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Ji Y, Ma BJ, Guo XQ, Dong HP, Ma K. [Discussion on the composition and implementation of diagnosis and treatment strategies for whole field pain management strategy]. Zhonghua Yi Xue Za Zhi 2023; 103:3083-3087. [PMID: 37840179 DOI: 10.3760/cma.j.cn112137-20230704-01135] [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: 10/17/2023]
Abstract
Pain is the fifth major vital sign, and chronic pain is a large category of diseases that affects health seriously. At present, the incidence of chronic pain is high, but the overall treatment satisfaction is low. It is necessary to continuously optimize pain diagnosis and treatment strategies and improve the connotation of pain management. Based on the clinical practice of our pain center, combined with relevant literature, the article proposes a diagnosis and treatment strategy of "whole field pain management" should be carried out from the four dimensions of feeling, emotion, cognition, and behavior. Innovative digital pain diagnosis and treatment technologies such as VR/MR and brain-computer interface are used to regulate emotional, cognitive, and behavioral regulation, and combined with lifestyle changes, rehabilitation physiotherapy, drugs, and minimally invasive interventional therapy to constitute a " whole field pain management strategy" to explore the new development direction of further improving the management of chronic pain.
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Affiliation(s)
- Y Ji
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200090, China
| | - B J Ma
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200090, China
| | - X Q Guo
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200090, China
| | - H P Dong
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200090, China
| | - K Ma
- Department of Pain Management, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200090, China
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Cao F, Lyu X, Dong KF, Fan C, Zhang JJ, Chen K, Zhang Y, Ma BJ, Hou CL, Zhang CH. [AMG-102 inhibits proliferation and induces apoptosis of laryngeal squamous cell carcinoma cells by regulating c-Met/PI3K/Akt pathway]. Zhonghua Zhong Liu Za Zhi 2020; 42:99-104. [PMID: 32135642 DOI: 10.3760/cma.j.issn.0253-3766.2020.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To investigate the effects of c-Met inhibitor AMG-102 on the proliferation and apoptosis of laryngeal squamous carcinoma Hep-2 cells and the underlying mechanism. Methods: Laryngeal squamous carcinoma cell line Hep-2 cells were treated with 2.5, 5 and 10 μmol/L AMG-102, respectively. The proliferation activities of Hep-2 cells were detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT). The apoptotic rate of Hep-2 cells was detected by flow cytometry analysis and Hoechst staining. The mRNA expression levels of apoptosis-related genes were detected by real-time quantitative polymerase Chain reaction (RT-qPCR), and the protein expressions of c-Met/PI3K/AKT pathway were detected by western blot. Results: Compared with the control group, the proliferation rates of Hep-2 cells treated with 2.5, 5 and 10 μmol/L AMG-102 for 24 hours were (89.8±1.1)%, (79.8±1.0)% and (69.1±1.2)%, respectively; for 48 hours were (76.8±2.0)%, (60.2±1.1)% and (49.8±1.2)%, respectively; for 72 hours were (50.1±2.0)%, (41.5±1.1)% and (33.6±1.0), respectively, with significant differences (all P<0.05). The apoptotic rates of Hep-2 cells treated with 2.5, 5 and 10 μmol/L AMG-102 for 48 hours were (16.09±1.53)%, (27.51±2.02)% and (36.57±1.42)%, respectively, which were significantly higher than (3.62±0.10) % in the control group (all P<0.05). After treated with 2.5, 5 and 10 μmol/L AMG-102 for 48 hours, the relative expression levels of Bcl-2 mRNA in Hep-2 cells were 0.58±0.13, 0.38±0.12 and 0.20±0.13, respectively; the relative protein expression of p-Met were 80.0±3.8, 50.6±4.2 and 28.5±1.3, respectively; the relative protein expression of p-PI3K were 87.1±0.9, 54.2±1.2 and 21.0±1.2, respectively; the relative protein expression of p-AKT were 98.7±5.6, 56.9±3.2 and 32.2±4.3, respectively; which were significantly lower than those in the control group (all P<0.05). The relative expression levels of Bax mRNA were 1.78±0.13, 2.37±0.14 and 3.05±0.13, respectively, and the relative expression levels of caspase-3 mRNA were 1.98±0.14, 2.47±0.14 and 3.15±0.13, respectively, which were significantly higher than those in the control group (all P<0.05). Conclusion: c-Met inhibitor AMG-102 could inhibit the proliferation and induce apoptosis of laryngeal squamous carcinoma Hep-2 cells by regulating the c-Met/PI3K/Akt pathway.
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Affiliation(s)
- F Cao
- Department of Radiation Oncology, the Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, China
| | - X Lyu
- Medical Department, Central Hospital of Baixiang County, Xingtai 055450, China
| | - K F Dong
- Department of Otolaryngology, the First Hospital of Hebei Medical University, Shijiazhuang 050031, China
| | - C Fan
- Department of Radiation Oncology, the 980th Hospital of PLA Joint Logistics Support Force, Shijiazhuang 050082, China
| | - J J Zhang
- Department of Radiation Oncology, the 980th Hospital of PLA Joint Logistics Support Force, Shijiazhuang 050082, China
| | - K Chen
- Department of Otolaryngology Head and Neck Surgery, the 980th Hospital of PLA Joint Logistics Support Force, Shijiazhuang 050082, China
| | - Y Zhang
- Department of Radiation Oncology, the 980th Hospital of PLA Joint Logistics Support Force, Shijiazhuang 050082, China
| | - B J Ma
- Department of Radiation Oncology, the 980th Hospital of PLA Joint Logistics Support Force, Shijiazhuang 050082, China
| | - C L Hou
- Department of Oncology, the 980th Hospital of PLA Joint Logistics Support Force, Shijiazhuang 050082, China
| | - C H Zhang
- Department of Radiation Oncology, the 980th Hospital of PLA Joint Logistics Support Force, Shijiazhuang 050082, China
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Cao F, Lyu X, Dong KF, Fan C, Zhang JJ, Chen K, Ma BJ, Hou CL, Zhang CH. [Effect of c-Met inhibitor AMG-102 on radiosensitivity in laryngeal squamous carcinoma cells]. Zhonghua Zhong Liu Za Zhi 2020; 41:909-917. [PMID: 31874548 DOI: 10.3760/cma.j.issn.0253-3766.2019.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To investigate the effect of c-Met inhibitor AMG-102 on proliferation and radiosensitivity in laryngeal squamous carcinoma cells. Methods: The effects of AMG-102 on proliferation and radiosensitivity of laryngeal squamous carcinoma cell lines Hep-2 and KBV200 were detected by 3-(4, 5-dimethy-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assay and colony formation assay, respectively. The apoptosis of Hep-2 and KBV200 cells was detected by flow cytometry. The expression levels of c-Met, phospho-Met (p-Met), cleaved caspase-3 and Akt/p-Akt, Erk/p-Erk were detected by Western blot. Specific small interfering RNA targeting c-Met or plasmid of c-Met were transfected into Hep-2 and KBV200 cells to investigate the cell sensitivity to AMG-102. Results: Compared with KBV200 cells, Hep-2 cells were more sensitive to AMG-102 with IC(50) of 14 and 9 μmol/L, respectively. The relative expression levels of c-Met and p-Met proteins in Hep-2 cells were 194.48±0.57 and 177.76±1.53, respectively, which were significantly higher than those in KBV200 cells (171.24±1.00 and 115.37±0.56, respectively, P<0.001 for both). Exogenous hepatocyte growth factor (HGF) was added to increase the expression level of p-Met protein in KBV200 cells. The results showed that AMG-102 significantly reduced the expression of p-Met in KBV200 cells treated with HGF (P<0.001). Compared with the dimethyl sulfoxide (DMSO) group, AMG-102 treatment combined with radiotherapy significantly increased the radiosensitivity of Hep-2 cells (SER=1.28, P<0.001). However, AMG-102 had little effect on the radiosensitivity of KBV200 cells (SER=1.18, P=0.002). Compared with the 4 Gy radiotherapy alone group and the 5 μmol/L of AMG-102 alone treatment group, the apoptosis rate of Hep-2 cells in the combined treatment group was significantly increased. Meanwhile, the expression level of cleaved caspase-3 protein was also markedly increased. However, there were no significant changes in the apoptotic rate and cleaved caspase-3 expression in each treatment group of KBV200 cells. Compared with DMSO treatment group, the expression levels of p-Met, p-Akt and p-Erk were significantly decreased in the 4 Gy radiotherapy group, 5 μmol/L of AMG-102 treatment group and combined treatment group of Hep-2 cells. And the levels of p-Met, p-Akt and p-Erk in the combined treatment group were significantly lower than those in the 4 Gy radiotherapy alone group and 5 μmol/L of AMG-102 treatment alone group. By contrast, in KBV200 cells, the expression of p-Met, p-Akt and p-Erk in each group was not changed. The relative expression of p-Met in Hep-2 cells before and after radiotherapy at 30 min, 1 h, 4 h, 8 h, 24 h were 99.89±0.61, 138.62±1.00, 163.07±5.00, 87.80±1.85, 90.67±0.65 and 94.09±1.41, respectively. The level of p-Met was slightly increased after radiotherapy at 30 min and 1 h (P<0.001 for all), whereas it was significantly decreased from 4 h to 24 h after radiotherapy (P<0.05 for all). By contrast, the expression of p-Met in KBV200 cells did not change with time after radiotherapy (P>0.05). The sensitivity of Hep-2 cells to AMG-102 was decreased after silencing of c-Met, while the sensitivity of KBV200 cells to AMG-102 was not significantly changed (P>0.05). Moreover, the radiosensitivity of Hep-2 cells in c-Met knockdown group had a slightly increasing trend (SER=1.07, P=0.068). After the treatment with 10 μmol/L of AMG-102, the proliferation rate of c-Met ectopically expressed KBV200 cells was 60.05%±3.23%, It was significantly lower than that of the blank control 90.08%±1.04% and siRNA negative control (90.12%±1.01%, P<0.001). The results suggested that the overexpression of c-Met in KBV200 cells increased the radiosensitivity to AMG-102, whereas depletion of c-Met resulted in resistance to AMG-102 in Hep-2 cells. Furthermore, the radiosensitivity of KBV200 cells that overexpressed c-Met showed a decreased trend (SER=0.7, P=0.005). Conclusions: c-Met inhibitor AMG-102 has a significant inhibitory effect on the proliferation of c-Met overexpressing laryngeal squamous carcinoma cells, leading to increased radiosensitivity. It suggests that molecular targeted therapy against c-Met receptor is more effective in c-Met overexpressed subtype of laryngeal squamous cell carcinoma.
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Affiliation(s)
- F Cao
- Department of Radiation Oncology, the Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, China
| | - X Lyu
- Department of Medical Services, the Central Hospital of Baixiang County, Xingtai 055450, China
| | - K F Dong
- Department of Otolaryngology, the First Hospital of Hebei Medical University, Shijiazhuang 050031, China
| | - C Fan
- Department of Radiation Oncology, the 980th Hospital of the Joint Logistic Support Unit of the People's Liberation Army of China, Shijiazhuang 050082, China
| | - J J Zhang
- Department of Radiation Oncology, the 980th Hospital of the Joint Logistic Support Unit of the People's Liberation Army of China, Shijiazhuang 050082, China
| | - K Chen
- Department of Otolaryngology Head and Neck Surgery, the 980th Hospital of the Joint Logistic Support Unit of the People's Liberation Army of China, Shijiazhuang 050082, China
| | - B J Ma
- Department of Radiation Oncology, the 980th Hospital of the Joint Logistic Support Unit of the People's Liberation Army of China, Shijiazhuang 050082, China
| | - C L Hou
- Department of Oncology, the 980th Hospital of the Joint Logistic Support Unit of the People's Liberation Army of China, Shijiazhuang 050082, China
| | - C H Zhang
- Department of Radiation Oncology, the 980th Hospital of the Joint Logistic Support Unit of the People's Liberation Army of China, Shijiazhuang 050082, China
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Wang YF, Wu M, Ma BJ, Cai DA, Yin BB. Role of high mobility group box-1 and protection of growth hormone and somatostatin in severe acute pancreatitis. ACTA ACUST UNITED AC 2014; 47:1075-84. [PMID: 25387675 PMCID: PMC4244674 DOI: 10.1590/1414-431x20143165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 05/27/2014] [Indexed: 01/24/2023]
Abstract
In this study, we investigated the potential role of high-mobility group box 1
(HMGB1) in severe acute pancreatitis (SAP) and the effects of growth hormone (G) and
somatostatin (S) in SAP rats. The rats were randomly divided into 6 groups of 20
each: sham-operated, SAP, SAP+saline, SAP+G, SAP+S and SAP+G+S. Ileum and pancreas
tissues of rats in each group were evaluated histologically. HMGB1 mRNA expression
was measured by reverse transcription-PCR. Levels of circulating TNF-α, IL-1, IL-6,
and endotoxin were also measured. In the SAP group, interstitial congestion and
edema, inflammatory cell infiltration, and interstitial hemorrhage occurred in ileum
and pancreas tissues. The levels of HMGB1, TNF-α, IL-1, IL-6 and endotoxin were
significantly up-regulated in the SAP group compared with those in the sham-operated
group, and the 7-day survival rate was 0%. In the SAP+G and SAP+S groups, the
inflammatory response of the morphological structures was alleviated, the levels of
HMGB1, TNF-α, IL-1, IL-6, and endotoxin were significantly decreased compared with
those in the SAP group, and the survival rate was increased. Moreover, in the SAP+G+S
group, all histological scores were significantly improved and the survival rate was
significantly higher compared with the SAP group. In conclusion, HMGB1 might
participate in pancreas and ileum injury in SAP. Growth hormone and somatostatin
might play a therapeutic role in the inflammatory response of SAP.
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Affiliation(s)
- Y F Wang
- Department of Surgery, Huashan Hospital, Fudan University, Shanghai, China
| | - M Wu
- Department of Surgery, Jinshan Pavilion Forest Hospital, Shanghai, China
| | - B J Ma
- Department of Surgery, Huashan Hospital, Fudan University, Shanghai, China
| | - D A Cai
- Department of Surgery, Huashan Hospital, Fudan University, Shanghai, China
| | - B B Yin
- Department of Surgery, Huashan Hospital, Fudan University, Shanghai, China
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Abstract
Biotransformation of grandiflorenic acid by permeabilised fungus Fusarium graminearum to yield its hydroxylation derivative, 12α-hydroxygrandiflorenic acid, was studied. The biotransformed product was isolated by column chromatography and its structure was determined by mass spectrum and nuclear magnetic resonance analysis. Grandiflorenic acid was efficiently metabolised by the fungus. After 72 h, the substrate was almost completely converted into the product.
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Affiliation(s)
- Y Ruan
- a Department of Traditional Chinese Medicine , College of Agronomy, Henan Agricultural University , Zhengzhou 450002 , P.R. China
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Jeong SH, Nakatsuhara K, Mizumoto T, Ma BJ, Nakano Y. Dependence of Threshold Switching Power on the Control-Light Wavelength in a Nonlinear Distributed-Feedback GaInAsP Waveguide. Appl Opt 2001; 40:6042-6048. [PMID: 18364901 DOI: 10.1364/ao.40.006042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We demonstrate all-optical bistable switching by using orthogonally and parallelly polarized control light in a nonlinear distributed feedback GaInAsP waveguide. When the control light that is orthogonally polarized to the signal light is within its stopband, it is possible to extract the signal without using any external devices. Also, we investigate theoretically and experimentally the dependence of threshold switching power on the wavelength and polarization of control light.
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Ma BJ, Hatch GM. Monolysocardiolipin acyltransferase activity: effect of insulin and localization of activity. Proc West Pharmacol Soc 2001; 43:39-41. [PMID: 11056953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Affiliation(s)
- B J Ma
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
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Ma BJ, Hang CS. [Membrane protein Fas/FasL system in viral infections]. Zhonghua Shi Yan He Lin Chuang Bing Du Xue Za Zhi 2001; 15:94-7. [PMID: 12526314] [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: 02/28/2023]
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Mutter T, Dolinsky VW, Ma BJ, Taylor WA, Hatch GM. Thyroxine regulation of monolysocardiolipin acyltransferase activity in rat heart. Biochem J 2000; 346 Pt 2:403-6. [PMID: 10677359 PMCID: PMC1220866] [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: 02/15/2023]
Abstract
Treatment of rats with thyroxine has been shown to elevate the biosynthesis and content of cardiolipin in the heart [Cao, Cheng, Angel and Hatch (1995) Biochim. Biophys. Acta 1256, 241-244]. Treatment with thyroxine resulted in a 1.8-fold increase (P<0.025) in [1-(14)C]linoleate and a 1.7-fold increase (P<0.025) in [1-(14)C]oleate incorporated into cardiolipin in perfused hearts, compared with controls. The mechanism for the elevation in incorporation of unsaturated fatty acids into cardiolipin was a 1. 6-fold (P<0.025) increase in mitochondrial monolysocardiolipin acyltransferase activity. The results demonstrate that the acylation of cardiac monolysocardiolipin is regulated by thyroid hormone. Thus an elevation in cardiolipin biosynthesis is accompanied by an elevation in monolysocardiolipin acyltransferase activity to maintain the appropriate molecular species composition of cardiolipin in the cardiac mitochondrial membrane. We postulate that monolysocardiolipin acyltransferase might be a rate-limiting enzyme for the molecular remodelling of cardiolipin in the heart.
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Affiliation(s)
- T Mutter
- Department of Pharmacology and Therapeutics, University of Manitoba, A307 Chown Building, 753 McDermot Avenue, Winnipeg, Manitoba, Canada R3E OW3
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Zhao B, Wang WM, Zheng XW, Wang CL, Ma BJ, Xue QZ, Zhu LH, Zhai WX. [Introduction of wide spectrum rice bacterial blight resistance gene Xa21 into two-line genic male sterile rice variety Pei'ai 64S]. Sheng Wu Gong Cheng Xue Bao 2000; 16:137-41. [PMID: 10976312] [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: 02/17/2023]
Abstract
Agrobacterium-mediated transformation of two-line genic male sterile Indica rice variety Pei'ai 64S was conducted using a cloned gene, Xa21, as the foreign gene and mature embryo calli as the recipients. A total of 46 transgenic plants had been obtained. The PCR analysis and Southern blotting showed the integration of Xa21 gene into the genome the transgenic plants. Results of inoculation with philippine race 6 of Xanthomonas oryzae pv. oryzae indicated that most of transgenic plants obtained high resistance to rice bacterial blight disease (Xoo). Analyses of T1 plants of the tested transgenic lines showed that integrated Xa21 gene could be steadily inherited and segregated in a 3:1 ratio.
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Affiliation(s)
- B Zhao
- Institute of Genetics, Chinese Academy of Sciences, Beijing
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Ma BJ, Taylor WA, Dolinsky VW, Hatch GM. Acylation of monolysocardiolipin in rat heart. J Lipid Res 1999; 40:1837-45. [PMID: 10508203] [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: 02/14/2023] Open
Abstract
Cardiolipin is a major mitochondrial membrane glycerophospholipid in the mammalian heart. In this study, the ability of the isolated intact rat heart to remodel cardiolipin and the mitochondrial enzyme activities that reacylate monolysocardiolipin to cardiolipin in vitro were characterized. Adult rat heart cardiolipin was found to contain primarily linoleic and oleic acids. Perfusion of the isolated intact rat heart in the Langendorff mode with various radioactive fatty acids, followed by analysis of radioactivity incorporated into cardiolipin and its immediate precursor phosphatidylglycerol, indicated that unsaturated fatty acids entered into cardiolipin mainly by deacylation followed by reacylation. The in vitro mitochondrial acylation of monolysocardiolipin to cardiolipin was coenzyme A-dependent with a pH optimum in the alkaline range. Significant activity was also present at physiological pH. With oleoyl-coenzyme A as substrate, the apparent K(m) for oleoyl-coenzyme A and monolysocardiolipin were 12.5 microm and 138.9 microm, respectively. With linoleoyl-coenzyme A as substrate, the apparent K(m) for linoleoyl-coenzyme A and monolysocardiolipin were 6.7 microm and 59.9 microm, respectively. Pre-incubation at 50 degrees C resulted in different profiles of enzyme inactivation for the two activities. Both activities were affected similarly by phospholipids, triacsin C, and various lipid binding proteins but were affected differently by various detergents and myristoyl-coenzyme A. [(3)H]cardiolipin was not formed from monolyso[(3)H]cardiolipin in the absence of acyl-coenzyme A. Monolysocardiolipin acyltransferase activities were observed in mitochondria prepared from various other rat tissues. In summary, the data suggest that the isolated intact rat heart has the ability to rapidly remodel cardiolipin and that rat heart mitochondria contain coenzyme A-dependent acyltransferase(s) for the acylation of monolysocardiolipin to cardiolipin. A simple and reproducible in vitro assay for the determination of acyl-coenzyme A- dependent monolysocardiolipin acyltransferase activity in mammalian tissues with exogenous monolysocardiolipin substrate is also presented.
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Affiliation(s)
- B J Ma
- Departments of Pharmacology and Therapeutics, Center On Aging, University of Manitoba, Winnipeg, Manitoba, Canada, R3E 0W3
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Nakatsuhara K, Mizumoto T, Takahashi E, Hossain S, Saka Y, Ma BJ, Nakano Y. All-optical switching in a distributed-feedback GaInAsP waveguide. Appl Opt 1999; 38:3911-3916. [PMID: 18319998 DOI: 10.1364/ao.38.003911] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The characteristics of all-optical switching in a waveguide device with a distributed-feedback structure were experimentally investigated. The device was composed of a strip-loaded GaInAsP/InP waveguide and a distributed-feedback structure, which was fabricated by a combination of reactive-ion etching and electron-beam exposure. In the experiments, several optical switching operations were demonstrated. In particular, the all-optical set-reset operation and threshold operation were obtained.
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Affiliation(s)
- K Nakatsuhara
- Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-Ku, Tokyo 152-8552, Japan.
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Abstract
Small heat shock proteins (smHSPs) and alpha-crystallins constitute a family of related molecular chaperones that exhibit striking variability in size, ranging from 16 to 43 kDa. Structural studies on these proteins have been hampered by their tendency to form large, often dynamic and heterogeneous oligomeric complexes. Here we describe the structure and expression of HSP12.6, a member of a novel class of smHSPs from the nematode Caenorhabditis elegans. Like other members of its class, HSP12.6 possesses a conserved alpha-crystallin domain but has the shortest N- and C-terminal regions of any known smHSP. Expression of HSP12.6 is limited to the first larval stage of C. elegans and is not significantly up-regulated by a wide range of stressors. Unlike other smHSPs, HSP12.6 does not form large oligomeric complexes in vivo. HSP12.6 was produced in Escherichia coli as a soluble protein and purified. Cross-linking and sedimentation velocity analyses indicate that the recombinant HSP12.6 is monomeric, making it an ideal candidate for structure determination. Interestingly, HSP12.6 does not function as a molecular chaperone in vitro, since it is unable to prevent the thermally induced aggregation of a test substrate. The structural and functional implications of these findings are discussed.
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Affiliation(s)
- M R Leroux
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
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