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Bonilla DA, Kreider RB, Stout JR, Forero DA, Kerksick CM, Roberts MD, Rawson ES. Metabolic Basis of Creatine in Health and Disease: A Bioinformatics-Assisted Review. Nutrients 2021; 13:nu13041238. [PMID: 33918657 PMCID: PMC8070484 DOI: 10.3390/nu13041238] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/01/2021] [Accepted: 04/07/2021] [Indexed: 02/06/2023] Open
Abstract
Creatine (Cr) is a ubiquitous molecule that is synthesized mainly in the liver, kidneys, and pancreas. Most of the Cr pool is found in tissues with high-energy demands. Cr enters target cells through a specific symporter called Na+/Cl−-dependent Cr transporter (CRT). Once within cells, creatine kinase (CK) catalyzes the reversible transphosphorylation reaction between [Mg2+:ATP4−]2− and Cr to produce phosphocreatine (PCr) and [Mg2+:ADP3−]−. We aimed to perform a comprehensive and bioinformatics-assisted review of the most recent research findings regarding Cr metabolism. Specifically, several public databases, repositories, and bioinformatics tools were utilized for this endeavor. Topics of biological complexity ranging from structural biology to cellular dynamics were addressed herein. In this sense, we sought to address certain pre-specified questions including: (i) What happens when creatine is transported into cells? (ii) How is the CK/PCr system involved in cellular bioenergetics? (iii) How is the CK/PCr system compartmentalized throughout the cell? (iv) What is the role of creatine amongst different tissues? and (v) What is the basis of creatine transport? Under the cellular allostasis paradigm, the CK/PCr system is physiologically essential for life (cell survival, growth, proliferation, differentiation, and migration/motility) by providing an evolutionary advantage for rapid, local, and temporal support of energy- and mechanical-dependent processes. Thus, we suggest the CK/PCr system acts as a dynamic biosensor based on chemo-mechanical energy transduction, which might explain why dysregulation in Cr metabolism contributes to a wide range of diseases besides the mitigating effect that Cr supplementation may have in some of these disease states.
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Affiliation(s)
- Diego A. Bonilla
- Research Division, Dynamical Business & Science Society–DBSS International SAS, Bogotá 110861, Colombia
- Research Group in Biochemistry and Molecular Biology, Universidad Distrital Francisco José de Caldas, Bogotá 110311, Colombia
- Research Group in Physical Activity, Sports and Health Sciences (GICAFS), Universidad de Córdoba, Montería 230002, Colombia
- kDNA Genomics, Joxe Mari Korta Research Center, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain
- Correspondence: ; Tel.: +57-320-335-2050
| | - Richard B. Kreider
- Exercise & Sport Nutrition Laboratory, Human Clinical Research Facility, Texas A&M University, College Station, TX 77843, USA;
| | - Jeffrey R. Stout
- Physiology of Work and Exercise Response (POWER) Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL 32816, USA;
| | - Diego A. Forero
- Professional Program in Sport Training, School of Health and Sport Sciences, Fundación Universitaria del Área Andina, Bogotá 111221, Colombia;
| | - Chad M. Kerksick
- Exercise and Performance Nutrition Laboratory, School of Health Sciences, Lindenwood University, Saint Charles, MO 63301, USA;
| | - Michael D. Roberts
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA;
- Edward via College of Osteopathic Medicine, Auburn, AL 36849, USA
| | - Eric S. Rawson
- Department of Health, Nutrition and Exercise Science, Messiah University, Mechanicsburg, PA 17055, USA;
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Antonio J, Candow DG, Forbes SC, Gualano B, Jagim AR, Kreider RB, Rawson ES, Smith-Ryan AE, VanDusseldorp TA, Willoughby DS, Ziegenfuss TN. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? J Int Soc Sports Nutr 2021; 18:13. [PMID: 33557850 PMCID: PMC7871530 DOI: 10.1186/s12970-021-00412-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/28/2021] [Indexed: 01/01/2023] Open
Abstract
Supplementing with creatine is very popular amongst athletes and exercising individuals for improving muscle mass, performance and recovery. Accumulating evidence also suggests that creatine supplementation produces a variety of beneficial effects in older and patient populations. Furthermore, evidence-based research shows that creatine supplementation is relatively well tolerated, especially at recommended dosages (i.e. 3-5 g/day or 0.1 g/kg of body mass/day). Although there are over 500 peer-refereed publications involving creatine supplementation, it is somewhat surprising that questions regarding the efficacy and safety of creatine still remain. These include, but are not limited to: 1. Does creatine lead to water retention? 2. Is creatine an anabolic steroid? 3. Does creatine cause kidney damage/renal dysfunction? 4. Does creatine cause hair loss / baldness? 5. Does creatine lead to dehydration and muscle cramping? 6. Is creatine harmful for children and adolescents? 7. Does creatine increase fat mass? 8. Is a creatine 'loading-phase' required? 9. Is creatine beneficial for older adults? 10. Is creatine only useful for resistance / power type activities? 11. Is creatine only effective for males? 12. Are other forms of creatine similar or superior to monohydrate and is creatine stable in solutions/beverages? To answer these questions, an internationally renowned team of research experts was formed to perform an evidence-based scientific evaluation of the literature regarding creatine supplementation.
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Affiliation(s)
- Jose Antonio
- Department of Health and Human Performance, Nova Southeastern University, Davie, Florida, USA.
| | - Darren G Candow
- Faculty of Kinesiology and Health Studies, University of Regina, Regina, Canada
| | - Scott C Forbes
- Department of Physical Education, Faculty of Education, Brandon University, Brandon, MB, Canada
| | - Bruno Gualano
- Applied Physiology & Nutrition Research Group; School of Medicine, FMUSP, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Andrew R Jagim
- Sports Medicine Department, Mayo Clinic Health System, La Crosse, WI, USA
| | - Richard B Kreider
- Exercise & Sport Nutrition Lab, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, USA
| | - Eric S Rawson
- Department of Health, Nutrition, and Exercise Science, Messiah University, Mechanicsburg, PA, USA
| | - Abbie E Smith-Ryan
- Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC, USA
| | - Trisha A VanDusseldorp
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, GA, USA
| | - Darryn S Willoughby
- School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, TX, USA
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Warepam M, Ahmad K, Rahman S, Rahaman H, Kumari K, Singh LR. N-Acetylaspartate Is an Important Brain Osmolyte. Biomolecules 2020; 10:biom10020286. [PMID: 32059525 PMCID: PMC7072545 DOI: 10.3390/biom10020286] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/29/2020] [Accepted: 02/08/2020] [Indexed: 01/11/2023] Open
Abstract
Most of the human diseases related to various proteopathies are confined to the brain, which leads to the development of various forms of neurological disorders. The human brain consists of several osmolytic compounds, such as N-Acetylaspartate (NAA), myo-inositol (mI), glutamate (Glu), glutamine (Gln), creatine (Cr), and choline-containing compounds (Cho). Among these osmolytes, the level of NAA drastically decreases under neurological conditions, and, hence, NAA is considered to be one of the most widely accepted neuronal biomarkers in several human brain disorders. To date, no data are available regarding the effect of NAA on protein stability, and, therefore, the possible effect of NAA under proteopathic conditions has not been fully uncovered. To gain an insight into the effect of NAA on protein stability, thermal denaturation and structural measurements were carried out using two model proteins at different pH values. The results indicate that NAA increases the protein stability with an enhancement of structure formation. We also observed that the stabilizing ability of NAA decreases in a pH-dependent manner. Our study indicates that NAA is an efficient protein stabilizer at a physiological pH.
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Affiliation(s)
- Marina Warepam
- Department of Biotechnology, Manipur University, Manipur 795003, India; (M.W.); (H.R.)
| | - Khurshid Ahmad
- Department of Medical Biotechnology, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Korea;
| | - Safikur Rahman
- Department of Botany, Munshi Singh College, BR Ambedkar Bihar University, Muzaffarpur, Bihar 845401, India;
| | - Hamidur Rahaman
- Department of Biotechnology, Manipur University, Manipur 795003, India; (M.W.); (H.R.)
| | - Kritika Kumari
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India;
| | - Laishram Rajendrakumar Singh
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India;
- Correspondence: ; Tel.: +91-9811630757; Fax: +91-11-27666248
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Xu J, Sun J, Ho PY, Luo Z, Ma W, Zhao W, Rathod SB, Fernandez CA, Venkataramanan R, Xie W, Yu AM, Li S. Creatine based polymer for codelivery of bioengineered MicroRNA and chemodrugs against breast cancer lung metastasis. Biomaterials 2019; 210:25-40. [PMID: 31054369 PMCID: PMC6538300 DOI: 10.1016/j.biomaterials.2019.04.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [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: 01/27/2019] [Revised: 04/05/2019] [Accepted: 04/21/2019] [Indexed: 02/06/2023]
Abstract
Metastasis is the major cause for breast cancer related mortality. The combination of miRNA-based therapy and chemotherapy represents a promising approach against breast cancer lung metastasis. The goal of this study is to develop an improved therapy that co-delivers a novel bioengineered miRNA prodrug (tRNA-mir-34a) and doxorubicin (DOX) via a multifunctional nanomicellar carrier that is based on a conjugate of amphiphilic copolymer POEG-VBC backbone with creatine, a naturally occurring cationic molecule. Co-delivery of DOX leads to more effective processing of tRNA-mir-34a into mature miR-34a and down-regulation of target genes. DOX + tRNA-mir-34a/POEG-PCre exhibits potent synergistic anti-tumor and anti-metastasis activity in vitro and in vivo. Interestingly, the enhanced immune response contributes to the overall antitumor efficacy. POEG-PCre may represent a safe and effective delivery system for an optimal chemo-gene combination therapy.
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Affiliation(s)
- Jieni Xu
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA; University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jingjing Sun
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA; University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Pui Yan Ho
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California-Davis, Sacramento, CA 96817, USA
| | - Zhangyi Luo
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA; University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Weina Ma
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA; University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Wenchen Zhao
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Sanjay B Rathod
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Christian A Fernandez
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Raman Venkataramanan
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Wen Xie
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA; University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Ai-Ming Yu
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California-Davis, Sacramento, CA 96817, USA
| | - Song Li
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA; University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Treibmann S, Spengler F, Degen J, Löbner J, Henle T. Studies on the Formation of 3-Deoxyglucosone- and Methylglyoxal-Derived Hydroimidazolones of Creatine during Heat Treatment of Meat. J Agric Food Chem 2019; 67:5874-5881. [PMID: 31050431 DOI: 10.1021/acs.jafc.9b01243] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Dicarbonyl compounds such as methylglyoxal (MGO) and 3-deoxyglucosone (3-DG) are formed via caramelization and the Maillard reaction in food during heating or in vivo as byproducts of glycolysis. Recently, it was shown that creatine, an amino compound linked to the energy metabolism in vertebrate muscle, reacts rapidly with methylglyoxal under physiological conditions to form N-(4-methyl-5-oxo-1-imidazolin-2-yl)sarcosine (MG-HCr), a methylglyoxal-derived hydroimidazolone of creatine. Based on the observation that heated meat contains only small amounts of MGO and 3-DG when compared to many other foodstuffs, the aim of this study was to investigate a possible reaction of creatine with 3-DG and MGO in meat. From incubation mixtures consisting of 3-DG and creatine, a new hydroimidazolone of creatine, namely N-(4-butyl-1,2,3-triol-5-oxo-1-imidazolin-2-yl)sarcosine (3-DG-HCr), was isolated and characterized via spectroscopic means. To quantitate 3-DG-HCr and MG-HCr, meat and fish products were analyzed via HPLC-MS/MS using isotopically labeled standard material. Whereas samples of raw fish and meat contained only trace amounts of the hydroimidazolones (below 5 μg/kg), up to 28.3 mg/kg MG-HCr and up to 15.3 mg/kg 3-DG-HCr were found in meat and fish products. The concentrations were dependent on the heat treatment and presumably on the smoking process. In comparison to the lysine and arginine derivatives CEL, pyrraline, and MG-H1, the derivatization rate of creatine as MG-HCr and 3-DG-HCr was higher than of lysine and arginine, which clearly demonstrates the 1,2-dicarbonyl scavenging properties of creatine in meat.
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Affiliation(s)
- Stephanie Treibmann
- Chair of Food Chemistry , Technische Universität Dresden , D-01062 Dresden , Germany
| | - Franz Spengler
- Chair of Food Chemistry , Technische Universität Dresden , D-01062 Dresden , Germany
| | - Julia Degen
- Chair of Food Chemistry , Technische Universität Dresden , D-01062 Dresden , Germany
| | - Jürgen Löbner
- Chair of Food Chemistry , Technische Universität Dresden , D-01062 Dresden , Germany
| | - Thomas Henle
- Chair of Food Chemistry , Technische Universität Dresden , D-01062 Dresden , Germany
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Zhou Z, Han P, Zhou B, Christodoulou AG, Shaw JL, Deng Z, Li D. Chemical exchange saturation transfer fingerprinting for exchange rate quantification. Magn Reson Med 2018; 80:1352-1363. [PMID: 29845651 PMCID: PMC6592698 DOI: 10.1002/mrm.27363] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [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: 12/14/2017] [Revised: 04/17/2018] [Accepted: 04/24/2018] [Indexed: 01/18/2023]
Abstract
PURPOSE There is an increased interest to determine the exchange rate using CEST to provide pH information. However, current CEST quantification methods require lengthy scan times and do not address magnetization transfer effects. The purpose of this work was to apply the magnetic resonance fingerprinting (MRF) concept to CEST to achieve more efficient and accurate exchange rate quantification. METHODS The proposed CEST fingerprinting method used varying saturation powers and saturation times to create unique signal evolutions for different exchange rates. The acquired signal was matched to a predefined dictionary to determine the exchange rate. The magnetization transfer effects were also addressed in the framework of CEST fingerprinting: The simulated dictionary could predict the signal curves without magnetization transfer effects, and comparing the dictionary to the acquired signals allowed the correction of the magnetization transfer effects. The CEST fingerprinting method was compared with the conventional pulsed quantitative CEST method using omega plots in the creatine phantom study. RESULTS The CEST fingerprinting method has a significantly reduced scan time (10 minutes versus 50 minutes) while providing more accurate exchange rate quantification using literature values as the reference. CONCLUSION In this study, we demonstrate that CEST fingerprinting is more efficient (5 times faster) compared with pulsed quantitative CEST. It is also shown that the results of the proposed CEST fingerprinting technique are much closer to the literature values than pulsed quantitative CEST at 3 T.
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Affiliation(s)
- Zhengwei Zhou
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California
| | - Pei Han
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Department of Engineering Physics, Tsinghua University, Beijing, China
| | - Bill Zhou
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
- University of California Los Angeles David Geffen School of Medicine, Los Angeles, California
| | | | - Jaime L. Shaw
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California
| | - Zixin Deng
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California
| | - Debiao Li
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California
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Cai K, Tain RW, Zhou XJ, Damen FC, Scotti AM, Hariharan H, Poptani H, Reddy R. Creatine CEST MRI for Differentiating Gliomas with Different Degrees of Aggressiveness. Mol Imaging Biol 2017; 19:225-232. [PMID: 27541025 PMCID: PMC5824619 DOI: 10.1007/s11307-016-0995-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [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] [Indexed: 10/21/2022]
Abstract
PURPOSE Creatine (Cr) is a major metabolite in the bioenergetic system. Measurement of Cr using conventional MR spectroscopy (MRS) suffers from low spatial resolution and relatively long acquisition times. Creatine chemical exchange saturation transfer (CrCEST) magnetic resonance imaging (MRI) is an emerging molecular imaging method for tissue Cr measurements. Our previous study showed that the CrCEST contrast, obtained through multicomponent Z-spectral fitting, was lower in tumors compared to normal brain, which further reduced with tumor progression. The current study was aimed to investigate if CrCEST MRI can also be useful for differentiating gliomas with different degrees of aggressiveness. PROCEDURES Intracranial 9L gliosarcoma and F98 glioma bearing rats with matched tumor size were scanned with a 9.4 T MRI scanner at two time points. CEST Z-spectra were collected using a customized sequence with a frequency-selective rectangular saturation pulse (B1 = 50 Hz, duration = 3 s) followed by a single-shot readout. Z spectral data were fitted pixel-wise with five Lorentzian functions, and maps of CrCEST peak amplitude, linewidth, and integral were produced. For comparison, single-voxel proton MR spectroscopy (1H-MRS) was performed to quantify and compare the total Cr concentration in the tumor. RESULTS CrCEST contrasts decreased with tumor progression from weeks 3 to 4 in both 9L and F98 phenotypes. More importantly, F98 tumors had significantly lower CrCEST integral compared to 9L tumors. On the other hand, integrals of other Z-spectral components were unable to differentiate both tumor progression and phenotype with limited sample size. CONCLUSIONS Given that F98 is a more aggressive tumor than 9L, this study suggests that CrCEST MRI may help differentiate gliomas with different aggressiveness.
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Affiliation(s)
- Kejia Cai
- Department of Radiology and the Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA.
| | - Rong-Wen Tain
- Department of Radiology and the Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Xiaohong Joe Zhou
- Department of Radiology and the Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Frederick C Damen
- Department of Radiology and the Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Alessandro M Scotti
- Department of Radiology and the Center for MR Research, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Hari Hariharan
- The Center for Magnetic Resonance and Optical Imaging, Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Harish Poptani
- Centre for Preclinical Imaging, University of Liverpool, Liverpool, UK
| | - Ravinder Reddy
- The Center for Magnetic Resonance and Optical Imaging, Department of Radiology, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Li Q, Fan S, Li X, Jin Y, He W, Zhou J, Cen S, Yang Z. Insights into the Phosphoryl Transfer Mechanism of Human Ubiquitous Mitochondrial Creatine Kinase. Sci Rep 2016; 6:38088. [PMID: 27909311 PMCID: PMC5133464 DOI: 10.1038/srep38088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 11/03/2016] [Indexed: 12/31/2022] Open
Abstract
Human ubiquitous mitochondrial creatine kinase (uMtCK) is responsible for the regulation of cellular energy metabolism. To investigate the phosphoryl-transfer mechanism catalyzed by human uMtCK, in this work, molecular dynamic simulations of uMtCK∙ATP-Mg2+∙creatine complex and quantum mechanism calculations were performed to make clear the puzzle. The theoretical studies hereof revealed that human uMtCK utilizes a two-step dissociative mechanism, in which the E227 residue of uMtCK acts as the catalytic base to accept the creatine guanidinium proton. This catalytic role of E227 was further confirmed by our assay on the phosphatase activity. Moreover, the roles of active site residues in phosphoryl transfer reaction were also identified by site directed mutagenesis. This study reveals the structural basis of biochemical activity of uMtCK and gets insights into its phosphoryl transfer mechanism.
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Affiliation(s)
- Quanjie Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Shuai Fan
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Xiaoyu Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Yuanyuan Jin
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Weiqing He
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Jinming Zhou
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Shan Cen
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - ZhaoYong Yang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
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Guo YK, Li ZL, Rong Y, Xia CC, Zhang LZ, Peng WL, Liu X, Xu HY, Zhang TJ, Zuo PL, Schmitt B. [Chemical Exchange Saturation Transfer Imaging of Creatine Metabolites: a 3.0 T MRI Pilot]. Sichuan Da Xue Xue Bao Yi Xue Ban 2016; 47:257-261. [PMID: 27263306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To determine the feasibility of using chemical exchange saturation transfer (CEST) imaging to measure creatine (Cr) metabolites with 3.0 T MR. METHODS Phantoms containing different concentrations of Cr under various pH conditions were studied with CEST sequence on 3.0 T MR imaging. CEST effect and Z spectra were analyzed. RESULTS Cr exhibited significant CEST effect (± 1.8 ppm, F = 99.08, P < 0.001) on 3.0 T MR imaging, and positive correlation was found between the signal intensity and concentration of Cr (r = 0.963, P < 0.001). The CEST effect showed pH dependency of Cr (r = 0.41, P = 0.035). CONCLUSION Creatine CEST imaging can be performed on 3.0 T MR imaging. Creatine concentrations and pH influence CEST effect.
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Gangopadhyay D, Sharma P, Singh RK. Temperature dependent Raman and DFT study of creatine. Spectrochim Acta A Mol Biomol Spectrosc 2015; 150:9-14. [PMID: 26010702 DOI: 10.1016/j.saa.2015.05.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 04/22/2015] [Accepted: 05/04/2015] [Indexed: 06/04/2023]
Abstract
Temperature dependent Raman spectra of creatine powder have been recorded in the temperature range 420-100K at regular intervals and different clusters of creatine have been optimized using density functional theory (DFT) in order to determine the effect of temperature on the hydrogen bonded network in the crystal structure of creatine. Vibrational assignments of all the 48 normal modes of the zwitterionic form of creatine have been done in terms of potential energy distribution obtained from DFT calculations. Precise analysis gives information about thermal motion and intermolecular interactions with respect to temperature in the crystal lattice. Formation of higher hydrogen bonded aggregates on cooling can be visualized from the spectra through clear signature of phase transition between 200K and 180K.
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Affiliation(s)
| | - Poornima Sharma
- Department of Physics, Banaras Hindu University, Varanasi 221005, India
| | - Ranjan K Singh
- Department of Physics, Banaras Hindu University, Varanasi 221005, India.
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Wu R, Longo DL, Aime S, Sun PZ. Quantitative description of radiofrequency (RF) power-based ratiometric chemical exchange saturation transfer (CEST) pH imaging. NMR Biomed 2015; 28:555-65. [PMID: 25807919 PMCID: PMC4423622 DOI: 10.1002/nbm.3284] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 01/07/2015] [Accepted: 02/10/2015] [Indexed: 02/05/2023]
Abstract
Chemical exchange saturation transfer (CEST) MRI holds great promise for the imaging of pH. However, routine CEST measurement varies not only with the pH-dependent chemical exchange rate, but also with CEST agent concentration, providing pH-weighted information. Conventional ratiometric CEST imaging normalizes the confounding concentration factor by analyzing the relative CEST effect from different exchangeable groups, requiring CEST agents with multiple chemically distinguishable labile proton sites. Recently, a radiofrequency (RF) power-based ratiometric CEST MRI approach has been developed for concentration-independent pH MRI using CEST agents with a single exchangeable group. To facilitate quantification and optimization of the new ratiometric analysis, we quantified the RF power-based ratiometric CEST ratio (rCESTR) and derived its signal-to-noise and contrast-to-noise ratios. Using creatine as a representative CEST agent containing a single exchangeable site, our study demonstrated that optimized RF power-based ratiometric analysis provides good pH sensitivity. We showed that rCESTR follows a base-catalyzed exchange relationship with pH independent of creatine concentration. The pH accuracy of RF power-based ratiometric MRI was within 0.15-0.20 pH units. Furthermore, the absolute exchange rate can be obtained from the proposed ratiometric analysis. To summarize, RF power-based ratiometric CEST analysis provides concentration-independent pH-sensitive imaging and complements conventional multiple labile proton group-based ratiometric CEST analysis.
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Affiliation(s)
- Renhua Wu
- Department of Radiology, 2Affiliated Hospital of Shantou University Medical College, Shantou, China
| | - Dario Livio Longo
- Institute of Biostructure and Bioimaging (CNR) c/o Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Silvio Aime
- Department of Molecular Biotechnology and Health Sciences, Molecular Imaging Center, University of Torino, Torino, Italy
| | - Phillip Zhe Sun
- Athinoula A. Martinos Center for Biomedical Imaging, MGH and Harvard Medical School, Boston, MA, USA
- Corresponding Author: Dr. Phillip Zhe Sun, Ph.D., Biomarker and Metabolism Imaging Lab, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH and Harvard Medical School, Rm 2301, 149 13th Street, Charlestown, MA 02129, Phone: 617-726-4060, Fax: 617-726-7422,
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12
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Saito S, Mori Y, Tanki N, Yoshioka Y, Murase K. Factors affecting the chemical exchange saturation transfer of Creatine as assessed by 11.7 T MRI. Radiol Phys Technol 2014; 8:146-52. [PMID: 25477238 DOI: 10.1007/s12194-014-0303-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 11/26/2014] [Accepted: 11/27/2014] [Indexed: 11/25/2022]
Abstract
Chemical exchange saturation transfer (CEST) is a new contrast enhancement approach for imaging exogenous or endogenous substances such as creatine (Cr), amide protons, and glutamate in the human body. An increase in field strength is beneficial for CEST imaging because of the increased chemical shift and longer longitudinal relaxation time (T1). In high-field magnetic resonance imaging (MRI), establishing and evaluating the CEST effect is important for optimizing the magnetization transfer (MT) saturation radio frequency (RF) pulses. In this study, the CEST effect on Cr was evaluated at different concentrations in pH phantoms by appropriately selecting MT saturation RF pulses using 11.7 T MRI. The results showed that the CEST efficiency increased gradually with increasing applied saturation RF pulse power and that it was affected by the number of saturation RF pulses and their bandwidths. However, spillover effects were observed with higher saturation RF pulse powers. In conclusion, we successfully performed in vitro Cr CEST imaging under optimized conditions of MT saturation RF pulses.
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Affiliation(s)
- Shigeyoshi Saito
- Department of Medical Physics and Engineering, Division of Medical Technology and Science, Faculty of Health Science, Graduate School of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka, 565-0871, Japan,
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13
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Tee YK, Khrapitchev AA, Sibson NR, Payne SJ, Chappell MA. Optimal sampling schedule for chemical exchange saturation transfer. Magn Reson Med 2013; 70:1251-62. [PMID: 23315799 DOI: 10.1002/mrm.24567] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [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: 07/17/2012] [Revised: 10/02/2012] [Accepted: 10/29/2012] [Indexed: 12/27/2022]
Abstract
The sampling schedule for chemical exchange saturation transfer imaging is normally uniformly distributed across the saturation frequency offsets. When this kind of evenly distributed sampling schedule is used to quantify the chemical exchange saturation transfer effect using model-based analysis, some of the collected data are minimally informative to the parameters of interest. For example, changes in labile proton exchange rate and concentration mainly affect the magnetization near the resonance frequency of the labile pool. In this study, an optimal sampling schedule was designed for a more accurate quantification of amine proton exchange rate and concentration, and water center frequency shift based on an algorithm previously applied to magnetization transfer and arterial spin labeling. The resulting optimal sampling schedule samples repeatedly around the resonance frequency of the amine pool and also near to the water resonance to maximize the information present within the data for quantitative model-based analysis. Simulation and experimental results on tissue-like phantoms showed that greater accuracy and precision (>30% and >46%, respectively, for some cases) were achieved in the parameters of interest when using optimal sampling schedule compared with evenly distributed sampling schedule. Hence, the proposed optimal sampling schedule could replace evenly distributed sampling schedule in chemical exchange saturation transfer imaging to improve the quantification of the chemical exchange saturation transfer effect and parameter estimation.
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Affiliation(s)
- Y K Tee
- Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, UK; Department of Engineering Science, Institute of Biomedical Engineering, Centre for Doctoral Training in Healthcare Innovation, University of Oxford, UK
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14
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Ravera S, Adriano E, Balestrino M, Panfoli I. Creatine ethyl ester: a new substrate for creatine kinase. Mol Biol (Mosk) 2012; 46:162-165. [PMID: 22642114] [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: 06/01/2023]
Abstract
The creatine kinase/phosphocreatine system plays a key role in cell energy buffering and transport, particularly in cells with high or fluctuating energy requirements, like neurons, i.e. it participates in the energetic metabolism of the brain. Creatine depletion causes several nervous system diseases, alleviated by phosphagen supplementation. Often, the supplementation contains both creatine and creatine ethyl ester, known to improve the effect of creatine through an unknown mechanism. In this work we showed that purified creatine kinase is able to phosphorilate the creatine ethyl ester. The K(m) and V(max) values, as well as temperature and pH optima were determined. Conversion of the creatine ethyl ester into its phosphorylated derivative, sheds light on the role of the creatine ethyl ester as an energy source in supplementation for selected individuals.
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Affiliation(s)
- S Ravera
- Department of Biology, University of Genova, Viale Bendetto XV, 3 16132 Genova, Italy.
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15
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Klomp DWJ, Scheenen TWJ, Arteaga CS, van Asten J, Boer VO, Luijten PR. Detection of fully refocused polyamine spins in prostate cancer at 7 T. NMR Biomed 2011; 24:299-306. [PMID: 20925128 DOI: 10.1002/nbm.1592] [Citation(s) in RCA: 14] [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] [Received: 02/26/2010] [Revised: 06/19/2010] [Accepted: 06/21/2010] [Indexed: 05/30/2023]
Abstract
(1)H MRSI is often used at 1.5 or 3 T to study prostate cancer, where the ratio of choline + creatine to citrate is taken as a marker for tumour presence. Recently, the level of polyamines (mainly spermine) has been shown to improve specificity even further. However, the in vivo detection of these polyamines (at 3.1 ppm) is hampered by signal cancellation as a result of J-coupling effects and signal overlap with choline (3.2 ppm) and creatine (3.0 ppm) resonances. At higher magnetic field strengths, the chemical shift dispersion will increase, which allows the use of very selective radiofrequency pulses to refocus J-coupled spins. In this work, we added selective refocusing pulses to a semi-LASER (localisation based on adiabatic selective refocusing) sequence at 7 T, and optimised the inter-pulse timings of the sequence for fully refocused detection of spermine spins, whilst maintaining optimised detection of choline, creatine and the strongly coupled spin system of citrate.
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Affiliation(s)
- D W J Klomp
- Department of Radiology, Radiotherapy and Nuclear Medicine, University Medical Center Utrecht, Utrecht, the Netherlands.
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16
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Zu Z, Li K, Janve VA, Does MD, Gochberg DF. Optimizing pulsed-chemical exchange saturation transfer imaging sequences. Magn Reson Med 2011; 66:1100-8. [PMID: 21432903 DOI: 10.1002/mrm.22884] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [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] [Received: 07/19/2010] [Revised: 01/03/2011] [Accepted: 01/30/2011] [Indexed: 11/07/2022]
Abstract
Chemical exchange saturation transfer (CEST) provides a new imaging contrast mechanism sensitive to labile proton exchange. Pulsed-CEST imaging is better suited to the hardware constraints on clinical imaging systems when compared with traditional continuous wave-CEST imaging methods. However, designing optimum pulsed-CEST imaging sequences entails complicated and time-consuming numerical integrations. In this work, a simplified and computationally efficient technique is provided to optimize the pulsed-CEST imaging sequence. An analysis was performed of the optimal average irradiation power and the optimal irradiation flip angle as a function of the acquisition parameters and sample properties in both a two-pool model and a three-pool model of endogenous amine exchange. Key simulated and experimental results based on a creatine/agar tissue phantom show that (1) the average irradiation power is a more meaningful sequence metric than is the average irradiation field amplitude, (2) the optimal average powers for continuous wave and pulsed-CEST imaging are approximately equal to each other for a relevant range of solute frequency offsets, exchange rates, and concentrations, (3) an irradiation flip angle of 180° is optimal or near optimal, independent of the other acquisition parameters and the sample properties, and (4) higher duty cycles yield higher CEST contrast.
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Affiliation(s)
- Zhongliang Zu
- Vanderbilt University Institute of Imaging Science, Nashville, Tennessee 37232-2310, USA
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17
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Antoniou MG, Nambiar U, Dionysiou DD. Investigation of the photocatalytic degradation pathway of the urine metabolite, creatinine: the effect of pH. Water Res 2009; 43:3956-3963. [PMID: 19595423 DOI: 10.1016/j.watres.2009.06.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 04/27/2009] [Accepted: 06/09/2009] [Indexed: 05/28/2023]
Abstract
This study investigated the degradation pathway of creatinine (a urine metabolite) with immobilized titanium dioxide photocatalysts. The degradation of creatinine was studied at three different pH values (acidic, neutral and basic) in the absence of buffering solutions. The intermediates formed were identified by using electrospray ionization mass spectrometer (ESI-MS) in both negative and positive ion mode. Two distinct mechanistic pathways which govern the photocatalytic degradation of creatinine irrespective of the pH of the initial solution were identified. The initial solution pH affected only the selectivity between the two mechanisms. The primary oxidation steps of creatinine with hydroxyl radicals included demethylation, hydrogen abstraction, hydroxylation, oxidation, and ring opening. At acidic pH, additional transformation steps of the two mechanisms were identified. The intermediates detected in the positive ion mode, contained at least one atom of nitrogen in their structure, explaining the observed low nitrogen mineralization of creatinine with TiO(2) photocatalysis. The intermediates in the negative ion mode were low molecular weight organic acids that contained only carbon and hydrogen atoms.
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Affiliation(s)
- Maria G Antoniou
- Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221-0071, USA
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18
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Watanabe H, Takaya N, Mitsumori F. Simultaneous observation of glutamate, gamma-aminobutyric acid, and glutamine in human brain at 4.7 T using localized two-dimensional constant-time correlation spectroscopy. NMR Biomed 2008; 21:518-526. [PMID: 18351694 DOI: 10.1002/nbm.1223] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Localized two-dimensional constant-time correlation spectroscopy (CT-COSY) was used to resolve glutamate (Glu), gamma-aminobutyric acid (GABA), and glutamine (Gln) in the human brain at 4.7 T. In this method, three-dimensional localization was achieved using three radio frequency pulses of the CT-COSY module for slice selection. As this sequence could decouple JHH along the F1 direction, peak resolution of metabolites was improved even on a magnitude-mode display. In experiments on a phantom containing N-acetylaspartate, creatine, Glu, Gln, and GABA with a constant time delay (Tct) of 110 ms, cross peaks of Glu, Gln, and GABA were obtained on a spectrum processed with standard sine-bell windows, which emphasize sine-dependent signals along the t2 direction. In contrast, diagonal peaks of Glu C4H at 2.35 ppm, GABA C2H at 2.28 ppm, and Gln C4H at 2.44 ppm were resolved on a spectrum processed with Gaussian windows, which emphasize cosine-dependent signals along t2. Human brain spectra were obtained from a 27 mL voxel within the parieto-occipital region using a volume transverse electromagnetic (TEM) coil for both transmission and reception. Tct was 110 ms; the total scan time was 30 min. Diagonal peaks of Glu C4H, GABA C2H, and Gln C4H were also resolved on the spectrum processed with Gaussian windows. These results show that the localized two-dimensional CT-COSY method featuring 1H decoupling along the F1 direction could resolve Glu, GABA, and Gln signals in the human brain.
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Affiliation(s)
- H Watanabe
- Environmental Chemistry Division, National Institute for Environmental Studies, Ibaraki, Japan
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19
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Rubtsov DV, Griffin JL. Time-domain Bayesian detection and estimation of noisy damped sinusoidal signals applied to NMR spectroscopy. J Magn Reson 2007; 188:367-79. [PMID: 17827043 DOI: 10.1016/j.jmr.2007.08.008] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 08/11/2007] [Accepted: 08/13/2007] [Indexed: 05/17/2023]
Abstract
The problem of model detection and parameter estimation for noisy signals arises in different areas of science and engineering including audio processing, seismology, electrical engineering, and NMR spectroscopy. We have adopted the Bayesian modeling framework to jointly detect and estimate signal resonances. This considers a model of the time-domain complex free induction decay (FID) signal as a sum of exponentially damped sinusoidal components. The number of model components and component parameters are considered unknown random variables to be estimated. A Reversible Jump Markov Chain Monte Carlo technique is used to draw samples from the joint posterior distribution on the subspaces of different dimensions. The proposed algorithm has been tested on synthetic data, the (1)H NMR FID of a standard of L-glutamic acid and a blood plasma sample. The detection and estimation performance is compared with Akaike information criterion (AIC), minimum description length (MDL) and the matrix pencil method. The results show the Bayesian algorithm superior in performance especially in difficult cases of detecting low-amplitude and strongly overlapping resonances in noisy signals.
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Affiliation(s)
- Denis V Rubtsov
- Department of Biochemistry, The Hopkins Building, University of Cambridge, Cambridge, UK.
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20
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Meat in the hot seat. Cooking meat at high temperatures produces cancer-causing chemicals, but grilling can be made safer. Harv Health Lett 2007; 32:1-2. [PMID: 17639620] [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: 05/16/2023]
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21
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Ramanavicius A. Amperometric biosensor for the determination of creatine. Anal Bioanal Chem 2007; 387:1899-906. [PMID: 17221239 DOI: 10.1007/s00216-006-1065-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 11/27/2006] [Accepted: 11/30/2006] [Indexed: 10/23/2022]
Abstract
An amperometric biosensor for the determination of creatine was developed. The carbon rod electrode surface was coated with sarcosine oxidase (SOX) and creatine amidinohydrolase by cross-linking under glutaraldehyde vapour. The SOX from Arthrobacter sp. 1-1 N was purified and previously used for creation of a creatine biosensor. The natural SOX electron acceptor, oxygen, was replaced by an [Fe(CN)(6)](3-) /[ Fe(CN)(6)](4-) redox mediating system, which allowed amperometric detection of an analytical signal at +400-mV potential. The response time of the biosensor was less than 1 min. The biosensor showed a linear dependence of the signal vs. creatine concentration at physiological creatine concentration levels. The optimal pH in 0.1 M tris(hydroxymethyl)aminomethane (Tris)-HCl buffer was found to be at pH 8.0. The half-life of the biosensor was 8 days in 0.1 M Tris-HCl buffer (pH 8.0) at 20 degrees C. Principal scheme of consecutively followed catalytic reactions used to design a biosensor for the determination of creatine.
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Affiliation(s)
- A Ramanavicius
- Centre of Nanotechnology and Material Science, Department of Analytical and Environmental Chemistry, Vilnius University, Naugarduko 24, 2006 Vilnius, Lithuania.
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22
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Zoeller RF, Stout JR, O'kroy JA, Torok DJ, Mielke M. Effects of 28 days of beta-alanine and creatine monohydrate supplementation on aerobic power, ventilatory and lactate thresholds, and time to exhaustion. Amino Acids 2006; 33:505-10. [PMID: 16953366 DOI: 10.1007/s00726-006-0399-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Accepted: 07/17/2006] [Indexed: 11/30/2022]
Abstract
The effect of beta-alanine (beta-Ala) alone or in combination with creatine monohydrate (Cr) on aerobic exercise performance is unknown. The purpose of this study was to examine the effects of 4 weeks of beta-Ala and Cr supplementation on indices of endurance performance. Fifty-five men (24.5 +/- 5.3 yrs) participated in a double-blind, placebo-controlled study and randomly assigned to one of 4 groups; placebo (PL, n = 13), creatine (Cr, n = 12), beta-alanine (beta-Ala, n = 14), or beta-alanine plus creatine (CrBA, n = 16). Prior to and following supplementation, participants performed a graded exercise test on a cycle ergometer to determine VO(2peak), time to exhaustion (TTE), and power output, VO(2), and percent VO(2peak) associated with VT and LT. No significant group effects were found. However, within groups, a significant time effect was observed for CrBa on 5 of the 8 parameters measured. These data suggest that CrBA may potentially enhance endurance performance.
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Affiliation(s)
- R F Zoeller
- Department of Exercise Science and Health Promotion, Florida Atlantic University, Davie, FL, USA.
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24
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Arias-Dimas A, Vilaseca MA, Artuch R, Ribes A, Campistol J. [Diagnosis and treatment of brain creatine deficiency syndromes]. Rev Neurol 2006; 43:302-8. [PMID: 16941429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
AIM To review the clinical, biochemical and genetic aspects of brain creatine deficiency syndromes, as well as the therapeutic options available. DEVELOPMENT Brain creatine deficiency syndrome has recently been described as a series of inborn errors of metabolism that affect the synthesis and transport of creatine. Three metabolic defects are known: two affect synthesis -guanidinoacetate methyltransferase (GAMT) and arginine:glycine amidinotransferase (AGAT)- and one affects the transport of creatine. Clinically, these patients can display mental retardation, language disorders, epilepsy, autistic behaviour, neurological impairment and movement disorders. After the clinical selection, the different defects can be identified by a biochemical study involving the analysis of metabolites in biological fluids (guanidinoacetate and creatine/ creatinine ratio). Before continuing with the molecular studies, it is important to confirm the deficiency of brain creatine by means of magnetic resonance imaging with spectroscopy. Diagnostic confirmation of AGAT and GAMT deficits is carried out by determining the enzymatic activity in fibroblasts or lymphoblasts, or the incorporation of creatine in the case of studies of transport defects. The study of mutations in AGAT, GAMT (autosomal recessive inheritance) and SLC6A8 (X-linked) genes completes the diagnosis. CONCLUSIONS Brain creatine deficiency syndromes are mainly associated to mental retardation and autism. GAMT and AGAT deficiencies respond to treatment with creatine, whereas patients with transport defects do not respond to this therapy; new therapeutic approaches are therefore being evaluated for this disease.
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Affiliation(s)
- A Arias-Dimas
- Servico de Bioquímica. Hospital Sant Joan de Deu, 08950 Esplugues de Llobregat, Espana
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Abstract
Studies on model systems of amino acids and sugars have indicated that acrylamide can be generated from asparagine or from amino acids that can produce acrylic acid either directly such as beta-alanine, aspartic acid and carnosine or indirectly such as cysteine and serine. The main pathway specifically involves asparagine and produces acrylamide directly after a sugar-assisted decarboxylation and 1,2-elimination steps and the second non-specific pathway involves the initial formation of acrylic acid from different sources and its subsequent interaction with ammonia to produce acrylamide. Aspartic acid, beta-alanine and carnosine were found to follow acrylic acid pathway. Labeling studies with [13C-4]aspartic acid have confirmed the occurrence in aspartic acid model system, of a previously proposed sugar-assisted decarboxylation mechanism identified in asparagine model systems. In addition, creatine was found to be a good source of methylamine and was responsible for the formation of N-methylacrylamide in model systems through acrylic acid pathway. Furthermore, certain amino acids such as serine and cysteine were found to generate pyruvic acid that can be converted into acrylic acid and generate acrylamide when reacted with ammonia.
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Affiliation(s)
- Varoujan A Yaylayan
- McGill University, Department of Food Science and Agricultural Chemistry, 21, 111 Lakeshore, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9.
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Sakata Y, Shiraishi S, Otsuka M. Effect of pulverization of the bulk powder on the hydration of creatine anhydrate tablets and their pharmaceutical properties. Colloids Surf B Biointerfaces 2005; 46:92-100. [PMID: 16274970 DOI: 10.1016/j.colsurfb.2005.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Revised: 09/08/2005] [Accepted: 10/04/2005] [Indexed: 11/25/2022]
Abstract
The hydration behavior and expansion properties of untreated and pulverized creatine anhydrate (CRA) tablets were studied under 60 and 75%RH at 25 degrees C by using differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). The tablet hardness of untreated and pulverized CRA tablets was significantly decreased after hydration. There was a linear relationship between the degree of hydration and the tablet hardness of untreated CRA tablets compressed at 1000 kg/cm2. In contrast, the relationship between the degree of hydration and the tablet hardness of pulverized CRA tablets was nonlinear. These results suggest that the reduction in hardness of pulverized CRA tablets does not depend solely on the hydration level of crystal water. PXRD analysis indicated that the diffraction pattern of the pulverized CRA powder was similar to that of the untreated CRA powder. However, the diffraction intensity of the pulverized CRA powder was slightly lower than that of the untreated CRA powder at high angle. The micropore radius of both untreated and pulverized CRA tablets was significantly increased after hydration, but analysis of the relationship between micropore radius and fractional hydration of crystal water showed that untreated CRA tablets were more affected than pulverized CRA tablets. Therefore, the reduction in tablet hardness depends not only on the hydration behavior but also on the crystal orientation of the CRA powder.
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Affiliation(s)
- Yukoh Sakata
- Healthcare Research Institute, Wakunaga Pharmaceutical Co., Ltd., 1624 Shimokotachi, Kodacho, Takatagun, Hiroshima 739-1195, Japan.
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27
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Gallant M, Rak M, Szeghalmi A, Del Bigio MR, Westaway D, Yang J, Julian R, Gough KM. Focally elevated creatine detected in amyloid precursor protein (APP) transgenic mice and Alzheimer disease brain tissue. J Biol Chem 2005; 281:5-8. [PMID: 16267054 DOI: 10.1074/jbc.c500244200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The creatine/phosphocreatine system, regulated by creatine kinase, plays an important role in maintaining energy balance in the brain. Energy metabolism and the function of creatine kinase are known to be affected in Alzheimer diseased brain and in cells exposed to the beta-amyloid peptide. We used infrared microspectroscopy to examine hippocampal, cortical, and caudal tissue from 21-89-week-old transgenic mice expressing doubly mutant (K670N/M671L and V717F) amyloid precursor protein and displaying robust pathology from an early age. Microcrystalline deposits of creatine, suggestive of perturbed energetic status, were detected by infrared microspectroscopy in all animals with advanced plaque pathology. Relatively large creatine deposits were also found in hippocampal sections from post-mortem Alzheimer diseased human brain, compared with hippocampus from non-demented brain. We therefore speculate that this molecule is a marker of the disease process.
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Affiliation(s)
- Meghan Gallant
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
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28
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Sakata Y, Shiraishi S, Otsuka M. Effect of tablet geometrical structure on the dehydration of creatine monohydrate tablets, and their pharmaceutical properties. AAPS PharmSciTech 2005; 6:E527-35. [PMID: 16354014 PMCID: PMC2750400 DOI: 10.1208/pt060366] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The effects of compression and pulverization on the dehydration kinetics and hardness of creatine monohydrate tablets were studied using a variety of kinetic equations and physical models. The dehydration behavior of unpulverized and pulverized tablets was investigated by using differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). The hardness of both unpulverized and pulverized monohydrate tablets was significantly decreased after dehydration. The relationship between the degree of dehydration and the tablet hardness of both unpulverized and pulverized monohydrate tablets formed a straight line. The results suggest that the reduction in tablet hardness is dependent on the dehydration of crystal water, and the values of the slopes indicate that the bonding energy of the unpulverized sample was stronger than that of the pulverized sample. The dehydration kinetics of the unpulverized and pulverized monohydrate tablets were evaluated by analyzing the fit of the isothermal DSC data using a variety of solid-state kinetic models. The dehydration of the unpulverized tablets at various levels of compression pressure followed the 3-dimensional growth of nuclei mechanism. In contrast, although the dehydration kinetics of pulverized monohydrate tablets compressed at 500 and 750 kg/cm2 followed the 3-dimensional diffusion mechanism, those compressed at 1000 kg/cm2 followed the 3-dimensional growth of nuclei mechanism. The PXRD analysis indicated that the diffraction intensity of the pulverized monohydrate powder was significantly lower than that of the unpulverized powder. The diffraction peaks of the (h00) planes and the micropore structure of the unpulverized monohydrate tablets were affected by pulverization and compression force, respectively.
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Affiliation(s)
- Yukoh Sakata
- Healthcare Research Institute, Wakunaga Pharmaceutical Co, Ltd, 1624 Shimokotachi, Kodacho, Takatagun, Hiroshima 739-1195, Japan.
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Jourden MJ, Geiss PR, Thomenius MJ, Horst LA, Barty MM, Brym MJ, Mulligan GB, Almeida RM, Kersteen BA, Myers NR, Snider MJ, Borders CL, Edmiston PL. Transition state stabilization by six arginines clustered in the active site of creatine kinase. Biochim Biophys Acta 2005; 1751:178-83. [PMID: 16005271 DOI: 10.1016/j.bbapap.2005.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2005] [Revised: 06/01/2005] [Accepted: 06/02/2005] [Indexed: 11/17/2022]
Abstract
Six fully conserved arginine residues (R129, R131, R235, R291, R319, and R340) closely grouped in the nucleotide binding site of rabbit muscle creatine kinase (rmCK) were mutated; four to alanine and all six to lysine. Kinetic analyses in the direction of phosphocreatine formation showed that all four alanine mutants led to substantial losses of activity with three (R129A, R131A, and R235A) having no detectable activity. All six lysine mutants retained variable degrees of reduced enzymatic activity. Static quenching of intrinsic tryptophan fluorescence was used to measure the binding constants for MgADP and MgATP. Nucleotide binding was at most only modestly affected by mutation of the arginine residues. Thus, the cluster of arginines seem to be primarily responsible for transition state stabilization which is further supported by the observation that none of the inactive mutants demonstrated the ability to form a transition analogue complex of MgADP.nitrate.creatine as determined by fluorescence quenching assays. As a whole, the results suggest that the most important role these residues play is to properly align the substrates for stabilization of the phosphoryl transfer reaction.
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Abstract
We used metabonomics to discriminate the urinary signature of different anabolic steroid treatments in cattle having different physiological backgrounds (age, sex, and race). (1)H-(13)C heteronuclear multiple bonding connectivity NMR spectroscopy and multivariate statistical methods reveal that metabolites such as trimethylamine-N-oxide, dimethylamine, hippurate, creatine, creatinine, and citrate characterize the biological fingerprint of anabolic treatment. These urinary biomarkers suggest an overall homeostatic adaptation in nitrogen and energy metabolism. From results obtained in this study, it is now possible to consider metabonomics as a complementary method usable to improve doping control strategies to detect fraudulent anabolic treatment in cattle since the oriented global metabolic response provides helpful discrimination.
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Affiliation(s)
- Marc-Emmanuel Dumas
- Biological Chemistry Section, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London SW7 2AZ, United Kingdom.
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Uda K, Tanaka K, Bailly X, Zal F, Suzuki T. Phosphagen kinase of the giant tubeworm Riftia pachyptila. Cloning and expression of cytoplasmic and mitochondrial isoforms of taurocyamine kinase. Int J Biol Macromol 2005; 37:54-60. [PMID: 16188310 DOI: 10.1016/j.ijbiomac.2005.08.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 08/23/2005] [Accepted: 08/23/2005] [Indexed: 11/28/2022]
Abstract
The giant tubeworm Riftia pachyptila lives at deep-sea hydrothermal vents along the East Pacific Rise and the Galapagos Rift. The large size and high growth rate of R. pachyptila is supported by an endosymbiotic relationship with a chemosynthetic bacterium. Elucidation of the regulation of energy metabolism of the giant tubeworm remains an interesting problem. The purpose of this study is to determine the cDNA sequence of phosphagen kinase, one of the most important enzymes in energy metabolism, and to characterize its function. Two phosphagen kinase cDNA sequences amplified from the cDNA library of R. pachyptila showed high derived amino acid sequence identity (74%) with those of cytoplasmic taurocyamine kinase (TK) and mitochondrial TK from an annelid Arenicola brasiliensis. The cytoplasmic form of the Riftia recombinant enzyme showed stronger activity for the substrates taurocyamine and also considerable activity for lombricine (21% that of taurocyamine). The mitochondrial form, which was structurally similar to mitochondrial creatine kinase, showed stronger activity for taurocyamine, and a broader activity for various guanidine compounds: glycocyamine (35% that of taurocyamine), lombricine (31%) and arginine (3%). Both forms showed no activity for creatine. The difference in substrate specificities between the cytoplasmic and mitochondrial forms might be attributable to the large difference in the amino acid sequence of the GS region and/or several key amino acid residues for establishing guanidine substrate specificity. Based on these results, we conclude that Riftia contains at least two forms of TK as phosphagen kinase. We also report the kinetic parameters, Km and kcat, of Arenicola and Riftia TKs for the first time. The Km values for taurocyamine of Arenicola and Riftia TKs ranged from 0.9 to 4.0 mM and appear to be comparable to those of other annelid-specific enzymes, lombricine kinase and glycocyamine kinase, but are significantly lower than those of Neanthes cytoplasmic and mitochondrial creatine kinases. Comparison of kcat/Km value in various annelid phosphagen kinases indicates that Arenicola mitochondrial TK has the highest catalytic efficiency (16.2 s-1 mM-1). In Arenicola TKs, the mitochondrial form has seven-fold higher efficiency than the cytoplasmic form.
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Affiliation(s)
- Kouji Uda
- Laboratory of Biochemistry, Faculty of Science, Kochi University, Kochi 780-8520, Japan
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Abstract
Rejection characteristics of organic and inorganic compounds were examined for six reverse osmosis (RO) membranes and two nanofiltration (NF) membranes that are commercially available. A batch stirred-cell was employed to determine the membrane flux and the solute rejection for solutions at various concentrations and different pH conditions. The results show that for ionic solutes the degree of separation is influenced mainly by electrostatic exclusion, while for organic solutes the removal depends mainly upon the solute radius and molecular structure. In order to provide a better understanding of rejection mechanisms for the RO and NF membranes, the ratio of solute radius (r(i,s)) to effective membrane pore radius (r(p)) was employed to compare rejections. An empirical relation for the dependence of the rejection of organic compounds on the ratio r(i,s)/r(p) is presented. The rejection for organic compounds is over 75% when r(i,s)/r(p) is greater than 0.8. In addition, the rejection of organic compounds is examined using the extended Nernst-Planck equation coupled with a steric hindrance model. The transport of organic solutes is controlled mainly by diffusion for the compounds that have a high r(i,s)/r(p) ratio, while convection is dominant for compounds that have a small r(i,s)/r(p) ratio.
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Affiliation(s)
- Yeomin Yoon
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208-3111, USA
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Likavcanová K, Dobrota D, Liptaj T, Prónayová N, Mlynárik V, Belan V, Galanda M, Béres A, De Riggo J. In vitro study of astrocytic tumour metabolism by proton magnetic resonance spectroscopy. Gen Physiol Biophys 2005; 24:327-35. [PMID: 16308427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In vivo magnetic resonance spectroscopy (MRS) studies of glial brain tumours reported that higher grade of astrocytoma is associated with increased level of choline-containing compounds (Cho) and decreased levels of N-acetylaspartate (NAA) and creatine and phosphocreatine (Cr). In this work, we studied the metabolism of glioma tumours by in vitro proton magnetic resonance spectroscopy (1H-MRS). 1H-MR spectra were recorded in vitro from perchloric acid extracts of astrocytoma (WHO II) and glioblastoma multiforme (WHO IV) samples. We observed differences between astrocytoma and glioblastoma multiforme in the levels of Cho, alanine, lactate, NAA, and glutamate/glutamine. In astrocytoma samples, we found higher MR signal of NAA and lower signal of Cho and alanine. MR spectra of glioblastoma samples reported significantly higher levels of lactate and glutamate/glutamine. In contrast, levels of Cr were the same in both tumour types. We also determined NAA/Cr and Cho/Cr ratios in the tumour samples. The NAA/Cr ratio was higher in astrocytomas than in glioblastomas multiforme. Conversely, the Cho/Cr ratio was higher in glioblastoma multiforme. The results indicate that MRS is a promising method for distinguishing pathologies in human brain and for pre-surgical grading of brain tumours.
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Affiliation(s)
- K Likavcanová
- Department of Biochemistry, Jessenius Faculty of Medicine, Malá Hora 4, 037 54 Martin, Slovakia.
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Abstract
Twenty-two amino acid residues from transmembrane domain 3 of the creatine transporter were replaced, one at a time, with cysteine. The background for mutagenesis was a C144S mutant retaining approximately 75% of wild-type transport activity but resistant to methanethiosulfonate (MTS) reagents. Each substitution mutant was tested for creatine transport activity and sensitivity to the following MTS reagents: 2-aminoethyl methanethiosulfonate (MTSEA), 2-(trimethylammonium) ethyl methanethiosulfonate (MTSET), and 2-sulfonatoethyl methanethiosulfonate (MTSES). Two mutants (G134C and Y148C) were inactive, but most mutants showed significant levels of creatine transport. Treatment with MTSEA inhibited the activity of the W154C, Y147C, and I140C mutants. Creatine partially protected I140C from inactivation, and this residue, like Cys-144 in the wild-type CreaT, is predicted to be close to a creatine binding site. MTSEA inactivation of Y147C was dependent on Na+ and Cl- suggesting that solvent accessibility was ion-dependent. Helical wheel and helical net projections indicate that the three MTSEA-sensitive mutants (W154C, Y147C, and I140C) and two inactive mutants (V151C and Y148C) are aligned on a face of an alpha-helix, suggesting that they form part of a substrate pathway. The W154C mutant, located near the external face of the membrane, was accessible to the larger MTS reagents, whereas those implicated in creatine binding were only accessible to the smaller MTSEA. Consideration of our data, together with a study on the serotonin transporter (Chen, J. G., Sachpatzidis, A., and Rudnick, G. (1997) J. Biol. Chem. 272, 28321-28327), suggests that involvement of residues from transmembrane domain 3 is a common feature of the substrate pathway of Na+- and Cl- -dependent neurotransmitter transporters.
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Affiliation(s)
- Joanna R Dodd
- Cell Biology and Biochemistry Section, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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Schröder L, Schmitz C, Bachert P. Molecular dynamics and information on possible sites of interaction of intramyocellular metabolites in vivo from resolved dipolar couplings in localized 1H NMR spectra. J Magn Reson 2004; 171:213-224. [PMID: 15546747 DOI: 10.1016/j.jmr.2004.08.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Revised: 08/18/2004] [Indexed: 05/24/2023]
Abstract
Proton NMR resonances of the endogenous metabolites creatine and phosphocreatine ((P)Cr), taurine (Tau), and carnosine (Cs, beta-alanyl-L-histidine) were studied with regard to residual dipolar couplings and molecular mobility. We present an analysis of the direct 1H-1H interaction that provides information on motional reorientation of subgroups in these molecules in vivo. For this purpose, localized 1H NMR experiments were performed on m. gastrocnemius of healthy volunteers using a 1.5-T clinical whole-body MR scanner. We evaluated the observable dipolar coupling strength SD0 (S=order parameter) of the (P)Cr-methyl triplet and the Tau-methylene doublet by means of the apparent line splitting. These were compared to the dipolar coupling strength of the (P)Cr-methylene doublet. In contrast to the aliphatic protons of (P)Cr and Tau, the aromatic H2 (delta=8 ppm) and H4 (delta=7 ppm) protons of the imidazole ring of Cs exhibit second-order spectra at 1.5 T. This effect is the consequence of incomplete transition from Zeeman to Paschen-Back regime and allows a determination of SD0 from H2 and H4 of Cs as an alternative to evaluating the multiplet splitting which can be measured directly in high-resolution 1H NMR spectra. Experimental data showed striking differences in the mobility of the metabolites when the dipolar coupling constant D0 (calculated with the internuclear distance known from molecular geometry in the case of complete absence of molecular dynamics and motion) is used for comparison. The aliphatic signals involve very small order parameters S approximately (1.4-3) x 10(-4) indicating rapid reorientation of the corresponding subgroups in these metabolites. In contrast, analysis of the Cs resonances yielded S approximately (113-137) x 10(-4). Thus, the immobilization of the Cs imidazole ring owing to an anisotropic cellular substructure in human m. gastrocnemius is much more effective than for (P)Cr and Tau subgroups. Furthermore, 1H NMR experiments on aqueous model solutions of histidine and N-acetyl-L-aspartate (NAA) enabled the assignment of an additional signal component at delta=8 ppm of Cs in vivo to the amide group at the peptide bond. The visibility of this proton could result from hydrogen bonding which would agree with the anticipated stronger motional restriction of Cs. Referring to the observation that all dipolar-coupled multiplets resolved in localized in vivo 1H NMR spectra of human m. gastrocnemius collapse simultaneously when the fibre structure is tilted towards the magic angle (theta; approximately 55 degrees), a common model for molecular confinement in muscle tissue is proposed on the basis of an interaction of the studied metabolites with myocellular membrane phospholipids.
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Affiliation(s)
- Leif Schröder
- Abteilung Medizinische Physik in der Radiologie, Deutsches Krebsforschungszentrum (dkfz), D-69120 Heidelberg, Germany.
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Sakata Y, Shiraishi S, Otsuka M. Effect of pulverization on hydration kinetic behaviors of creatine anhydrate powders. Colloids Surf B Biointerfaces 2004; 39:187-93. [PMID: 15555902 DOI: 10.1016/j.colsurfb.2004.07.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2004] [Accepted: 07/28/2004] [Indexed: 11/26/2022]
Abstract
The crystal orientation of creatine monohydrate varies significantly with tableting performance and pulverizing mechanism. Furthermore, the X-ray diffraction patterns of anhydrous forms of untreated creatine monohydrate and of pulverized creatine monohydrate exhibit different crystal orientations. However, hygroscopic forms of unpulverized creatine anhydrate and pulverized creatine anhydrate was exhibit the same diffraction peak pattern. The hygroscopicity of unpulverized and pulverized creatine anhydrate has been investigated by hydration kinetic methods using isothermal differential scanning calorimetry data. Testing of the hygroscopicity of unpulverized and pulverized creatine anhydrate at various levels of relative humidity (RH) at 25 degrees C revealed that the anhydrate was stable at less than 33% RH, but was transformed into the monohydrate at more than 52% RH. Hydration data of unpulverized and pulverized creatine anhydrate at 60% and 75% RH were calculated to determine hydration kinetics using various solid-state kinetic models. The hydration type of unpulverized and pulverized creatine anhydrate powder follows the zero-order mechanism (Polany-Winger equation) R1. The transition rate constant of pulverized creatine anhydrate, calculated from the slope of the straight line, was about 1.34-1.36 times higher than that of unpulverized creatine anhydrate.
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Affiliation(s)
- Yukoh Sakata
- Healthcare Research Institute, Wakunaga Pharmaceutical Co. Ltd., 1624 Shimokotachi, Kodacho, Takatagun, Hiroshima 739-1195, Japan.
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Schröder L, Schmitz C, Bachert P. Phase modulation in dipolar-coupled A2 spin systems: effect of maximum state mixing in 1H NMR in vivo. J Magn Reson 2004; 171:207-212. [PMID: 15546746 DOI: 10.1016/j.jmr.2004.08.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Revised: 08/19/2004] [Indexed: 05/24/2023]
Abstract
Coupling constants of nuclear spin systems can be determined from phase modulation of multiplet resonances. Strongly coupled systems such as citrate in prostatic tissue exhibit a more complex modulation than AX connectivities, because of substantial mixing of quantum states. An extreme limit is the coupling of n isochronous spins (An system). It is observable only for directly connected spins like the methylene protons of creatine and phosphocreatine which experience residual dipolar coupling in intact muscle tissue in vivo. We will demonstrate that phase modulation of this "pseudo-strong" system is quite simple compared to those of AB systems. Theory predicts that the spin-echo experiment yields conditions as in the case of weak interactions, in particular, the phase modulation depends linearly on the line splitting and the echo time.
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Affiliation(s)
- Leif Schröder
- Abteilung Medizinische Physik in der Radiologie, Deutsches Krebsforschungszentrum (dkfz), D-69120 Heidelberg, Germany.
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Yaylayan VA, Locas CP, Wnorowski A, O'Brien J. The role of creatine in the generation of N-methylacrylamide: a new toxicant in cooked meat. J Agric Food Chem 2004; 52:5559-5565. [PMID: 15315400 DOI: 10.1021/jf049421g] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Investigations of different sources of acrylamide formation in model systems consisting of amino acids and sugars have indicated the presence of two pathways of acrylamide generation; the main pathway specifically involves asparagine to directly produce acrylamide after a sugar-assisted decarboxylation step, and the second, nonspecific pathway involves the initial formation of acrylic acid from different sources and its subsequent interaction with ammonia and/or amines to produce acrylamide or its N-alkylated derivatives. Aspartic acid, beta-alanine, and carnosine were found to follow the acrylic acid pathway. Labeling studies using [(13)C-4]aspartic acid have confirmed the occurrence in this amino acid of a previously proposed sugar-assisted decarboxylation mechanism identified in the asparagine/glucose model system. In addition, creatine was found to be a good source of methylamine in model systems and was responsible for the formation of N-methylacrylamide through the acrylic acid pathway. Labeling studies using creatine (methyl-d(3)) and (15)NH(4)Cl have indicated that both the nitrogen and the methyl groups of methylamine had originated from creatine. Furthermore, analysis of cooked meat samples has also confirmed the formation of N-methylacrylamide during cooking.
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Affiliation(s)
- Varoujan A Yaylayan
- Department of Food Science and Agricultural Chemistry, McGill University, 21111 Lakeshore, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada.
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Wang XY, Meng FG, Zhou HM. Inactivation and conformational changes of creatine kinase at low concentrations of hexafluoroisopropanol solutions. Biochem Cell Biol 2004; 81:327-33. [PMID: 14569296 DOI: 10.1139/o03-061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Using the methods of far-ultraviolet circular dichroism (CD) spectra, fluorescence spectra, and enzyme activity assays, the inactivation and conformational changes of creatine kinase (CK) induced by 1,1,1,3,3,3-hexafluoro-2-propanol (hexafluoroisopropanol (HFIP)) of different concentrations were investigated. To avoid the aggregation of CK that occurs with high HFIP, concentrations of 0%-5% HFIP were used in this study. The CD spectra showed that HFIP concentrations above 2.5% strongly induced the formation of secondary structures of CK. No marked conformational changes were observed at low concentrations of HFIP (0%-2.5%). After incubation with 0.2% HFIP for 10 min, CK lost most of its activity. The kinetic theory of the substrate reaction during irreversible inhibition of enzyme activity described previously by Tsou was applied to study the kinetics of CK inactivation during denaturation by HFIP. The inactivation rate constants for the free enzyme and the substrate-enzyme complex were determined by Tsou's method. The results suggested that low concentrations of HFIP had a high potential to induce helices of protein and that the active site of the enzyme was situated in a limited and flexible region of the enzyme molecule that was more susceptible to the denaturant than was the protein as a whole.
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Affiliation(s)
- Xiao-Yun Wang
- College of Life Science, Shandong Agricultural University, People's Republic of China
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Sakata Y, Shiraishi S, Otsuka M. Characterization of dehydration behavior of untreated and pulverized creatine monohydrate powders. Colloids Surf B Biointerfaces 2004; 35:185-91. [PMID: 15261030 DOI: 10.1016/j.colsurfb.2004.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Accepted: 03/06/2004] [Indexed: 11/30/2022]
Abstract
Creatine, which is well known as an important substance for muscular activity, is synthesized from amino acids such as glycine, arginine and ornithine in liver and kidney. It then accumulates in skeletal muscle as creatine phosphoric acid. The aim of this study was to understand the dehydration behavior of untreated and pulverized creatine monohydrate at various temperatures. The removal of crystal water was investigated by using differential scanning calorimetry (DSC), X-ray powder diffraction and scanning electron microscopy (SEM). The X-ray diffraction pattern of untreated and pulverized creatine monohydrate agreed with reported data for creatine monohydrate. However, the diffraction peaks of the (100), (200) and (300) planes of pulverized creatine monohydrate were much stronger than those of untreated creatine monohydrate. On the other hand, the diffraction peaks of the (012) and (013) planes of untreated creatine monohydrate were much stronger than those of pulverized creatine monohydrate. The dehydration of untreated and pulverized creatine monohydrate was investigated at various storage temperatures, and the results indicated that untreated and pulverized creatine monohydrate were transformed into the anhydrate at more than 30 degrees C. After dehydration, the particles of untreated and pulverized creatine anhydrate had many cracks. The dehydration kinetics of untreated and pulverized creatine monohydrate were analyzed by the Hancock-Sharp equation on the basis of the isothermal DSC data. The dehydrations of untreated and pulverized creatine monohydrate both followed a zero-order mechanism (Polany-Winger equation). However, the transition rate constant, calculated from the slope of the straight line, was about 2.2-7.7 times higher for pulverized creatine monohydrate than for untreated creatine monohydrate. The Arrhenius plots (natural logarithm of the dehydration rate constant versus the reciprocal of absolute temperature) of the isothermal DSC data for untreated and pulverized creatine monohydrate were linear. The activation energies of dehydration in the 40-60 degrees C range for untreated and pulverized creatine monohydrate were 15.02 and 10.1 kJ/mol, respectively. Dehydration of untreated creatine monohydrate had a pronounced effect on the particle size of the powder. Compared with pulverized creatine monohydrate, the particle size of untreated creatine monohydrate was significantly decreased by dehydration.
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Affiliation(s)
- Yukoh Sakata
- Healthcare Research Institute, Wakunaga Pharmaceutical Co., Ltd., 1624 Shimokotachi, Kodacho, Takatagun, Hiroshima 739-1195, Japan.
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Mahon MM, deSouza NM, Dina R, Soutter WP, McIndoe GA, Williams AD, Cox IJ. Preinvasive and invasive cervical cancer: an ex vivo proton magic angle spinning magnetic resonance spectroscopy study. NMR Biomed 2004; 17:144-153. [PMID: 15137039 DOI: 10.1002/nbm.869] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The aim of this study was to obtain (1)H MR spectra using magic angle spinning (MAS) techniques from punch biopsies (<20 mg) of preinvasive and invasive cervical disease and to correlate the spectral profiles with sample classification on the basis of histopathology. Tissue samples were obtained at colposcopic examination, during local treatment of cervical intraepithelial neoplasia (CIN) or at hysterectomy. (1)H MAS MRS was performed at 25 degrees C while spinning the sample at 4.5 kHz. After measurement, the tissue was immersed in formalin and the pathology determined. Histological examination after (1)H MAS MRS defined 27 samples with squamous cell carcinoma (SCC), 12 with CIN and 39 with only normal tissue. The standardized integrals of the lipid, choline and creatine regions of the spectra were significantly higher in SCC than in normal or CIN tissue. There was no obvious difference in the standardized integral of the region 4.15-3.5 ppm. The acyl fatty acid side-chain length was longer or less unsaturated in SCC than in normal tissue. Normal tissue from patients with SCC showed significantly higher triglycerides than normal tissue from patients with benign uterine disease but significantly lower triglycerides than SCC tissue. (1)H MAS MRS of the uterine cervix ex vivo may be used to differentiate non-invasive from invasive cervical lesions, increase interpretation of in vivo MRS and provide insights into tumor biology.
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Affiliation(s)
- Marrita M Mahon
- Robert Steiner MR Department, Imaging Sciences Department, Division of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK
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Yoshimoto T, Tanaka N, Kanada N, Inoue T, Nakajima Y, Haratake M, Nakamura KT, Xu Y, Ito K. Crystal Structures of Creatininase Reveal the Substrate Binding Site and Provide an Insight into the Catalytic Mechanism. J Mol Biol 2004; 337:399-416. [PMID: 15003455 DOI: 10.1016/j.jmb.2004.01.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2003] [Revised: 01/02/2004] [Accepted: 01/09/2004] [Indexed: 10/26/2022]
Abstract
Creatininase from Pseudomonas putida is a member of the urease-related amidohydrolase superfamily. The crystal structure of the Mn-activated enzyme has been solved by the single isomorphous replacement method at 1.8A resolution. The structures of the native creatininase and the Mn-activated creatininase-creatine complex have been determined by a difference Fourier method at 1.85 A and 1.6 A resolution, respectively. We found the disc-shaped hexamer to be roughly 100 A in diameter and 50 A in thickness and arranged as a trimer of dimers with 32 (D3) point group symmetry. The enzyme is a typical Zn2+ enzyme with a binuclear metal center (metal1 and metal2). Atomic absorption spectrometry and X-ray crystallography revealed that Zn2+ at metal1 (Zn1) was easily replaced with Mn2+ (Mn1). In the case of the Mn-activated enzyme, metal1 (Mn1) has a square-pyramidal geometry bound to three protein ligands of Glu34, Asp45, and His120 and two water molecules. Metal2 (Zn2) has a well-ordered tetrahedral geometry bound to the three protein ligands of His36, Asp45, and Glu183 and a water molecule. The crystal structure of the Mn-activated creatininase-creatine complex, which is the first structure as the enzyme-substrate/inhibitor complex of creatininase, reveals that significant conformation changes occur at the flap (between the alpha5 helix and the alpha6 helix) of the active site and the creatine is accommodated in a hydrophobic pocket consisting of Trp174, Trp154, Tyr121, Phe182, Tyr153, and Gly119. The high-resolution crystal structure of the creatininase-creatine complex enables us to identify two water molecules (Wat1 and Wat2) that are possibly essential for the catalytic mechanism of the enzyme. The structure and proposed catalytic mechanism of the creatininase are different from those of urease-related amidohydrolase superfamily enzymes. We propose a new two-step catalytic mechanism possibly common to creatininases in which the Wat1 acts as the attacking nucleophile in the water-adding step and the Wat2 acts as the catalytic acid in the ring-opening step.
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Affiliation(s)
- Tadashi Yoshimoto
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
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44
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Mazon H, Marcillat O, Forest E, Vial C. Changes in MM-CK conformational mobility upon formation of the ADP-Mg(2+)-NO(3)(-)-creatine transition state analogue complex as detected by hydrogen/deuterium exchange. Biochemistry 2004; 42:13596-604. [PMID: 14622006 DOI: 10.1021/bi035208m] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the presence of ADP, Mg(2+), creatine, and the planar nitrate ion, creatine kinase isoenzymes undergo significant structural changes accompanying the formation of a very stable transition state analogue complex (TSAC). We have compared, by using hydrogen/deuterium exchange followed by proteolysis of the labeled enzyme and mass spectrometric analysis of the peptic peptides, the backbone dynamics fluctuations of the free enzyme and those of the TSAC. In most peptides, exchange is not affected by ligand binding, except that observed in seven areas located in or at the entrance to the active site, where some protection is detected. On the basis of a comparison with the three-dimensional structures of free or liganded guanidino kinases, four of these peptides (residues 54-72, 226-234, 287-311, and 315-333) can be considered part of the substrate binding site. The other three (residues 162-186, 193-201, and 202-224) are not directly involved in the binding of substrates and are located in a dynamic domain, which allows the enzyme to properly align the substrates for optimal catalysis.
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Affiliation(s)
- Hortense Mazon
- UMR CNRS 5013, Biomembranes et enzymes associés, Université Claude Bernard Lyon 1, 43, boulevard du 11 Novembre 1918, 69622 Villeurbanne cedex, France
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45
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Abstract
The objectives of this study were to determine the cause of the crystallization in a large volume creatine supplement solution made from effervescent powders containing di-creatine citrate, and to characterize these crystals using thermal analyses and x-ray diffractometry. Creatine effervescent powders were dissolved in deionized water (pH 6.2) and stored both at room temperature (RT) (25 degrees C) and refrigerated condition (4 degrees C) over a period of 45 days. Creatine concentration was determined using high-performance liquid chromatography (HPLC). Intrinsic dissolution and saturated solubility of creatine, creatine monohydrate, and di-creatine citrate in water were determined and compared. Crystal growth was detected only in the refrigerated samples on the seventh day of storage. Differential Scanning Calorimetry (DSC) and x-ray diffraction (XRD) studies revealed that the crystals formed were of creatine monohydrate. Ninety percent creatine degradation was observed within 45 days for RT samples. However, at refrigerated condition this degradation was 80% within the same time period. The pH of the RT samples also increased from 3.6 to 4.5 during storage. No such increase was observed in the case of refrigerated samples. The intrinsic dissolution rate constants of the compounds decreased in the following order: di-creatine citrate > creatine > creatine monohydrate. In conclusion, di-creatine citrate used in effervescent formulation dissociates to creatine in aqueous solution and eventually crystallizes out as creatine monohydrate. Significant decrease in solubility and effect of pH contribute to this crystallization process.
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Affiliation(s)
- Sudipta Ganguly
- Department of Pharmacy Sciences, School of Pharmacy and Heath Professions, Creighton University Medical Center, 2500 California Plaza, 68178 Omaha, NE
| | - Sheela Jayappa
- Department of Pharmacy Sciences, School of Pharmacy and Heath Professions, Creighton University Medical Center, 2500 California Plaza, 68178 Omaha, NE
| | - Alekha K. Dash
- Department of Pharmacy Sciences, School of Pharmacy and Heath Professions, Creighton University Medical Center, 2500 California Plaza, 68178 Omaha, NE
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46
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Rutgers DR, van der Grond J. Relaxation times of choline, creatine and N-acetyl aspartate in human cerebral white matter at 1.5 T. NMR Biomed 2002; 15:215-221. [PMID: 11968137 DOI: 10.1002/nbm.762] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Several studies have investigated the T1 and T2 relaxation time of choline, creatine and N-acetyl aspartate in cerebral white matter in normal human subjects. However, these studies demonstrate a large variation in T1 and T2 values. In the present study, relaxation times of choline, creatine and N-acetyl aspartate were determined in cerebral white matter in 15 control subjects (age 21 +/- 2 y, mean +/- SD) at 1.5 T. Using PRESS, seven or eight data points were obtained to fit the T1 and T2 relaxation curves to, respectively. The mean voxel size was 14 cm3. The T1 relaxation times of choline, creatine and N-acetyl aspartate were 1091 +/- 132 (mean +/- SD), 1363 +/- 137 and 1276 +/- 132 ms. The T2 relaxation times were 352 +/- 52, 219 +/- 29 and 336 +/- 46 ms, respectively.
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Affiliation(s)
- D R Rutgers
- Department of Radiology, University Medical Center Utrecht, The Netherlands.
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47
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Abstract
Creatine monohydrate (CM) is a nutritional supplement and an ergogenic aid for athletes. It appears to increase lean body mass, high-intensity power output and strength in healthy humans. The crystal structure of creatine monohydrate has previously been reported. However, little information is available on its solid-state properties. In this investigation, creatine monohydrate was subjected to Thermal Analyses, Karl-Fisccher Titrimetry (KFT), Scanning Electron Microscopy (SEM), and Variable Temperature X-ray Powder Diffractometry (VTXRD) to characterize its solid-state properties. The results of this study suggested that commercially available creatine monohydrate dehydrates at about 97-125 degrees C. A phase transition after dehydration was confirmed by X-ray diffraction studies. This dehydrated phase at a temperature above 230 degrees C undergoes intramolecular cyclization with a loss of an additional mole of water to form creatinine. Creatinine finally melts with decomposition at about 290 degrees C. VTXRD, confirmed that the above solid-state thermal transformation was kinetically driven, and occurred within a narrow temperature range. Mass Spectrometric (MS) studies further indicated a possible dimerization of creatinine formed during the solid-state transformation.
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Affiliation(s)
- Alekha K Dash
- Department of Pharmacy Sciences, School of Pharmacy and Allied Health Professions, Creighton University, 2500 California Plaza, Omaha, Nebraska 68178, USA.
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48
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Harada M, Uno M, Hong F, Hisaoka S, Nishitani H, Matsuda T. Diffusion-weighted in vivo localized proton MR spectroscopy of human cerebral ischemia and tumor. NMR Biomed 2002; 15:69-74. [PMID: 11840555 DOI: 10.1002/nbm.759] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The apparent diffusion coefficients (ADCs) of water and brain metabolites were determined by proton MR spectroscopy on a clinical MR scanner for healthy volunteers and for pathological changes in cases of acute cerebral infarction and brain tumor. The ADCs of N-acetyl aspartate (NAA) and creatines in tissue involved in acute infarction were decreased compared to normal control values, while in tumors they showed increased values. Since NAA is a neuronal marker, these findings suggest that neuronal cell viscosity changes according to the pathological status of the tissue. The lactate ADC was significantly larger than the values for other major metabolites in cases of ischemia and tumor, suggesting that lactate is present in a different compartment. These results indicate that metabolite diffusion data can be used to reveal changes in the intracellular environment depending on the pathological status.
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Affiliation(s)
- Masafumi Harada
- Department of Radiology, University of Tokushima, Tokushima, Japan
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49
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Vaillancourt VA, Larsen SD, Tanis SP, Burr JE, Connell MA, Cudahy MM, Evans BR, Fisher PV, May PD, Meglasson MD, Robinson DD, Stevens FC, Tucker JA, Vidmar TJ, Yu JH. Synthesis and biological activity of aminoguanidine and diaminoguanidine analogues of the antidiabetic/antiobesity agent 3-guanidinopropionic acid. J Med Chem 2001; 44:1231-48. [PMID: 11312923 DOI: 10.1021/jm000094n] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
3-Guanidinopropionic acid (1) has been demonstrated both to improve insulin sensitivity and to promote weight loss selectively from adipose tissue in animal models of non-insulin-dependent diabetes mellitus (NIDDM). However, 1 has also been shown to be a substrate for both the creatine transporter and creatine kinase, leading to marked accumulation in muscle tissue as the corresponding N-phosphate. The corresponding aminoguanidine analogue 2 was recently discovered to retain the antidiabetic activity of 1 while being markedly less susceptible to creatine-like metabolism, suggesting that it should have less potential to accumulate in muscle. Further structural modification of 2 was undertaken to investigate whether the antidiabetic potency could be augmented while maintaining resistance to creatine-like metabolism. Modifications such as alpha-alkylation, homologation, and bioisosteric replacement of the aminoguanidine all were detrimental to antidiabetic activity. However, the simple regioisomeric aminoguanidinoacetic acid 9 and diaminoguanidinoacetic acid analogue 7 were found to be equipotent to 2, leading eventually to the discovery of the significantly more potent diaminoguanidinoacetic acid regioisomers 52 and 53. Further attempts to modify the more active template represented by 52 led only to reductions in antidiabetic activity. Each of the new active analogues displayed the same resistance to creatine-like metabolism as 2. Further testing of 7, 9, and 53 in obese diabetic ob/ob mice confirmed that weight loss is induced selectively from adipose tissue, similar to the lead 1. Administration of 53 to insulin-resistant rhesus monkeys led to reductions in both fasting and post-prandial plasma glucose levels with concomitant reductions in plasma insulin levels, suggesting that the compound improved the action of endogenous insulin. Compounds 7 and 53 were selected for further preclinical development.
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Affiliation(s)
- V A Vaillancourt
- Departments of Medicinal Chemistry, Pharmacology, and Research Biostatistics, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49007, USA.
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50
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Larsen SD, Connell MA, Cudahy MM, Evans BR, May PD, Meglasson MD, O'Sullivan TJ, Schostarez HJ, Sih JC, Stevens FC, Tanis SP, Tegley CM, Tucker JA, Vaillancourt VA, Vidmar TJ, Watt W, Yu JH. Synthesis and biological activity of analogues of the antidiabetic/antiobesity agent 3-guanidinopropionic acid: discovery of a novel aminoguanidinoacetic acid antidiabetic agent. J Med Chem 2001; 44:1217-30. [PMID: 11312922 DOI: 10.1021/jm000095f] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [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: 01/19/2023]
Abstract
3-Guanidinopropionic acid (1, PNU-10483) has been demonstrated to both improve insulin sensitivity and to promote weight loss selectively from adipose tissue in animal models of non-insulin-dependent diabetes mellitus (NIDDM). However, 1 has also been shown to be a substrate for both the creatine transporter and creatine kinase, leading to marked accumulation in muscle tissue as the corresponding N-phosphate 4. In an effort to identify novel entities that maintain antidiabetic potency without susceptibility to creatine-like metabolism, an analogue program was undertaken to explore the effects of various structural modifications, including homologation, simple substitution, single atom mutations, and bioisosteric replacements for the guanidine and carboxylic acid. Overall, the scope of activity encompassed by the set of new analogues proved to be exceedingly narrow. Notable exceptions demonstrating equivalent or improved antidiabetic activity included the alpha-amino derivative 29, aminopyridine 47, isothiourea 67, and aminoguanidine 69. On the basis of its superior therapeutic ratio, aminoguanidine 69 was selected for preclinical development and became the foundation for a second phase of analogue work. Furthermore, in vitro studies demonstrated that 69 is markedly less susceptible to phosphorylation by creatine kinase than the lead 1, suggesting that it should have less potential for accumulation in muscle tissue than 1.
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Affiliation(s)
- S D Larsen
- Departments of Medicinal Chemistry, Pharmacology, Structural, Analytical and Medicinal Chemistry, and Research Biostatistics, Pharmacia Corporation, 301 Henrietta Street, Kalamazoo, Michigan 49007, USA.
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