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Zeng A, Li Y, Lyu L, Zhang S, Zhang Y, Ding H, Li L. Risk factors and predictive nomograms for bedside emergency endoscopic treatment following endotracheal intubation in cirrhotic patients with esophagogastric variceal bleeding. Sci Rep 2024; 14:9467. [PMID: 38658605 PMCID: PMC11043454 DOI: 10.1038/s41598-024-59802-0] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 04/15/2024] [Indexed: 04/26/2024] Open
Abstract
Data on emergency endoscopic treatment following endotracheal intubation in patients with esophagogastric variceal bleeding (EGVB) remain limited. This retrospective study aimed to explore the efficacy and risk factors of bedside emergency endoscopic treatment following endotracheal intubation in severe EGVB patients admitted in Intensive Care Unit. A total of 165 EGVB patients were enrolled and allocated to training and validation sets in a randomly stratified manner. Univariate and multivariate logistic regression analyses were used to identify independent risk factors to construct nomograms for predicting the prognosis related to endoscopic hemostasis failure rate and 6-week mortality. In result, white blood cell counts (p = 0.03), Child-Turcotte-Pugh (CTP) score (p = 0.001) and comorbid shock (p = 0.005) were selected as independent clinical predictors of endoscopic hemostasis failure. High CTP score (p = 0.003) and the presence of gastric varices (p = 0.009) were related to early rebleeding after emergency endoscopic treatment. Furthermore, the 6-week mortality was significantly associated with MELD scores (p = 0.002), the presence of hepatic encephalopathy (p = 0.045) and postoperative rebleeding (p < 0.001). Finally, we developed practical nomograms to discern the risk of the emergency endoscopic hemostasis failure and 6-week mortality for EGVB patients. In conclusion, our study may help identify severe EGVB patients with higher hemostasis failure rate or 6-week mortality for earlier implementation of salvage treatments.
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Affiliation(s)
- Ajuan Zeng
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital Affiliated to Capital Medical University, Beijing, 100069, China
| | - Yangjie Li
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital Affiliated to Capital Medical University, Beijing, 100069, China
| | - Lingna Lyu
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital Affiliated to Capital Medical University, Beijing, 100069, China
| | - Shibin Zhang
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital Affiliated to Capital Medical University, Beijing, 100069, China
| | - Yuening Zhang
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital Affiliated to Capital Medical University, Beijing, 100069, China
| | - Huiguo Ding
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital Affiliated to Capital Medical University, Beijing, 100069, China.
| | - Lei Li
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital Affiliated to Capital Medical University, Beijing, 100069, China.
- Department of Gastroenterology, Beijing Jishuitan Hospital, Capital Medical University, Beijing, 102208, China.
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Sayoga G, Bueschler V, Beisch H, Zeng A, Fiedler B, Liese A. Bioelectrochemical Hydroxylation by Unspecific Peroxygenase in an All‐in‐One Electrode System. CHEM-ING-TECH 2022. [DOI: 10.1002/cite.202255187] [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: 11/07/2022]
Affiliation(s)
- G. V. Sayoga
- Hamburg University of Technology Institute of Technical Biocatalysis Denickestr. 15 21073 Hamburg Germany
| | - V. S. Bueschler
- Hamburg University of Technology Institute of Technical Biocatalysis Denickestr. 15 21073 Hamburg Germany
| | - H. Beisch
- Hamburg University of Technology Institute of Polymers and Composites Denickestr. 15 21073 Hamburg Germany
| | - A. Zeng
- Hamburg University of Technology Institute of Bioprocess and Biosystems Engineering Denickestr. 15 21073 Hamburg Germany
| | - B. Fiedler
- Hamburg University of Technology Institute of Polymers and Composites Denickestr. 15 21073 Hamburg Germany
| | - A. Liese
- Hamburg University of Technology Institute of Technical Biocatalysis Denickestr. 15 21073 Hamburg Germany
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Zhou Q, Li J, Wang J, Yang L, Fang J, Dong X, Yi T, Min X, Xu F, Chen J, Zhong D, Bai J, Liu L, Zeng A, Tang J, Wu H, Luo X, Yu J, Su W, Wu YL. EP08.02-063 SANOVO: A Phase 3 Study of Savolitinib or Placebo in Combination with Osimertinib in Patients with EGFR-mutant and MET Overexpressed NSCLC. J Thorac Oncol 2022. [DOI: 10.1016/j.jtho.2022.07.745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Herzog J, Mook A, Bengelsdorf F, Zeng A. Caproate production from CO
2
and H
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in synthetic co‐culture with lactate‐dependent process control. CHEM-ING-TECH 2022. [DOI: 10.1002/cite.202255186] [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: 11/06/2022]
Affiliation(s)
- J. Herzog
- Hamburg University of Technology Institute of Bioprocess and Biosystems Engineering Denickestr. 15 21073 Hamburg Germany
| | - A. Mook
- Ulm University Institute of Microbiology and Biotechnology Albert-Einstein-Allee 11 89081 Ulm Germany
| | - F. R. Bengelsdorf
- Ulm University Institute of Microbiology and Biotechnology Albert-Einstein-Allee 11 89081 Ulm Germany
| | - A. Zeng
- Hamburg University of Technology Institute of Bioprocess and Biosystems Engineering Denickestr. 15 21073 Hamburg Germany
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Jiang Q, Li Q, Liu B, Li G, Riedemann G, Gaitantzi H, Breitkopf-Heinlein K, Zeng A, Ding H, Xu K. BMP9 promotes methionine- and choline-deficient diet-induced nonalcoholic steatohepatitis in non-obese mice by enhancing NF-κB dependent macrophage polarization. Int Immunopharmacol 2021; 96:107591. [PMID: 33812253 DOI: 10.1016/j.intimp.2021.107591] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 02/22/2021] [Accepted: 03/11/2021] [Indexed: 12/24/2022]
Abstract
Our previous study confirmed that bone morphogenetic protein 9 (BMP9) participated in the development of nonalcoholic steatohepatitis (NASH) by affecting macrophage polarization. The focus of this study was to further confirm the role of macrophages in BMP9-mediated NASH and to analyze the underlying mechanism. In vivo, mice that were administered adeno-associated viral (AAV) vectors containing a null transgene (AAV-null) or the BMP9 transgene (AAV-BMP9) were divided into methionine- and choline-deficient (MCD) and control diet (CD) groups, and they were administered either control liposomes or clodronate liposomes via tail vein injection, the latter to deplete macrophages. The mice were sacrificed after 4 weeks of MCD diet feeding. In vitro, RAW264.7 cells were pretreated with or without BAY11-7085 (an NF-κB inhibitor) and stimulated with recombinant human BMP9 (rh-BMP9). To explore the underlying mechanism of action of BMP9, primary human monocyte-derived macrophages were additionally investigated and immunohistochemistry, biochemical assays, qRT-PCR, and Western blotting were used. The characteristics of NASH-related inflammation were assessed by hepatic histological analysis. Serum AST and ALT and hepatic triglyceride were examined by biochemical assays. We found that the expression of M1 macrophage genes (including CD86, IL1β, IL6, MCP-1 and TNFα) and the number of M1 macrophages (iNOS+ macrophages) in the liver were significantly elevated after BMP9 overexpression and BMP9 directly upregulated TLR4 expression in MCD-induced NASH. These effects were eliminated by macrophage depletion. In vitro, we discovered that BMP9 enhanced the nuclear translocation of NF-κB to induce macrophage M1 polarization in RAW264.7 cells and it promoted LPS-mediated activation of the NF-κB pathway in primary human macrophages. Taken together, this study demonstrates that BMP9 promotes NASH development by directly acting on macrophages.
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Affiliation(s)
- Qianqian Jiang
- Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Qi Li
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital Affiliated with Capital Medical University, Beijing 100069, China
| | - Beibei Liu
- Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Guixin Li
- Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Gabriel Riedemann
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim 68167, Germany
| | - Haristi Gaitantzi
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim 68167, Germany; Department of Surgery, Medical Faculty Mannheim, Heidelberg University, Mannheim 68167, Germany
| | - Katja Breitkopf-Heinlein
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim 68167, Germany; Department of Surgery, Medical Faculty Mannheim, Heidelberg University, Mannheim 68167, Germany
| | - Ajuan Zeng
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital Affiliated with Capital Medical University, Beijing 100069, China
| | - Huiguo Ding
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital Affiliated with Capital Medical University, Beijing 100069, China.
| | - Keshu Xu
- Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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May K, Jilcott Pitts S, Stage VC, Kelley CJ, Burkholder S, Fang X, Zeng A, Lazorick S. Use of the Veggie Meter® as a tool to objectively approximate fruit and vegetable intake among youth for evaluation of preschool and school-based interventions. J Hum Nutr Diet 2020; 33:869-875. [PMID: 32281191 DOI: 10.1111/jhn.12755] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [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: 12/16/2019] [Revised: 03/13/2020] [Accepted: 03/15/2020] [Indexed: 12/31/2022]
Abstract
BACKGROUND Reflection spectroscopy is an emerging, non-invasive objective measure used to approximate fruit and vegetable intake. The present study aimed to use a reflection spectroscopy device (the Veggie Meter®, Longevity Link Corporation, Salt Lake City, UT, USA) to assess skin carotenoid status in preschool, middle- and high-school students and to examine associations between skin carotenoids and self-reported dietary intake. METHODS In Autumn 2018, we used the Veggie Meter® to assess skin carotenoids and age-appropriate validated dietary assessment measures to approximate fruit and vegetable (FV) intake. Preschool participants completed a previously validated pictorial liking tool using an iPad (Apple Inc., Cupertino, CA, USA). Middle-school participants completed selected questions from the validated School Physical Activity and Nutrition (SPAN) (Michael & Susan Dell Center for Healthy Living, University of Texas, Austin, TX, USA) questionnaire regarding frequency of their FV and beverage intake on the previous day, with additional questions about physical activity. High-school participants' FV intake was assessed using the Fruit and Vegetable Screener (National Cancer Institute, Bethesda, MD, USA). Spearman correlation coefficients were used to determine bivariate associations between measures of dietary intake and Veggie Meter®-assessed skin carotenoid levels. RESULTS Mean (SD) Veggie Meter® readings were 266 (82.9), 219 (68.1) and 216 (67.2) among preschool, middle- and high-school students. There was an inverse association between soda intake and Veggie Meter® readings (r = -0.22, P = 0.03) among middle-school students; and a positive association between daily fruit intake and Veggie Meter® readings (r = 0.25, P = 0.06) among high-school students. CONCLUSIONS The Veggie Meter® comprises a promising evaluation tool for preschool and school-based nutrition interventions.
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Affiliation(s)
- K May
- Brody School of Medicine at East Carolina University, Greenville, NC, USA
| | - S Jilcott Pitts
- Department of Public Health, East Carolina University, Greenville, NC, USA
| | - V C Stage
- Department of Nutrition Science, College of Allied Health Sciences, East Carolina University, Greenville, NC, USA
| | - C J Kelley
- Department of Public Health, East Carolina University, Greenville, NC, USA
| | - S Burkholder
- Department of Nutrition Science, College of Allied Health Sciences, East Carolina University, Greenville, NC, USA
| | - X Fang
- Department of Biostatistics, College of Allied Health Sciences, East Carolina University, Greenville, NC, USA
| | - A Zeng
- ECU Honors Medical Research Program, Greenville, NC, USA
| | - S Lazorick
- Departments of Pediatrics and Public Health, East Carolina University, Greenville, NC, USA
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Fujita M, Domae Y, Noda A, Garcia Ricardez GA, Nagatani T, Zeng A, Song S, Rodriguez A, Causo A, Chen IM, Ogasawara T. What are the important technologies for bin picking? Technology analysis of robots in competitions based on a set of performance metrics. Adv Robot 2019. [DOI: 10.1080/01691864.2019.1698463] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- M. Fujita
- Corporate Research and Development, Mitsubishi Electric Corporation, Tokyo, Japan
| | - Y. Domae
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - A. Noda
- Faculty of Robotics and Design, Osaka Institute of Technology, Osaka, Japan
| | - G. A. Garcia Ricardez
- Division of Information Science, Nara Institute of Science and Technology, Nara, Japan
| | - T. Nagatani
- Corporate Research and Development, Mitsubishi Electric Corporation, Tokyo, Japan
| | - A. Zeng
- Department of Computer Science, Princeton University, Princeton, NJ, USA
| | - S. Song
- Department of Computer Science, Princeton University, Princeton, NJ, USA
| | - A. Rodriguez
- Mechanical Engineering Department, Massachusetts Institute of Technology, Boston, MA, USA
| | - A. Causo
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - I. M. Chen
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - T. Ogasawara
- Division of Information Science, Nara Institute of Science and Technology, Nara, Japan
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Liu Z, Li W, Zeng A, Meng P, Cheng M, Xu C, Tao Y, Shen Z, Zhang S, Li Z. 028 Is suction blister epidermal grafting a simple and reliable way to screen patients with large area vitiligo for ReCell treatment? J Invest Dermatol 2017. [DOI: 10.1016/j.jid.2017.07.124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Zeng A, Chen P, Korth K, Hancock F, Pereira A, Brye K, Wu C, Shi A. Genome-wide association study (GWAS) of salt tolerance in worldwide soybean germplasm lines. Mol Breeding 2017. [PMID: 0 DOI: 10.1007/s11032-017-0634-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
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Han Y, Zeng A, Liao H, Liu Y, Chen Y, Ding H. The efficacy and safety comparison between tenofovir and entecavir in treatment of chronic hepatitis B and HBV related cirrhosis: A systematic review and Meta-analysis. Int Immunopharmacol 2016; 42:168-175. [PMID: 27915131 DOI: 10.1016/j.intimp.2016.11.022] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [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: 08/15/2016] [Revised: 10/09/2016] [Accepted: 11/21/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND The purpose of this study was to assess the efficacy and safety between tenofovir and entecavir in the treatment of CHB and HBV related cirrhosis through Meta-analysis. Methods The electronic databases of PubMed, the Cochrane Library, Nature, CNKI and WanFang data were searched. The key words were: ("tenofovir", "entecavir") and ("Chronic Hepatitis B" or "CHB") and "Liver cirrhosis". Heterogeneity and report bias were analyzed. RESULTS There was significant difference of ALT norm level in the short-term period of 3months (RR=1.43, 95%CI: 1.06-1.94, P<0.017) and 6months (RR=0.89, 95%CI: 0.81-0.97, P<0.017), and significant difference of undetectable HBV-DNA only in 3months follow-up period (RR=1.59, 95%CI: 1.04-2.42, P<0.017) between TDF and ETV, but no significant difference in the long-term period. There is significant difference between TDF and ETV in eGFR level (RR=1.601, 95%CI: 1.035-2.478, P=0.0034) and hypophosphatemia incidence (RR=4.008, 95%CI: 1.485-10.820, P=0.006). CONCLUSION TDF has a better efficacy than ETV in 3months treatment duration, but intriguingly, TDF might not better than ETV during the 6months treatment period in the viral suppression and liver function improvement. There's no significant difference between TDF and ETV in the long-term treatment duration and in the treatment of HBV related liver cirrhosis. Both TDF and ETV could influence renal function but patients under TDF therapy may have more risk to suffer from renal damage and hypophosphatemia.
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Affiliation(s)
- Ying Han
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital affiliated with Capital Medical University, China
| | - Ajuan Zeng
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital affiliated with Capital Medical University, China
| | - Huiyu Liao
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital affiliated with Capital Medical University, China
| | - Yanmin Liu
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital affiliated with Capital Medical University, China
| | - Yuhan Chen
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital affiliated with Capital Medical University, China
| | - Huiguo Ding
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital affiliated with Capital Medical University, China.
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Crist RC, Ambrose-Lanci LM, Vaswani M, Clarke TK, Zeng A, Yuan C, Ferraro TN, Hakonarson H, Kampman KM, Dackis CA, Pettinati HM, O'Brien CP, Oslin DW, Doyle GA, Lohoff FW, Berrettini WH. Case-control association analysis of polymorphisms in the δ-opioid receptor, OPRD1, with cocaine and opioid addicted populations. Drug Alcohol Depend 2013; 127:122-8. [PMID: 22795689 PMCID: PMC3509227 DOI: 10.1016/j.drugalcdep.2012.06.023] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 06/18/2012] [Accepted: 06/21/2012] [Indexed: 11/27/2022]
Abstract
BACKGROUND Addiction susceptibility and treatment responsiveness are greatly influenced by genetic factors. Sequence variation in genes involved in the mechanisms of drug action have the potential to influence addiction risk and treatment outcome. The opioid receptor system is involved in mediating the rewarding effects of cocaine and opioids. The μ-opioid receptor (MOR) has traditionally been considered the primary target for opioid addiction. The MOR, however, interacts with and is regulated by many known MOR interacting proteins (MORIPs), including the δ-opioid receptor (DOR). METHODS The present study evaluated the contribution of OPRD1, the gene encoding the DOR, to the risk of addiction to opioids and cocaine. The association of OPRD1 polymorphisms with both opioid addiction (OA) and cocaine addiction (CA) was analyzed in African American (OA n=336, CA n=503) and European American (OA n=1007, CA n=336) populations. RESULTS The primary finding of this study is an association of rs678849 with cocaine addiction in African Americans (allelic p=0.0086). For replication purposes, this SNP was analyzed in a larger independent population of cocaine addicted African Americans and controls and the association was confirmed (allelic p=4.53 × 10(-5); n=993). By performing a meta-analysis on the expanded populations, the statistical evidence for an association was substantially increased (allelic p=8.5 × 10(-7)) (p-values non-FDR corrected). CONCLUSION The present study suggests that polymorphisms in OPRD1 are relevant for cocaine addiction in the African American population and provides additional support for a broad role for OPRD1 variants in drug dependence.
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Affiliation(s)
- R C Crist
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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Nusse R, Fuerer C, Ching W, Harnish K, Logan C, Zeng A, ten Berge D, Kalani Y. Wnt signaling and stem cell control. Cold Spring Harb Symp Quant Biol 2008; 73:59-66. [PMID: 19028988 DOI: 10.1101/sqb.2008.73.035] [Citation(s) in RCA: 186] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In many contexts, self-renewal and differentiation of stem cells are influenced by signals from their environment, constituting a niche. It is postulated that stem cells compete for local growth factors in the niche, thereby maintaining a balance between the numbers of self-renewing and differentiated cells. A critical aspect of the niche model for stem cell regulation is that the availability of self-renewing factors is limited and that stem cells compete for these factors (Fig. 1). Consequently, the range and concentrations of the niche factors are of critical importance. Now that some of the few self-renewing factors have become identified, aspects of the niche models can be tested experimentally. In this chapter, we address mechanisms of signal regulation that take place at the level of signal-producing cells, constituting a niche for stem cells. We emphasize the biochemical properties and posttranslational modifications of the signals, all in the context of Wnt signaling. We propose that these modifications control the range of Wnt signaling and have critical roles in establishing niches for stem cells in various tissues.
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Affiliation(s)
- R Nusse
- Howard Hughes Medical Institute, Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA
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Menzel K, Ahrens K, Zeng A, Deckwer W. Kinetic, dynamic, and pathway studies of glycerol metabolism by Klebsiella pneumoniae in anaerobic continuous culture: IV. Enzymes and fluxes of pyruvate metabolism. Biotechnol Bioeng 1998; 60:617-26. [PMID: 10099470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The activities of pyruvate kinase (PK), pyruvate: formate-lyase (PFL), pyruvate dehydrogenase (PDH), and citrate synthase (CS) involved in the anaerobic glycerol conversion by Klebsiella pneumoniae were studied in continuous culture under conditions of steady states and sustained oscillations. Both the in vitro and in vivo activities of PK, PFL, and PDH are strongly affected by the substrate concentration and its uptake rate, as is the in vitro activity of CS. The flux from phosphoenolpyruvate to pyruvate is found to be mainly regulated on a genetic level by the synthesis rate of PK, particularly at low substrate concentration and low growth rate. In contrast, the conversion of pyruvate to acetyl-CoA is mainly regulated on a metabolic level by the in vivo activities of PFL and PDH. The ratio of in vitro to in vivo activities is in the range of 1 to 1.5 for PK, 5 to 17 for PFL and 5 to 80 for PDH under the experimental conditions. The regulation of in vivo activity and synthesis of these enzymes is sensitive to fluctuations of culture conditions, leading to oscillations of both the in vitro and in vivo activities. In particular, PFL is strongly affected during oscillations; its average in vitro activity is only about half of its corresponding steady-state value under similar environmental conditions. The average in vitro activities of PDH and PK under oscillations are close to their corresponding steady-state values. In contrast to all other enzymes measured for the glycerol metabolism by K. pneumoniae PFL and PDH are more effectively in vivo utilized under oscillations than under steady state, underlining the peculiar role of pyruvate metabolism in the dynamic responses of the culture.
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Affiliation(s)
- K Menzel
- GBF-Gesellschaft für Biotechnologische Forschung mbH, Biochemical Engineering Division, Mascheroder Weg 1, D-38124 Braunschweig Germany
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Ahrens K, Menzel K, Zeng A, Deckwer W. Kinetic, dynamic, and pathway studies of glycerol metabolism by Klebsiella pneumoniae in anaerobic continuous culture: III. Enzymes and fluxes of glycerol dissimilation and 1,3-propanediol formation. Biotechnol Bioeng 1998; 59:544-52. [PMID: 10099370 DOI: 10.1002/(sici)1097-0290(19980905)59:5<544::aid-bit3>3.0.co;2-a] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.2] [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: 11/09/2022]
Abstract
The initial steps of glycerol dissimilation and 1,3-propanediol (1, 3-PD) formation by Klebsiella pneumoniae anaerobically grown on glycerol were studied by quantifying the in vitro and in vivo activities of enzymes in continuous culture under conditions of steady state and oscillation and during transient phases. The enzymes studied included glycerol dehydrogenase (GDH), glycerol dehydratase (GDHt), and 1,3-propanediol oxidoreductase (PDOR). Three conclusions can be drawn from the steady-state results. First, glycerol concentration in the culture is a key parameter that inversely affects the in vitro activities (concentrations) of all three enzymes, but has a positive effect on their in vivo activities. Growth rate significantly affects the ratio of in vitro and in vivo enzyme activities under low glycerol concentrations, but not under glycerol excess. Second, whereas the flux through the oxidative pathway of glycerol dissimilation is governed mainly by the regulation of in vivo enzyme activity on a metabolic level, the flux through the reductive pathway is largely controlled by the synthesis of enzymes. Third, GDHt is a major rate-liming enzyme for the consumption of glycerol and the formation of 1,3-PD in K. pneumoniae at high glycerol concentrations. Results from oscillating cultures revealed that both in vitro and in vivo activities of the enzymes oscillated. The average values of the in vitro activities during an oscillation cycle agreed well with their corresponding values for nonoscillating cultures under similar environmental conditions. Experiments with step changes in the feed concentration of glycerol demonstrated that growth and product formation are very sensitive to changes of substrate concentration in the culture. This sensitivity is due to the dynamic responses of the genetic and metabolic networks. They should be considered when modeling the dynamics of the culture and attempting to improve the formation of 1,3-PD.
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Affiliation(s)
- K Ahrens
- GBF-Gesellschaft für Biotechnologische Forschung mbH, Biochemical Engineering Division, Mascheroder Weg 1, D-38124 Braunschweig, Germany
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