1
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Bannerman D, Pascual-Gil S, Campbell S, Jiang R, Wu Q, Okhovatian S, Wagner KT, Montgomery M, Laflamme MA, Davenport Huyer L, Radisic M. Itaconate and citrate releasing polymer attenuates foreign body response in biofabricated cardiac patches. Mater Today Bio 2024; 24:100917. [PMID: 38234461 PMCID: PMC10792972 DOI: 10.1016/j.mtbio.2023.100917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 01/19/2024] Open
Abstract
Application of cardiac patches to the heart surface can be undertaken to provide support and facilitate regeneration of the damaged cardiac tissue following ischemic injury. Biomaterial composition is an important consideration in the design of cardiac patch materials as it governs host response to ultimately prevent the undesirable fibrotic response. Here, we investigate a novel patch material, poly (itaconate-co-citrate-co-octanediol) (PICO), in the context of cardiac implantation. Citric acid (CA) and itaconic acid (ITA), the molecular components of PICO, provided a level of protection for cardiac cells during ischemic reperfusion injury in vitro. Biofabricated PICO patches were shown to degrade in accelerated and hydrolytic conditions, with CA and ITA being released upon degradation. Furthermore, the host response to PICO patches after implantation on rat epicardium in vivo was explored and compared to two biocompatible cardiac patch materials, poly (octamethylene (anhydride) citrate) (POMaC) and poly (ethylene glycol) diacrylate (PEGDA). PICO patches resulted in less macrophage infiltration and lower foreign body giant cell reaction compared to the other materials, with corresponding reduction in smooth muscle actin-positive vessel infiltration into the implant region. Overall, this work demonstrates that PICO patches release CA and ITA upon degradation, both of which demonstrate cardioprotective effects on cardiac cells after ischemic injury, and that PICO patches generate a reduced inflammatory response upon implantation to the heart compared to other materials, signifying promise for use in cardiac patch applications.
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Affiliation(s)
- Dawn Bannerman
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Simon Pascual-Gil
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Scott Campbell
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Richard Jiang
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Qinghua Wu
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Sargol Okhovatian
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Karl T. Wagner
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Miles Montgomery
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
| | - Michael A. Laflamme
- McEwen Stem Cell Institute, University Health Network, Toronto, ON, Canada
- Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Locke Davenport Huyer
- Applied Oral Sciences, Dalhousie University, Halifax, NS, Canada
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
- Department of Microbiology & Immunology, Dalhousie University, Halifax, NS, Canada
- Nova Scotia Health, Halifax, NS, Canada
| | - Milica Radisic
- Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Health Research Institute, University Health Network, Toronto, ON, Canada
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2
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Mathai S, Krupad K, Sohal S, Mehta A, Montgomery M, Murthy S, Visveshwaran G, Sims D, Jorde U. Comparison of In-Hospital Outcomes in Acute Myocardial Infarction-Cardiogenic Shock (AMICS) versus Non-AMICS Following ECPELLA. J Heart Lung Transplant 2023. [DOI: 10.1016/j.healun.2023.02.1530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
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3
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Grewal J, Mughal M, Nnaoma C, Montgomery M, Kapoor S. Axillary IABP Migration into SMA. J Heart Lung Transplant 2022. [DOI: 10.1016/j.healun.2022.01.1735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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4
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Siddiqui E, Okoh A, Tibuakuu M, Hirji S, Hameed I, Osho A, Singh S, Grewal J, Montgomery M, Camacho M, Bravo C. Racial Differences in In-Hospital Outcomes after the Use of Temporary Mechanical Circulatory Support as a Bridge to Heart Transplant. J Heart Lung Transplant 2021. [DOI: 10.1016/j.healun.2021.01.1136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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5
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Huyer LD, Mandla S, Wang Y, Campbell S, Yee B, Euler C, Lai BF, Bannerman D, Lin DSY, Montgomery M, Nemr K, Bender T, Epelman S, Mahadevan R, Radisic M. Macrophage immunomodulation through new polymers that recapitulate functional effects of itaconate as a power house of innate immunity. Adv Funct Mater 2021; 31:2003341. [PMID: 33708036 PMCID: PMC7942808 DOI: 10.1002/adfm.202003341] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Indexed: 05/12/2023]
Abstract
Itaconate (ITA) is an emerging powerhouse of innate immunity with therapeutic potential that is limited in its ability to be administered in a soluble form. We developed a library of polyester materials that incorporate ITA into polymer backbones resulting in materials with inherent immunoregulatory behavior. Harnessing hydrolytic degradation release from polyester backbones, ITA polymers resulted in the mechanism specific immunoregulatory properties on macrophage polarization in vitro. In a functional assay, the polymer-released ITA inhibited bacterial growth on acetate. Translation to an in vivo model of biomaterial associated inflammation, intraperitoneal injection of ITA polymers demonstrated a rapid resolution of inflammation in comparison to a control polymer silicone, demonstrating the value of sustained biomimetic presentation of ITA.
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Affiliation(s)
- L. Davenport Huyer
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - S. Mandla
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Y. Wang
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - S. Campbell
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - B. Yee
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - C. Euler
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - B. F. Lai
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - D. Bannerman
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - D. S. Y. Lin
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - M. Montgomery
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - K. Nemr
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - T. Bender
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - S. Epelman
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - R. Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - M. Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
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6
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Bannerman AD, Davenport Huyer L, Montgomery M, Zhao N, Velikonja C, Bender TP, Radisic M. Elastic Biomaterial Scaffold with Spatially Varying Adhesive Design. Adv Biosyst 2020; 4:e2000046. [PMID: 32567253 PMCID: PMC7665997 DOI: 10.1002/adbi.202000046] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 05/08/2020] [Indexed: 12/20/2022]
Abstract
In order to secure biomaterials to tissue surfaces, sutures or glues are commonly used. Of interest is the development of a biomaterial patch for applications in tissue engineering and regeneration that incorporates an adhesive component to simplify patch application and ensure sufficient adhesion. A separate region dedicated to fulfilling the specific requirements of an application such as mechanical support or tissue delivery is also desirable. Here, the design and fabrication of a unique patch are presented with distinct regions for adhesion and function, resulting in a biomaterial patch resembling the Band-Aid. The adhesive region contains a novel polymer, synthesized to incorporate a molecule capable of adhesion to tissue, dopamine. The desired polymer composition for patch development is selected based on chemical assessment and evaluation of key physical properties such as swelling and elastic modulus, which are tailored for use in soft tissue applications. The selected polymer formulation, referred to as the adhesive patch (AP) polymer, demonstrates negligible cytotoxicity and improves adhesive capability to rat cardiac tissue compared to currently used patch materials. Finally, the AP polymer is used in the patch, designed to possess distinct adhesive and nonadhesive domains, presenting a novel design for the next generation of biomaterials.
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Affiliation(s)
- A Dawn Bannerman
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, M5G 2C4, Canada
| | - Locke Davenport Huyer
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, M5G 2C4, Canada
| | - Miles Montgomery
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, M5G 2C4, Canada
| | - Nicholas Zhao
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
| | - Claire Velikonja
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
| | - Timothy P Bender
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, M5S 3G9, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario, M5G 2C4, Canada
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7
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Ringe J, Baik S, Shalabi D, Montgomery M, Rosenbloom J, Nikbakht N. 162 Unique expression of a fibronectin isoform in mycosis fungoides. J Invest Dermatol 2019. [DOI: 10.1016/j.jid.2019.03.238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Sultani G, Bentley N, Osborne B, Joshi S, Araki T, Montgomery M, Polly P, Byrne F, Wu L, Turner N. PO-011 Impact of compartment-specific changes in NAD biosynthesis on diethylnitrosamine-induced liver cancer. ESMO Open 2018. [DOI: 10.1136/esmoopen-2018-eacr25.56] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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9
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Rosenbloom J, Montgomery M, South A, Uitto J, Macarak E. 141 Potential consequences of the interaction of squamous cell carcinoma cells with EDA fibronectin in recessive dystrophic epidermolysis bullosa. J Invest Dermatol 2018. [DOI: 10.1016/j.jid.2018.03.146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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10
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Montgomery M, Davenport Huyer L, Bannerman D, Mohammadi MH, Conant G, Radisic M. Method for the Fabrication of Elastomeric Polyester Scaffolds for Tissue Engineering and Minimally Invasive Delivery. ACS Biomater Sci Eng 2018; 4:3691-3703. [DOI: 10.1021/acsbiomaterials.7b01017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
| | | | | | | | | | - Milica Radisic
- Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 2C4, Canada
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11
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Montgomery M, Ahadian S, Davenport Huyer L, Lo Rito M, Civitarese RA, Vanderlaan RD, Wu J, Reis LA, Momen A, Akbari S, Pahnke A, Li RK, Caldarone CA, Radisic M. Flexible shape-memory scaffold for minimally invasive delivery of functional tissues. Nat Mater 2017; 16:1038-1046. [PMID: 28805824 DOI: 10.1038/nmat4956] [Citation(s) in RCA: 206] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/04/2017] [Indexed: 06/07/2023]
Abstract
Despite great progress in engineering functional tissues for organ repair, including the heart, an invasive surgical approach is still required for their implantation. Here, we designed an elastic and microfabricated scaffold using a biodegradable polymer (poly(octamethylene maleate (anhydride) citrate)) for functional tissue delivery via injection. The scaffold's shape memory was due to the microfabricated lattice design. Scaffolds and cardiac patches (1 cm × 1 cm) were delivered through an orifice as small as 1 mm, recovering their initial shape following injection without affecting cardiomyocyte viability and function. In a subcutaneous syngeneic rat model, injection of cardiac patches was equivalent to open surgery when comparing vascularization, macrophage recruitment and cell survival. The patches significantly improved cardiac function following myocardial infarction in a rat, compared with the untreated controls. Successful minimally invasive delivery of human cell-derived patches to the epicardium, aorta and liver in a large-animal (porcine) model was achieved.
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Affiliation(s)
- Miles Montgomery
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Samad Ahadian
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Locke Davenport Huyer
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Mauro Lo Rito
- Division of Cardiovascular Surgery, Labatt Family Heart Centre, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
- Department of Surgery, University of Toronto, Toronto, Ontario M5T 1P5, Canada
| | - Robert A Civitarese
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Rachel D Vanderlaan
- Division of Cardiovascular Surgery, Labatt Family Heart Centre, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
- Department of Surgery, University of Toronto, Toronto, Ontario M5T 1P5, Canada
| | - Jun Wu
- Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Lewis A Reis
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Abdul Momen
- Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Saeed Akbari
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8, Canada
| | - Aric Pahnke
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Ren-Ke Li
- Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Christopher A Caldarone
- Division of Cardiovascular Surgery, Labatt Family Heart Centre, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
- Department of Surgery, University of Toronto, Toronto, Ontario M5T 1P5, Canada
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
- Toronto General Research Institute, University Health Network, Toronto, Ontario M5G 1L7, Canada
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12
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Affiliation(s)
- C L Yang
- British Columbia Children's Hospital, Department of Pediatrics, Division of Respiratory Medicine, Vancouver, BC, Canada.
| | - M Chilvers
- British Columbia Children's Hospital, Department of Pediatrics, Division of Respiratory Medicine, Vancouver, BC, Canada
| | - M Montgomery
- Alberta Children's Hospital, Pediatrics and Child Health, Calgary, AB, Canada
| | - S J Nolan
- The University of Liverpool, Department of Biostatistics, Liverpool, UK
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13
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14
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Zhang B, Montgomery M, Chamberlain MD, Ogawa S, Korolj A, Pahnke A, Wells LA, Massé S, Kim J, Reis L, Momen A, Nunes SS, Wheeler A, Nanthakumar K, Keller G, Sefton MV, Radisic M. Biodegradable scaffold with built-in vasculature for organ-on-a-chip engineering and direct surgical anastomosis. Nat Mater 2016; 15:669-78. [PMID: 26950595 PMCID: PMC4879054 DOI: 10.1038/nmat4570] [Citation(s) in RCA: 347] [Impact Index Per Article: 43.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 01/19/2016] [Indexed: 05/12/2023]
Abstract
We report the fabrication of a scaffold (hereafter referred to as AngioChip) that supports the assembly of parenchymal cells on a mechanically tunable matrix surrounding a perfusable, branched, three-dimensional microchannel network coated with endothelial cells. The design of AngioChip decouples the material choices for the engineered vessel network and for cell seeding in the parenchyma, enabling extensive remodelling while maintaining an open-vessel lumen. The incorporation of nanopores and micro-holes in the vessel walls enhances permeability, and permits intercellular crosstalk and extravasation of monocytes and endothelial cells on biomolecular stimulation. We also show that vascularized hepatic tissues and cardiac tissues engineered by using AngioChips process clinically relevant drugs delivered through the vasculature, and that millimetre-thick cardiac tissues can be engineered in a scalable manner. Moreover, we demonstrate that AngioChip cardiac tissues implanted with direct surgical anastomosis to the femoral vessels of rat hindlimbs establish immediate blood perfusion.
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Affiliation(s)
- Boyang Zhang
- Department of Chemical Engineering, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Miles Montgomery
- Department of Chemical Engineering, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - M. Dean Chamberlain
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Shinichiro Ogawa
- McEwen Center for Regenerative Medicine, Toronto, Ontario, Canada
| | - Anastasia Korolj
- Department of Chemical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Aric Pahnke
- Department of Chemical Engineering, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Laura A. Wells
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Stéphane Massé
- The Toby Hull Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada
| | - Jihye Kim
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Lewis Reis
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Abdulah Momen
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Sara S. Nunes
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Aaron Wheeler
- Department of Chemical Engineering, University of Toronto, Toronto, Ontario, Canada
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Kumaraswamy Nanthakumar
- The Toby Hull Cardiac Fibrillation Management Laboratory, Toronto General Hospital, Toronto, Ontario, Canada
| | - Gordon Keller
- McEwen Center for Regenerative Medicine, Toronto, Ontario, Canada
| | - Michael V. Sefton
- Department of Chemical Engineering, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Milica Radisic
- Department of Chemical Engineering, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- The Heart and Stroke/Richard Lewar Centre of Excellence, Toronto, Ontario, Canada
- Correspondence should be addressed to M.R. ()
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15
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Davenport Huyer L, Zhang B, Korolj A, Montgomery M, Drecun S, Conant G, Zhao Y, Reis L, Radisic M. Highly Elastic and Moldable Polyester Biomaterial for Cardiac Tissue Engineering Applications. ACS Biomater Sci Eng 2016; 2:780-788. [PMID: 33440575 DOI: 10.1021/acsbiomaterials.5b00525] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polyester biomaterials are used in tissue engineering as scaffolds for implantation of tissues developed in vitro. An ideal biodegradable elastomer for cardiac tissue engineering exhibits a relatively low Young's modulus, with high elongation and tensile strength. Here we describe a novel polyester biomaterial that exhibits improved elastic properties for cardiac tissue engineering applications. We synthesized poly(octamethylene maleate (anhydride) 1,2,4-butanetricarboxylate) (124 polymer) prepolymer gel in a one-step polycondensation reaction. The prepolymer was then molded as desired and exposed to ultraviolet (UV) light to produce a cross-linked elastomer. 124 polymer exhibited highly elastic properties under aqueous conditions that were tunable according to the UV light exposure, monomer composition, and porosity of the cured elastomer. Its elastomeric properties fell within the range of adult heart myocardium, but they could also be optimized for higher elasticity for weaker immature constructs. The polymer showed relatively stable degradation characteristics, both hydrolytically and in a cellular environment, suggesting maintenance of material properties as a scaffold support for potential tissue implants. When assessed for cell interaction, this polymer supported rat cardiac cell attachment in vitro as well as comparable acute in vivo host response when compared to poly(l-lactic acid) control. This suggests the potential applicability of this material as an elastomer for cardiac tissue engineered constructs.
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Affiliation(s)
- Locke Davenport Huyer
- Department of Chemical Engineering and Applied Chemistry, ‡Institute of Biomaterials and Biomedical Engineering, and §Human Biology, University of Toronto, Toronto, Ontario, Canada
| | - Boyang Zhang
- Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, and §Human Biology, University of Toronto, Toronto, Ontario, Canada
| | - Anastasia Korolj
- Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, and Human Biology, University of Toronto, Toronto, Ontario, Canada
| | - Miles Montgomery
- Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, and Human Biology, University of Toronto, Toronto, Ontario, Canada
| | - Stasja Drecun
- Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, and Human Biology, University of Toronto, Toronto, Ontario, Canada
| | - Genevieve Conant
- Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, and Human Biology, University of Toronto, Toronto, Ontario, Canada
| | - Yimu Zhao
- Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, and Human Biology, University of Toronto, Toronto, Ontario, Canada
| | - Lewis Reis
- Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, and Human Biology, University of Toronto, Toronto, Ontario, Canada
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, and Human Biology, University of Toronto, Toronto, Ontario, Canada
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16
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Smith R, Montgomery M, Kilroy G, Tang S, Müller S. Tropical low formation during the Australian monsoon: the events of January 2013 (paper updated July 2016). ACTA ACUST UNITED AC 2015. [DOI: 10.22499/2.6503.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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Håkansson B, Montgomery M, Cadiere GB, Rajan A, Bruley des Varannes S, Lerhun M, Coron E, Tack J, Bischops R, Thorell A, Arnelo U, Lundell L. Randomised clinical trial: transoral incisionless fundoplication vs. sham intervention to control chronic GERD. Aliment Pharmacol Ther 2015; 42:1261-70. [PMID: 26463242 DOI: 10.1111/apt.13427] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Revised: 08/08/2015] [Accepted: 09/21/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND Until recently only two therapeutic options have been available to control symptoms and the esophagitis in chronic gastro-oesophageal reflux disease (GERD), i.e. lifelong proton pump inhibitor (PPI) therapy or anti-reflux surgery. Lately, transoral incisionless fundoplication (TIF) has been developed and found to offer a therapeutic alternative for these patients. AIM To perform a double-blind sham-controlled study in GERD patients who were chronic PPI users. METHODS We studied patients with objectively confirmed GERD and persistent moderate to severe GERD symptoms without PPI therapy. Of 121 patients screened, we finally randomised 44 patients with 22 patients in each group. Those allocated to TIF had the TIF2 procedure completed during general anaesthesia by the EsophyX device with SerosaFuse fasteners. The sham procedure consisted of upper GI endoscopy under general anaesthesia. Neither the patient nor the assessor was aware of the patients' group affiliation. The primary effectiveness endpoint was the proportion of patients in clinical remission after 6-month follow-up. Secondary outcomes were: PPI consumption, oesophageal acid exposure, reduction in Quality of Life in Reflux and Dyspepsia and Gastrointestinal Symptom Rating Scale scores and healing of reflux esophagitis. RESULTS The time (average days) in remission offered by the TIF2 procedure (197) was significantly longer compared to those submitted to the sham intervention (107), P < 0.001. After 6 months 13/22 (59%) of the chronic GERD patients remained in clinical remission after the active intervention. Likewise, the secondary outcome measures were all in favour of the TIF2 procedure. No safety issues were raised. CONCLUSION Transoral incisionless fundoplication (TIF2) is effective in chronic PPI-dependent GERD patients when followed up for 6 months. Clinicaltrials.gov: CT01110811.
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Affiliation(s)
- B Håkansson
- Department of Surgery, Ersta Hospital, Karolinska Institutet, Danderyds Hospital, Stockholm, Sweden
| | - M Montgomery
- Department of Surgery, Ersta Hospital, Karolinska Institutet, Danderyds Hospital, Stockholm, Sweden
| | - G B Cadiere
- Department of Surgery and Gastroenterology, Park Leopold Clinic, CHIREC, Brussels, Belgium
| | - A Rajan
- Department of Surgery and Gastroenterology, Park Leopold Clinic, CHIREC, Brussels, Belgium
| | | | - M Lerhun
- CHU Hotel Dieu Institut des Maladies de l' Appareil Digestif, Nantes, France
| | - E Coron
- CHU Hotel Dieu Institut des Maladies de l' Appareil Digestif, Nantes, France
| | - J Tack
- Department of Gastroenterology, University Hospitals Leuven, Leuven, Belgium
| | - R Bischops
- Department of Gastroenterology, University Hospitals Leuven, Leuven, Belgium
| | - A Thorell
- Department of Surgery, Ersta Hospital, Karolinska Institutet, Danderyds Hospital, Stockholm, Sweden
| | - U Arnelo
- Department of Surgery, Centre for Digestive Diseases, Karolinska University Huddinge Hospital, Karolinska Institutet, Stockholm, Sweden
| | - L Lundell
- Department of Surgery, Centre for Digestive Diseases, Karolinska University Huddinge Hospital, Karolinska Institutet, Stockholm, Sweden
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Zhang B, Montgomery M, Davenport-Huyer L, Korolj A, Radisic M. Platform technology for scalable assembly of instantaneously functional mosaic tissues. Sci Adv 2015; 1:e1500423. [PMID: 26601234 PMCID: PMC4643798 DOI: 10.1126/sciadv.1500423] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 07/13/2015] [Indexed: 05/05/2023]
Abstract
Engineering mature tissues requires a guided assembly of cells into organized three-dimensional (3D) structures with multiple cell types. Guidance is usually achieved by microtopographical scaffold cues or by cell-gel compaction. The assembly of individual units into functional 3D tissues is often time-consuming, relying on cell ingrowth and matrix remodeling, whereas disassembly requires an invasive method that includes either matrix dissolution or mechanical cutting. We invented Tissue-Velcro, a bio-scaffold with a microfabricated hook and loop system. The assembly of Tissue-Velcro preserved the guided cell alignment realized by the topographical features in the 2D scaffold mesh and allowed for the instant establishment of coculture conditions by spatially defined stacking of cardiac cell layers or through endothelial cell coating. The assembled cardiac 3D tissue constructs were immediately functional as measured by their ability to contract in response to electrical field stimulation. Facile, on-demand tissue disassembly was demonstrated while preserving the structure, physical integrity, and beating function of individual layers.
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Affiliation(s)
- Boyang Zhang
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Miles Montgomery
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Locke Davenport-Huyer
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Anastasia Korolj
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
- Corresponding author. E-mail:
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Abstract
Cardiovascular disease is a leading cause of death worldwide, necessitating the development of effective treatment strategies. A myocardial infarction involves the blockage of a coronary artery leading to depletion of nutrient and oxygen supply to cardiomyocytes and massive cell death in a region of the myocardium. Cardiac tissue engineering is the growth of functional cardiac tissue in vitro on biomaterial scaffolds for regenerative medicine application. This strategy relies on the optimization of the complex relationship between cell networks and biomaterial properties. In this review, we discuss important biomaterial properties for cardiac tissue engineering applications, such as elasticity, degradation, and induced host response, and their relationship to engineered cardiac cell environments. With these properties in mind, we also emphasize in vitro use of cardiac tissues for high-throughput drug screening and disease modelling.
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Affiliation(s)
- Locke Davenport Huyer
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Miles Montgomery
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Yimu Zhao
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Yun Xiao
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Genevieve Conant
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Anastasia Korolj
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Toronto General Research Institute, University Health Network and IBBME, University of Toronto, Toronto, ON, Canada
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Abstract
Myocardial infarction results from a blockage of a major coronary artery that shuts the delivery of oxygen and nutrients to a region of the myocardium, leading to massive cardiomyocytes death and regression of microvasculature. Growth factor and cell delivery methods have been attempted to revascularize the ischemic myocardium and prevent further cell death. Implantable cardiac tissue patches were engineered to directly revascularize as well as remuscularize the affected muscle. However, inadequate vascularization in vitro and in vivo limits the efficacy of these new treatment options. Breakthroughs in cardiac tissue vascularization will profoundly impact ischemic heart therapies. In this review, we discuss the full spectrum of vascularization approaches ranging from biological angiogenesis to microfluidic blood vessels as related to cardiac tissue engineering.
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Affiliation(s)
- Miles Montgomery
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Boyang Zhang
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Milica Radisic
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
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Spicer C, Fite K, Montgomery M, Dollar B. Percutaneous needle biopsy in the setting of decubitus ulcer and spondylodiscitis: are the yields rates for these procedures clinically useful? J Vasc Interv Radiol 2014. [DOI: 10.1016/j.jvir.2013.12.301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Levin ML, Zemtsova GE, Montgomery M, Killmaster LF. Effects of homologous and heterologous immunization on the reservoir competence of domestic dogs for Rickettsia conorii (israelensis). Ticks Tick Borne Dis 2014; 5:33-40. [PMID: 24201056 PMCID: PMC5659121 DOI: 10.1016/j.ttbdis.2013.07.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [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: 03/18/2013] [Revised: 06/24/2013] [Accepted: 07/03/2013] [Indexed: 11/28/2022]
Abstract
A number of spotted fever group (SFG) rickettsiae cause serious infections in humans. Several antigenically related rickettsial agents may coexist within the same geographical area, and humans or vertebrate hosts may be sequentially exposed to multiple SFG agents. We assessed whether exposure of a vertebrate reservoir to one SFG Rickettsia will affect the host's immune response to a related pathogen and the efficiency of transmission to uninfected ticks. Two pairs of dogs were each infected with either Rickettsia massiliae or Rickettsia conorii israelensis, and their immune response was monitored twice weekly by IFA. The four immunized dogs and a pair of naïve dogs were each challenged with R. conorii israelensis-infected Rhipicephalus sanguineus nymphs. Uninfected Rh. sanguineus larvae were acquisition-fed on the dogs on days 1, 7, and 14 post-challenge. These ticks were tested for the presence of rickettsial DNA after molting to the nymphal stage. The naive dogs became infected with R. conorii israelensis and were infectious to ticks for at least 3 weeks, whereas reservoir competence of dogs previously infected with either R. massiliae or R. conorii was significantly diminished. This opens an opportunity for decreasing the efficiency of transmission and propagation of pathogenic Rickettsia in natural foci by immunizing the primary hosts with closely related nonpathogenic SFG bacteria. However, neither homologous immunization nor cross-immunization significantly affected the efficiency of R. conorii transmission between cofeeding infected nymphs and uninfected larvae. At high densities of ticks, the efficiency of cofeeding transmission may be sufficient for yearly amplification and persistent circulation of a rickettsial pathogen in the vector population.
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Affiliation(s)
- M L Levin
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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Inwald DP, Arul GS, Montgomery M, Henning J, McNicholas J, Bree S. Management of children in the deployed intensive care unit at Camp Bastion, Afghanistan. J ROY ARMY MED CORPS 2013; 160:236-40. [PMID: 24307254 PMCID: PMC4154587 DOI: 10.1136/jramc-2013-000177] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND The deployed Intensive Therapy Unit (ITU) in the British military field hospital in Camp Bastion, Afghanistan, admits both adults and children. The purpose of this paper is to review the paediatric workload in the deployed ITU and to describe how the unit copes with the challenge of looking after critically injured and ill children. METHODS Retrospective review of patients <16 years of age admitted to the ITU in the British military field hospital in Camp Bastion, Afghanistan, over a 1-year period from April 2011 to April 2012. RESULTS 112/811 (14%) admissions to the ITU were paediatric (median age 8 years, IQR 6-12, range 1-16). 80/112 were trauma admissions, 13 were burns, four were non-trauma admissions and 15 were readmissions. Mechanism of injury in trauma was blunt in 12, blast (improvised explosive device) in 45, blast (indirect fire) in seven and gunshot wound in 16. Median length of stay was 0.92 days (IQR 0.45-2.65). 82/112 admissions (73%) were mechanically ventilated, 16/112 (14%) required inotropic support. 12/112 (11%) died before unit discharge. Trauma scoring was available in 65 of the 80 trauma admissions. Eight had Injury Severity Score or New Injury Severity Score >60, none of whom survived. However, of the 16 patients with predicted mortality >50% by Trauma Injury Severity Score, seven survived. Seven cases required specialist advice and were discussed with the Birmingham Children's Hospital paediatric intensive care retrieval service. The mechanisms by which the Defence Medical Services support children admitted to the deployed adult ITU are described, including staff training in clinical, ethical and child protection issues, equipment, guidelines and clinical governance and rapid access to specialist advice in the UK. CONCLUSIONS With appropriate support, it is possible to provide intensive care to children in a deployed military ITU.
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Affiliation(s)
- David P Inwald
- Faculty of Medicine, Imperial College, Wright Fleming Institute, London, UK
| | - G S Arul
- Birmingham Children's Hospital, Birmingham, UK
| | | | - J Henning
- Ministry of Defence Hospital, Unit Northallerton, The James Cook University Hospital, Middlesbrough, UK
| | - J McNicholas
- Ministry of Defence Hospital Unit Portsmouth, Queen Alexandra Hospital, Portsmouth, UK
| | - S Bree
- Ministry of Defence Hospital Unit Derriford, Derriford Hospital, Plymouth, UK
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Yang S, Pelton R, Abarca C, Dai Z, Montgomery M, Xu M, Bos JA. Towards nanoparticle flotation collectors for pentlandite separation. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.minpro.2013.05.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Yang S, Pelton R, Montgomery M, Cui Y. Nanoparticle flotation collectors III: the role of nanoparticle diameter. ACS Appl Mater Interfaces 2012; 4:4882-4890. [PMID: 22871900 DOI: 10.1021/am301215h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The ability of polystyrene nanoparticles to promote glass bead flotation was measured as a function of nanoparticle diameter. In all cases, smaller nanoparticles were more effective flotation collectors, even when compared at constant nanoparticle number concentration. The superior performance of smaller particles was explained by two mechanisms, acting in parallel. First, smaller particles deposit more quickly giving more effective flotation in those cases where nanoparticle deposition kinetics is rate determining; the sensitivity of nanoparticle deposition rates to particle size was illustrated by kinetic measurements on a quartz crystal microbalance silica surface. Second, for a given coverage of nanoparticles on the glass beads, the mean distance between neighboring nanoparticle surfaces decreases with particle diameter. We propose that the expansion of the three phase contact line, after initial bead/bubble attachment, is favored with decreasing the distance between neighboring hydrophobic particles.
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Affiliation(s)
- Songtao Yang
- Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7
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Yang S, Pelton R, Raegen A, Montgomery M, Dalnoki-Veress K. Nanoparticle flotation collectors: mechanisms behind a new technology. Langmuir 2011; 27:10438-10446. [PMID: 21790133 DOI: 10.1021/la2016534] [Citation(s) in RCA: 29] [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] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This is the first report describing a new technology where hydrophobic nanoparticles adsorb onto much larger, hydrophilic mineral particle surfaces to facilitate attachment to air bubbles in flotation. The adsorption of 46 nm cationic polystyrene nanoparticles onto 43 μm diameter glass beads, a mineral model, facilitates virtually complete removal of the beads by flotation. As little as 5% coverage of the bead surfaces with nanoparticles promotes high flotation efficiencies. The maximum force required to pull a glass bead from an air bubble interface into the aqueous phase was measured by micromechanics. The pull-off force was 1.9 μN for glass beads coated with nanoparticles, compared to 0.0086 μN for clean beads. The pull-off forces were modeled using Scheludko's classical expression. We propose that the bubble/bead contact area may not be dry (completely dewetted). Instead, for hydrophobic nanoparticles sitting on a hydrophilic surface, it is possible that only the nanoparticles penetrate the air/water interface to form a three-phase contact line. We present a new model for pull-off forces for such a wet contact patch between the bead and the air bubble. Contact angle measurements of both nanoparticle coated glass and smooth films from dissolved nanoparticles were performed to support the modeling.
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Affiliation(s)
- Songtao Yang
- McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7
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Loftus B, Newsom B, Montgomery M, Von Gynz-Rekowski K, Riser M, Inman S, Garces P, Rill D, Zhang J, Williams J. Autologous attenuated T-cell vaccine (Tovaxin®) dose escalation in multiple sclerosis relapsing–remitting and secondary progressive patients nonresponsive to approved immunomodulatory therapies. Clin Immunol 2009; 131:202-15. [DOI: 10.1016/j.clim.2009.01.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 12/14/2008] [Accepted: 01/06/2009] [Indexed: 11/24/2022]
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Soni S, Termuhlen A, Bajwa R, Clayton J, Montgomery M, Hardin D. Prevalence, Risk Factors and Management of Metabolic Syndrome After Stem Cell Transplantation In Pediatric Patients. Biol Blood Marrow Transplant 2009. [DOI: 10.1016/j.bbmt.2008.12.248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
The retrieval of critically ill patients is frequently done in difficult circumstances and often under considerable time pressures. These adverse conditions have a finite risk of serious injury or death. The level of risk is poorly described in the literature and reliable data on accident rates are hard to find. Most of the information comes from North America. There are no clear published statistics for the UK. We report for the first time data on accidents and casualties involving vehicles classified as having an ambulance body type and air ambulances within Great Britain between 1999 and 2004.
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Affiliation(s)
- D Lutman
- Children's Acute Transport Service, 44B Bedford Row, London WC1R 4LL, UK
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Montgomery M, Mathee A. A preliminary study of residential paint lead concentrations in Johannesburg. Environ Res 2005; 98:279-83. [PMID: 15910783 DOI: 10.1016/j.envres.2004.10.006] [Citation(s) in RCA: 14] [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] [Received: 05/07/2004] [Revised: 10/20/2004] [Accepted: 10/22/2004] [Indexed: 05/02/2023]
Abstract
While efforts are underway to phase out the use of leaded petrol in South Africa, relatively little attention has been devoted to the potential for childhood exposure to lead used in paint. This is one of the first studies undertaken on the African continent to report on the presence of lead-based paint. In South Africa, there is a dearth of information available on the extent of past and current use of lead-based paint. Recent studies demonstrate that large numbers of young South African children continue to be at risk of elevated blood lead concentrations. To investigate the prevalence of lead-based paint in Johannesburg dwellings, the South African Medical Research Council recently undertook a preliminary study in which samples of residential paint were collected from homes in 60 randomly selected suburbs across the city. The results indicate that 17% of all of the samples collected were lead-based paint (paint that contains lead levels equal to or greater than 0.5% by weight). The percentage of lead by weight in the samples ranged from 0.01% to 29.00%. Lead-based residential paint was found in 20% of the sampled homes, located in both new and old suburbs, and in suburbs from a variety of different socioeconomic backgrounds. These results, in conjunction with those emanating from other studies of childhood lead exposure currently being conducted by the Medical Research Council, indicate that weathering, peeling, or chipping lead-based paint may play an important role in childhood lead exposure in South Africa. Children who have a pica tendency may be at particular risk.
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Affiliation(s)
- M Montgomery
- The Watson Institute for International Scholars, Brown University, 111 Thayer Street, Brown University, Box 1970, Providence, RI 02912-1970, USA.
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Abstract
Cardiogenic fate maps are used to address questions on commitment, differentiation, morphogenesis and organogenesis of the heart. Recently, the accuracy of classical cardiogenic fate maps has been questioned, raising concerns about the conclusions drawn in studies based on these maps. We present accurate fate maps of the heart-forming region (HFR) in avian embryos and show that the putative cardiogenic molecular markers Bmp2 and Nkx2.5 do not govern the boundaries of the HFR as suggested in the literature. Moreover, this paper presents the first fate map of the HFR at stage 4 and addresses a void in the literature concerning rostrocaudal patterning of heart cells between stages 4 and 8.
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Affiliation(s)
- A Redkar
- Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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Abstract
OBJECTIVE determine the frequency of initial rhythms in in-hospital resuscitation and examine its relationship to survival. Assess changes in outcome over time. METHODS retrospective cohort (registry) including all admissions to the Medical Center of Central Georgia in which a resuscitation was attempted between 1 January, 1987 and 31 December, 1996. RESULTS the registry includes 3327 admissions in which 3926 resuscitations were attempted. Only the first event is reported. There were 961 hospital survivors. Survival increased from 24.2% in 1987 to 33.4% in 1996 (chi(2)=39.0, df=1, P<0.0001). Survival was affected strongly by initial rhythm (chi(2)=420.0, df=1, P<0.0001) and decreased from 63.2% for supraventricular tachycardia (SVT) to 55.3% for ventricular tachycardia (VT), 51.0% for perfusing rhythms (PER), 34.8% for ventricular fibrillation (VF), 14.3% for pulseless electrical activity (PEA) and 10.0% for asystole (ASYS). PEA was the most frequent rhythm (1180 cases) followed by perfusing (963), asystole (580), VF (459), VT (94) and SVT (38). DISCUSSION the powerful effect of initial rhythm on survival has been reported in pre-hospital and in-hospital resuscitation. VF is considered the dominant rhythm and generally accounts for the most survivors. We report good outcome for each; however, VF represents only 13.8% of events and 16.7% of survivors. PEA accounts for more survivors (169) than does VF (160). Our improved outcome is partially explained by changes in rhythms, but other institutional variables need to be identified to fully explain the results. Further studies are needed to see if our findings can be sustained or replicated.
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Affiliation(s)
- D C Parish
- Department of Internal Medicine, Medical Center of Central Georgia and Mercer University School of Medicine, 707 Pine Street, Macon, GA 31201, USA.
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Holmes AJ, Bowyer J, Holley MP, O'Donoghue M, Montgomery M, Gillings MR. Diverse, yet-to-be-cultured members of the Rubrobacter subdivision of the Actinobacteria are widespread in Australian arid soils. FEMS Microbiol Ecol 2000; 33:111-120. [PMID: 10967210 DOI: 10.1111/j.1574-6941.2000.tb00733.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Phylogenetic analyses of ribosomal RNA gene sequences (rDNAs) retrieved from an Australian desert soil sample (Sturt National Park) revealed the presence of a number of clones which branched deeply from the high GC Gram-positive division line of descent. The most abundant group of these clones were related to Rubrobacter. An oligonucleotide probe was designed to have broad specificity to Rubrobacter and relatives. This probe was used to interrogate eight rDNA libraries representing four distinct land forms within the Australian arid zone. Relative abundance of Rubrobacter-relatives in these samples ranged from 2.6 to 10.2%. Clones from these libraries were selected for sequence analysis on the basis of a heteroduplex mobility assay to maximise the diversity represented in the sample. Phylogenetic analyses of these rDNA clones and Rubrobacter-related clones reported in the literature show strong support for three distinct groups. Database-searching revealed 'Rubrobacteria' were relatively abundant in a number of published soil rDNA libraries but absent from others. A PCR assay for group-1 'Rubrobacteria' was used to test for their presence in 21 environmental samples. Only marine and arid-zone soil samples gave positive PCR results. Taken together these results indicate 'Rubrobacteria' are a widespread group of variable abundance and diversity.
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Affiliation(s)
- AJ Holmes
- Key Centre for Biodiversity and Bioresources, Department of Biological Sciences, Macquarie University, 2109, Sydney, N.S.W., Australia
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Abstract
During chick embryogenesis, cells destined to form cardiac myocytes are located within the primitive streak at stage 3 in the same relative anterior-posterior distribution as in the prelooped heart. The most rostral cells contribute to the extreme anterior pole of the heart, the bulbus cordis, and the most caudal to the extreme posterior end, the sinoatrial region. After gastrulation, these cells commit to the myocyte lineage and, retaining their relative positions, migrate to the anterior lateral plate. From stages 5 to 10 they diversify into atrial and ventricular myocytes, with the former located posteriorly and the latter, anteriorly. To determine the effect of a change in the rostro-caudal position of these cells on their diversification, anterior lateral plate mesoderm and the underlying endoderm were cut and rotated 180 degrees along the longitudinal axis, at stages 4-8. The subsequent diversification of these precursor cells into atrial and ventricular myocytes was examined using lineage-specific markers. Our results showed that altering location along the longitudinal axis through stage 6 changed the normal fate of a precursor cell. The orientation of the overlying ectoderm did not alter normal morphogenesis or determination of fate.
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Affiliation(s)
- V Patwardhan
- Department of Anatomy and Cell Biology, Temple University, Philadelphia, Pennsylvania 19140, USA
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Abstract
A total of 104 couples participated in a randomized crossover trial to compare a new baggy condom with a straight-shaft condom produced by the same manufacturer. Participants completed a coital log after using each condom. All couples used five condoms of each type. Among 102 couples who did not report major deviations from the protocol, the breakage rate was eight of 510 (1.6%) for the baggy condom, and six of 510 (1.2%) for the standard condom (rate difference, RD = 0. 4%, 95% confidence interval of the RD, CI = -1.0%; +1.8%). Slippage was reported in 50 baggy condom logs and in 58 standard condom logs; the slippage rate was 50 of 510 (9.8%) for the baggy condom, and 58 of 510 (11.4%) for the standard condom (RD = -1.6%, 95% CI = -5.4%; +2.2%). Slippage was most often partial (<1 inch) and may not indicate condom failure. Severe slippage rates were 11 of 510 (2.2%) for the baggy condom, and 18 of 510 (3.5%) for the standard condom (RD = -1.4%, 95% CI = -3.4%; +0.7%). The findings support the conclusion that the two condoms are equivalent with respect to breakage and slippage. The participants appeared to prefer the baggy condom, suggesting that the new product may be more acceptable to the public than the traditional straight-shaft condoms, and may be easier to use consistently over long time periods.
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Affiliation(s)
- M Macaluso
- Department of Epidemiology and International Health, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama 35294-2010, USA
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Johnson JA, Connolly MA, Jacobs P, Montgomery M, Brown NE, Zuberbuhler P. Cost of care for individuals with cystic fibrosis: a regression approach to determining the impact of recombinant human DNase. Pharmacotherapy 1999; 19:1159-66. [PMID: 10512065 DOI: 10.1592/phco.19.15.1159.30580] [Citation(s) in RCA: 27] [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] [Indexed: 11/23/2022]
Abstract
We estimated direct medical costs of care and important determinants of the costs in patients with cystic fibrosis (CF), including therapy with recombinant human DNase (rhDNase). Costs were estimated with resource use data from the Epidemiologic Study of Cystic Fibrosis. Ordinary least squares regression was used to determine the effect of clinical and demographic variables on individual cost of care. The estimated cost of caring for 303 patients in Alberta was $2,279,801 in 1996. The mean cost of care was $7524 (range $386-92,376)/patient. Regression results indicated that age and forced expiratory volume predicted had a negative association with costs. Being female, receiving rhDNase, and having Pseudomonas aeruginosa or Burkholderia cepacia were all associated with high costs. Our estimates indicated large interindividual variation in cost of care for patients with CF.
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Affiliation(s)
- J A Johnson
- Institute of Health Economics, Faculty of Pharmacy and Pharmaceutical Sciences, the University of Alberta, Edmonton, Canada
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Abstract
OBJECTIVE Assess the frequency and outcome of inhospital resuscitation and determine the relationship between patient age and survival and whether it is affected by initial rhythm. DESIGN Retrospective, single-institution, registry study of inhospital resuscitation. SETTING A 550-bed, tertiary-care, teaching hospital in Macon, GA. PATIENTS All admissions for which a resuscitation was attempted in the Medical Center of Central Georgia during the period of January 1, 1987 through December 31, 1993. The registry sample included 2,394 admissions, for which 2,813 resuscitation attempts were made; only the first resuscitation attempt during an admission was analyzed. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Rates of survival to discharge steadily increased from 24.4% in 1987 to 38.6% in 1993; the overall survival rate was 26.8%. Age, used as a continuous variable, was strongly related to survival (odds ratio = 0.984; p < .0001). Categorically, overall survival rates for pediatric, adult, and geriatric patients were 56.4%, 29.0%, and 24.0%, respectively. Survival rates also varied significantly (odds ratio = 0.469; p < .0001) among initial rhythms, i.e., supraventricular tachycardia (60.7%), ventricular tachycardia (57.6%), perfusing rhythms (49.84%), ventricular fibrillation (32.0%), pulseless electrical activity (14.6%), and asystole (9.1%). The relationship between age and survival did not change across the years included in the study, but did vary as a function of initial rhythm (p < .0001). Age was positively related to survival when initial rhythm was supraventricular tachycardia (p = .04), negatively related to survival when the initial rhythm was perfusing (p < .0001) or pulseless electrical activity (p = .0002), and not related to survival when the initial rhythm was ventricular tachycardia (p = .98), ventricular fibrillation (p = .14), or asystole (p = .21). CONCLUSIONS The relationship between patient age and a successful resuscitation attempt is not as simple as reported earlier. Whether age is related to increased or decreased survival, or is unrelated to survival, depends on the rhythm extant when resuscitation attempts begin. Survival rates were higher than most reported elsewhere and improved significantly over time. Multicentered studies are needed to determine whether these results are unique to the institution studied.
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Affiliation(s)
- D C Parish
- Department of Internal Medicine, Medical Center of Central Georgia and Mercer University School of Medicine, Macon, USA
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Lee FY, Montgomery M, Hazan EJ, Keel SB, Mankin HJ, Kattapuram S. Recurrent giant-cell tumor presenting as a soft-tissue mass. A report of four cases. J Bone Joint Surg Am 1999; 81:703-7. [PMID: 10360699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- F Y Lee
- Massachusetts General Hospital and Harvard Medical School, Boston 02114, USA
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41
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Mehta A, Dreyer KJ, Montgomery M, Wittenberg J. A World Wide Web Internet engine for collaborative entry and peer review of radiologic teaching files. AJR Am J Roentgenol 1999; 172:893-6. [PMID: 10587117 DOI: 10.2214/ajr.172.4.10587117] [Citation(s) in RCA: 21] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Radiologists can now use the Internet as a dissemination medium for radiologic teaching files. This has greatly increased the availability of radiologic information to a larger number of people. However, the creation of the teaching files themselves remains a static and labor-intensive process. As a partial solution to this problem, we set out to create a World Wide Web-based Internet engine for the collaborative entry and peer review of radiologic teaching files. CONCLUSION We created a system that facilitates, simplifies, and improves the generation of radiologic teaching files. We used the Internet to help promote the creation of teaching files in a more timely, efficient, and effective manner.
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Affiliation(s)
- A Mehta
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston 02114. USA
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42
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Abstract
BACKGROUND Patients with repaired esophageal atresia often show persistent motility disorders of the esophagus. METHODS In this study, the authors used a newly developed method, videomanometry, to study intraluminal pressures and function of the pharynx and upper esophagus in such a group of patients and compared the results with those in healthy age-matched controls. RESULTS A significant difference was found between timing of the pharynx contraction and upper esophageal sphincter (UES) relaxation, indicating a dyscoordination of swallowing in the patient group. Transit time of bolus from the pharynx to the esophagus was also shorter for the patient group. Such dyscoordination may be a risk factor that can cause aspiration and respiratory symptoms. CONCLUSION UES resting pressure and residual pressure on swallowing, did not differ between the two groups.
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Affiliation(s)
- M Montgomery
- Department of Pediatric Surgery, St. Göran's/Karolinska Hospital, Karolinska Institute, Stockholm, Sweden
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43
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Abstract
Purified bovine milk proteins that were added to cultures of murine spleen cells significantly increased cell proliferation and production of immunoglobulin M. Casein and a whey mixture consisting of alpha-lactalbumin, bovine serum albumin, bovine gamma globulin, and beta-lactoglobulin (beta-LG) were stimulatory. Of the three beta-LG preparations that are commercially available (beta-LG containing variants A and B, purified variant A, and purified variant B), the unseparated mixture containing both the A and B variants showed the most immunomodulatory activity. Both alkaline treatment and trypsin digestion of the beta-LG preparation markedly reduced its effectiveness. Polymyxin B, while greatly diminishing the stimulatory effect of lipopolysaccharide, had no significant effect on either the enhancement of cell proliferation or the enhancement of immunoglobulin production by beta-LG. In the presence of S-(n-butyl)-homocysteine sulfoxamine, the stimulatory effect of beta-LG on cell proliferation and IgM production in vitro was markedly reduced.
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Affiliation(s)
- K F Wong
- Department of Human Ecology, Mount Saint Vincent University, Halifax, NS, Canada
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Abstract
A neuropathological study of autism was established and brain tissue examined from six mentally handicapped subjects with autism. Clinical and educational records were obtained and standardized diagnostic interviews conducted with the parents of cases not seen before death. Four of the six brains were megalencephalic, and areas of cortical abnormality were identified in four cases. There were also developmental abnormalities of the brainstem, particularly of the inferior olives. Purkinje cell number was reduced in all the adult cases, and this reduction was sometimes accompanied by gliosis. The findings do not support previous claims of localized neurodevelopmental abnormalities. They do point to the likely involvement of the cerebral cortex in autism.
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Affiliation(s)
- A Bailey
- MRC Child Psychiatry Unit, Institute of Psychiatry, London, UK
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45
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Abstract
BACKGROUND Scintigraphy is considered the "gold standard" for investigating gastric emptying. The lack of standards regarding registration technique and meal composition has been a problem especially in pediatric patients. METHODS In this study, gastric emptying of a solid meal was assessed by scintigraphy in 10 patients with repaired esophageal atresia (5 to 10 years old), and the results were compared with those in 11 healthy control children (5 to 11 years old). The meal consisted of pancakes with a fixed energy composition labeled with Tc-99m. Fractional meal retention values were plotted as a function of time. RESULTS Half-emptying time and lag phase values were longer in the patient group, whereas the emptying rate was slower and the retention values at 60 and 90 minutes were higher than in the control group. Extremely long lag phase and slow emptying rates were seen in two patients with reflux symptoms and abdominal complaints. Gastric emptying in healthy children has not previously been studied by scintigraphy. The results of this study show that values for gastric emptying of solids in healthy children correspond well to those reported in healthy adults. CONCLUSION Scintigraphy is an easy and reliable method for gastric emptying studies in children. The radioactive dose can be kept very low, which makes it a safe method even for pediatric patients. Delayed gastric emptying can occur in patients who have repaired esophageal atresia, and may be associated with reflux symptoms and abdominal complaints.
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Affiliation(s)
- M Montgomery
- Department of Pediatric Surgery, St Göran's/Karolinska Hospital, Karolinska Institute, Stockholm, Sweden
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46
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Affiliation(s)
- M Montgomery
- Department of Radiology, Massachusetts General Hospital, Boston, USA
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47
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Kaplan JL, Braitman LE, Dalsey WC, Montgomery M, Mangione A. Alkalinization is ineffective for severe hyperkalemia in nonnephrectomized dogs. Hyperkalemia Research Group. Acad Emerg Med 1997; 4:93-9. [PMID: 9043534 DOI: 10.1111/j.1553-2712.1997.tb03713.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To determine whether alkalinization with sodium bicarbonate (NaHCO3) in near-lethal hyperkalemia either lowers potassium (K) rapidly or shortens duration of cardiac conduction disturbances. METHODS A controlled canine laboratory investigation of 3 treatments for severe hyperkalemia. Conditioned dogs (n = 8; 17-30 kg) received, in random order, 2 mmol/kg of each of 3 treatments (matched in sodium and water) in separate experiments > or = 1 week apart: 1.05% NaHCO3 over 60 minutes (infusion therapy); 8.4% NaHCO3 over 5 minutes, then 14 mL/kg sterile water over 55 minutes (bolus therapy); 8.4% NaCl over 5 minutes, then 14 mL/kg sterile water over 55 minutes (saline therapy). Prior to administering one of the above therapies, the animals were anesthetized with 0.5-2.5% isoflurane and ventilated to maintain a normal PCO2. After 30 minutes of equilibration, 2 mmol/kg/hr (loading dose) of a 2-mmol/mL KCl solution was given until idioventricular or relative junctional bradycardic dysrhythmias were sustained for 15 minutes. Then KCl was decreased to 1 mmol/kg/hr (maintenance dose) for 2 hours and 45 minutes. Treatment was begun after 45 minutes of maintenance KCl infusion. RESULTS The pretreatment K level (all studies) was 9.06 +/- 0.82 mmol/L (mean +/- SD). Although the mean K level decreased more after saline therapy than after bolus therapy at every time, differences were neither statistically significant nor clinically important during the first 30 minutes. The means of the differences in decreases (saline minus bolus) were small, 0.26 (95% CI, -0.48 to 1.00) at 15 minutes, 0.16 (95% CI, -0.67 to 0.98) at 30 minutes. Dysrhythmia duration was shorter with bolus therapy than for saline therapy in only 1 of 5 dogs (p = 0.38). CONCLUSIONS Hypertonic saline bolus lowered plasma K as effectively as NaHCO3 bolus in this animal model within the first 30 minutes. Clinically meaningful decreases due to alkalinization alone within 30 minutes are unlikely.
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Affiliation(s)
- J L Kaplan
- Department of Emergency Medicine, Albert Einstein Medical Center, Philadelphia, PA 19141, USA.
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48
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Abstract
This review addresses the presentation and management of gynecologic disorders in older women. While these conditions are often managed by a primary caregiver, many women may present to the ED because they lack a primary gynecologic caregiver, their established gynecologic caregiver is not available, they are embarrassed to discuss their symptoms with an established caregiver, or they seek immediate relief of symptoms and reassurance. The emergency physician (EP) must be aware of the normal physiologic changes that occur with aging and how these changes may produce symptoms in older women. This review addresses physiologic changes and pathophysiologic conditions. Knowledge of these conditions and their management will facilitate reassurance of the patient, expedite appropriate initial therapy, and enable the EP to efficiently refer patients requiring further gynecologic assessment.
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Affiliation(s)
- J S Jones
- Butterworth Hospital, Emergency Medicine Residency Program, Michigan State University College of Human Medicine, Grand Rapids, USA
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49
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Abstract
Low birthweight and associated anomalies are important risk factors in patients with esophageal atresia. Gastroesophageal reflux is also a common problem in these patients and can lead to serious complications. The aim of this retrospective study was to analyse complications and mortality in 110 patients treated for esophageal atresia between January 1971-December 1987, in order to determine what role reflux may play. Symptoms of reflux were common in most patients during the first years of life. In some cases the symptoms were serious and even caused some late deaths by aspiration. The overall mortality was 12% (13/110). Early mortality (six patients) was caused by prematurity and associated anomalies, whereas late mortality often was caused by aspiration or other respiratory complications. Patients who had been operated with a circular myotomy showed more complications, but did not show a higher mortality rate than the remainder. This study confirms the importance of identifying patients with reflux at an early stage in order to prevent serious complications and mortality.
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Affiliation(s)
- M Montgomery
- Department of Pediatric Surgery, Karolinska Institute, St Göran's Hospital, Stockholm, Sweden
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50
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Cornblath DR, Kurland LT, Boylan KB, Morrison L, Radhakrishnan K, Montgomery M. Conjugal amyotrophic lateral sclerosis: report of a young married couple. Neurology 1993; 43:2378-80. [PMID: 8232960 DOI: 10.1212/wnl.43.11.2378] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We report a 38-year-old nurse who developed amyotrophic lateral sclerosis (ALS) beginning in September 1990. In May 1991, her 38-year-old husband developed dysarthria, which progressed to typical ALS. This is the fourth report in the literature of conjugal ALS occurring outside of Guam. Although this event is most likely due to coincidence, exogenous agents should be considered in the etiology of ALS.
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Affiliation(s)
- D R Cornblath
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD
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