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Bruce JI, O’Connell PJ, Taylor PG, Smith DP, Adkin RC, Pearson VK. Synthesis of Organosilicon Ligands for Europium (III) and Gadolinium (III) as Potential Imaging Agents. Molecules 2020; 25:molecules25184253. [PMID: 32947960 PMCID: PMC7570700 DOI: 10.3390/molecules25184253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/11/2020] [Accepted: 09/11/2020] [Indexed: 11/30/2022] Open
Abstract
The relaxivity of MRI contrast agents can be increased by increasing the size of the contrast agent and by increasing concentration of the bound gadolinium. Large multi-site ligands able to coordinate several metal centres show increased relaxivity as a result. In this paper, an “aza-type Michael” reaction is used to prepare cyclen derivatives that can be attached to organosilicon frameworks via hydrosilylation reactions. A range of organosilicon frameworks were tested including silsesquioxane cages and dimethylsilylbenzene derivatives. Michael donors with strong electron withdrawing groups could be used to alkylate cyclen on three amine centres in a single step. Hydrosilylation successfully attached these to mono-, di-, and tri-dimethylsilyl-substituted benzene derivatives. The europium and gadolinium complexes were formed and studied using luminescence spectroscopy and relaxometry. This showed the complexes to contain two bound water moles per lanthanide centre and T1 relaxation time measurements demonstrated an increase in relaxivity had been achieved, in particular for the trisubstituted scaffold 1,3,5-tris((pentane-sDO3A)dimethylsilyl)benzene-Gd3. This showed a marked increase in the relaxivity (13.1 r1p/mM−1s−1).
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Affiliation(s)
- James I. Bruce
- School of Life Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK; (P.J.O.); (P.G.T.); (D.P.T.S.)
- Correspondence:
| | - Patrick J. O’Connell
- School of Life Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK; (P.J.O.); (P.G.T.); (D.P.T.S.)
| | - Peter G. Taylor
- School of Life Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK; (P.J.O.); (P.G.T.); (D.P.T.S.)
| | - David P.T. Smith
- School of Life Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK; (P.J.O.); (P.G.T.); (D.P.T.S.)
| | - Roy C. Adkin
- School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK; (R.C.A.); (V.K.P.)
| | - Victoria K. Pearson
- School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK; (R.C.A.); (V.K.P.)
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Balamurugan AN, Naziruddin B, Lockridge A, Tiwari M, Loganathan G, Takita M, Matsumoto S, Papas K, Trieger M, Rainis H, Kin T, Kay TW, Wease S, Messinger S, Ricordi C, Alejandro R, Markmann J, Kerr-Conti J, Rickels MR, Liu C, Zhang X, Witkowski P, Posselt A, Maffi P, Secchi A, Berney T, O’Connell PJ, Hering BJ, Barton FB. Islet product characteristics and factors related to successful human islet transplantation from the Collaborative Islet Transplant Registry (CITR) 1999-2010. Am J Transplant 2014; 14:2595-606. [PMID: 25278159 PMCID: PMC4282081 DOI: 10.1111/ajt.12872] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 05/30/2014] [Accepted: 06/18/2014] [Indexed: 02/05/2023]
Abstract
The Collaborative Islet Transplant Registry (CITR) collects data on clinical islet isolations and transplants. This retrospective report analyzed 1017 islet isolation procedures performed for 537 recipients of allogeneic clinical islet transplantation in 1999-2010. This study describes changes in donor and islet isolation variables by era and factors associated with quantity and quality of final islet products. Donor body weight and BMI increased significantly over the period (p<0.001). Islet yield measures have improved with time including islet equivalent (IEQ)/particle ratio and IEQs infused. The average dose of islets infused significantly increased in the era of 2007-2010 when compared to 1999-2002 (445.4±156.8 vs. 421.3±155.4×0(3) IEQ; p<0.05). Islet purity and total number of β cells significantly improved over the study period (p<0.01 and <0.05, respectively). Otherwise, the quality of clinical islets has remained consistently very high through this period, and differs substantially from nonclinical islets. In multivariate analysis of all recipient, donor and islet factors, and medical management factors, the only islet product characteristic that correlated with clinical outcomes was total IEQs infused. This analysis shows improvements in both quantity and some quality criteria of clinical islets produced over 1999-2010, and these parallel improvements in clinical outcomes over the same period.
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Affiliation(s)
- A N Balamurugan
- Schulze Diabetes Institute, Department of Surgery, University of MinnesotaMinneapolis, MN
- * Corresponding authors: Appakalai N. Balamurugan, and Franca B. Barton,
| | - B Naziruddin
- Baylor Annette C. and Harold C. Simmons Transplant InstituteDallas, TX
| | - A Lockridge
- Schulze Diabetes Institute, Department of Surgery, University of MinnesotaMinneapolis, MN
| | - M Tiwari
- Schulze Diabetes Institute, Department of Surgery, University of MinnesotaMinneapolis, MN
| | - G Loganathan
- Schulze Diabetes Institute, Department of Surgery, University of MinnesotaMinneapolis, MN
| | - M Takita
- Baylor Annette C. and Harold C. Simmons Transplant InstituteDallas, TX
| | - S Matsumoto
- Research and Development Center, Otsuka Pharmaceutical Factory, Inc.Tokushima, Japan
| | - K Papas
- Institute for Cellular Transplantation, University of ArizonaTucson, AZ
| | | | - H Rainis
- The EMMES CorporationRockville, MD
| | - T Kin
- Clinical Islet Laboratory, University of AlbertaEdmonton, AB
| | - T W Kay
- St. Vincent's HospitalMelbourne, Australia
| | - S Wease
- The EMMES CorporationRockville, MD
| | - S Messinger
- Department of Public Health Services, University of MiamiMiami, FL
| | - C Ricordi
- Diabetes Research Institute, University of MiamiMiami, FL
| | - R Alejandro
- Diabetes Research Institute, University of MiamiMiami, FL
| | - J Markmann
- Department of Surgery, Massachusetts General HospitalBoston, MA
| | | | - M R Rickels
- Department of Medicine, University of PennsylvaniaPhiladelphia, PA
| | - C Liu
- Department of Surgery, University of PennsylvaniaPhiladelphia, PA
| | - X Zhang
- Feinberg School of Medicine, Northwestern UniversityChicago, IL
| | - P Witkowski
- Department of Surgery, University of ChicagoChicago, IL
| | - A Posselt
- Department of Surgery, University of California, San FranciscoSan Francisco, CA
| | - P Maffi
- Vita-Salute, San Raffaele UniversityMilan, Italy
| | - A Secchi
- Vita-Salute, San Raffaele UniversityMilan, Italy
| | - T Berney
- Department of Surgery, Geneva University HospitalGeneva, Switzerland
| | - P J O’Connell
- National Pancreas Transplant Unit, University of Sydney at Westmead HospitalSydney, Australia
| | - B J Hering
- Schulze Diabetes Institute, Department of Surgery, University of MinnesotaMinneapolis, MN
| | - F B Barton
- The EMMES CorporationRockville, MD
- * Corresponding authors: Appakalai N. Balamurugan, and Franca B. Barton,
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