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Sun MC, Wu SF, Cai YM, Liu YY, Li KM, Zhao DC, Zeng X. [Quantitative HER2 mRNA assay in breast cancer with HER2 immunohistochemistry 0]. Zhonghua Bing Li Xue Za Zhi 2024; 53:464-469. [PMID: 38678327 DOI: 10.3760/cma.j.cn112151-20240125-00063] [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] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/29/2024]
Abstract
Objective: To investigate HER2 mRNA expression in breast cancer with HER2 immunohistochemistry (IHC) 0 and to analyze the feasibility of distinguishing between the tumor with HER2 μltra-low expression and the one without expression of HER2 (no staining by IHC) by HER2 mRNA level preliminarily. Methods: HER2 mRNA was analyzed by reverse transcription digital PCR in 41 cases of formalin-fixed paraffin-embedded surgical tissue samples of invasive breast cancer obtained between January 2020 and March 2023 at Peking Union Medical College Hospital. The cohort included 21 HER2 IHC 1+ and 20 IHC 0 (12 ultra-low and 8 non-expression of HER2). HER2 mRNA expression level was quantitatively evaluated by the FAM (HER2)/VIC (reference gene) ratio. Results: The expression of HER2 mRNA for the cases with 1+, ultra-low, and non-expression of HER2 by IHC was 0.30 to 1.78 (average 0.90, median 0.82), 0.55 to 1.51 (average 0.93, median 0.90) and 0.22 to 0.78 (average 0.41, median 0.36), respectively. For the mean and median HER2 mRNA levels, there was no significant difference between HER2 IHC 1+ and HER2 ultra-low expression diseases (P=0.757). A remarkable difference in HER2 gene expression was found between the tumors with 1+ and non-expression of HER2 by IHC (P=0.002). And, HER2 ultra-low cases contained statistically higher levels of HER2 mRNA compared with non-expression of HER2 subgroup by IHC (P=0.001). Conclusions: Based on HER2 mRNA, HER2 non-expression and HER2 weak expression (including HER2 IHC 1+ and ultra-low) belong to two different types of the tumor and the disease with HER2 IHC 1+ and HER2 ultra-low expression may be the same. It is necessary to further test the performance of HER2 mRNA detection for stratifying the HER2 weak expression subgroup and to determine the threshold.
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Affiliation(s)
- M C Sun
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - S F Wu
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Y M Cai
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Y Y Liu
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - K M Li
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - D C Zhao
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - X Zeng
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
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Sun MC, Liu SY, Wei W, Wang ZN, Tian XY, Li LM, Wang YF. [Overview of the ten global conferences on health promotion and implications for future work]. Zhonghua Liu Xing Bing Xue Za Zhi 2024; 45:591-596. [PMID: 38678358 DOI: 10.3760/cma.j.cn112338-20230922-00179] [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: 04/29/2024]
Abstract
Since 1986, the WHO has held ten global health promotion conferences covering various health promotion issues and sustainable development worldwide. These sessions have formed a series of consensus and actions that guide promoting health globally. This study analyzed the declarations, reports, and news materials from the ten conferences that studied health promotion action areas, focal topics, actor networks, partnership relationships, and other significant outcomes. It also explored how these conferences contributed to the construction and advancement of global health promotion consensus and actions. The first Global Conference on Health Promotion identified the concept of health promotion and five key action areas, laying the foundation for subsequent conferences and health promotion actions. Over the years, the ten conferences continuously expanded the essence of health promotion, developed partnership relationships, formulated public health promotion policies, and called for health promotion actions. This process culminated in the formation of global consensus and collective actions. The latter conferences have gained significant attention and influence. The conferences offer valuable insights for future global health promotion endeavors and provide global perspectives and pathways for the development of Healthy China.
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Affiliation(s)
- M C Sun
- Global Health Institute, School of Public Health, Xi'an Jiaotong University, Xi'an 710061, China
| | - S Y Liu
- Global Health Institute, School of Public Health, Xi'an Jiaotong University, Xi'an 710061, China
| | - W Wei
- Global Health Institute, School of Public Health, Xi'an Jiaotong University, Xi'an 710061, China Institute of Health Sciences, China Medical University, Shenyang 110122, China
| | - Z N Wang
- School of Journalism and Communication, Peking University, Beijing 100871, China
| | - X Y Tian
- Chinese Center for Health Education, Beijing 100011, China
| | - L M Li
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing 100191, China Peking University Center for Public Health and Epidemic Preparedness & Response, Beijing 100191, China
| | - Y F Wang
- Global Health Institute, School of Public Health, Xi'an Jiaotong University, Xi'an 710061, China
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Wu H, Li ZX, Fang K, Zhao ZY, Sun MC, Feng AQ, Leng ZY, Zhang ZH, Chu Y, Zhang L, Chen T, Xu MD. IGF-1-mediated FOXC1 overexpression induces stem-like properties through upregulating CBX7 and IGF-1R in esophageal squamous cell carcinoma. Cell Death Discov 2024; 10:102. [PMID: 38413558 PMCID: PMC10899262 DOI: 10.1038/s41420-024-01864-0] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 01/27/2024] [Accepted: 02/12/2024] [Indexed: 02/29/2024] Open
Abstract
Substantial evidence attests to the pivotal role of cancer stem cells (CSC) in both tumorigenesis and drug resistance. A member of the forkhead box (FOX) family, FOXC1, assumes significance in embryonic development and organogenesis. Furthermore, FOXC1 functions as an overexpressed transcription factor in various tumors, fostering proliferation, enhancing migratory capabilities, and promoting drug resistance, while maintaining stem-cell-like properties. Despite these implications, scant attention has been devoted to its role in esophageal squamous cell carcinoma. Our investigation revealed a pronounced upregulation of FOXC1 expression in ESCC, correlating with a poor prognosis. The downregulation of FOXC1 demonstrated inhibitory effects on ESCC tumorigenesis, proliferation, and tolerance to chemotherapeutic agents, concurrently reducing the levels of stemness-related markers CD133 and CD44. Further studies validated that FOXC1 induces ESCC stemness by transactivating CBX7 and IGF-1R. Additionally, IGF-1 activated the PI3K/AKT/NF-κB and MEK/ERK/NF-κB pathways through its binding to IGF-1R, thereby augmenting FOXC1 expression. Conversely, suppressing FOXC1 impeded ESCC stemness induced by IGF-1. The presence of a positive feedback loop, denoted by IGF-1-FOXC1-IGF-1R, suggests the potential of FOXC1 as a prognostic biomarker for ESCC. Taken together, targeting the IGF-1-FOXC1-IGF-1R axis emerges as a promising approach for anti-CSC therapy in ESCC.
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Affiliation(s)
- Hao Wu
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, 200120, Shanghai, China
| | - Zhao-Xing Li
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, 200120, Shanghai, China
| | - Kang Fang
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, 200120, Shanghai, China
| | - Zi-Ying Zhao
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, 200120, Shanghai, China
| | - Ming-Chuang Sun
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, 200120, Shanghai, China
| | - An-Qi Feng
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, 200120, Shanghai, China
| | - Zhu-Yun Leng
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, 200120, Shanghai, China
| | - Ze-Hua Zhang
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, 200120, Shanghai, China
| | - Yuan Chu
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, 200120, Shanghai, China
| | - Li Zhang
- Department of Pathology, Shanghai East Hospital, School of Medicine, Tongji 8 University, 200120, Shanghai, China
| | - Tao Chen
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, 200120, Shanghai, China.
| | - Mei-Dong Xu
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, 200120, Shanghai, China.
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Li ZX, Sun MC, Fang K, Zhao ZY, Leng ZY, Zhang ZH, Xu AP, Chu Y, Zhang L, Lian J, Chen T, Xu MD. Transcription factor 3 promotes migration and invasion potential and maintains cancer stemness by activating ID1 expression in esophageal squamous cell carcinoma. Cancer Biol Ther 2023; 24:2246206. [PMID: 37607071 PMCID: PMC10443991 DOI: 10.1080/15384047.2023.2246206] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 10/09/2022] [Accepted: 06/06/2023] [Indexed: 08/24/2023] Open
Abstract
Transcription factor 3 (TCF3) is a member of the basic Helix - Loop - Helix (bHLH) transcription factor (TF) family and is encoded by the TCF3 gene (also known as E2A). It has been shown that TCF3 functions as a key transcription factor in the pathogenesis of several human cancers and plays an important role in stem cell maintenance and carcinogenesis. However, the effect of TCF3 in the progression of esophageal squamous cell carcinoma (ESCC) is poorly known. In our study, TCF3 was found to express highly and correlated with cancer stage and prognosis. TCF3 was shown to promote ESCC invasion, migration, and drug resistance both from the results of in vivo and in vitro assays. Moreover, further studies suggested that TCF3 played these roles through transcriptionally regulating Inhibitor of DNA binding 1(ID1). Notably, we also found that TCF3 or ID1 was associated with ESCC stemness. Furthermore, TCF3 was correlated with the expression of cancer stemness markers CD44 and CD133. Therefore, maintaining cancer stemness might be the underlying mechanism that TCF3 transcriptionally regulated ID1 and further promoted ESCC progression and drug resistance.
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Affiliation(s)
- Zhao-Xing Li
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Ming-Chuang Sun
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Kang Fang
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Zi-Ying Zhao
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Zhu-Yun Leng
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Ze-Hua Zhang
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Ai-Ping Xu
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yuan Chu
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Li Zhang
- Department of Pathology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Jingjing Lian
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Tao Chen
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Mei-Dong Xu
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
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Sun MC, Fang K, Li ZX, Chu Y, Xu AP, Zhao ZY, Leng ZY, Zhang YW, Zhang ZH, Zhang L, Chen T, Xu MD. ETV5 overexpression promotes progression of esophageal squamous cell carcinoma by upregulating SKA1 and TRPV2. Int J Med Sci 2022; 19:1072-1081. [PMID: 35813298 PMCID: PMC9254378 DOI: 10.7150/ijms.71892] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 05/30/2022] [Indexed: 01/23/2023] Open
Abstract
Esophageal squamous cell carcinoma (ESCC) is notorious for the rapid progression especially early tumor metastasis due to the unclear mechanism. Recently, ETV5 attracts much attention for its potential role as an oncogenic transcription factor involved in multiple cancers. However, no one reported the mechanism behind the association between ETV5 expression and esophageal squamous cell carcinoma progression. In this study, we found that ETV5 was upregulated in ESCC both from online database and our ESCC tissues and ETV5 was associated with tumor staging and prognosis. Knockdown of ETV5 or its downstream genes SKA1 and TRPV2 significantly suppress ESCC cells migration and invasion, respectively. Additionally, in vivo study showed knockdown of ETV5 inhibited tumor metastasis. Further experiments unveiled ETV5 could transcriptionally upregulate the expression of SKA1 and TRPV2 and further activate MMPs in ESCC progression. In conclusion, ETV5 was associated with ESCC tumor staging and ESCC prognosis clinically. ETV5 promoted metastasis of ESCC by activating MMPs through augmenting the transcription of SKA1 and TRPV2. ETV5 was likely to be a novel oncogene and therapeutic target in ESCC.
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Affiliation(s)
- Ming-Chuang Sun
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
| | - Kang Fang
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
| | - Zhao-Xing Li
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
| | - Yuan Chu
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
| | - Ai-Ping Xu
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
| | - Zi-Ying Zhao
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
| | - Zhu-Yun Leng
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
| | - Yun-Wei Zhang
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
| | - Ze-Hua Zhang
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
| | - Li Zhang
- Department of Pathology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
| | - Tao Chen
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
| | - Mei-Dong Xu
- Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, 200120, China
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Song LM, Sun MC, Chen JD, Song L. [Nasal sinus tuberculosis misdiagnosed as chronic nasal sinusitis in 2 cases]. Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2017; 31:959-960. [PMID: 29798422 DOI: 10.13201/j.issn.1001-1781.2017.12.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Indexed: 06/08/2023]
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Sun MC, Chen JD, Song L, Song LM, Zhang LL, Jia XQ. [The expericence of diagnosis and treatment of foreign body within the pharyngeal soft tissue(3 cases)]. Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2016; 30:833-834. [PMID: 29798068 DOI: 10.13201/j.issn.1001-1781.2016.10.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Indexed: 06/08/2023]
Abstract
Through the diagnosis and treatment of the foreign body in the soft tissue of phargnx,reduce missed diagnosis. Flexible using of imaging methods for diagnosis and localization,and selecting the best surgical approach are important.
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Abstract
An astrocyte antioxidant enzyme, quinone reductase (QR), was studied in vivo to assess whether its activity was up-regulated following cerebral ischemia. Rats were given a unilateral focal cerebral infarct and regions of interest within the ischemic penumbra compared to the non-ischemic side for QR activity. At 7 days post-ischemia, QR activity was significantly up-regulated within cells of astrocyte morphology in the cortex (p = 0.007) and subcortical (p = 0.005) areas adjacent to the infarct. This enzyme activity peaked at 7 days but was still significantly up-regulated at 14 days. Up-regulation of QR activity occurs within the ischemic penumbra of a stroke in this animal model and may contribute to factors that limit ischemic damage to neurons in this area.
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Affiliation(s)
- A W Laxton
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
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Chen YC, Sun MC. Determination of trace quaternary ammonium surfactants in water by combining solid-phase extraction with surface-assisted laser desorption/ionization mass spectrometry. Rapid Commun Mass Spectrom 2001; 15:2521-2525. [PMID: 11746926 DOI: 10.1002/rcm.534] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This study demonstrates the feasibility of combining solid-phase extraction (SPE) with surface-assisted laser desorption/ionization (SALDI) mass spectrometry to determine trace quaternary ammonium surfactants in water. The trace surfactants in water were directly concentrated on the surface of activated carbon sorbent in SPE. The activated carbon sorbent was then mixed with the SALDI liquid for SALDI analysis. No SPE elution procedure was necessary. Experimental results indicate that the surfactants with longer chain alkyl groups exhibit higher sensitivities than those with shorter chain alkyl groups in SPE-SALDI analysis. The detection limit for hexadecyltrimethylammonium bromide is around 10 ppt in SPE-SALDI analysis by sampling 100 mL of aqueous solution, while that of tetradecyltrimethylammonium bromide is about 100 ppt. The detection limit for decyltrimethylammonium bromide and dodecyltrimethylammonium bromide is in the low-ppb range.
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Affiliation(s)
- Y C Chen
- Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan.
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10
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Geraci JP, Sun MC, Mariano MS. Amelioration of radiation nephropathy in rats by postirradiation treatment with dexamethasone and/or captopril. Radiat Res 1995; 143:58-68. [PMID: 7597145] [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: 01/26/2023]
Abstract
Dexamethasone (DEX) and captopril are effective drugs in the treatment of radiation nephropathy in experimental animals. The aim of the present study was to determine the relative effectiveness of the two drugs and to see if their combination is more effective than either drug alone. For this purpose both kidneys of 143 rats were exposed surgically and irradiated with 13-20 Gy gamma rays. The surrounding tissues, with the exception of a segment of lumbar cord, were shielded. Each group had free access to acidified drinking water containing either DEX (94 micrograms/l), captopril (500 mg/l), DEX (94 micrograms/l) + captopril (500 mg/l) or drug-free water. Dexamethasone treatment was stopped after 90 days, but animals continued to receive captopril until death. At approximately monthly intervals the animals were weighed and renal function (PUN, hematocrit, 51Cr-EDTA retention) was measured. A side effect of treatment with DEX and DEX+captopril was a reduced increase in body weight. Paralysis of the hind limbs developed in nine animals that received captopril and/or DEX treatment. The classical histological lesions associated with radiation myelopathy were not evident in these paretic rats. It is therefore suggested that paralysis may be attributed in part to drug-induced neurotoxicity in animals with impaired renal clearance. Macroscopically and histologically, nearly all the animals that survived more than 400 days had evidence of renal tumor development. Dexamethasone and/or captopril appear to selectively ameliorate glomerular compared to tubular damage, based on histological findings. All three experimental treatments delayed but did not stop the progression of lethal renal injury as measured by kidney function tests and survival time. Median survival times for nontreated and captopril-, DEX- and DEX+captopril-treated animals exposed to 14.5 to 19.0 Gy kidney irradiation were 175, 242, 261 and 395 days, respectively. The combination of captopril and DEX appears to be at least additive in that the therapeutic effect is equal to or greater than the sum of the therapeutic effect of the individual drugs. Dexamethasone appears to be as effective as or more effective than captopril in delaying renal failure.
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Affiliation(s)
- J P Geraci
- Department of Environmental Health, School of Public Health and Community Medicine, University of Washington, Seattle 98195, USA
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Wang SM, Jeng CJ, Sun MC. Studies on the interaction between titin and myosin. Histol Histopathol 1992; 7:333-7. [PMID: 1504452] [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: 12/27/2022]
Abstract
This study examines the interaction of titin and myosin. In order to analyze the domains of myosin contributing to the binding for titin, we conducted a solid phase binding assay. Different portions of myosin (heavy chains, light chains and myosin fragments) were coated on the microtiter wells and reacted with biotinylated titin. Then the binding of biotinylated titin to these polypeptides was detected by using the avidinbiotin-peroxidase method. The results demonstrated that light meromyosin and subfragment 1 were the major domains of myosin interacting with titin. Titin fragments obtained by trypsin digestion were allowed to react with myosin in an affinity column, and the bound fragments were isolated by an acidic elution. Immunoblot analysis of myosin-bound titin fragments revealed that an A-band domain of titin was responsible for the binding of myosin. In addition, biotinylated titin labelled the outer A-bands and Z-bands in intact myofibrils, thus confirming the in situ binding of titin to myosin.
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Affiliation(s)
- S M Wang
- Department of Anatomy, College of Medicine, National Taiwan University, Taipei, Republic of China
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12
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Abstract
Acetylcholinesterases (EC 3.1.1.7, AChE) have varying amounts of carbohydrates attached to the core protein. Sequence analysis of the known primary structures gives evidence for several asparagine-linked carbohydrates. From the differences in molecular mass determined on sodium dodecyl sulfate-polyacrylamide gel before and after deglycosylation with N-glycosidase F (EC 3.2.2.18), it is seen that dimeric AChE from red cell membranes is more heavily glycosylated than the tetrameric brain enzyme. Furthermore, dimeric and tetrameric forms of bovine AChE are more heavily glycosylated than the corresponding human enzymes. Monoclonal antibodies 2E6, 1H11, and 2G8 raised against detergent-soluble AChE from electric organs of Torpedo nacline timilei as well as Elec-39 raised against AChE from Electrophorus electricus cross-reacted with AChE from bovine and human brain but not with AChE from erythrocytes. Treatment of the enzyme with N-glycosidase F abolished binding of monoclonal antibodies, suggesting that the epitope, or part of it, consists of N-linked carbohydrates. Analysis of N-acetylglucosamine sugars revealed the presence of N-acetylglucosamine in all forms of cholinesterases investigated, giving evidence for N-linked glycosylation. On the other hand, N-acetylgalactosamine was not found in AChE from human and bovine brain or in butyrylcholinesterase (EC 3.1.1.8) from human serum, indicating that these forms of cholinesterase did not contain O-linked carbohydrates. Despite the notion that within one species, the different forms of AChE arise from one gene by different splicing, our present results show that dimeric erythrocyte and tetrameric brain AChE must undergo different postsynthetic modifications leading to differences in their glycosylation patterns.
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Affiliation(s)
- J Liao
- Institute of Biochemistry and Molecular Biology, University of Bern, Switzerland
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Liao J, Heider H, Sun MC, Stieger S, Brodbeck U. The monoclonal antibody 2G8 is carbohydrate-specific and distinguishes between different forms of vertebrate cholinesterases. Eur J Biochem 1991; 198:59-65. [PMID: 2040291 DOI: 10.1111/j.1432-1033.1991.tb15986.x] [Citation(s) in RCA: 21] [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: 12/29/2022]
Abstract
The monoclonal antibody (mAb) 2G8 (subclass IgG2a) raised against acetylcholinesterase (AChE, EC 3.1.1.7) from electric organ of Torpedo nacline timilei crossreacted with AChE from Torpedo marmorata, electric eel (Electrophorus electricus), flounder (Platichthys flesus) body muscle, rat brain, bovine brain, and human brain, this suggests that the epitope to which mAb 2G8 bound had been highly conserved during evolution. No crossreaction was found with AChE from human and bovine erythrocytes, nor with butyrylcholinesterase (BtChE, EC 3.1.1.8) from human serum. Binding of mAb 2G8 to the globular G2 form of AChE from T. marmorata strongly decreased enzyme activity, while no significant inhibition was found with either collagen-tailed, asymmetric forms, or with the enzymes from flounder body muscle or mammalian sources. The possibility that mAb 2G8 bound to anionic sites of AChE could be excluded since neither edrophonium chloride nor decamethonium bromide influenced the binding of 2G8 to the enzymes. Enzyme-linked immunosorbent assay and Western blot showed that heat-denatured, diisopropylfluorophosphate-treated, CNBr- and trypsin-digested AChE from T. marmorata still reacted with mAb 2G8; this indicates that the epitope to which 2G8 bound, at least partially, belonged to a continuous determinant. Treatment of cholinesterases with N-glycosidase F abolished crossreaction with 2G8, showing that an essential part of the epitope consisted of N-linked carbohydrates.
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Affiliation(s)
- J Liao
- Institute of Biochemistry and Molecular Biology, University of Bern, Switzerland
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Abstract
Limited proteolysis of titin with trypsin yielded a number of polypeptides which were electrophoresed and transferred to a nitrocellulose membrane. Proteolytic removal of the C-terminal residues on the nitrocellulose-bound polypeptides was achieved by using carboxypeptidase Y. The species of the polypeptides left after the digestion was quantified by immunoblotting with two distinct monoclonal anti-titin antibodies A2 and A12 of which the epitopes were located at 0.74 micron and 0.69 micron away from the center of an A-band, respectively. Two polypeptides (266 kd and 84 kd) reactive to both antibodies were identified in the control group. Fifteen minutes after the digestion, the immunoreactivities of A2 on 266 kd and 84 kd polypeptides were disappeared, while those of A12 on these polypeptides were not affected. The results indicate that the C-terminal end of titin is located near the Z-line region and the N-terminal end at the M-line region in the sarcomere.
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Affiliation(s)
- S M Wang
- Department of Anatomy, College of Medicine, National Taiwan University, Taipei, Republic of China
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Sun MC, McIlwain H, Pull I. The metabolism of adenine derivatives in different parts of the brain of the rat, and their release from hypothalamic preparations on excitation. J Neurobiol 1976; 7:109-22. [PMID: 1262867 DOI: 10.1002/neu.480070204] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Five enzymes concerned with the metabolism of adenine derivatives were assayed in seven regions of the rat brain. A region which included the hypothalamus had the highest AMP deaminase and adenosine deaminase activities, while its 5'-nucleotidase activities were relatively low. The enzymes named and also the uptake of [14C]adenine by incubated tissue samples were more active with hypothalamic than with neocortical tissues. On superfusion with glucose-bicarbonate saline after assimilating [14C]adenine, the hypothalamic tissues released about 0.2 per cent of their 14C content per minute. This release was increased fourfold with electrical excitation but the presence of 0.25 muM tetrodotoxin prevented most of this increase. The compounds released during superfusion and electrical stimulation were preponderantly hypoxanthine, inosine, and adenosine, with only small amounts of adenine nucleotides. The output of all these compounds increased during the period of stimulation and also the proportion of adenine nucleotides increased when stimulation was carried out in the presence of tetrodotoxin. The output of the nucleotides and adenosine increased more promptly when stimulated than did that of the other compounds named. The results are discussed in terms of the metabolic roles of the enzymes concerned. and in relation to whether the enzymes are acting on intracellular or extracellular substrates.
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