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Kim H, Xue H, Li X, Yue G, Zhu J, Eh T, Wang S, Jin LH. Orostachys malacophylla (pall.) fisch extracts alleviate intestinal inflammation in Drosophila. J Ethnopharmacol 2024; 330:118215. [PMID: 38641073 DOI: 10.1016/j.jep.2024.118215] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 04/11/2024] [Accepted: 04/16/2024] [Indexed: 04/21/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Orostachys malacophylla (Pall.) Fisch (O. malacophylla) is a succulent herbaceous plant that is the Orostachys genus of Crassulaceae family. O. malacophylla has been widely used as a traditional Chinese medicine with antioxidant, anti-inflammatory, anti-febrile, antidote, anti-Toxoplasma gondii properties. However, the biological function of alleviating intestinal inflammation and key bioactive compounds were still unknown. AIM OF THE STUDY We used a Drosophila model to study the protective effects and bioactive compounds of O. malacophylla water extract (OMWE) and butanol extract (OMBE) on intestinal inflammation. MATERIALS AND METHODS Drosophila intestinal inflammation was induced by oral invasion of dextran sodium sulfate (DSS) or Erwinia carotovora carotovora 15 (Ecc15). We revealed the protective effects of two extracts by determining intestinal reactive oxygen species (ROS) and antimicrobial peptide (AMP) levels and intestinal integrity, and using network pharmacology analysis to identify bioactive compounds. RESULTS We demonstrated that both OMWE and OMBE could ameliorate the detrimental effects of DSS, including a decreased survival rate, elevated ROS levels, increased cell death, excessive proliferation of ISCs, acid-base imbalance, and disruption of intestinal integrity. Moreover, the overabundance of lipid droplets (LDs) and AMPs by Ecc15 infection is mitigated by these extracts, thereby enhancing the flies' resistance to adverse stimuli. In addition, we used widely targeted metabolomics and network pharmacology analysis to identify bioactive compounds associated with IBD healing that are present in OMWE and OMBE. CONCLUSIONS In summary, our research indicates that OMWE and OMBE significantly mitigate intestinal inflammation and have the potential to be effective therapeutic agents for IBD in humans.
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Affiliation(s)
- Hyonil Kim
- College of Life Science, Northeast Forestry University, Harbin, Heilongjiang Province, China; College of Life Science, Kim Il Sung University, Pyongyang, Democratic People's Republic of Korea.
| | - Hongmei Xue
- Department of Children's Emergency Medicine, Women's and Children's Hospital Affiliated to Qingdao University, Qingdao, China.
| | - Xiao Li
- College of Life Science, Northeast Forestry University, Harbin, Heilongjiang Province, China.
| | - Guanhua Yue
- Department of Basic Medical, Shenyang Medical College, Shenyang, China.
| | - Jiahua Zhu
- Department of Basic Medical, Shenyang Medical College, Shenyang, China.
| | - Tongju Eh
- College of Life Science, Northeast Forestry University, Harbin, Heilongjiang Province, China; College of Life Science, Kim Il Sung University, Pyongyang, Democratic People's Republic of Korea.
| | - Sihong Wang
- Analysis and Test Center, Yanbian University, Yanji 133002, Jilin Province, PR China.
| | - Li Hua Jin
- College of Life Science, Northeast Forestry University, Harbin, Heilongjiang Province, China.
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Abstract
The output of the bacterial chemotaxis signaling pathway, the level of the intracellular regulator CheY-P, modulates the rotation direction of the flagellar motor, thereby regulating bacterial run-and-tumble behavior. The multiple flagellar motors on an E. coli cell are controlled by a common cytoplasmic pool of CheY-P. Fluctuation of the CheY-P level was thought to be able to coordinate the switching of multiple motors. Here, we measured the correlation of rotation directions between two motors on a cell, finding that it surprisingly exhibits two well separated timescales. We found that the slow timescale (∼6 s) can be explained by the slow fluctuation of the CheY-P level due to stochastic activity of the chemotactic adaptation enzymes, whereas the fast timescale (∼0.3 s) can be explained by the random pulse-like fluctuation of the CheY-P level, due probably to the activity of the chemoreceptor clusters. We extracted information on the properties of the fast CheY-P pulses based on the correlation measurements. The two well-separated timescales in the fluctuation of CheY-P level help to coordinate multiple motors on a cell and to enhance bacterial chemotactic performance.
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Affiliation(s)
- Guanhua Yue
- Department of Physics, University of Science and Technology of China, 96 Jinzhai Rd., Hefei, Anhui, 230026, CHINA
| | - Rongjing Zhang
- Department of Physics, University of Science and Technology of China, 96 Jinzhai Rd., Hefei, Anhui, 230026, CHINA
| | - Junhua Yuan
- Department of Physics, University of Science and Technology of China, 96 Jinzhai Rd., Hefei, Anhui, 230026, CHINA
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Hao Y, Pan J, Chen Q, Gu H, Ji G, Yue G, Yang S. Jumu is required for the activation of JAK/STAT in Drosophila lymph gland development and epidermal wounds. Biochem Biophys Res Commun 2022; 591:68-75. [PMID: 34999256 DOI: 10.1016/j.bbrc.2021.12.115] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 12/26/2021] [Accepted: 12/29/2021] [Indexed: 11/02/2022]
Abstract
The regulatory mechanism of hematopoiesis and innate immunity in Drosophila is highly similar to that in mammals, and Drosophila has become a suitable model to understand vertebrate hematopoiesis and the immune response. JAK-STAT signaling pathway components are widely conserved during evolution, and contribute to hematopoiesis and multiple tissue damage and immune responses. Here, we demonstrate that Stat92E is widely expressed in the lymph gland, and the loss of jumu inhibits the maintenance of the JAK/STAT pathway in the CZ and MZ but not in the PSC of the lymph gland. Furthermore, we found that clean puncture wounding of the larval epidermis can lead to the activation of JAK/STAT signaling and the generation of lamellocytes, and Jumu is required for the activation of JAK/STAT in response to epidermal wounds.
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Affiliation(s)
- Yangguang Hao
- Department of Basic Medical, Shenyang Medical College, Shenyang, 110034, China.
| | - Jichuan Pan
- Department of Basic Medical, Shenyang Medical College, Shenyang, 110034, China
| | - Qing Chen
- Department of Basic Medical, Shenyang Medical College, Shenyang, 110034, China
| | - Heze Gu
- Department of Basic Medical, Shenyang Medical College, Shenyang, 110034, China
| | - Guanglin Ji
- Department of Basic Medical, Shenyang Medical College, Shenyang, 110034, China
| | - Guanhua Yue
- Department of Basic Medical, Shenyang Medical College, Shenyang, 110034, China
| | - Shuting Yang
- Department of Basic Medical, Shenyang Medical College, Shenyang, 110034, China
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Zhang X, Shi C, Yue G, Guo H, Fu X, Li X, Li L, Wang X, Li Z, Chang Y, Zhang M, Chen Q. The Effects of Lentivirus-mediated shRNA Interference Targeting Mcl-1 on Growth of NK/T-cell Lymphoma. Neoplasma 2017; 64:511-517. [PMID: 28485156 DOI: 10.4149/neo_2017_404] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Myeloid leukemia-1 (Mcl-1) gene has been reported as an important factor in various types of cancer, but little research was processed on natural killer (NK)/T-cell lymphoma, a kind of a highly aggressive disease with a poor prognosis. Here we investigated the expression of Mcl-1 in seven lymphoma cell lines and its potential role as a molecular drug target for NK/T-cell lymphoma therapy by using lentivirus-mediated shRNA interference targeting Mcl-1 (lenti-shMcl-1). In our study, the expression of Mcl-1 in different lymphoma cell lines were evaluated firstly, after that lenti-shMcl-1 was constructed and transduced into NK/T-cell lymphoma cell line SNK-6 which had a high level expression of Mcl-1. Methylthiazolete-Trazolium (MTT) assay and flow cytometry (FCA) were employed to detect the status of proliferation and apoptosis after infection. Lastly we investigated the effects of chemotherapy agent vincristine (VCR) combination with lenti-shMcl-1 by MTT and FCA assay. The results showed that Mcl-1 gene expressed in all seven lymphoma cell lines at different levels. Recombinant lentiviruses could infect SNK-6 cells effectively. Mcl-1 expression level was remarkably down-regulated after infection with lenti-shMcl-1. The growth of SNK-6 cells was inhibited significantly through apoptosis pathway. Otherwise, lenti-shMcl-1 also revealed a significant chemosensitizing effect in combination with vincristine. In a word, we demonstrated that lenti-shMcl-1 had a significant anti-NK/T cell lymphoma effect and targeting Mcl-1 therapy could be a promising novel approach in treatment of lymphoma.
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Wei J, Costa C, Shen J, Yu L, Sanchez JJ, Qian X, Sun X, Zou Z, Gimenez-Capitan A, Yue G, Guan W, Rosell R, Liu B. Differential effect of MMSET mRNA levels on survival to first-line FOLFOX and second-line docetaxel in gastric cancer. Br J Cancer 2014; 110:2662-8. [PMID: 24809779 PMCID: PMC4037835 DOI: 10.1038/bjc.2014.231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [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: 01/24/2014] [Revised: 04/07/2014] [Accepted: 04/08/2014] [Indexed: 12/22/2022] Open
Abstract
Background: Breast cancer susceptibility gene 1 (BRCA1) expression differentially affects outcome to platinum- and taxane-based chemotherapy. Mediator of DNA damage checkpoint protein 1 (MDC1), p53-binding protein 1 (53BP1), multiple myeloma SET domain (MMSET) and ubiquitin-conjugating enzyme 9 (UBC9) are involved in DNA repair and could modify the BRCA1 predictive model. Methods: Mediator of DNA damage checkpoint protein 1, 53BP1, MMSET and UBC9 mRNA were assessed in gastric tumours from patients in whom BRCA1 levels had previously been determined. Results: In vitro chemosensitivity assay, MMSET levels were higher in docetaxel-sensitive samples. In a separate cohort, survival was longer in those with low MMSET (12.3 vs 8.8 months; P=0.04) or UBC9 (12.4 vs 8.8 months; P=0.01) in patients receiving only folinic acid, fluorouracil (5-FU) and oxaliplatin (FOLFOX). Conversely, among patients receiving second-line docetaxel, longer survival was associated with high MMSET (19.1 vs 13.9 months; P=0.003). Patients with high MMSET and BRCA1 attained a median survival of 36.6 months, compared with 13.9 months for those with high BRCA1 and low MMSET (P=0.003). In the multivariate analyses, low MMSET (hazard ratio (HR), 0.59; P=0.04) and low UBC9 (HR, 0.52; P=0.01) levels were markers of longer survival to first-line FOLFOX, whereas palliative surgery (HR, 2.47; P=0.005), low BRCA1 (HR, 3.17; P=0.001) and low MMSET (HR, 2.52; P=0.004) levels were markers of shorter survival to second-line docetaxel. Conclusions: Breast cancer susceptibility gene 1, MMSET and UBC9 can be useful for customising chemotherapy in gastric cancer patients.
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Affiliation(s)
- J Wei
- The Comprehensive Cancer Centre of Drum Tower Hospital, Medical School of Nanjing University and Clinical Cancer Institute of Nanjing University, Nanjing 210008, China
| | - C Costa
- Pangaea Biotech, USP Dexeus University Institute, Barcelona 08028, Spain
| | - J Shen
- The Comprehensive Cancer Centre of Drum Tower Hospital, Medical School of Nanjing University and Clinical Cancer Institute of Nanjing University, Nanjing 210008, China
| | - L Yu
- The Comprehensive Cancer Centre of Drum Tower Hospital, Medical School of Nanjing University and Clinical Cancer Institute of Nanjing University, Nanjing 210008, China
| | - J J Sanchez
- Department of Preventive Medicine and Public Health, Autonomous University of Madrid, Madrid 28049, Spain
| | - X Qian
- The Comprehensive Cancer Centre of Drum Tower Hospital, Medical School of Nanjing University and Clinical Cancer Institute of Nanjing University, Nanjing 210008, China
| | - X Sun
- The Comprehensive Cancer Centre of Drum Tower Hospital, Medical School of Nanjing University and Clinical Cancer Institute of Nanjing University, Nanjing 210008, China
| | - Z Zou
- The Comprehensive Cancer Centre of Drum Tower Hospital, Medical School of Nanjing University and Clinical Cancer Institute of Nanjing University, Nanjing 210008, China
| | - A Gimenez-Capitan
- Pangaea Biotech, USP Dexeus University Institute, Barcelona 08028, Spain
| | - G Yue
- The Comprehensive Cancer Centre of Drum Tower Hospital, Medical School of Nanjing University and Clinical Cancer Institute of Nanjing University, Nanjing 210008, China
| | - W Guan
- Department of General Surgery, Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China
| | - R Rosell
- 1] Pangaea Biotech, USP Dexeus University Institute, Barcelona 08028, Spain [2] Catalan Institute of Oncology, Hospital Germans Trias i Pujol, Medical Oncology Service, Badalona 08916, Spain
| | - B Liu
- The Comprehensive Cancer Centre of Drum Tower Hospital, Medical School of Nanjing University and Clinical Cancer Institute of Nanjing University, Nanjing 210008, China
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Geldermann H, Müller E, Beeckmann P, Knorr C, Yue G, Moser G. Mapping of quantitative-trait loci by means of marker genes in F2 generations of Wild boar, Pietrain and Meishan pigs. J Anim Breed Genet 2011. [DOI: 10.1111/j.1439-0388.1996.tb00629.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Yu L, Yue Q, Yue G, Eaton DC, Malik B. Stability of functional ENaC at the apical membrane of A6 cells. FASEB J 2006. [DOI: 10.1096/fasebj.20.4.a796-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ling Yu
- PhysiologyEmory university615 Michael StAtlantaGA30322
| | - Q Yue
- PhysiologyEmory university615 Michael StAtlantaGA30322
| | - G Yue
- PhysiologyEmory university615 Michael StAtlantaGA30322
| | | | - Bela Malik
- PhysiologyEmory university615 Michael StAtlantaGA30322
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Davis MP, Ranganthan V, Walsh D, Siemionow V, Yue G, Kirkova J, Yavuzsen T, LeGrand SB, Lagman RL. Cancer related fatigue: Central or peripheral? J Clin Oncol 2005. [DOI: 10.1200/jco.2005.23.16_suppl.8048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- M. P. Davis
- The Cleveland Clinic Fdn, Cleveland, OH; Cleveland Clinic Foundation, Cleveland, OH
| | - V. Ranganthan
- The Cleveland Clinic Fdn, Cleveland, OH; Cleveland Clinic Foundation, Cleveland, OH
| | - D. Walsh
- The Cleveland Clinic Fdn, Cleveland, OH; Cleveland Clinic Foundation, Cleveland, OH
| | - V. Siemionow
- The Cleveland Clinic Fdn, Cleveland, OH; Cleveland Clinic Foundation, Cleveland, OH
| | - G. Yue
- The Cleveland Clinic Fdn, Cleveland, OH; Cleveland Clinic Foundation, Cleveland, OH
| | - J. Kirkova
- The Cleveland Clinic Fdn, Cleveland, OH; Cleveland Clinic Foundation, Cleveland, OH
| | - T. Yavuzsen
- The Cleveland Clinic Fdn, Cleveland, OH; Cleveland Clinic Foundation, Cleveland, OH
| | - S. B. LeGrand
- The Cleveland Clinic Fdn, Cleveland, OH; Cleveland Clinic Foundation, Cleveland, OH
| | - R. L. Lagman
- The Cleveland Clinic Fdn, Cleveland, OH; Cleveland Clinic Foundation, Cleveland, OH
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Malik B, Yue Q, Yue G, Chen XJ, Price SR, Mitch WE, Eaton DC. Role of Nedd4-2 and polyubiquitination in epithelial sodium channel degradation in untransfected renal A6 cells expressing endogenous ENaC subunits. Am J Physiol Renal Physiol 2005; 289:F107-16. [PMID: 15769939 DOI: 10.1152/ajprenal.00179.2002] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Amiloride-sensitive epithelial sodium channels (ENaC) are responsible for transepithelial Na(+) transport in the kidney, lung, and colon. The channel consists of three subunits (alpha, beta, and gamma). In Madin-Darby canine kidney (MDCK) cells and Xenopus laevis oocytes transfected with all three ENaC subunits, neural precursor cell-expressed developmentally downregulated protein (Nedd4-2) promotes ubiquitin conjugation of ENaC. For native proteins in some cells, ubiquitin conjugation is a signal for their degradation by the ubiquitin-proteasome pathway, whereas in other cell types ubiquitin conjugation is a signal for endocytosis and lysosomal protein degradation. When ENaC are transfected into MDCK cells, ubiquitin conjugation leads to lysosomal degradation. In this paper, we characterize the involvement of the ubiquitin-proteasome proteolytic pathway in the regulation of functional ENaC in untransfected renal A6 cells expressing native ENaC subunits. In contrast to transfected cells, we show that total cellular alpha-, beta-, and gamma-ENaC subunits are polyubiquitinated and that ubiquitin conjugation of subunits increases when the cells are treated with a proteasome inhibitor. We show that Nedd4-2 is associated with alpha- and beta-subunits and is associated with the apical membrane. We also show the Nedd4-2 can regulate the number of functional ENaC subunits in the apical membrane. The results reported here suggest that the ubiquitin-proteasome proteolytic pathway is an important determinant of ENaC function in untransfected renal cells expressing endogenous ENaC.
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Affiliation(s)
- B Malik
- Dept. of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Yue G, Stratil A, Cepica S, Schroffel J, Schroffelova D, Fontanesi L, Cagnazzo M, Moser G, Bartenschlager H, Reiner G, Geldermann H. Linkage and QTL mapping for Sus scrofa chromosome 7. J Anim Breed Genet 2003. [DOI: 10.1046/j.0931-2668.2003.00424.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Yue G, Russo V, Davoli R, Sternstein I, Brunsch C, Schroffelova D, Stratil A, Moser G, Bartenschlager H, Reiner G, Geldermann H. Linkage and QTL mapping for Sus scrofa chromosome 13. J Anim Breed Genet 2003. [DOI: 10.1046/j.0931-2668.2003.00430.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Yue G, Stratil A, Kopecny M, Schroffelova D, Schroffel J, Hojny J, Cepica S, Davoli R, Zambonelli P, Brunsch C, Sternstein I, Moser G, Bartenschlager H, Reiner G, Geldermann H. Linkage and QTL mapping for Sus scrofa chromosome 6. J Anim Breed Genet 2003. [DOI: 10.1046/j.0931-2668.2003.00423.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
An original mathematical model describing particle diffusion in human nasal passages is presented. A unique feature of the model is that it combines effects of both turbulent and laminar flows. To account for turbulence, concentration equations written in cylindrical coordinates are first simplified by a scaling technique and then solved analytically based on momentum/mass transfer analogy. To describe laminar motion, the work of Martonen et al. (1995a) is modified for application to nasal passages. The predictions of the new model agree well with particle deposition data from experiments using human replica nasal casts over a wide range of flow rates (4-30 L/min) and particle sizes (0.001-0.1 micro m). The results of our study suggest that a complex fluid dynamics situation involving a natural transition from laminar to turbulent motion may exist within human nasal passages during inspiration. The model may be used to predict deposition efficiencies of inhaled particles for inhalation toxicology (e.g., the risk assessment of air pollutants) and aerosol therapy (e.g., the treatment of lung diseases) applications.
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Affiliation(s)
- Ted B Martonen
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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Becchetti A, Malik B, Yue G, Duchatelle P, Al-Khalili O, Kleyman TR, Eaton DC. Phosphatase inhibitors increase the open probability of ENaC in A6 cells. Am J Physiol Renal Physiol 2002; 283:F1030-45. [PMID: 12372779 DOI: 10.1152/ajprenal.00011.2002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We studied the cellular phosphatase inhibitors okadaic acid (OKA), calyculin A, and microcystin on the epithelial sodium channel (ENaC) in A6 renal cells. OKA increased the amiloride-sensitive current after approximately 30 min with maximal stimulation at 1-2 h. Fluctuation analysis of cell-attached patches containing a large number of ENaC yielded power spectra with corner frequencies in untreated cells almost two times as large as in cells pretreated for 30 min with OKA, implying an increase in single channel open probability (P(o)) that doubled after OKA. Single channel analysis showed that, in cells pretreated with OKA, P(o) and mean open time approximately doubled. Two other phosphatase inhibitors, calyculin A and microcystin, had similar effects on P(o) and mean open time. An analog of OKA, okadaone, that does not inhibit phosphatases had no effect. Pretreatment with 10 nM OKA, which blocks protein phosphatase 2A (PP2A) but not PP1 in mammalian cells, had no effect even though both phosphatases are present in A6 cells. Several proteins were differentially phosphorylated after OKA, but ENaC subunit phosphorylation did not increase. We conclude that, in A6 cells, there is an OKA-sensitive phosphatase that suppresses ENaC activity by altering the phosphorylation of a regulatory molecule associated with the channel.
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Affiliation(s)
- A Becchetti
- Center for Cell and Molecular Signaling, Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Abstract
Aldosterone maintains total organism sodium balance in all higher vertebrates. The level of sodium reabsorption is primarily determined by the action of aldosterone on epithelial sodium channels (ENaC) in the distal nephron. Recent work shows that, in an aldosterone-sensitive renal cell line (A6), aldosterone regulates sodium reabsorption by short- and long-term processes. In the short term, aldosterone regulates sodium transport by inducing expression of the small G-protein, K-Ras2A, by stimulating the activity of methyl transferase and S-adenosyl-homocysteine hydrolase to activate Ras by methylation, and, possibly, by subsequent activation by K-Ras2A of phosphatidylinositol phosphate-5-kinase (PIP-5-K) and phosphatidylinositol-3-kinase (PI-3-K), which ultimately activates ENaC. In the long term, aldosterone regulates sodium transport by altering trafficking, assembly, and degradation of ENaC.
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Affiliation(s)
- D C Eaton
- Center for Cell & Molecular Signaling and Department of Physiology, Emory University, 1648 Pierce Drive, Atlanta, GA 30322, USA.
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Hagstrom SA, Adamian M, Scimeca M, Pawlyk BS, Yue G, Li T. A role for the Tubby-like protein 1 in rhodopsin transport. Invest Ophthalmol Vis Sci 2001; 42:1955-62. [PMID: 11481257] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
PURPOSE To test the hypothesis that a lack of Tubby-like protein 1 (TULP1) function causes aberrant transport of nascent rhodopsin and to examine the functional relationship between the homologous proteins TULP1 and Tubby by studying mice carrying combined mutations. METHODS Subcellular localization of TULP1 and rhodopsin in photoreceptors was determined by immunofluorescence and by postembedding immunoelectron microscopy. Mice carrying different tulp1/tubby allele combinations were examined by histology, electroretinograms (ERGs), and immunofluorescence microscopy. RESULTS TULP1 is distributed throughout the photoreceptor cytoplasm but is excluded from the outer segments and the nuclei. In the tulp1-/- mice, ectopic accumulation of rhodopsin occurs at an early age. Both the vesicular profiles in the interphotoreceptor space and the inner segment plasma membranes are immunoreactive for rhodopsin. Mice doubly homozygous for null mutations in the tulp1 and tubby genes initially develop photoreceptors and express a battery of photoreceptor markers at age 14 days. Thereafter their photoreceptors undergo a fulminant degeneration that reaches completion by postnatal day 17. The disease phenotype in the double homozygote is much more severe than either single homozygote. Double heterozygotes are phenotypically normal. CONCLUSIONS A lack of TULP1 function results in misrouting of nascent rhodopsin. TULP1 may be a component of the cellular machinery that targets nascent rhodopsin to the outer segments. Comparison of disease phenotypes in the single and double mutants suggests that TULP1 and Tubby are not functionally interchangeable in photoreceptors nor do they form an obligate functional complex.
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Affiliation(s)
- S A Hagstrom
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114, USA
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Song H, Yue G, Zhou Z, Xie Y, Yang P, Mao Y, Xu Y, Wang H. Identification of a new gene product of PKIbeta by HPLC-ESIMS. Fresenius J Anal Chem 2001; 370:1003-8. [PMID: 11583078 DOI: 10.1007/s002160100840] [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: 10/27/2022]
Abstract
An identification method using high-performance liquid chromatography combined with electrospray mass spectrometry (HPLC-ESIMS) has been developed to verify an expressed gene product of kinase inhibitor (PKIbeta). This protein was expressed in this university for the first time from a newly cloned gene in the cDNA library of human fetal brain. The measured MW (8468.9 Da) of PKIbeta-78 was consistent with expectations. The gene product of PKIbeta-78 was monitored by ESIMS to ensure there was no mis-expressed PKIbeta-70 in the process of gene engineering. The peptide mapping of PKIbeta-78 and its partial sequence were, furthermore, determined. By database searching based on the experimental MWs and partial sequences provided, it was verified that this gene product is a new protein. The pseudosubstrate site and leucine-rich site for the function region of PKIbeta-78 are also confirmed.
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Affiliation(s)
- H Song
- State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
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Yue G, Lai PS, Yin K, Sun FF, Nagele RG, Liu X, Linask KK, Wang C, Lin KT, Wong PY. Colon epithelial cell death in 2,4,6-trinitrobenzenesulfonic acid-induced colitis is associated with increased inducible nitric-oxide synthase expression and peroxynitrite production. J Pharmacol Exp Ther 2001; 297:915-25. [PMID: 11356911] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023] Open
Abstract
Peroxynitrite, derived from the reaction of nitric oxide (NO(.)) with superoxide (O(2)), is a potent nitrating and oxidizing agent that can induce apoptosis in a variety of different cell types. In the present study, we investigated the possible role of peroxynitrite as a mediator of colon epithelial cell death in rat colitis. Rat colon inflammation was induced by intracolonic administration of 2,4,6-trinitrobenzenesulfonic acid (TNBS) and rats were sacrificed 24 h after TNBS administration. Expression of inducible nitric-oxide synthase (iNOS) was detected by reverse transcription-polymerase chain reaction and immunohistochemistry. The enzymatic activities of Ca(2+)-independent iNOS and Ca(2+)-dependent constitutive nitric-oxide synthase were determined biochemically. Evidence of peroxynitrite-mediated cell injury was detected by immunostaining of nitrotyrosine. Apoptosis was examined by in situ terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and DNA gel electrophoresis. To evaluate the specific contribution of peroxynitrite to the observed cell injury, a selective iNOS inhibitor, L-N(G)-[1-iminoethyl]lysine (L-NIL), was administered after TNBS induction. Morphological examination and analysis of TUNEL/cytokeratin double immunofluorescence revealed significant apoptosis in mucosal epithelial cells. Nitrotyrosine was colocalized with TUNEL, strongly demonstrating the association of peroxynitrite with the apoptotic death of colon epithelial cells. The administration of L-NIL reduced iNOS activity in 24-h lesions by 92% and also significantly attenuated both nitrotyrosine staining and apoptotic cell counts in the colon epithelium. These results strongly suggest that local elevated level of peroxynitrite produced from increased iNOS expression and activity is a major contributor to colon epithelial apoptosis during colon inflammation.
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Affiliation(s)
- G Yue
- Department of Cell Biology, School of Osteopathic Medicine, University of Medicine and Dentistry of New Jersey, Stratford, New Jersey, USA.
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Malik B, Schlanger L, Al-Khalili O, Bao HF, Yue G, Price SR, Mitch WE, Eaton DC. Enac degradation in A6 cells by the ubiquitin-proteosome proteolytic pathway. J Biol Chem 2001; 276:12903-10. [PMID: 11278712 DOI: 10.1074/jbc.m010626200] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Amiloride-sensitive epithelial Na(+) channels (ENaC) are responsible for trans-epithelial Na(+) transport in the kidney, lung, and colon. The channel consists of three subunits (alpha, beta, gamma) each containing a proline rich region (PPXY) in their carboxyl-terminal end. Mutations in this PPXY domain cause Liddle's syndrome, an autosomal dominant, salt-sensitive hypertension, by preventing the channel's interactions with the ubiquitin ligase Neural precursor cell-expressed developmentally down-regulated protein (Nedd4). It is postulated that this results in defective endocytosis and lysosomal degradation of ENaC leading to an increase in ENaC activity. To show the pathway that degrades ENaC in epithelial cells that express functioning ENaC channels, we used inhibitors of the proteosome and measured sodium channel activity. We found that the inhibitor, MG-132, increases amiloride-sensitive trans-epithelial current in Xenopus distal nephron A6 cells. There also is an increase of total cellular as well as membrane-associated ENaC subunit molecules by Western blotting. MG-132-treated cells also have increased channel density in patch clamp experiments. Inhibitors of lysosomal function did not reproduce these findings. Our results suggest that in native renal cells the proteosomal pathway is an important regulator of ENaC function.
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Affiliation(s)
- B Malik
- Department of Physiology and Renal Division, Emory University, Atlanta, Georgia 30322, USA.
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22
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Hong DH, Yue G, Adamian M, Li T. Retinitis pigmentosa GTPase regulator (RPGRr)-interacting protein is stably associated with the photoreceptor ciliary axoneme and anchors RPGR to the connecting cilium. J Biol Chem 2001; 276:12091-9. [PMID: 11104772 DOI: 10.1074/jbc.m009351200] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Retinitis pigmentosa (RP) is a blinding retinal disease in which the photoreceptor cells degenerate. Mutations in the gene for retinitis pigmentosa GTPase regulator (RPGR) are a frequent cause of RP. The function of RPGR is not well understood, but it is thought to be a putative guanine nucleotide exchange factor for an unknown G protein. Ablation of the RPGR gene in mice suggested a role in maintaining the polarized distribution of opsin across the cilia. To investigate its function, we used a protein interaction screen to identify candidate proteins that may interact physiologically with RPGR. One such protein, designated RPGR-interacting protein (RPGRIP), is expressed specifically in rod and cone photoreceptors. It consists of an N-terminal region predicted to form coiled coil structures linked to a C-terminal tail that binds RPGR. In vivo, both proteins co-localize in the photoreceptor connecting cilia. RPGRIP is stably associated with the ciliary axoneme independent of RPGR and is resistant to extraction under conditions that partially solubilized other cytoskeletal components. When over-expressed in heterologous cell lines, RPGRIP appears in insoluble punctate and filamentous structures. These data suggest that RPGRIP is a structural component of the ciliary axoneme, and one of its functions is to anchor RPGR within the cilium. RPGRIP is the only protein known to localize specifically in the photoreceptor connecting cilium. As such, it is a candidate gene for human photoreceptor disease. The tissue-specific expression of RPGRIP explains why mutations in the ubiquitously expressed RPGR confer a photoreceptor-specific phenotype.
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Affiliation(s)
- D H Hong
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114, USA
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Sun FF, Lai PS, Yue G, Yin K, Nagele RG, Tong DM, Krzesicki RF, Chin JE, Wong PY. Pattern of cytokine and adhesion molecule mRNA in hapten-induced relapsing colon inflammation in the rat. Inflammation 2001; 25:33-45. [PMID: 11293664 DOI: 10.1023/a:1007023611478] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We examined the mRNA expression of cytokines, chemokines, integrins, and selectins in colon lesions of rat colitis with a semi-quantitative RT-PCR assay. Rat colitis was induced by trinitrobenzene sulfonic acid (TNBS) in 50% ethanol. Within 24 h, an acute inflammation occurred with hyperemia, edema, necrosis and an intense infiltration of granulocytes in the mucosa. The lesion proceeded into a T-lymphocyte/monocyte-driven chronic inflammation for two weeks and healed in 6 weeks. An acute inflammation recurred at the same site when the recovered animals were systemically injected with TNBS. We isolated RNA from colon tissue at 24 h, 1, 2, 4, 6 weeks after TNBS treatment and from the relapsed animals. The mRNA for cytokines IL-1beta, IL-6, IL-10 and the chemokines CINC, MIP-1alpha, MCP-1 were significantly (P < 0.05) elevated and persisted for 2 weeks, decreased in 6 weeks and increased again during relapse. IFN-gamma mRNA stayed at control levels initially, but increased dramatically in the second weeks of chronic inflammation as well as in relapse. The mRNA levels of adhesion molecules, ICAM-1, VCAM-1, the mucosal homing integrin beta7 as well as P- and E-selectin were greatly enhanced between 1 and 3 weeks. The data showed that the chronically inflamed tissue expresses a time-dependent changing pattern of TH1 cytokines and adhesion molecules that maintain the infiltration and activation of inflammatory cells and tissue injury.
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Affiliation(s)
- F F Sun
- Department of Cell Biology, School of Osteopathic Medicine, UMDNJ, Stratford, New Jersey 08084, USA
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24
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Merlin D, Yue G, Lencer WI, Selsted ME, Madara JL. Cryptdin-3 induces novel apical conductance(s) in Cl- secretory, including cystic fibrosis, epithelia. Am J Physiol Cell Physiol 2001; 280:C296-302. [PMID: 11208524 DOI: 10.1152/ajpcell.2001.280.2.c296] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Opening of anion-conductive pathways in apical membranes of secretory cells lining mucosal surfaces is a critical step in salt and water secretion and, thus, hydration of sites including airway and intestine. In intestine, Paneth cells are positioned at the base of the secretory gland (crypt) and release defensin peptide, in mice termed cryptdins, into the crypt lumen. Because at least some defensins have been shown to form anion-conductive channels in phospholipid bilayers, we tested whether these endogenous antimicrobial peptides could act as soluble inducers of channel-like activity when applied to apical membranes. To directly evaluate the possibility of cryptdin-3-mediated apical anion conductance (G(ap)), we have utilized amphotericin B to selectively permeabilize basolateral membranes of electrically tight monolayers of polarized human intestinal secretory epithelia (T84 cells), thus isolating the apical membrane for study. Cryptdin-3 induces G(ap) that is voltage independent (deltaG(ap) = 1.90 +/- 0.60 mS/cm2) and exhibits ion selectivity contrasting to that elicited by forskolin or thapsigargin (for cryptdin-3, Cl- = gluconate; for forskolin and thapsigargin, Cl- >> gluconate). We cannot exclude the possibility that the macroscopic current induced by cryptdin could be the sum of cation and Cl- currents. Cryptdin-3 induces a current in basolaterally permeabilized epithelial monolayers derived from airway cells harboring the deltaF508 mutation of cystic fibrosis (CF; deltaG(ap) = 0.80 +/- 0.06 mS/cm2), demonstrating that cryptdin-3 restores anion secretion in CF cells; this occurs independently of the CF transmembrane conductance regulator channel. These results support the idea that cryptdin-3 may associate with apical membranes of Cl--secreting epithelia and self-assemble into conducting channels capable of mediating a physiological response.
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Affiliation(s)
- D Merlin
- Department of Pathology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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25
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Yue G, Li Y, Orban L. Characterization of microsatellites in the IGF-2 and GH genes of Asian seabass (Lates calcarifer). Mar Biotechnol (NY) 2001; 3:1-3. [PMID: 14961383 DOI: 10.1007/s101260000043] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Four microsatellites were identified by screening the DNA sequences of Asian seabass (Lates calcarifer) deposited to GenBank. Two markers each are located in the growth hormone gene (GH) and in the insulin-like growth factor II gene ( IGF-2), respectively. The markers were characterized by genotyping 34 Asian seabass individuals. All 4 microsatellites showed polymorphism: the number of alleles per locus ranged from 2 to 11 (average, 5.0), while the expected heterozygosity ranged from 0.51 to 0.85 (average, 0.63) at the 4 loci. Cross-priming with all 4 primer pairs was tested in species belonging to 5 different genera, but no bands were amplified. These microsatellites are the first genomic DNA markers characterized in L. calcarifer; thus they may be valuable for research and aquaculture production of this species.
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Affiliation(s)
- G Yue
- Laboratory of Fish Biotechnology, Institute of Molecular Agrobiology, National University of Singapore, 1 Research Link, NUS Campus, 117604 Singapore
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26
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Abstract
Aldosterone increases Na(+) reabsorption by renal epithelial cells: the acute actions (<4 h) appear to be promoted by protein methylation. This paper describes the relationship between protein methylation and aldosterone's action and describes aldosterone-mediated targets for methylation in cultured renal cells (A6). Aldosterone increases protein methylation from 7.90 +/- 0.60 to 20.1 +/- 0.80 methyl ester cpm/microg protein. Aldosterone stimulates protein methylation by increasing methyltransferase activity from 14.0 +/- 0.64 in aldosterone-depleted cells to 31.8 +/- 2.60 methyl ester cpm/microg protein per hour in aldosterone-treated cells. Three known methyltransferase inhibitors reduce the aldosterone-induced increase in methyltransferase activity. One of these inhibitors, the isoprenyl-cysteine methyltransferase-specific inhibitor, S-trans, trans-farnesylthiosalicylic acid, completely blocks aldosterone-induced protein methylation and also aldosterone-induced short-circuit current. Aldosterone induces protein methylation in two molecular weight ranges: near 90 kDa and around 20 kDa. The lower molecular weight range is the weight of small G proteins, and aldosterone does increase both Ras protein 1.6-fold and Ras methylation almost 12-fold. Also, Ras antisense oligonucleotides reduce the activity of Na(+) channels by about fivefold. We conclude that 1) protein methylation is essential for aldosterone-induced increases in Na(+) transport; 2) one target for methylation is p21(ras); and 3) inhibition of Ras expression or Ras methylation inhibits Na(+) channel activity.
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Affiliation(s)
- N F Al-Baldawi
- Center for Cell and Molecular Signaling, Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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27
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Abstract
Rapamycin and FK-506 are immunosuppressive drugs that bind a ubiquitous immunophilin, FKBP12, but immunosuppressive mechanisms and side effects appear to be different. Rapamycin binds renal FKBP12 to change renal transport. We used cell-attached patch clamp to examine rapamycin's effect on Na(+) channels in A6 cells. Channel NP(o) was 0.5 +/- 0.08 (n = 6) during the first 5 min but fell close to zero after 20 min. Application of 1 microM rapamycin reactivated Na(+) channels (NP(o) = 0.47 +/- 0.1; n=6), but 1 microM FK-506 did not. Also, GF-109203X, a protein kinase C (PKC) inhibitor, mimicked the rapamycin-induced reactivation in a nonadditive manner. However, rapamycin did not reactivate Na(+) channels if cells were exposed to 1 microM FK-506 before rapamycin. In PKC assays, rapamycin was as effective as the PKC inhibitor; however, epithelial Na(+) channel (ENaC) phosphorylation was low under baseline conditions and was not altered by PKC inhibitors or activators. These results suggest that rapamycin activates Na(+) channels by binding FKBP12 and inhibiting PKC, and, in renal cells, despite binding the same immunophilin, rapamycin and FK-506 activate different intracellular signaling pathways.
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Affiliation(s)
- G Yue
- Center for Cell and Molecular Signaling, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Abstract
A 44-year-old Chinese man developed severe occipital headache, nausea, and vomiting during acupuncture treatment of the posterior neck for chronic neck pain. Computed tomography of the head showed hemorrhage in the fourth, third, and lateral ventricles. A lumbar puncture confirmed the presence of blood. Magnetic resonance angiography with gadolinium did not reveal any saccular aneurysms or arteriovenous malformations. The patient's headache resolved over a period of 28 days without any neurological deficits. Acupuncture of the posterior neck can cause acute intracranial hemorrhage.
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Affiliation(s)
- D C Choo
- Department of Medicine, Loma Linda University Medical Center, CA, USA
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29
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Stockand JD, Spier BJ, Worrell RT, Yue G, Al-Baldawi N, Eaton DC. Regulation of Na(+) reabsorption by the aldosterone-induced small G protein K-Ras2A. J Biol Chem 1999; 274:35449-54. [PMID: 10585415 DOI: 10.1074/jbc.274.50.35449] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Xenopus laevis A6 cells were used as model epithelia to test the hypothesis that K-Ras2A is an aldosterone-induced protein necessary for steroid-regulated Na(+) transport. The possibility that increased K-Ras2A alone is sufficient to mimic aldosterone action on Na(+) transport also was tested. Aldosterone treatment increased K-Ras2A protein expression 2.8-fold within 4 h. Active Ras is membrane associated. After aldosterone treatment, 75% of K-Ras was localized to the plasma membrane compared with 25% in the absence of steroid. Aldosterone also increased the amount of active (phosphorylated) mitogen-activated protein kinase kinase likely through K-Ras2A signaling. Steroid-induced K-Ras2A protein levels and Na(+) transport were decreased with antisense K-ras2A oligonucleotides, showing that K-Ras2A is necessary for the natriferic actions of aldosterone. Aldosterone-induced Na(+) channel activity, was decreased from 0.40 to 0.09 by pretreatment with antisense ras oligonucleotide, implicating the luminal Na(+) channel as one final effector of Ras signaling. Overexpression of K-Ras2A increased Na(+) transport approximately 2.2-fold in the absence of aldosterone. These results suggest that aldosterone signals to the luminal Na(+) channel via multiple pathways and that K-Ras2A levels are limiting for a portion of the aldosterone-sensitive Na(+) transport.
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Affiliation(s)
- J D Stockand
- Center for Cell and Molecular Signaling, Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA. jstocka2emory.edu
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30
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Geldermann H, Moser G, Müller E, Beeckmann P, Yue G, Dragos M, Bartenschlager H, Cepica S, Stratil A, Schröffel J. Status of Genome and QTL Mapping in Pigs – Data of Hohenheim F<sub>2</sub> Families. Arch Anim Breed 1999. [DOI: 10.5194/aab-42-67-1999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract. Three informative F2 families (by use of European Wild boar (W), Pietrain (P) and Meishan (M)), each with more than 300 animals, were genotyped for evenly spaced marker loci and recorded for more than 100 quantitative traits. Linkage and QTL mapping data for 8 chromosomes are presented (74, 76 and 75 mapped loci in families WxP, MxP and WxM, resp). Linkage maps gave evidence of heterogeneity in recombination between sexes and families. The male to female recombination ratio were 1.19 (WxP), 1.35 (MxP) and 1.27 (WxM). Several QTLs were mapped for performance traits of growth, carcass and meat quality. These QTLs are located on different chromosomes and influenced by families. Larger effects were found on chromosome 6 and 7, and e.g. up to 60% of the phenotypic F2 variance for meat quality traits was associated with chromosome 6. Candidate genes are proposed for some of the QTL intervals. The subsequent QTL mapping use a combined strategy of genome-wide marker mapping with a positional candidate gene approach in order to identify genes which are significant for breeding.
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31
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Abstract
Interferon-gamma (IFN-gamma) has been implicated in the mortality of animal models of endotoxemia. On the other hand, the specific role of IFN-gamma in the development of organ inflammation in a model of polymicrobial sepsis has not been elucidated. In this study, we hypothesized that IFN-gamma plays an important role in lung inflammation after cecal ligation and puncture (CLP). To verify this hypothesis, lung tissue was removed 5 h after CLP or from sham controls. The mRNA expression (by RT-PCR) of IFN-gamma was increased in lung homogenates of CLP rats compared to sham controls. Using immunohistochemistry, we show for the first time the increased presence of IFN-gamma staining cells in the lung following CLP. Only very small amounts of positive staining for IFN-gamma was observed in lungs of sham controls. The presence of IFN-gamma in the lung 5 h after CLP correlated with a twofold increases in lung superoxide generation and MPO activity (index of neutrophil sequestration). Plasma and lung nitrite levels (breakdown product of nitric oxide) were also significantly increased in CLP rats. IFN-gamma antibody (1.2 mg/kg, i.v.) administered immediately after CLP significantly decreased lung superoxide levels to levels similar to the sham controls without affecting MPO activity, or lung or plasma nitrite levels. These results provide evidence that IFN-gamma may contribute to lung inflammation 5 h following CLP via increased production of superoxide.
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Affiliation(s)
- K Yin
- Department of Cell Biology, University of Medicine and Dentistry, New Jersey, School of Osteopathic Medicine, Stratford 08084, USA
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Yu W, Yue G, Han X, Chen J, Tian B. Measurements of the neutron yields from 7Li(p,n)7Be reaction (thick target) with incident energies from 1.885 to 2.0 MeV. Med Phys 1998; 25:1222-4. [PMID: 9682210 DOI: 10.1118/1.598299] [Citation(s) in RCA: 16] [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: 11/07/2022] Open
Abstract
Accelerator-based neutron source have been considered to be practical for boron neutron capture therapy (BNCT). Based on experience with a parameters of the Brookhaven National Laboratory BMRR reactor neutron source, which has been used in treatment experiments, the future accelerator-based neutron source for BNCT should have the properties of low energy distribution (< 100 keV) and high flux (about 10(9) neutrons per second per square centimeter) in the patient zone. Using protons to bombard thick 7Li targets, generating neutrons via the 7Li(p,n)7Be reaction, is one of the optimal choices for this kind of neutron source. Neutron yield data versus incident energy are necessary in order to select the proper incident energy and for estimating how high the incident proton current should be. The required proton beam current intensity is one of the key parameters for an accelerator useful for BNCT. In the present work, neutron yields of the 7Li(p,n)7Be reaction with a thick lithium target and incident energies of 1.885 and 1.9 MeV were measured at 0 degree with respect to the incident beam direction. The results are (3.08 +/- 0.17) x 10(12) and (5.71 +/- 0.32) x 10(12) neutrons/C sr, respectively. Neutron yield angular distribution measurements at 2 MeV incident energy were also performed. The proton beams were generated by the Peking University 4.5 MV electrostatic accelerator. The emitted neutrons from these reactions have the advantages of low energy distribution and forward angular distribution, which are requirements for a BNCT neutron source. The data obtained in this work can be used as a reference to study the accelerator-based neutron sources for BNCT.
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Affiliation(s)
- W Yu
- China Institute of Atomic Energy, Beijing, China
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Wong PY, Yue G, Yin K, Liu P, Lin M, Rodriguez A, Nomen M, Spur BW, Geng JG, Spokas EG, Sun FF. Anti-P-selectin antibody exacerbated inflammatory responses in acetic acid-induced colitis. Adv Exp Med Biol 1998; 433:323-6. [PMID: 9561162 DOI: 10.1007/978-1-4899-1810-9_69] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- P Y Wong
- Department of Cell Biology, University of Medicine and Dentistry-School of Osteopathic Medicine, Stratford, NJ 08084, USA
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Abstract
The proton transverse relaxation time (T2) of human skeletal muscles has been increasingly used in magnetic resonance imaging experiments to examine muscle physiology and neuromuscular control. However, little attention has been paid to the experimental factors affecting the accuracy or sensitivity of the T2 measurement. We have explored theoretically and experimentally the structure of several magnetic resonance pulse sequences for measuring T2 of the first dorsal interosseous muscle and found that a multiecho imaging technique using non-slice-selective refocusing pulses (MENSS) produces more accurate T2 estimates than multiecho slice-selective (MESS) imaging methods that are commonly used. Using either technique we acquired four 5-mm-thick transverse images of the first dorsal interosseous muscle with a spatial resolution of 0.6 mm within 5 min. The T2 measured by the MENSS method was closer to the true T2 than was the T2 estimated by the MESS method. After a given amount of exercise, the MENSS technique revealed an average 28 +/- 10% increase in T2 compared with a 13 +/- 3% increase measured with an equivalent MESS technique. We conclude that the MENSS method is a more accurate and sensitive procedure for studying neuromuscular physiology compared with the more commonly used MESS method.
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Affiliation(s)
- P A Hardy
- Department of Radiology, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
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35
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Abstract
Neutron sources created by 4-, 3.5-, and 3-MeV protons striking a thick beryllium target were studied via the time-of-flight technique. Protons were accelerated by the Peking University 4.5 MV electrostatic accelerator. Two disk-shaped 9Be targets with thickness 1.5 and 3 mm were used in the measurements. The time-of-flight spectra were observed at zero degrees with respect to the incident proton beam. The analysis to these time-of-flight spectra is given. The time-of-flight spectra were converted to the energy spectra and compared to a neutron spectrum of 7Li(p, n)7 Be reaction with incident energy 2.5 MeV, which was also measured in this work. Restricted by the spectrometer itself, the threshold of the measurements is 400 keV. The results show that by using several MeV protons bombarding a thick beryllium target, reactions other than 9Be(p, n)9B produce significant contributions to the neutron yield with energy less than 1 MeV.
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Affiliation(s)
- G Yue
- Department of Technical Physics, Peking University, Beijing, People's Republic of China
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36
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Abstract
We instilled 4 ml isotonic fluid containing trace amounts of fluorescently labeled dextran (molecular mass 150 kDa) in the lungs of rats exposed to either 85% O(2) for 7 days or to 85% O(2) for 7 days and 100% O(2) for 3 days. We withdrew the fluid every hour for a 3-h period and calculated alveolar fluid clearance (AFC) from changes in dextran concentration. Postinstillation (3 h), AFC values in the control and the two hyperoxic groups were 51 +/- 1, 63 +/- 2, and 62 +/- 3 (SE), respectively (%instilled volume; n > or = 5; P < 0.05). Addition of either 1 mM amiloride or N-ethyl-N-isopropyl amiloride (EIPA) in the instillate decreased the AFC values in all groups 3 h later to approximately 30% of instilled volume. Instillation of phenamil, an irreversible blocker of epithelial Na+ channels into the lungs of rats exposed to 85% O(2) for 7 days and 100% O(2) for 2 days, resulted in a significant increase of their extravascular lung fluid volumes 24 h later. These results demonstrate the existence of EIPA-inhibitable Na+ channels in alveolar epithelial cells in vivo and indicate that an increase in Na+ transport plays an important role in limiting the amount of alveolar edema in O(2)-damaged lungs.
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Affiliation(s)
- G Yue
- Department of Anesthesiology, University of Alabama at Birmingham, 35233, USA
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Li Y, Wang D, Zheng J, Zhao S, Yue G, Deng Z, He Y. [Dynamic changes of brainstem auditory evoked potential and the protective effect of Piper Wallchii Hand-Mazz during brainstem ischemia in dogs]. Zhongguo Ying Yong Sheng Li Xue Za Zhi 1997; 13:92-3. [PMID: 10074334] [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: 02/11/2023]
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38
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Abstract
Nitric oxide (NO) has been implicated in the pathogenesis of the circulatory dysfunction of endotoxin shock. We investigated the effect of aminoguanidine (AG), an inhibitor of nitric oxide synthase (NOS) that is more selective for the inducible NOS, on the circulatory and inflammatory sequelae after administration of a bolus (10 mg/kg iv) of lipopolysaccharide (LPS) (Salmonella enteritidis). Rats receiving LPS + vehicle (LPS + Veh) exhibited a 73% decrease in mean arterial blood pressure (MABP) and a 50% decrease in cardiac index (CI) and SV index (SVI) within 10 min after LPS administration. MABP recovered to 64 +/- 3, 81 +/- 6, and 79 +/- 8 mmHg, at 60, 120, and 180 min post-LPS, respectively. However, CI and SVI remained depressed by 40-50% for the entire experimental period. Systemic vascular resistance (SVRI), heart rate (HR), and hematocrit were significantly elevated at 180 min after LPS administration. There was a 15-fold increase in plasma nitrite/nitrate and significantly elevated tissue nitrite/nitrate in the lung, heart, liver, and intestine after 3 h of acute endotoxemia. Treatment with AG markedly decreased plasma nitrite/nitrate but did not alter the initial hypotension or cardiac depression. However, at 60 min after LPS administration the HR, MABP, and SVRI were higher in the AG-treated rats compared with vehicle, whereas CI and SVI remained depressed. Myeloperoxidase activity was significantly increased in the lung but not in the other tissues after LPS. The AG infusion significantly reduced tissue nitrite/nitrate in the lung and heart compared with LPS + Veh. The data suggest that neither NO nor acute inflammatory cell accumulation is solely responsible for the depressed cardiovascular function after intravenous administration of LPS.
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Affiliation(s)
- C E Hock
- Department of Medicine, School of Osteopathic Medicine, University of Medicine and Dentistry of New Jersey, Stratford 08084, USA
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39
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Abstract
We investigated the presence of Ca(2+)-activated Cl-channels in adult rat alveolar type II (ATII) using patch-clamp techniques. Only one active channel each, with a single channel conductance of 50 pS and an opening probability (Po) of 0.76 was found among 130 successful cell-attached and 5 inside-out patches. Addition of CPT-cAMP into the bath (500 microM) induced one active patch from 33 silent cell-attached patches. Incubation of 9 ATII cells, with ionomycin (1 microM), failed to elicit chloride single currents in 9 cell-attached patches. Cl- currents were also absent from 35 whole cell patches, even after the addition of 10 microM terbutaline in the bath or 1 mM ATP and 5 mM MgCl2 in the pipette. These results indicate that only a very small fraction of adult rat ATII cells express CFTR and suggest that Cl- ions are passively transported across the cell junctions.
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Affiliation(s)
- S Zhu
- Department of Anesthesiology, University of Alabama at Birmingham 35233, USA
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40
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Yue G, Sun FF, Dunn C, Yin K, Wong PY. The 21-aminosteroid tirilazad mesylate can ameliorate inflammatory bowel disease in rats. J Pharmacol Exp Ther 1996; 276:265-70. [PMID: 8558441] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The 21-aminosteroid tirilazad mesylate (U74006F) is a lipophilic antioxidant and free radical scavenger that has been reported to attenuate brain or spinal cord injury caused by trauma, stroke, ischemia and reperfusion injury. In this study, we have examined the effect of U74006F in reducing the inflammatory parameters of trinitrobenzene sulfonic acid (TNBS)-induced inflammatory bowel disease (IBD) in rats. To induce IBD, rats were given ethanolic TNBS intracolonically. Rats received either 1) TNBS and U74006F 2) TNBS and vehicle or 3) saline and vehicle. Rats were sacrificed 1, 2 and 3 weeks after IBD induction. Colon to body weight ratio (an index of tissue edema) was markedly increased in the vehicle-treated IBD rats after 1 week of administration of TNBS. The ratio was significantly lower after U74006F treatment and the trend remained even after 3 weeks of chronic inflammation. Myeloperoxidase (MPO) activity in vehicle-treated IBD rats was substantially increased compared with controls during the entire 3 weeks of the experiment. U74006F-treated animals had significantly reduced MPO activity (60% lower) when compared with vehicle-treated animals at the end of the second and third weeks. These observations were confirmed by histopathology studies showing reduced granulocyte infiltration after drug treatment. U74006F treatment decreased basal (by 70%) and fMLP stimulated (by 75%) superoxide generation from colonic tissue from IBD rats compared with vehicle treatment after 2 weeks, but there was no apparent difference in superoxide generation among all three groups after 3 weeks. The results of this study suggested that administration of U74006F effectively reduces the inflammatory parameters in this chronic rat model of IBD. As such, U74006F may be therapeutically beneficial for the treatment of IBD in humans.
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Affiliation(s)
- G Yue
- Department of Cell Biology, University of Medicine and Dentistry of New Jersey-School of Osteopathic Medicine, Stratford, USA
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41
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Yue G, Russell WJ, Benos DJ, Jackson RM, Olman MA, Matalon S. Increased expression and activity of sodium channels in alveolar type II cells of hyperoxic rats. Proc Natl Acad Sci U S A 1995; 92:8418-22. [PMID: 7667305 PMCID: PMC41168 DOI: 10.1073/pnas.92.18.8418] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We investigated the cellular and molecular events associated with the increase in sodium transport across the alveolar epithelium of rats exposed to hyperoxia (85% O2 for 7 days followed by 100% O2 for 4 days). Alveolar type II (ATII) cell RNA was isolated and probed with a cDNA for one of the rat colonic epithelial sodium channel subunits (alpha rENaC). The alpha rENaC mRNA (3.7-kb transcript) increased 3-fold in ATII cell RNA isolated from rats exposed to 85% O2 for 7 days and 6-fold after 4 days of subsequent exposure to 100% O2. In situ hybridization revealed increased expression of alpha rENaC mRNA transcripts in both airway and alveolar epithelial cells of hyperoxic rats. When immunostained with a polyclonal antibody to kidney sodium channel protein, ATII cells from hyperoxic rats exhibited a significant increase in the amount of immunogenic protein present in both the plasma membrane and the cytoplasm. When patched in the whole-cell mode, ATII cells from hyperoxic rats exhibited amiloride and 5-(N-ethyl-N-isopropyl)-2',4'-amiloride (EIPA)-sensitive currents that were 100% higher compared with those obtained from air-breathing rats. Single-channel sodium currents (mean conductance of 25 pS) were seen in ATII cells patched in both the inside-out and cell-attached modes. The number and open probability of these channels increased significantly during exposure to hyperoxia. Exposure to sublethal hyperoxia up-regulated both alpha rENaC mRNA and the functional expression of sodium channels in ATII cells.
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Affiliation(s)
- G Yue
- Department of Anesthesiology, University of Alabama at Birmingham 35233-6810, USA
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42
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Yue G, Fuglevand AJ, Nordstrom MA, Enoka RM. Limitations of the surface electromyography technique for estimating motor unit synchronization. Biol Cybern 1995; 73:223-233. [PMID: 7548311 DOI: 10.1007/bf00201424] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Motor unit synchronization was estimated from the surface electromyograms (EMG) of the first dorsal interosseus muscle of human volunteers by a simplified surface-EMG technique (Milner-Brown et al. 1973, 1975). Single motor units were identified from intramuscular recordings and were used to obtain a spike-triggered average of the surface-EMG. The discharge rate of a reference motor unit was controlled at two levels (high and low), and the effect of motor unit activity on the surface-EMG estimate of synchronization was studied in 56 motor units. The surface-EMG estimate of motor unit synchronization was significantly higher when the reference motor unit discharged at the high rate than when it discharged at the low rate. A regression analysis indicated that the synchronization ratio calculated from the surface EMG was significantly correlated with the level of EMG activity in the muscle. Motor unit synchronization was also estimated from surface-EMG measurements that were derived by computer simulation. The simulation permitted manipulation of motor unit activity (discharge rate and recruitment) with a complete absence of synchrony among the units in the pool. The stimulated surface-EMG index was influenced by an artifact associated with signal rectification, and this effect changed non-monotonically with motor unit activity. Furthermore, the increase in the motor unit activity reduced the signal-to-noise ratio of the spike-triggered surface EMG average, and consequently decreased the sensitivity of the surface-EMG index as an estimate of motor unit synchronization. We conclude that the simplified surface-EMG method (Milner-Brown et al. 1973, 1975) does not provide a useful index of motor unit synchronization due to its inability to accurately distinguish the synchronization from methodological effects related to a rectification artifact and variation in the signal-to-noise ratio.
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Affiliation(s)
- G Yue
- Department of Exercise & Sport Sciences, University of Arizona, USA
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43
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Wong PY, Yue G, Yin K, Miyasaka M, Lane CL, Manning AM, Anderson DC, Sun FF. Antibodies to intercellular adhesion molecule-1 ameliorate the inflammatory response in acetic acid-induced inflammatory bowel disease. J Pharmacol Exp Ther 1995; 274:475-80. [PMID: 7616434] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The transendothelial migration of leukocytes in many inflammatory responses is now believed to be dependent on the interaction of leukocyte and endothelial cell-derived adhesion molecules. To examine the role of intercellular adhesion molecule-1 (ICAM-1) in the development of inflammation in a rat model of colitis, we investigated the effects of antibodies to rat ICAM-1 given 24 hrs after inflammation was induced by acetic acid. Antibodies to rat ICAM-1 substantially ameliorated the inflammatory response as indicated by a reduction in gross inflammatory characteristics, tissue/body weight ratio, myeloperoxidase activity and superoxide levels. The results demonstrate that ICAM-1 plays an important role in the development of inflammatory bowel disease in rats. The use of antibodies to ICAM-1 to inhibit the adherence of leukocytes to endothelium, may be of potential therapeutic value in the treatment of inflammatory bowel disease in man.
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Affiliation(s)
- P Y Wong
- Department of Cell Biology, University of Medicine and Dentistry New Jersey, Stratford, USA
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Abstract
We determined the mechanisms by which beta-agonists increase sodium (Na+) currents across rat alveolar type II (ATII) cells grown in primary culture. When ATII cells were patched in the cell-attached mode using symmetrical Na+ solutions (150 mM Na(+)-glutamate), single-channel currents were observed for holding potentials between -80 and 30 mV (referenced to the pipette solution) with a single-channel conductance of 27 +/- 3 pS, a mean open time (tau 1) of 3.3 +/- 0.15 ms and an open probability (Po) of 0.36 +/- 0.06 (n = 7). Addition of 10 microM terbutaline into the bath increased tau 1 to 6.43 +/- 0.5 ms and Po to 0.62 +/- 0.06 (n = 7) without affecting channel conductance. Single-channel currents with a conductance of 25 +/- 2 pS were also recorded across ATII cells patched in the inside-out mode. Addition of 250 U/ml of protein kinase A (PKA), 1 mM ATP, and 5 mM MgCl2 in the bath solution (150 mM Na(+)-glutamate) increased the single channel tau 1 from 3.26 +/- 0.15 to 7.38 +/- 0.38 and Po from 0.41 +/- 0.06 to 0.72 +/- 0.07 (n = 6) without altering conductance. Addition of 1 microM amiloride or ethylisopropylamiloride (EIPA) in the pipette solution (150 mM Na(+)-glutamate) blocked single-channel activity almost completely. Ionic substitution experiments showed the relative permeability of Na+ to K+ and Na+ to Cl- to be 7:1 and 8:1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- G Yue
- Department of Anesthesiology, University of Alabama, Birmingham 35233
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46
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Yue G, Alexander AL, Laidlaw DH, Gmitro AF, Unger EC, Enoka RM. Sensitivity of muscle proton spin-spin relaxation time as an index of muscle activation. J Appl Physiol (1985) 1994; 77:84-92. [PMID: 7961279 DOI: 10.1152/jappl.1994.77.1.84] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The purpose of this study was to determine the minimum number of contractions that are needed to detect an increase in the muscle proton spin-spin relaxation time (T2) at a given exercise intensity. Five healthy human subjects performed five sets of an exercise that included concentric and eccentric contractions of the elbow-flexor muscles with loads that were 25 or 80% of maximum. With the 80% load, the five sets involved 1, 2, 5, 10, or 20 repetitions of the exercise; with the 25% load the five sets were 2, 5, 10, 20, or 40 repetitions. The upper arm of each subject was imaged before and immediately after each set of the exercise. Spin-echo images (repetition time/echo time = 2,000 ms/30, 60, 90, and 120 ms) were collected using an extremity coil, and T2 values were calculated. The signal intensity was measured from the elbow-flexor and -extensor muscles and from the bone marrow of the humerus. With the 80% load, T2 increased in the short head of the biceps brachii after two repetitions of the elbow exercise and after five repetitions in the brachialis and the long head of the biceps brachii. With the 25% load, T2 became longer after five repetitions of the exercise for the short head of the biceps brachii and after 10 repetitions for the brachialis and the long head of the biceps brachii. T2 varied linearly with the number of contraction repetitions for each of the elbow-flexor muscles at either load (r2 > or = 0.97, P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- G Yue
- Department of Physiology, University of Arizona, Tucson 85721
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Yue G, Alexander AL, Laidlaw DH, Gmitro AF, Unger EC, Enoka RM. 1093 SENSITIVITY OF MAGNETIC RESONANCE PROTON SPIN-SPIN RELAXATION TIME AS AN INDEX OF MUSCLE ACTIVATION. Med Sci Sports Exerc 1994. [DOI: 10.1249/00005768-199405001-01095] [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: 11/21/2022]
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48
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Abstract
We investigated whether exposure of rats to sublethal hyperoxia (85% O2 for 7 days) raises the levels of proteins antigenically related to Na+ channels in alveolar type II (ATII) cells and, if so, whether this rise was accompanied by an increase in conductive Na+ transport in vitro. ATII cells were isolated from the lungs of these rats at the end of the exposure period. In Western blot studies, a polyclonal antibody raised against Na+ channel protein (NaAb), recognized in a specific manner a 135 +/- 10 kDa polypeptide in plasma membrane vesicles of ATII cells from both control and oxygen-exposed rats. However, higher levels of immunoreactivity were seen in ATII cells from oxygen-exposed rats. When ATII cells were patched in the whole cell mode using symmetrical solutions (150 mM Na(+)-glutamate), outward rectified Na+ currents were observed. When corrected for cell capacitance, both inward and outward currents of ATII cells from rats exposed to hyperoxia were significantly higher than control. Addition of either 1 microM amiloride or 1 microM 5-(N-ethyl-N-isopropyl)-2'-4'-amiloride in the bath solution decreased the magnitude of outward currents of both control and hyperoxic ATII cells by approximately 50%. Taken together, these results indicate that exposure of rats to sublethal hyperoxia results in upregulation of ATII cell conductive pathways with low affinity to amiloride and increased Na+ transport. This may be an early adaptive response that limits the degree of alveolar edema in injured lungs.
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Affiliation(s)
- J F Haskell
- Department of Anesthesiology, University of Alabama at Birmingham 35233-6810
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49
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Abstract
The purpose of this study was to evaluate the effects of the levels of voluntary isometric contraction on the Hoffman reflex in human soleus and medial gastrocnemius (MG) muscles. H-reflexes were recorded in sixteen healthy adults at each of 16 isometric plantarflexion (pf) torque levels ranging from 0-100% of their maximum voluntary isometric contraction (MVC) and were elicited at two intensities of stimulation: (i) supramaximal for M-response and (ii) a submaximal stimulus that produced an H-reflex in soleus that was 50% of maximum H-reflex at rest. The H-reflex peak-to-peak amplitudes were linearly related to pf torque levels ranging from 0 to 50% MVC at both supramaximal and submaximal stimulus intensities. The slope of this relationship was higher for the submaximal stimulation. Beyond 60% of MVC, the soleus H-reflex amplitude showed no further increase with increasing pf torque for both stimulus intensities. Thus, beyond 50-60% of MVC the soleus H-reflex does not provide an accurate measure of soleus motor neuron pool excitability. Further experimental results showed that the H-reflex amplitude at a given torque level depended on whether torque was increasing or decreasing. When torque was increasing, the amplitude of the H-reflex was larger than when the same torque was maintained at a constant level. In contrast, if the torque was decreasing, amplitude of the reflex was lower than when torque was increasing. Therefore, variations in H-reflex amplitudes at a given torque level may be more closely correlated to the direction of the ongoing contraction than to the actual muscle force being produced at the time the H-reflex is elicited.
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Affiliation(s)
- A J Butler
- Department of Exercise Science, University of Iowa, Iowa City 52242
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50
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Yue G, Hu P, Oh Y, Jilling T, Shoemaker RL, Benos DJ, Cragoe EJ, Matalon S. Culture-induced alterations in alveolar type II cell Na+ conductance. Am J Physiol 1993; 265:C630-40. [PMID: 8214019 DOI: 10.1152/ajpcell.1993.265.3.c630] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Changes in Na+ transport in rat alveolar type II (ATII) cells during culture were quantified and related to alterations in spatial distribution of proteins antigenically related to amiloride-sensitive Na+ channels. Adult rat ATII cells were cultured for periods ranging from 24 to 96 h. When patch clamped in the whole cell mode, both freshly isolated and cultured ATII cells exhibited outwardly rectified Na+ currents. At 0 and 24 h in culture, these currents were equally inhibited by amiloride, benzamil, and 5-(N-ethyl-N-isopropyl)-2',4'-amiloride (inhibitory constant approximately 1 microM). These conductive pathways were equally permeable to Na+ and K+. Immunocytochemical localization at 0 or 24 h in culture revealed the presence of plasma membrane antigenic sites; after 48 h, the appearance of intracellular antigenic sites increased significantly. A single band of molecular mass 135 kDa in membrane proteins of freshly isolated ATII cells was recognized in Western blots; at 48 h in culture, two lower bands with molecular masses of 75 and 65 kDa were detected in either membrane or cytoplasmic proteins. Photolabeling with 2'-methoxy-5'-nitrobenzamil showed that the 135-, 75-, and 65-kDa bands contained amiloride-binding sites. These results suggest the presence of low amiloride affinity conductive pathways in freshly isolated and cultured ATII cells. Culturing ATII cells resulted in internalization and possible breakdown of these pathways and decreased Na+ transport.
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Affiliation(s)
- G Yue
- Department of Anesthesiology, University of Alabama at Birmingham 35294
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