2-fold. Dicyclohexylcarbodiimide, Zn2+, 4-acetamido-4'-isothiocyanostilben-2,2'disulfonate and tetrachlorosalicylanilide inhibited F0F1-ATPase activity. Ethanol, which stimulated F1-ATPase activity, inhibited F0F1-ATPase activity. Methanol, Na3VO4 and bafilomycin A1 did not have any significant effect on F0F1-ATPase activity, although methanol, like ethanol, stimulated F1-ATPase activity.
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Affiliation(s)
- W Ogawa
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University, Japan
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Izawa S, Sakai-Tomita Y, Kinomura K, Kitazawa S, Tsuda M, Tsuchiya T. Introduction of a series of alkyl thiomaltosides, useful new non-ionic detergents, to membrane biochemistry. J Biochem 1993; 113:573-6. [PMID: 8340350 DOI: 10.1093/oxfordjournals.jbchem.a124085] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We synthesized a series of non-ionic detergents, alkyl thiomaltosides, and investigated their properties and usefulness. We solubilized membrane proteins of Vibrio parahaemolyticus using the detergents. With octyl thiomaltoside, nonyl thiomaltoside, decyl thiomaltoside, or undecyl thiomaltoside, we observed satisfactory solubilization of the membrane proteins. Alkyl thiomaltosides possessing longer alkyl chains showed better solubilization than ones possessing shorter chains. H(+)-translocating ATPase (F0F1), which is localized in the cytoplasmic membrane (inner membrane), was solubilized with the detergents, and the solubilized enzyme showed much higher specific activity than that solubilized with octyl glucoside or heptyl thioglucoside, other useful non-ionic detergents. 5'-Nucleotidase, which seems to be an outer membrane protein, was also efficiently solubilized with the alkyl thiomaltosides. Membrane proteins of Escherichia coli were also efficiently solubilized with the detergents. Octyl thiomaltoside and nonyl thiomaltoside were removed fairly rapidly on dialysis. Decyl thiomaltoside was removed slowly, and undecyl thiomaltoside and dodecyl thiomaltoside were difficult to remove by dialysis.
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Affiliation(s)
- S Izawa
- Department of Microbiology, Faculty of Pharmaceutical Sciences, Okayama University
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Ono T, Izawa S, Inoue Y. Structural and functional modulation of the manganese cluster in Ca(2+)-depleted photosystem II induced by binding of the 24-kilodalton extrinsic protein. Biochemistry 1992; 31:7648-55. [PMID: 1510950 DOI: 10.1021/bi00148a028] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Depletion of functional Ca2+ from photosystem (PS) II membranes impairs O2 evolution. Redox properties of the Mn cluster as probed by thermoluminescence were modified differently in Ca(2+)-depleted PSII depending on the procedure for Ca2+ extraction. Ca2+ depletion by low-pH treatment gave rise to an abnormally modified S2 state exhibiting a thermoluminescence band with elevated peak temperature accompanied by a marked upshift in threshold temperature for its formation, whereas Ca2+ depletion by NaCl washing in the light followed by the addition of EDTA could generate a similarly modified S2 state only when the Ca(2+)-depleted PSII was reconstituted with the 24-kDa extrinsic proteins. These results indicated that manifestation of the abnormal properties of the Ca(2+)-depleted S2 state is significantly contributed by the association of the 24-kDa extrinsic protein to PSII. It was inferred that the 24-kDa extrinsic protein regulates the structure and function of the Mn cluster in the absence of functional Ca2+ through a conformational modulation of the intrinsic protein(s) that bind(s) both Mn and Ca. Features of the extrinsic protein-dependent modulation of the Mn cluster were discussed in relation to the function of Ca2+ in O2 evolution.
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Affiliation(s)
- T Ono
- Solar Energy Research Group, Institute of Physical and Chemical Research (RIKEN), Saitama, Japan
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Kumazawa S, Izawa S, Mitsui A. Proton efflux coupled to dark H2 oxidation in whole cells of a marine sulfur photosynthetic bacterium (Chromatium sp. strain Miami PBS1071). J Bacteriol 1983; 154:185-91. [PMID: 6833176 PMCID: PMC217446 DOI: 10.1128/jb.154.1.185-191.1983] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Whole cells of photoanaerobically grown Chromatium sp. strain Miami PBS1071, a marine sulfur purple bacterium, oxidized H2 in the dark through the oxyhydrogen reaction at rates of up to 59 nmol of H2 per mg (dry weight) per min. H2 oxidation was routinely measured in H2 pulse experiments with air-equilibrated cells. The reaction was accompanied by a reversible H+ efflux from the cells, suggesting an outward H+ translocation reaction coupled to H2 oxidation. The H+/e- ratio, calculated from simultaneous measurements of H2, O2, and H+ changes in the medium, varied with the cultures from 0.7 to 1.2. The ratio increased considerably when the backflow of H+ was taken into account. Anaerobic H2 uptake with 2,5-dimethyl-p-benzoguinone as an oxidant also showed a weak H+-translocating activity. No H+-translocating activity was detected with methylene blue as an oxidant. Carbonylcyanide 3-chlorophenylhydrazone (1 microM) stimulated H2 oxidation and abolished the associated H+ changes when H2 oxidation was observed in O2 pulse experiments with H2-Ar-equilibrated cells. However, the uncoupler inhibited both H2 oxidation and H+ changes when measurements were made in H2 pulse experiments with air-equilibrated cells. It is suggested that in this bacterium the susceptibility of hydrogenase to reversible O2 inactivation in situ is enhanced by the presence of uncoupling agents.
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Furuse M, Saso K, Moteki Y, Inao S, Asai H, Izawa S, Kasai A. Proton density images and in vivo measurements of relaxation time in the human brains. Comparison of values in healthy volunteer and cerebrovascular disease. Magn Reson Imaging 1982. [DOI: 10.1016/0730-725x(82)90180-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Taguchi Y, Tanimura S, Sasaki T, Miura K, Kaneda I, Jimbo M, Satomi S, Nakano Y, Miyata Y, Kunori T, Tan M, Tsutsumi E, Kasai M, Yamagishi A, Izawa S, Takyu C, Inaba F. [Research and construction on automated biological cell sorting system and its clinical application (author's transl)]. Rinsho Byori 1980; 28:843-50. [PMID: 7253284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Abstract
Isolated maize bundle sheath chloroplasts showed substantial rates of noncyclic photophosphorylation. A typical rate of phosphorylation coupled to whole-chain electron transport (methylviologen or ferricyanide as acceptor) was 60 mumol per hour per milligram chlorophyll) with a coupling efficiency (P/e(2)) of 0.6. Partial electron transport reactions driven by photosystem I or II supported phosphorylation with P/e(2) values of 0.2 to 0.3. Thus, two sites of phosphorylation seem to be associated with the photosynthetic chain in much the same way as in spinach chloroplasts.Isolated bundle sheath cells were capable of photosynthetic electron transport with membrane permeant electron carriers (but not with ferricyanide) at rates which were similar to those found in isolated chloroplasts. ATP formation also occurred during electron transport when ADP and phosphate were present in the cell suspension. The rates of photophosphorylation reactions in cells were about 30 to 40% of those found in isolated chloroplasts (maximum rate in cells 80 mumoles ATP per hour per milligram chlorophyll with diaminodurene as electron carrier), with the exception of endogenous photophosphorylation (photophosphorylation without added electron carriers) whose rate was three to four times higher in cells than in chloroplasts. The endogenous photophosphorylation in cells appeared to be coupled to pseudo-cyclic, rather than cyclic, electron transport. It was accompanied by O(2) uptake (when the catalase inhibitor KCN was present), was sensitive to dichlorophenyldimethylurea and methylamine, but was totally insensitive to 20 micromolar antimycin which completely inhibited succinate-supported oxidative phosphorylation in the cells. The implications of these and other phenomena associated with photophosphorylation in bundle sheath cells are discussed.
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Affiliation(s)
- G H Walker
- Department of Biology, Wayne State University, Detroit, Michigan 48202
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Abstract
NH2OH-treated, non-water-splitting chloroplasts can oxidize H2O2 to O2 through Photosystem II at substantial rates (100--250 muequiv . h-1 . mg-1 chlorophyll with 5 mM H2O2) using 2,5-dimethyl-p-benzoquinone as an electron acceptor in the presence of the plastoquinone antagonist dibromothymoquinone. This H2O2 leads to Photosystem II leads to dimethylquinone reaction supports phosphorylation with a P/e2 ratio of 0.25--0.35 and proton uptake with H+/e values of 0.67 (pH 8)--0.85 (pH 6). These are close to the P/e2 value of 0.3--0.38 and the H+/e values of 0.7--0.93 found in parallel experiments for the H2O leads to Photosystem II leads to dimethylquinone reaction in untreated chloroplasts. Semi-quantitative data are also presented which show that the donor leads to Photosystem II leads to dibromothymoquinone (leads to O2) reaction can support phosphorylation when the donor used is a proton-releasing reductant (benzidine, catechol) but not when it is a non-proton carrier (I-, ferrocyanide).
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Abstract
Fragments of bundle sheath strands, free of mesophyll cells and showing a chlorophyll a/b ratio of 6.0 to 6.6 were prepared from Zea mays by a mechanical method. They were unable to photoreduce ferricyanide but were able to photoreduce the membrane-permeant 2,5-dimethylquinone at a rate of 250 to 420 microequivalents per hour per mg chlorophyll (mueq/hr . mg Chl) at 21 C. In the presence of the catalase inhibitor KCN, methylviologen catalyzed a Mehler reaction at a rate of 120 to 180 mueq/hr . mg Chl. This was increased to 200 to 350 mueq/hr . mg Chl when the uncoupler methylamine was added. The rate of endogenous pseudocyclic electron flow, detected as a Mehler reaction, was also considerable (100 to 150 mueq/hr . mg Chl with methylamine). Diaminodurene supported a high rate of photosystem I-mediated electron flow to methylviologen (400 to 750 mueq/hr . mg Chl).When the tissue fragments were illuminated in a weakly buffered suspension, a reversible rise in the medium pH was observed which apparently originated from H(+) translocation in the thylakoids. The kinetics of the pH changes was rather slow (t((1/2)) > 15 seconds for pH rise; > 30 seconds for dark decay) but the extent of H(+) uptake was substantial (0.1 to 0.3 mueq/mg Chl). All of the electron transport reactions tested, including partial reactions which involve only photosystem I or photosystem II, invariably supported H(+) uptake. This suggests that two sites of energy conservation are associated with the photosynthetic chain in the bundle sheath chloroplasts (as in spinach chloroplasts) and that both of these sites are functional in vivo. The pH changes observed in the absence of exogenous electron carriers were abolished by 3-(3,4-dichlorophenyl)-1,1-dimethylurea or by anaerobiosis, indicating that the underlying endogenous electron transport was strictly a pseudocyclic reaction. There was no evidence of endogenous cyclic electron flow which might contribute to the energy metabolism of the bundle sheath cells.
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Affiliation(s)
- G H Walker
- Department of Biology, Wayne State University, Detroit, Michigan 48202
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Izawa S, Pan RL. Photosystem I electron transport and phosphorylation supported by electron donation to the plastoquinone region. Biochem Biophys Res Commun 1978; 83:1171-7. [PMID: 708431 DOI: 10.1016/0006-291x(78)91518-8] [Citation(s) in RCA: 84] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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